drm/amd/display: Try RGB before YCbCr 4:4:4 in stream validationgrafted

amdgpu_dm_create_validate_stream_for_sink() walks encoding_order[] and
uses the first encoding that validates. YCbCr 4:4:4 is listed before
RGB, so an HDMI sink that advertises 4:4:4 gets YCbCr 4:4:4 whenever the
"color format" property is left at AUTO, even though RGB fits the same
link.

That contradicts the documented AUTO behaviour for HDMI in enum
drm_connector_color_format (RGB, falling back to YCbCr 4:2:0 only when
the bandwidth is not available or the mode is 4:2:0-only), which the
amdgpu implementation of the property also describes. It also leaves
the "Broadcast RGB" property without effect on such sinks, since the
quantization range it selects only applies to RGB output.

Try RGB first. The mask still holds every encoding the sink supports,
so a mode that cannot carry RGB falls back exactly as before.

For reference, v7.2 picked RGB here unless YCbCr 4:4:4 was forced
through debugfs, while earlier kernels picked YCbCr 4:4:4 for any HDMI
sink that advertised it.

Fixes: 0b0ff65d3ca1 ("drm/amd/display: Refactor stream validation")
Suggested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Assisted-by: Claude Code:claude-fable-5-1
Signed-off-by: Adrian Betschart <adrian.betschart@cinemaone.ch>
Reviewed-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Adolfo Rodrigues <adolfotregosa@gmail.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 7de432bc753133764dc40d37f9388da56de251e7)

4 files changed, 3069 insertions, 0 deletions

diff --git a/drivers/gpib/common/Makefile b/drivers/gpib/common/Makefile
new file mode 100644
index 000000000..460586edb
--- /dev/null
+++ b/drivers/gpib/common/Makefile
@@ -0,0 +1,6 @@
+
+obj-$(CONFIG_GPIB_COMMON) += gpib_common.o
+
+gpib_common-objs := gpib_os.o iblib.o
+
+
diff --git a/drivers/gpib/common/gpib_os.c b/drivers/gpib/common/gpib_os.c
new file mode 100644
index 000000000..384800e6b
--- /dev/null
+++ b/drivers/gpib/common/gpib_os.c
@@ -0,0 +1,2316 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/***************************************************************************
+ *    copyright            : (C) 2001, 2004 by Frank Mori Hess
+ ***************************************************************************
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#define dev_fmt pr_fmt
+
+#include "ibsys.h"
+#include <linux/module.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+#include <linux/pci.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <linux/fcntl.h>
+#include <linux/kmod.h>
+#include <linux/uaccess.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("GPIB base support");
+MODULE_ALIAS_CHARDEV_MAJOR(GPIB_CODE);
+
+static int board_type_ioctl(struct gpib_file_private *file_priv,
+			    struct gpib_board *board, unsigned long arg);
+static int read_ioctl(struct gpib_file_private *file_priv, struct gpib_board *board,
+		      unsigned long arg);
+static int write_ioctl(struct gpib_file_private *file_priv, struct gpib_board *board,
+		       unsigned long arg);
+static int command_ioctl(struct gpib_file_private *file_priv, struct gpib_board *board,
+			 unsigned long arg);
+static int open_dev_ioctl(struct file *filep, struct gpib_board *board, unsigned long arg);
+static int close_dev_ioctl(struct file *filep, struct gpib_board *board, unsigned long arg);
+static int serial_poll_ioctl(struct gpib_board *board, unsigned long arg);
+static int wait_ioctl(struct gpib_file_private *file_priv,
+		      struct gpib_board *board, unsigned long arg);
+static int parallel_poll_ioctl(struct gpib_board *board, unsigned long arg);
+static int online_ioctl(struct gpib_board *board, unsigned long arg);
+static int remote_enable_ioctl(struct gpib_board *board, unsigned long arg);
+static int take_control_ioctl(struct gpib_board *board, unsigned long arg);
+static int line_status_ioctl(struct gpib_board *board, unsigned long arg);
+static int pad_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+		     unsigned long arg);
+static int sad_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+		     unsigned long arg);
+static int eos_ioctl(struct gpib_board *board, unsigned long arg);
+static int request_service_ioctl(struct gpib_board *board, unsigned long arg);
+static int request_service2_ioctl(struct gpib_board *board, unsigned long arg);
+static int iobase_ioctl(struct gpib_board_config *config, unsigned long arg);
+static int irq_ioctl(struct gpib_board_config *config, unsigned long arg);
+static int dma_ioctl(struct gpib_board_config *config, unsigned long arg);
+static int autospoll_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+			   unsigned long arg);
+static int mutex_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+		       unsigned long arg);
+static int timeout_ioctl(struct gpib_board *board, unsigned long arg);
+static int status_bytes_ioctl(struct gpib_board *board, unsigned long arg);
+static int board_info_ioctl(const struct gpib_board *board, unsigned long arg);
+static int ppc_ioctl(struct gpib_board *board, unsigned long arg);
+static int set_local_ppoll_mode_ioctl(struct gpib_board *board, unsigned long arg);
+static int get_local_ppoll_mode_ioctl(struct gpib_board *board, unsigned long arg);
+static int query_board_rsv_ioctl(struct gpib_board *board, unsigned long arg);
+static int interface_clear_ioctl(struct gpib_board *board, unsigned long arg);
+static int select_pci_ioctl(struct gpib_board_config *config, unsigned long arg);
+static int select_device_path_ioctl(struct gpib_board_config *config, unsigned long arg);
+static int event_ioctl(struct gpib_board *board, unsigned long arg);
+static int request_system_control_ioctl(struct gpib_board *board, unsigned long arg);
+static int t1_delay_ioctl(struct gpib_board *board, unsigned long arg);
+
+static int cleanup_open_devices(struct gpib_file_private *file_priv, struct gpib_board *board);
+
+static int pop_gpib_event_nolock(struct gpib_board *board,
+				 struct gpib_event_queue *queue, short *event_type);
+
+/*
+ * Timer functions
+ */
+
+/* Watchdog timeout routine */
+
+static void watchdog_timeout(struct timer_list *t)
+{
+	struct gpib_board *board = timer_container_of(board, t, timer);
+
+	set_bit(TIMO_NUM, &board->status);
+	wake_up_interruptible(&board->wait);
+}
+
+/* install timer interrupt handler */
+void os_start_timer(struct gpib_board *board, unsigned int usec_timeout)
+/* Starts the timeout task  */
+{
+	if (timer_pending(&board->timer)) {
+		dev_err(board->gpib_dev, "bug! timer already running?\n");
+		return;
+	}
+	clear_bit(TIMO_NUM, &board->status);
+
+	if (usec_timeout > 0) {
+		board->timer.function = watchdog_timeout;
+		/* set number of ticks */
+		mod_timer(&board->timer, jiffies + usec_to_jiffies(usec_timeout));
+	}
+}
+
+void os_remove_timer(struct gpib_board *board)
+/* Removes the timeout task */
+{
+	if (timer_pending(&board->timer))
+		timer_delete_sync(&board->timer);
+}
+
+int io_timed_out(struct gpib_board *board)
+{
+	if (test_bit(TIMO_NUM, &board->status))
+		return 1;
+	return 0;
+}
+
+/*
+ * this is a function instead of a constant because of Suse
+ * defining HZ to be a function call to get_hz()
+ */
+static inline int pseudo_irq_period(void)
+{
+	return (HZ + 99) / 100;
+}
+
+static void pseudo_irq_handler(struct timer_list *t)
+{
+	struct gpib_pseudo_irq *pseudo_irq = timer_container_of(pseudo_irq, t,
+								timer);
+
+	if (pseudo_irq->handler)
+		pseudo_irq->handler(0, pseudo_irq->board);
+	else
+		pr_err("gpib: bug! pseudo_irq.handler is NULL\n");
+
+	if (atomic_read(&pseudo_irq->active))
+		mod_timer(&pseudo_irq->timer, jiffies + pseudo_irq_period());
+}
+
+int gpib_request_pseudo_irq(struct gpib_board *board, irqreturn_t (*handler)(int, void *))
+{
+	if (timer_pending(&board->pseudo_irq.timer) || board->pseudo_irq.handler) {
+		dev_err(board->gpib_dev, "only one pseudo interrupt per board allowed\n");
+		return -1;
+	}
+
+	board->pseudo_irq.handler = handler;
+	board->pseudo_irq.timer.function = pseudo_irq_handler;
+	board->pseudo_irq.board = board;
+
+	atomic_set(&board->pseudo_irq.active, 1);
+
+	mod_timer(&board->pseudo_irq.timer, jiffies + pseudo_irq_period());
+
+	return 0;
+}
+EXPORT_SYMBOL(gpib_request_pseudo_irq);
+
+void gpib_free_pseudo_irq(struct gpib_board *board)
+{
+	atomic_set(&board->pseudo_irq.active, 0);
+
+	timer_delete_sync(&board->pseudo_irq.timer);
+	board->pseudo_irq.handler = NULL;
+}
+EXPORT_SYMBOL(gpib_free_pseudo_irq);
+
+static const unsigned int serial_timeout = 1000000;
+
+unsigned int num_status_bytes(const struct gpib_status_queue *dev)
+{
+	if (!dev)
+		return 0;
+	return dev->num_status_bytes;
+}
+
+// push status byte onto back of status byte fifo
+int push_status_byte(struct gpib_board *board, struct gpib_status_queue *device, u8 poll_byte)
+{
+	struct list_head *head = &device->status_bytes;
+	struct gpib_status_byte *status;
+	static const unsigned int max_num_status_bytes = 1024;
+	int retval;
+
+	if (num_status_bytes(device) >= max_num_status_bytes) {
+		u8 lost_byte;
+
+		device->dropped_byte = 1;
+		retval = pop_status_byte(board, device, &lost_byte);
+		if (retval < 0)
+			return retval;
+	}
+
+	status = kmalloc_obj(*status);
+	if (!status)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&status->list);
+	status->poll_byte = poll_byte;
+
+	list_add_tail(&status->list, head);
+
+	device->num_status_bytes++;
+
+	dev_dbg(board->gpib_dev, "pushed status byte 0x%x, %i in queue\n",
+		(int)poll_byte, num_status_bytes(device));
+
+	return 0;
+}
+
+// pop status byte from front of status byte fifo
+int pop_status_byte(struct gpib_board *board, struct gpib_status_queue *device, u8 *poll_byte)
+{
+	struct list_head *head = &device->status_bytes;
+	struct list_head *front = head->next;
+	struct gpib_status_byte *status;
+
+	if (num_status_bytes(device) == 0)
+		return -EIO;
+
+	if (front == head)
+		return -EIO;
+
+	if (device->dropped_byte) {
+		device->dropped_byte = 0;
+		return -EPIPE;
+	}
+
+	status = list_entry(front, struct gpib_status_byte, list);
+	*poll_byte = status->poll_byte;
+
+	list_del(front);
+	kfree(status);
+
+	device->num_status_bytes--;
+
+	dev_dbg(board->gpib_dev, "popped status byte 0x%x, %i in queue\n",
+		(int)*poll_byte, num_status_bytes(device));
+
+	return 0;
+}
+
+struct gpib_status_queue *get_gpib_status_queue(struct gpib_board *board, unsigned int pad, int sad)
+{
+	struct gpib_status_queue *device;
+	struct list_head *list_ptr;
+	const struct list_head *head = &board->device_list;
+
+	for (list_ptr = head->next; list_ptr != head; list_ptr = list_ptr->next) {
+		device = list_entry(list_ptr, struct gpib_status_queue, list);
+		if (gpib_address_equal(device->pad, device->sad, pad, sad))
+			return device;
+	}
+
+	return NULL;
+}
+
+int get_serial_poll_byte(struct gpib_board *board, unsigned int pad, int sad,
+			 unsigned int usec_timeout, u8 *poll_byte)
+{
+	struct gpib_status_queue *device;
+
+	device = get_gpib_status_queue(board, pad, sad);
+	if (num_status_bytes(device))
+		return pop_status_byte(board, device, poll_byte);
+	else
+		return dvrsp(board, pad, sad, usec_timeout, poll_byte);
+}
+
+int autopoll_all_devices(struct gpib_board *board)
+{
+	int retval;
+
+	if (mutex_lock_interruptible(&board->user_mutex))
+		return -ERESTARTSYS;
+	if (mutex_lock_interruptible(&board->big_gpib_mutex)) {
+		mutex_unlock(&board->user_mutex);
+		return -ERESTARTSYS;
+	}
+
+	dev_dbg(board->gpib_dev, "autopoll has board lock\n");
+
+	retval = serial_poll_all(board, serial_timeout);
+	if (retval >= 0) {
+		dev_dbg(board->gpib_dev, "complete\n");
+		/*
+		 * need to wake wait queue in case someone is
+		 * waiting on RQS
+		 */
+		wake_up_interruptible(&board->wait);
+	}
+
+	if (retval <= 0) {
+		atomic_set(&board->stuck_srq, 1);
+		set_bit(SRQI_NUM, &board->status);
+	}
+	mutex_unlock(&board->big_gpib_mutex);
+	mutex_unlock(&board->user_mutex);
+
+	return retval;
+}
+
+static int setup_serial_poll(struct gpib_board *board, unsigned int usec_timeout)
+{
+	u8 cmd_string[8];
+	int i;
+	size_t bytes_written;
+	int ret;
+
+	os_start_timer(board, usec_timeout);
+	ret = ibcac(board, 1, 1);
+	if (ret < 0) {
+		os_remove_timer(board);
+		return ret;
+	}
+
+	i = 0;
+	cmd_string[i++] = UNL;
+	cmd_string[i++] = MLA(board->pad);	/* controller's listen address */
+	if (board->sad >= 0)
+		cmd_string[i++] = MSA(board->sad);
+	cmd_string[i++] = SPE;	// serial poll enable
+
+	ret = board->interface->command(board, cmd_string, i, &bytes_written);
+	if (ret < 0 || bytes_written < i) {
+		dev_dbg(board->gpib_dev, "failed to setup serial poll\n");
+		os_remove_timer(board);
+		return -EIO;
+	}
+	os_remove_timer(board);
+
+	return 0;
+}
+
+static int read_serial_poll_byte(struct gpib_board *board, unsigned int pad,
+				 int sad, unsigned int usec_timeout, u8 *result)
+{
+	u8 cmd_string[8];
+	int end_flag;
+	int ret;
+	int i;
+	size_t nbytes;
+
+	dev_dbg(board->gpib_dev, "entering  pad=%i sad=%i\n", pad, sad);
+
+	os_start_timer(board, usec_timeout);
+	ret = ibcac(board, 1, 1);
+	if (ret < 0) {
+		os_remove_timer(board);
+		return ret;
+	}
+
+	i = 0;
+	// send talk address
+	cmd_string[i++] = MTA(pad);
+	if (sad >= 0)
+		cmd_string[i++] = MSA(sad);
+
+	ret = board->interface->command(board, cmd_string, i, &nbytes);
+	if (ret < 0 || nbytes < i) {
+		dev_err(board->gpib_dev, "failed to setup serial poll\n");
+		os_remove_timer(board);
+		return -EIO;
+	}
+
+	ibgts(board);
+
+	// read poll result
+	ret = board->interface->read(board, result, 1, &end_flag, &nbytes);
+	if (ret < 0 || nbytes < 1) {
+		dev_err(board->gpib_dev, "serial poll failed\n");
+		os_remove_timer(board);
+		return -EIO;
+	}
+	os_remove_timer(board);
+
+	return 0;
+}
+
+static int cleanup_serial_poll(struct gpib_board *board, unsigned int usec_timeout)
+{
+	u8 cmd_string[8];
+	int ret;
+	size_t bytes_written;
+
+	os_start_timer(board, usec_timeout);
+	ret = ibcac(board, 1, 1);
+	if (ret < 0) {
+		os_remove_timer(board);
+		return ret;
+	}
+
+	cmd_string[0] = SPD;	/* disable serial poll bytes */
+	cmd_string[1] = UNT;
+	ret = board->interface->command(board, cmd_string, 2, &bytes_written);
+	if (ret < 0 || bytes_written < 2) {
+		dev_err(board->gpib_dev, "failed to disable serial poll\n");
+		os_remove_timer(board);
+		return -EIO;
+	}
+	os_remove_timer(board);
+
+	return 0;
+}
+
+static int serial_poll_single(struct gpib_board *board, unsigned int pad, int sad,
+			      unsigned int usec_timeout, u8 *result)
+{
+	int retval, cleanup_retval;
+
+	retval = setup_serial_poll(board, usec_timeout);
+	if (retval < 0)
+		return retval;
+	retval = read_serial_poll_byte(board, pad, sad, usec_timeout, result);
+	cleanup_retval = cleanup_serial_poll(board, usec_timeout);
+	if (retval < 0)
+		return retval;
+	if (cleanup_retval < 0)
+		return retval;
+
+	return 0;
+}
+
+int serial_poll_all(struct gpib_board *board, unsigned int usec_timeout)
+{
+	int retval = 0;
+	struct list_head *cur;
+	const struct list_head *head = NULL;
+	struct gpib_status_queue *device;
+	u8 result;
+	unsigned int num_bytes = 0;
+
+	head = &board->device_list;
+	if (head->next == head)
+		return 0;
+
+	retval = setup_serial_poll(board, usec_timeout);
+	if (retval < 0)
+		return retval;
+
+	for (cur = head->next; cur != head; cur = cur->next) {
+		device = list_entry(cur, struct gpib_status_queue, list);
+		retval = read_serial_poll_byte(board,
+					       device->pad, device->sad, usec_timeout, &result);
+		if (retval < 0)
+			continue;
+		if (result & request_service_bit) {
+			retval = push_status_byte(board, device, result);
+			if (retval < 0)
+				continue;
+			num_bytes++;
+		}
+	}
+
+	retval = cleanup_serial_poll(board, usec_timeout);
+	if (retval < 0)
+		return retval;
+
+	return num_bytes;
+}
+
+/*
+ * DVRSP
+ * This function performs a serial poll of the device with primary
+ * address pad and secondary address sad. If the device has no
+ * secondary address, pass a negative number in for this argument.  At the
+ * end of a successful serial poll the response is returned in result.
+ * SPD and UNT are sent at the completion of the poll.
+ */
+
+int dvrsp(struct gpib_board *board, unsigned int pad, int sad,
+	  unsigned int usec_timeout, u8 *result)
+{
+	int status = ibstatus(board);
+	int retval;
+
+	if ((status & CIC) == 0) {
+		dev_err(board->gpib_dev, "not CIC during serial poll\n");
+		return -1;
+	}
+
+	if (pad > MAX_GPIB_PRIMARY_ADDRESS || sad > MAX_GPIB_SECONDARY_ADDRESS || sad < -1) {
+		dev_err(board->gpib_dev, "bad address for serial poll");
+		return -1;
+	}
+
+	retval = serial_poll_single(board, pad, sad, usec_timeout, result);
+	if (io_timed_out(board))
+		retval = -ETIMEDOUT;
+
+	return retval;
+}
+
+static struct gpib_descriptor *handle_to_descriptor(const struct gpib_file_private *file_priv,
+						    int handle)
+{
+	if (handle < 0 || handle >= GPIB_MAX_NUM_DESCRIPTORS) {
+		pr_err("gpib: invalid handle %i\n", handle);
+		return NULL;
+	}
+
+	return file_priv->descriptors[handle];
+}
+
+static int init_gpib_file_private(struct gpib_file_private *priv)
+{
+	memset(priv, 0, sizeof(*priv));
+	atomic_set(&priv->holding_mutex, 0);
+	priv->descriptors[0] = kmalloc_obj(struct gpib_descriptor);
+	if (!priv->descriptors[0]) {
+		pr_err("gpib: failed to allocate default board descriptor\n");
+		return -ENOMEM;
+	}
+	init_gpib_descriptor(priv->descriptors[0]);
+	priv->descriptors[0]->is_board = 1;
+	mutex_init(&priv->descriptors_mutex);
+	return 0;
+}
+
+int ibopen(struct inode *inode, struct file *filep)
+{
+	unsigned int minor = iminor(inode);
+	struct gpib_board *board;
+	struct gpib_file_private *priv;
+
+	if (minor >= GPIB_MAX_NUM_BOARDS) {
+		pr_err("gpib: invalid minor number of device file\n");
+		return -ENXIO;
+	}
+
+	board = &board_array[minor];
+
+	filep->private_data = kmalloc_obj(struct gpib_file_private);
+	if (!filep->private_data)
+		return -ENOMEM;
+
+	priv = filep->private_data;
+	init_gpib_file_private((struct gpib_file_private *)filep->private_data);
+
+	if (board->interface) {
+		if (!try_module_get(board->provider_module)) {
+			dev_err(board->gpib_dev, "try_module_get() failed\n");
+			return -EIO;
+		}
+		board->use_count++;
+		priv->got_module = 1;
+	}
+	return 0;
+}
+
+int ibclose(struct inode *inode, struct file *filep)
+{
+	unsigned int minor = iminor(inode);
+	struct gpib_board *board;
+	struct gpib_file_private *priv = filep->private_data;
+	struct gpib_descriptor *desc;
+
+	if (minor >= GPIB_MAX_NUM_BOARDS) {
+		pr_err("gpib: invalid minor number of device file\n");
+		return -ENODEV;
+	}
+
+	board = &board_array[minor];
+
+	if (priv) {
+		desc = handle_to_descriptor(priv, 0);
+		if (desc) {
+			if (desc->autopoll_enabled) {
+				dev_dbg(board->gpib_dev, "decrementing autospollers\n");
+				if (board->autospollers > 0)
+					board->autospollers--;
+				else
+					dev_err(board->gpib_dev,
+						"Attempt to decrement zero autospollers\n");
+			}
+		} else {
+			dev_err(board->gpib_dev, "Unexpected null gpib_descriptor\n");
+		}
+
+		cleanup_open_devices(priv, board);
+
+		if (atomic_read(&priv->holding_mutex))
+			mutex_unlock(&board->user_mutex);
+
+		if (priv->got_module && board->use_count) {
+			module_put(board->provider_module);
+			--board->use_count;
+		}
+
+		kfree(filep->private_data);
+		filep->private_data = NULL;
+	}
+
+	return 0;
+}
+
+long ibioctl(struct file *filep, unsigned int cmd, unsigned long arg)
+{
+	unsigned int minor = iminor(file_inode(filep));
+	struct gpib_board *board;
+	struct gpib_file_private *file_priv = filep->private_data;
+	long retval = -EBADRQC;
+
+	if (minor >= GPIB_MAX_NUM_BOARDS) {
+		pr_err("gpib: invalid minor number of device file\n");
+		return -ENODEV;
+	}
+	board = &board_array[minor];
+
+	if (mutex_lock_interruptible(&board->big_gpib_mutex))
+		return -ERESTARTSYS;
+
+	dev_dbg(board->gpib_dev, "ioctl %d, interface=%s, use=%d, onl=%d\n",
+		cmd & 0xff,
+		board->interface ? board->interface->name : "",
+		board->use_count,
+		board->online);
+
+	switch (cmd) {
+	case CFCBOARDTYPE:
+		retval = board_type_ioctl(file_priv, board, arg);
+		goto done;
+	case IBONL:
+		retval = online_ioctl(board, arg);
+		goto done;
+	default:
+		break;
+	}
+	if (!board->interface) {
+		dev_err(board->gpib_dev, "no gpib board configured\n");
+		retval = -ENODEV;
+		goto done;
+	}
+	if (file_priv->got_module == 0)	{
+		if (!try_module_get(board->provider_module)) {
+			dev_err(board->gpib_dev, "try_module_get() failed\n");
+			retval = -EIO;
+			goto done;
+		}
+		file_priv->got_module = 1;
+		board->use_count++;
+	}
+	switch (cmd) {
+	case CFCBASE:
+		retval = iobase_ioctl(&board->config, arg);
+		goto done;
+	case CFCIRQ:
+		retval = irq_ioctl(&board->config, arg);
+		goto done;
+	case CFCDMA:
+		retval = dma_ioctl(&board->config, arg);
+		goto done;
+	case IBAUTOSPOLL:
+		retval = autospoll_ioctl(board, file_priv, arg);
+		goto done;
+	case IBBOARD_INFO:
+		retval = board_info_ioctl(board, arg);
+		goto done;
+	case IBMUTEX:
+		/*
+		 * Need to unlock board->big_gpib_mutex before potentially locking board->user_mutex
+		 * to maintain consistent locking order
+		 */
+		mutex_unlock(&board->big_gpib_mutex);
+		return mutex_ioctl(board, file_priv, arg);
+	case IBPAD:
+		retval = pad_ioctl(board, file_priv, arg);
+		goto done;
+	case IBSAD:
+		retval = sad_ioctl(board, file_priv, arg);
+		goto done;
+	case IBSELECT_PCI:
+		retval = select_pci_ioctl(&board->config, arg);
+		goto done;
+	case IBSELECT_DEVICE_PATH:
+		retval = select_device_path_ioctl(&board->config, arg);
+		goto done;
+	default:
+		break;
+	}
+
+	if (!board->online) {
+		retval = -EINVAL;
+		goto done;
+	}
+
+	switch (cmd) {
+	case IBEVENT:
+		retval = event_ioctl(board, arg);
+		goto done;
+	case IBCLOSEDEV:
+		retval = close_dev_ioctl(filep, board, arg);
+		goto done;
+	case IBOPENDEV:
+		retval = open_dev_ioctl(filep, board, arg);
+		goto done;
+	case IBSPOLL_BYTES:
+		retval = status_bytes_ioctl(board, arg);
+		goto done;
+	case IBWAIT:
+		retval = wait_ioctl(file_priv, board, arg);
+		if (retval == -ERESTARTSYS)
+			return retval;
+		goto done;
+	case IBLINES:
+		retval = line_status_ioctl(board, arg);
+		goto done;
+	case IBLOC:
+		board->interface->return_to_local(board);
+		retval = 0;
+		goto done;
+	default:
+		break;
+	}
+
+	spin_lock(&board->locking_pid_spinlock);
+	if (current->pid != board->locking_pid)	{
+		spin_unlock(&board->locking_pid_spinlock);
+		retval = -EPERM;
+		goto done;
+	}
+	spin_unlock(&board->locking_pid_spinlock);
+
+	switch (cmd) {
+	case IB_T1_DELAY:
+		retval = t1_delay_ioctl(board, arg);
+		goto done;
+	case IBCAC:
+		retval = take_control_ioctl(board, arg);
+		goto done;
+	case IBCMD:
+		/*
+		 * IO ioctls can take a long time, we need to unlock board->big_gpib_mutex
+		 * before we call them.
+		 */
+		mutex_unlock(&board->big_gpib_mutex);
+		return command_ioctl(file_priv, board, arg);
+	case IBEOS:
+		retval = eos_ioctl(board, arg);
+		goto done;
+	case IBGTS:
+		retval = ibgts(board);
+		goto done;
+	case IBPPC:
+		retval = ppc_ioctl(board, arg);
+		goto done;
+	case IBPP2_SET:
+		retval = set_local_ppoll_mode_ioctl(board, arg);
+		goto done;
+	case IBPP2_GET:
+		retval = get_local_ppoll_mode_ioctl(board, arg);
+		goto done;
+	case IBQUERY_BOARD_RSV:
+		retval = query_board_rsv_ioctl(board, arg);
+		goto done;
+	case IBRD:
+		/*
+		 * IO ioctls can take a long time, we need to unlock board->big_gpib_mutex
+		 * before we call them.
+		 */
+		mutex_unlock(&board->big_gpib_mutex);
+		return read_ioctl(file_priv, board, arg);
+	case IBRPP:
+		retval = parallel_poll_ioctl(board, arg);
+		goto done;
+	case IBRSC:
+		retval = request_system_control_ioctl(board, arg);
+		goto done;
+	case IBRSP:
+		retval = serial_poll_ioctl(board, arg);
+		goto done;
+	case IBRSV:
+		retval = request_service_ioctl(board, arg);
+		goto done;
+	case IBRSV2:
+		retval = request_service2_ioctl(board, arg);
+		goto done;
+	case IBSIC:
+		retval = interface_clear_ioctl(board, arg);
+		goto done;
+	case IBSRE:
+		retval = remote_enable_ioctl(board, arg);
+		goto done;
+	case IBTMO:
+		retval = timeout_ioctl(board, arg);
+		goto done;
+	case IBWRT:
+		/*
+		 * IO ioctls can take a long time, we need to unlock board->big_gpib_mutex
+		 * before we call them.
+		 */
+		mutex_unlock(&board->big_gpib_mutex);
+		return write_ioctl(file_priv, board, arg);
+	default:
+		goto done;
+	}
+
+done:
+	mutex_unlock(&board->big_gpib_mutex);
+	dev_dbg(board->gpib_dev, "ioctl done status = 0x%lx\n", board->status);
+	return retval;
+}
+
+static int board_type_ioctl(struct gpib_file_private *file_priv,
+			    struct gpib_board *board, unsigned long arg)
+{
+	struct list_head *list_ptr;
+	struct gpib_board_type_ioctl cmd;
+	int retval;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	if (board->online)
+		return -EBUSY;
+
+	retval = copy_from_user(&cmd, (void __user *)arg,
+				sizeof(struct gpib_board_type_ioctl));
+	if (retval)
+		return -EFAULT;
+
+	for (list_ptr = registered_drivers.next; list_ptr != &registered_drivers;
+	     list_ptr = list_ptr->next) {
+		struct gpib_interface_list *entry;
+
+		entry = list_entry(list_ptr, struct gpib_interface_list, list);
+		if (strcmp(entry->interface->name, cmd.name) == 0) {
+			int i;
+			int had_module = file_priv->got_module;
+
+			if (board->use_count) {
+				for (i = 0; i < board->use_count; ++i)
+					module_put(board->provider_module);
+				board->interface = NULL;
+				file_priv->got_module = 0;
+			}
+			board->interface = entry->interface;
+			board->provider_module = entry->module;
+			for (i = 0; i < board->use_count; ++i) {
+				if (!try_module_get(entry->module)) {
+					board->use_count = i;
+					return -EIO;
+				}
+			}
+			if (had_module == 0) {
+				if (!try_module_get(entry->module))
+					return -EIO;
+				++board->use_count;
+			}
+			file_priv->got_module = 1;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int read_ioctl(struct gpib_file_private *file_priv, struct gpib_board *board,
+		      unsigned long arg)
+{
+	struct gpib_read_write_ioctl read_cmd;
+	u8 __user *userbuf;
+	unsigned long remain;
+	int end_flag = 0;
+	int retval;
+	ssize_t read_ret = 0;
+	struct gpib_descriptor *desc;
+	size_t nbytes;
+
+	retval = copy_from_user(&read_cmd, (void __user *)arg, sizeof(read_cmd));
+	if (retval)
+		return -EFAULT;
+
+	if (read_cmd.completed_transfer_count > read_cmd.requested_transfer_count)
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(sizeof(userbuf) > sizeof(read_cmd.buffer_ptr)))
+		return -EFAULT;
+
+	userbuf = (u8 __user *)(unsigned long)read_cmd.buffer_ptr;
+	userbuf += read_cmd.completed_transfer_count;
+
+	remain = read_cmd.requested_transfer_count - read_cmd.completed_transfer_count;
+
+	/* Check write access to buffer */
+	if (!access_ok(userbuf, remain))
+		return -EFAULT;
+
+	/* Lock descriptors to prevent concurrent close from freeing descriptor */
+	if (mutex_lock_interruptible(&file_priv->descriptors_mutex))
+		return -ERESTARTSYS;
+	desc = handle_to_descriptor(file_priv, read_cmd.handle);
+	if (!desc) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -EINVAL;
+	}
+	atomic_inc(&desc->descriptor_busy);
+	mutex_unlock(&file_priv->descriptors_mutex);
+
+	atomic_set(&desc->io_in_progress, 1);
+
+	/* Read buffer loads till we fill the user supplied buffer */
+	while (remain > 0 && end_flag == 0) {
+		nbytes = 0;
+		read_ret = ibrd(board, board->buffer, (board->buffer_length < remain) ?
+				board->buffer_length : remain, &end_flag, &nbytes);
+		if (nbytes == 0)
+			break;
+		retval = copy_to_user(userbuf, board->buffer, nbytes);
+		if (retval) {
+			retval = -EFAULT;
+			break;
+		}
+		remain -= nbytes;
+		userbuf += nbytes;
+		if (read_ret < 0)
+			break;
+	}
+	read_cmd.completed_transfer_count = read_cmd.requested_transfer_count - remain;
+	read_cmd.end = end_flag;
+	/*
+	 * suppress errors (for example due to timeout or interruption by device clear)
+	 * if all bytes got sent.  This prevents races that can occur in the various drivers
+	 * if a device receives a device clear immediately after a transfer completes and
+	 * the driver code wasn't careful enough to handle that case.
+	 */
+	if (remain == 0 || end_flag)
+		read_ret = 0;
+	if (retval == 0)
+		retval = copy_to_user((void __user *)arg, &read_cmd, sizeof(read_cmd));
+
+	atomic_set(&desc->io_in_progress, 0);
+	atomic_dec(&desc->descriptor_busy);
+
+	wake_up_interruptible(&board->wait);
+	if (retval)
+		return -EFAULT;
+
+	return read_ret;
+}
+
+static int command_ioctl(struct gpib_file_private *file_priv,
+			 struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_read_write_ioctl cmd;
+	u8 __user *userbuf;
+	unsigned long remain;
+	int retval;
+	int fault = 0;
+	struct gpib_descriptor *desc;
+	size_t bytes_written;
+	int no_clear_io_in_prog;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	if (cmd.completed_transfer_count > cmd.requested_transfer_count)
+		return -EINVAL;
+
+	userbuf = (u8 __user *)(unsigned long)cmd.buffer_ptr;
+	userbuf += cmd.completed_transfer_count;
+
+	no_clear_io_in_prog = cmd.end;
+	cmd.end = 0;
+
+	remain = cmd.requested_transfer_count - cmd.completed_transfer_count;
+
+	/* Check read access to buffer */
+	if (!access_ok(userbuf, remain))
+		return -EFAULT;
+
+	/* Lock descriptors to prevent concurrent close from freeing descriptor */
+	if (mutex_lock_interruptible(&file_priv->descriptors_mutex))
+		return -ERESTARTSYS;
+	desc = handle_to_descriptor(file_priv, cmd.handle);
+	if (!desc) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -EINVAL;
+	}
+	atomic_inc(&desc->descriptor_busy);
+	mutex_unlock(&file_priv->descriptors_mutex);
+
+	/*
+	 * Write buffer loads till we empty the user supplied buffer.
+	 * Call drivers at least once, even if remain is zero, in
+	 * order to allow them to insure previous commands were
+	 * completely finished, in the case of a restarted ioctl.
+	 */
+
+	atomic_set(&desc->io_in_progress, 1);
+
+	do {
+		fault = copy_from_user(board->buffer, userbuf, (board->buffer_length < remain) ?
+				       board->buffer_length : remain);
+		if (fault) {
+			retval = -EFAULT;
+			bytes_written = 0;
+		} else {
+			retval = ibcmd(board, board->buffer, (board->buffer_length < remain) ?
+				       board->buffer_length : remain, &bytes_written);
+		}
+		remain -= bytes_written;
+		userbuf += bytes_written;
+		if (retval < 0) {
+			atomic_set(&desc->io_in_progress, 0);
+
+			wake_up_interruptible(&board->wait);
+			break;
+		}
+	} while (remain > 0);
+
+	cmd.completed_transfer_count = cmd.requested_transfer_count - remain;
+
+	if (fault == 0)
+		fault = copy_to_user((void __user *)arg, &cmd, sizeof(cmd));
+
+	/*
+	 * no_clear_io_in_prog (cmd.end) is true when io_in_progress should
+	 * not be set to zero because the cmd in progress is the address setup
+	 * operation for an async read or write. This causes CMPL not to be set
+	 * in general_ibstatus until the async read or write completes.
+	 */
+	if (!no_clear_io_in_prog || fault)
+		atomic_set(&desc->io_in_progress, 0);
+	atomic_dec(&desc->descriptor_busy);
+
+	wake_up_interruptible(&board->wait);
+	if (fault)
+		return -EFAULT;
+
+	return retval;
+}
+
+static int write_ioctl(struct gpib_file_private *file_priv, struct gpib_board *board,
+		       unsigned long arg)
+{
+	struct gpib_read_write_ioctl write_cmd;
+	u8 __user *userbuf;
+	unsigned long remain;
+	int retval = 0;
+	int fault;
+	struct gpib_descriptor *desc;
+
+	fault = copy_from_user(&write_cmd, (void __user *)arg, sizeof(write_cmd));
+	if (fault)
+		return -EFAULT;
+
+	if (write_cmd.completed_transfer_count > write_cmd.requested_transfer_count)
+		return -EINVAL;
+
+	userbuf = (u8 __user *)(unsigned long)write_cmd.buffer_ptr;
+	userbuf += write_cmd.completed_transfer_count;
+
+	remain = write_cmd.requested_transfer_count - write_cmd.completed_transfer_count;
+
+	/* Check read access to buffer */
+	if (!access_ok(userbuf, remain))
+		return -EFAULT;
+
+	/* Lock descriptors to prevent concurrent close from freeing descriptor */
+	if (mutex_lock_interruptible(&file_priv->descriptors_mutex))
+		return -ERESTARTSYS;
+	desc = handle_to_descriptor(file_priv, write_cmd.handle);
+	if (!desc) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -EINVAL;
+	}
+	atomic_inc(&desc->descriptor_busy);
+	mutex_unlock(&file_priv->descriptors_mutex);
+
+	atomic_set(&desc->io_in_progress, 1);
+
+	/* Write buffer loads till we empty the user supplied buffer */
+	while (remain > 0) {
+		int send_eoi;
+		size_t bytes_written = 0;
+
+		send_eoi = remain <= board->buffer_length && write_cmd.end;
+		fault = copy_from_user(board->buffer, userbuf, (board->buffer_length < remain) ?
+				       board->buffer_length : remain);
+		if (fault) {
+			retval = -EFAULT;
+			break;
+		}
+		retval = ibwrt(board, board->buffer, (board->buffer_length < remain) ?
+			       board->buffer_length : remain, send_eoi, &bytes_written);
+		remain -= bytes_written;
+		userbuf += bytes_written;
+		if (retval < 0)
+			break;
+	}
+	write_cmd.completed_transfer_count = write_cmd.requested_transfer_count - remain;
+	/*
+	 * suppress errors (for example due to timeout or interruption by device clear)
+	 * if all bytes got sent.  This prevents races that can occur in the various drivers
+	 * if a device receives a device clear immediately after a transfer completes and
+	 * the driver code wasn't careful enough to handle that case.
+	 */
+	if (remain == 0)
+		retval = 0;
+	if (fault == 0)
+		fault = copy_to_user((void __user *)arg, &write_cmd, sizeof(write_cmd));
+
+	atomic_set(&desc->io_in_progress, 0);
+	atomic_dec(&desc->descriptor_busy);
+
+	wake_up_interruptible(&board->wait);
+	if (fault)
+		return -EFAULT;
+
+	return retval;
+}
+
+static int status_bytes_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_status_queue *device;
+	struct gpib_spoll_bytes_ioctl cmd;
+	int retval;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	device = get_gpib_status_queue(board, cmd.pad, cmd.sad);
+	if (!device)
+		cmd.num_bytes = 0;
+	else
+		cmd.num_bytes = num_status_bytes(device);
+
+	retval = copy_to_user((void __user *)arg, &cmd, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int increment_open_device_count(struct gpib_board *board, struct list_head *head,
+				       unsigned int pad, int sad)
+{
+	struct list_head *list_ptr;
+	struct gpib_status_queue *device;
+
+	/*
+	 * first see if address has already been opened, then increment
+	 * open count
+	 */
+	for (list_ptr = head->next; list_ptr != head; list_ptr = list_ptr->next) {
+		device = list_entry(list_ptr, struct gpib_status_queue, list);
+		if (gpib_address_equal(device->pad, device->sad, pad, sad)) {
+			dev_dbg(board->gpib_dev, "incrementing open count for pad %i, sad %i\n",
+				device->pad, device->sad);
+			device->reference_count++;
+			return 0;
+		}
+	}
+
+	/* otherwise we need to allocate a new struct gpib_status_queue */
+	device = kmalloc_obj(struct gpib_status_queue, GFP_ATOMIC);
+	if (!device)
+		return -ENOMEM;
+	init_gpib_status_queue(device);
+	device->pad = pad;
+	device->sad = sad;
+	device->reference_count = 1;
+
+	list_add(&device->list, head);
+
+	dev_dbg(board->gpib_dev, "opened pad %i, sad %i\n", device->pad, device->sad);
+
+	return 0;
+}
+
+static int subtract_open_device_count(struct gpib_board *board, struct list_head *head,
+				      unsigned int pad, int sad, unsigned int count)
+{
+	struct gpib_status_queue *device;
+	struct list_head *list_ptr;
+
+	for (list_ptr = head->next; list_ptr != head; list_ptr = list_ptr->next) {
+		device = list_entry(list_ptr, struct gpib_status_queue, list);
+		if (gpib_address_equal(device->pad, device->sad, pad, sad)) {
+			dev_dbg(board->gpib_dev, "decrementing open count for pad %i, sad %i\n",
+				device->pad, device->sad);
+			if (count > device->reference_count) {
+				dev_err(board->gpib_dev, "bug! in %s()\n", __func__);
+				return -EINVAL;
+			}
+			device->reference_count -= count;
+			if (device->reference_count == 0) {
+				dev_dbg(board->gpib_dev, "closing pad %i, sad %i\n",
+					device->pad, device->sad);
+				list_del(list_ptr);
+				kfree(device);
+			}
+			return 0;
+		}
+	}
+	dev_err(board->gpib_dev, "bug! tried to close address that was never opened!\n");
+	return -EINVAL;
+}
+
+static inline int decrement_open_device_count(struct gpib_board *board, struct list_head *head,
+					      unsigned int pad, int sad)
+{
+	return subtract_open_device_count(board, head, pad, sad, 1);
+}
+
+static int cleanup_open_devices(struct gpib_file_private *file_priv, struct gpib_board *board)
+{
+	int retval = 0;
+	int i;
+
+	for (i = 0; i < GPIB_MAX_NUM_DESCRIPTORS; i++) {
+		struct gpib_descriptor *desc;
+
+		desc = file_priv->descriptors[i];
+		if (!desc)
+			continue;
+
+		if (desc->is_board == 0) {
+			retval = decrement_open_device_count(board, &board->device_list, desc->pad,
+							     desc->sad);
+			if (retval < 0)
+				return retval;
+		}
+		kfree(desc);
+		file_priv->descriptors[i] = NULL;
+	}
+
+	return 0;
+}
+
+static int open_dev_ioctl(struct file *filep, struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_open_dev_ioctl open_dev_cmd;
+	int retval;
+	struct gpib_file_private *file_priv = filep->private_data;
+	int i;
+
+	retval = copy_from_user(&open_dev_cmd, (void __user *)arg, sizeof(open_dev_cmd));
+	if (retval)
+		return -EFAULT;
+
+	if (mutex_lock_interruptible(&file_priv->descriptors_mutex))
+		return -ERESTARTSYS;
+	for (i = 0; i < GPIB_MAX_NUM_DESCRIPTORS; i++)
+		if (!file_priv->descriptors[i])
+			break;
+	if (i == GPIB_MAX_NUM_DESCRIPTORS) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -ERANGE;
+	}
+	file_priv->descriptors[i] = kmalloc_obj(struct gpib_descriptor);
+	if (!file_priv->descriptors[i]) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -ENOMEM;
+	}
+	init_gpib_descriptor(file_priv->descriptors[i]);
+
+	file_priv->descriptors[i]->pad = open_dev_cmd.pad;
+	file_priv->descriptors[i]->sad = open_dev_cmd.sad;
+	file_priv->descriptors[i]->is_board = open_dev_cmd.is_board;
+	mutex_unlock(&file_priv->descriptors_mutex);
+
+	retval = increment_open_device_count(board, &board->device_list, open_dev_cmd.pad,
+					     open_dev_cmd.sad);
+	if (retval < 0)
+		return retval;
+
+	/*
+	 * clear stuck srq state, since we may be able to find service request on
+	 * the new device
+	 */
+	atomic_set(&board->stuck_srq, 0);
+
+	open_dev_cmd.handle = i;
+	retval = copy_to_user((void __user *)arg, &open_dev_cmd, sizeof(open_dev_cmd));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int close_dev_ioctl(struct file *filep, struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_close_dev_ioctl cmd;
+	struct gpib_file_private *file_priv = filep->private_data;
+	struct gpib_descriptor *desc;
+	unsigned int pad;
+	int sad;
+	int retval;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	if (cmd.handle >= GPIB_MAX_NUM_DESCRIPTORS)
+		return -EINVAL;
+
+	mutex_lock(&file_priv->descriptors_mutex);
+	desc = file_priv->descriptors[cmd.handle];
+	if (!desc) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -EINVAL;
+	}
+	if (atomic_read(&desc->descriptor_busy)) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -EBUSY;
+	}
+	/* Remove from table while holding lock to prevent new IO from starting */
+	file_priv->descriptors[cmd.handle] = NULL;
+	pad = desc->pad;
+	sad = desc->sad;
+	mutex_unlock(&file_priv->descriptors_mutex);
+
+	retval = decrement_open_device_count(board, &board->device_list, pad, sad);
+
+	kfree(desc);
+	return retval;
+}
+
+static int serial_poll_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_serial_poll_ioctl serial_cmd;
+	int retval;
+
+	retval = copy_from_user(&serial_cmd, (void __user *)arg, sizeof(serial_cmd));
+	if (retval)
+		return -EFAULT;
+
+	retval = get_serial_poll_byte(board, serial_cmd.pad, serial_cmd.sad, board->usec_timeout,
+				      &serial_cmd.status_byte);
+	if (retval < 0)
+		return retval;
+
+	retval = copy_to_user((void __user *)arg, &serial_cmd, sizeof(serial_cmd));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int wait_ioctl(struct gpib_file_private *file_priv, struct gpib_board *board,
+		      unsigned long arg)
+{
+	struct gpib_wait_ioctl wait_cmd;
+	int retval;
+	struct gpib_descriptor *desc;
+
+	retval = copy_from_user(&wait_cmd, (void __user *)arg, sizeof(wait_cmd));
+	if (retval)
+		return -EFAULT;
+
+	/*
+	 * Lock descriptors to prevent concurrent close from freeing
+	 * descriptor.  ibwait() releases big_gpib_mutex when wait_mask
+	 * is non-zero, so desc must be pinned with descriptor_busy.
+	 */
+	mutex_lock(&file_priv->descriptors_mutex);
+	desc = handle_to_descriptor(file_priv, wait_cmd.handle);
+	if (!desc) {
+		mutex_unlock(&file_priv->descriptors_mutex);
+		return -EINVAL;
+	}
+	atomic_inc(&desc->descriptor_busy);
+	mutex_unlock(&file_priv->descriptors_mutex);
+
+	retval = ibwait(board, wait_cmd.wait_mask, wait_cmd.clear_mask,
+			wait_cmd.set_mask, &wait_cmd.ibsta, wait_cmd.usec_timeout, desc);
+
+	atomic_dec(&desc->descriptor_busy);
+
+	if (retval < 0)
+		return retval;
+
+	retval = copy_to_user((void __user *)arg, &wait_cmd, sizeof(wait_cmd));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int parallel_poll_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	u8 poll_byte;
+	int retval;
+
+	retval = ibrpp(board, &poll_byte);
+	if (retval < 0)
+		return retval;
+
+	retval = copy_to_user((void __user *)arg, &poll_byte, sizeof(poll_byte));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int online_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_online_ioctl online_cmd;
+	int retval;
+	void __user *init_data = NULL;
+
+	board->config.init_data = NULL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	retval = copy_from_user(&online_cmd, (void __user *)arg, sizeof(online_cmd));
+	if (retval)
+		return -EFAULT;
+	if (online_cmd.init_data_length > 0) {
+		board->config.init_data = vmalloc(online_cmd.init_data_length);
+		if (!board->config.init_data)
+			return -ENOMEM;
+		if (WARN_ON_ONCE(sizeof(init_data) > sizeof(online_cmd.init_data_ptr)))
+			return -EFAULT;
+		init_data = (void __user *)(unsigned long)(online_cmd.init_data_ptr);
+		retval = copy_from_user(board->config.init_data, init_data,
+					online_cmd.init_data_length);
+		if (retval) {
+			vfree(board->config.init_data);
+			return -EFAULT;
+		}
+		board->config.init_data_length = online_cmd.init_data_length;
+	} else {
+		board->config.init_data = NULL;
+		board->config.init_data_length = 0;
+	}
+	if (online_cmd.online)
+		retval = ibonline(board);
+	else
+		retval = iboffline(board);
+	if (board->config.init_data) {
+		vfree(board->config.init_data);
+		board->config.init_data = NULL;
+		board->config.init_data_length = 0;
+	}
+	return retval;
+}
+
+static int remote_enable_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	int enable;
+	int retval;
+
+	retval = copy_from_user(&enable, (void __user *)arg, sizeof(enable));
+	if (retval)
+		return -EFAULT;
+
+	return ibsre(board, enable);
+}
+
+static int take_control_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	int synchronous;
+	int retval;
+
+	retval = copy_from_user(&synchronous, (void __user *)arg, sizeof(synchronous));
+	if (retval)
+		return -EFAULT;
+
+	return ibcac(board, synchronous, 1);
+}
+
+static int line_status_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	short lines;
+	int retval;
+
+	retval = iblines(board, &lines);
+	if (retval < 0)
+		return retval;
+
+	retval = copy_to_user((void __user *)arg, &lines, sizeof(lines));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int pad_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+		     unsigned long arg)
+{
+	struct gpib_pad_ioctl cmd;
+	int retval;
+	struct gpib_descriptor *desc;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	desc = handle_to_descriptor(file_priv, cmd.handle);
+	if (!desc)
+		return -EINVAL;
+
+	if (desc->is_board) {
+		retval = ibpad(board, cmd.pad);
+		if (retval < 0)
+			return retval;
+	} else {
+		retval = decrement_open_device_count(board, &board->device_list, desc->pad,
+						     desc->sad);
+		if (retval < 0)
+			return retval;
+
+		desc->pad = cmd.pad;
+
+		retval = increment_open_device_count(board, &board->device_list, desc->pad,
+						     desc->sad);
+		if (retval < 0)
+			return retval;
+	}
+
+	return 0;
+}
+
+static int sad_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+		     unsigned long arg)
+{
+	struct gpib_sad_ioctl cmd;
+	int retval;
+	struct gpib_descriptor *desc;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	desc = handle_to_descriptor(file_priv, cmd.handle);
+	if (!desc)
+		return -EINVAL;
+
+	if (desc->is_board) {
+		retval = ibsad(board, cmd.sad);
+		if (retval < 0)
+			return retval;
+	} else {
+		retval = decrement_open_device_count(board, &board->device_list, desc->pad,
+						     desc->sad);
+		if (retval < 0)
+			return retval;
+
+		desc->sad = cmd.sad;
+
+		retval = increment_open_device_count(board, &board->device_list, desc->pad,
+						     desc->sad);
+		if (retval < 0)
+			return retval;
+	}
+	return 0;
+}
+
+static int eos_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_eos_ioctl eos_cmd;
+	int retval;
+
+	retval = copy_from_user(&eos_cmd, (void __user *)arg, sizeof(eos_cmd));
+	if (retval)
+		return -EFAULT;
+
+	return ibeos(board, eos_cmd.eos, eos_cmd.eos_flags);
+}
+
+static int request_service_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	u8 status_byte;
+	int retval;
+
+	retval = copy_from_user(&status_byte, (void __user *)arg, sizeof(status_byte));
+	if (retval)
+		return -EFAULT;
+
+	return ibrsv2(board, status_byte, status_byte & request_service_bit);
+}
+
+static int request_service2_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_request_service2 request_service2_cmd;
+	int retval;
+
+	retval = copy_from_user(&request_service2_cmd, (void __user *)arg,
+				sizeof(struct gpib_request_service2));
+	if (retval)
+		return -EFAULT;
+
+	return ibrsv2(board, request_service2_cmd.status_byte,
+		      request_service2_cmd.new_reason_for_service);
+}
+
+static int iobase_ioctl(struct gpib_board_config *config, unsigned long arg)
+{
+	u64 base_addr;
+	int retval;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	retval = copy_from_user(&base_addr, (void __user *)arg, sizeof(base_addr));
+	if (retval)
+		return -EFAULT;
+
+	if (WARN_ON_ONCE(sizeof(void *) > sizeof(base_addr)))
+		return -EFAULT;
+	config->ibbase = base_addr;
+
+	return 0;
+}
+
+static int irq_ioctl(struct gpib_board_config *config, unsigned long arg)
+{
+	unsigned int irq;
+	int retval;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	retval = copy_from_user(&irq, (void __user *)arg, sizeof(irq));
+	if (retval)
+		return -EFAULT;
+
+	config->ibirq = irq;
+
+	return 0;
+}
+
+static int dma_ioctl(struct gpib_board_config *config, unsigned long arg)
+{
+	unsigned int dma_channel;
+	int retval;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	retval = copy_from_user(&dma_channel, (void __user *)arg, sizeof(dma_channel));
+	if (retval)
+		return -EFAULT;
+
+	config->ibdma = dma_channel;
+
+	return 0;
+}
+
+static int autospoll_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+			   unsigned long arg)
+{
+	short enable;
+	int retval;
+	struct gpib_descriptor *desc;
+
+	retval = copy_from_user(&enable, (void __user *)arg, sizeof(enable));
+	if (retval)
+		return -EFAULT;
+
+	desc = handle_to_descriptor(file_priv, 0); /* board handle is 0 */
+
+	if (enable) {
+		if (!desc->autopoll_enabled) {
+			board->autospollers++;
+			desc->autopoll_enabled = 1;
+		}
+		retval = 0;
+	} else {
+		if (desc->autopoll_enabled) {
+			desc->autopoll_enabled = 0;
+			if (board->autospollers > 0) {
+				board->autospollers--;
+				retval = 0;
+			} else {
+				dev_err(board->gpib_dev,
+					"tried to set number of autospollers negative\n");
+				retval = -EINVAL;
+			}
+		} else {
+			dev_err(board->gpib_dev, "autopoll disable requested before enable\n");
+			retval = -EINVAL;
+		}
+	}
+	return retval;
+}
+
+static int mutex_ioctl(struct gpib_board *board, struct gpib_file_private *file_priv,
+		       unsigned long arg)
+{
+	int retval, lock_mutex;
+
+	retval = copy_from_user(&lock_mutex, (void __user *)arg, sizeof(lock_mutex));
+	if (retval)
+		return -EFAULT;
+
+	if (lock_mutex)	{
+		retval = mutex_lock_interruptible(&board->user_mutex);
+		if (retval)
+			return -ERESTARTSYS;
+
+		spin_lock(&board->locking_pid_spinlock);
+		board->locking_pid = current->pid;
+		spin_unlock(&board->locking_pid_spinlock);
+
+		atomic_set(&file_priv->holding_mutex, 1);
+
+		dev_dbg(board->gpib_dev, "locked board mutex\n");
+	} else {
+		spin_lock(&board->locking_pid_spinlock);
+		if (current->pid != board->locking_pid) {
+			dev_err(board->gpib_dev, "bug! pid %i tried to release mutex held by pid %i\n",
+				current->pid, board->locking_pid);
+			spin_unlock(&board->locking_pid_spinlock);
+			return -EPERM;
+		}
+		board->locking_pid = 0;
+		spin_unlock(&board->locking_pid_spinlock);
+
+		atomic_set(&file_priv->holding_mutex, 0);
+
+		mutex_unlock(&board->user_mutex);
+		dev_dbg(board->gpib_dev, "unlocked board mutex\n");
+	}
+	return 0;
+}
+
+static int timeout_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	unsigned int timeout;
+	int retval;
+
+	retval = copy_from_user(&timeout, (void __user *)arg, sizeof(timeout));
+	if (retval)
+		return -EFAULT;
+
+	board->usec_timeout = timeout;
+	dev_dbg(board->gpib_dev, "timeout set to %i usec\n", timeout);
+
+	return 0;
+}
+
+static int ppc_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_ppoll_config_ioctl cmd;
+	int retval;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	if (cmd.set_ist) {
+		board->ist = 1;
+		board->interface->parallel_poll_response(board, board->ist);
+	} else if (cmd.clear_ist) {
+		board->ist = 0;
+		board->interface->parallel_poll_response(board, board->ist);
+	}
+
+	if (cmd.config)	{
+		retval = ibppc(board, cmd.config);
+		if (retval < 0)
+			return retval;
+	}
+
+	return 0;
+}
+
+static int set_local_ppoll_mode_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	short cmd;
+	int retval;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	if (!board->interface->local_parallel_poll_mode)
+		return -ENOENT;
+	board->local_ppoll_mode = cmd != 0;
+	board->interface->local_parallel_poll_mode(board, board->local_ppoll_mode);
+
+	return 0;
+}
+
+static int get_local_ppoll_mode_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	short cmd;
+	int retval;
+
+	cmd = board->local_ppoll_mode;
+	retval = copy_to_user((void __user *)arg, &cmd, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int query_board_rsv_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	int status;
+	int retval;
+
+	status = board->interface->serial_poll_status(board);
+
+	retval = copy_to_user((void __user *)arg, &status, sizeof(status));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int board_info_ioctl(const struct gpib_board *board, unsigned long arg)
+{
+	struct gpib_board_info_ioctl info = { };
+	int retval;
+
+	info.pad = board->pad;
+	info.sad = board->sad;
+	info.parallel_poll_configuration = board->parallel_poll_configuration;
+	info.is_system_controller = board->master;
+	if (board->autospollers)
+		info.autopolling = 1;
+	else
+		info.autopolling = 0;
+	info.t1_delay = board->t1_nano_sec;
+	info.ist = board->ist;
+	info.no_7_bit_eos = board->interface->no_7_bit_eos;
+	retval = copy_to_user((void __user *)arg, &info, sizeof(info));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int interface_clear_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	unsigned int usec_duration;
+	int retval;
+
+	retval = copy_from_user(&usec_duration, (void __user *)arg, sizeof(usec_duration));
+	if (retval)
+		return -EFAULT;
+
+	return ibsic(board, usec_duration);
+}
+
+static int select_pci_ioctl(struct gpib_board_config *config, unsigned long arg)
+{
+	struct gpib_select_pci_ioctl selection;
+	int retval;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	retval = copy_from_user(&selection, (void __user *)arg, sizeof(selection));
+	if (retval)
+		return -EFAULT;
+
+	config->pci_bus = selection.pci_bus;
+	config->pci_slot = selection.pci_slot;
+
+	return 0;
+}
+
+static int select_device_path_ioctl(struct gpib_board_config *config, unsigned long arg)
+{
+	struct gpib_select_device_path_ioctl *selection;
+	int retval;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	selection = vmalloc(sizeof(struct gpib_select_device_path_ioctl));
+	if (!selection)
+		return -ENOMEM;
+
+	retval = copy_from_user(selection, (void __user *)arg,
+				sizeof(struct gpib_select_device_path_ioctl));
+	if (retval) {
+		vfree(selection);
+		return -EFAULT;
+	}
+
+	selection->device_path[sizeof(selection->device_path) - 1] = '\0';
+	kfree(config->device_path);
+	config->device_path = NULL;
+	if (strlen(selection->device_path) > 0)
+		config->device_path = kstrdup(selection->device_path, GFP_KERNEL);
+
+	vfree(selection);
+	return 0;
+}
+
+unsigned int num_gpib_events(const struct gpib_event_queue *queue)
+{
+	return queue->num_events;
+}
+
+static int push_gpib_event_nolock(struct gpib_board *board, short event_type)
+{
+	struct gpib_event_queue *queue = &board->event_queue;
+	struct list_head *head = &queue->event_head;
+	struct gpib_event *event;
+	static const unsigned int max_num_events = 1024;
+	int retval;
+
+	if (num_gpib_events(queue) >= max_num_events) {
+		short lost_event;
+
+		queue->dropped_event = 1;
+		retval = pop_gpib_event_nolock(board, queue, &lost_event);
+		if (retval < 0)
+			return retval;
+	}
+
+	event = kmalloc_obj(struct gpib_event, GFP_ATOMIC);
+	if (!event) {
+		queue->dropped_event = 1;
+		dev_err(board->gpib_dev, "failed to allocate memory for event\n");
+		return -ENOMEM;
+	}
+
+	INIT_LIST_HEAD(&event->list);
+	event->event_type = event_type;
+
+	list_add_tail(&event->list, head);
+
+	queue->num_events++;
+
+	dev_dbg(board->gpib_dev, "pushed event %i, %i in queue\n",
+		(int)event_type, num_gpib_events(queue));
+
+	return 0;
+}
+
+// push event onto back of event queue
+int push_gpib_event(struct gpib_board *board, short event_type)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&board->event_queue.lock, flags);
+	retval = push_gpib_event_nolock(board, event_type);
+	spin_unlock_irqrestore(&board->event_queue.lock, flags);
+
+	if (event_type == EVENT_DEV_TRG)
+		board->status |= DTAS;
+	if (event_type == EVENT_DEV_CLR)
+		board->status |= DCAS;
+
+	return retval;
+}
+EXPORT_SYMBOL(push_gpib_event);
+
+static int pop_gpib_event_nolock(struct gpib_board *board,
+				 struct gpib_event_queue *queue, short *event_type)
+{
+	struct list_head *head = &queue->event_head;
+	struct list_head *front = head->next;
+	struct gpib_event *event;
+
+	if (num_gpib_events(queue) == 0) {
+		*event_type = EVENT_NONE;
+		return 0;
+	}
+
+	if (front == head)
+		return -EIO;
+
+	if (queue->dropped_event) {
+		queue->dropped_event = 0;
+		return -EPIPE;
+	}
+
+	event = list_entry(front, struct gpib_event, list);
+	*event_type = event->event_type;
+
+	list_del(front);
+	kfree(event);
+
+	queue->num_events--;
+
+	dev_dbg(board->gpib_dev, "popped event %i, %i in queue\n",
+		(int)*event_type, num_gpib_events(queue));
+
+	return 0;
+}
+
+// pop event from front of event queue
+int pop_gpib_event(struct gpib_board *board, struct gpib_event_queue *queue, short *event_type)
+{
+	unsigned long flags;
+	int retval;
+
+	spin_lock_irqsave(&queue->lock, flags);
+	retval = pop_gpib_event_nolock(board, queue, event_type);
+	spin_unlock_irqrestore(&queue->lock, flags);
+	return retval;
+}
+
+static int event_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	short user_event;
+	int retval;
+	short event;
+
+	retval = pop_gpib_event(board, &board->event_queue, &event);
+	if (retval < 0)
+		return retval;
+
+	user_event = event;
+
+	retval = copy_to_user((void __user *)arg, &user_event, sizeof(user_event));
+	if (retval)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int request_system_control_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	int request_control;
+	int retval;
+
+	retval = copy_from_user(&request_control, (void __user *)arg, sizeof(request_control));
+	if (retval)
+		return -EFAULT;
+
+	return ibrsc(board, request_control);
+}
+
+static int t1_delay_ioctl(struct gpib_board *board, unsigned long arg)
+{
+	unsigned int cmd;
+	unsigned int delay;
+	int retval;
+
+	if (!board->interface->t1_delay)
+		return -ENOENT;
+
+	retval = copy_from_user(&cmd, (void __user *)arg, sizeof(cmd));
+	if (retval)
+		return -EFAULT;
+
+	delay = cmd;
+
+	retval = board->interface->t1_delay(board, delay);
+	if (retval < 0)
+		return retval;
+
+	board->t1_nano_sec = retval;
+	return 0;
+}
+
+static const struct file_operations ib_fops = {
+	.owner = THIS_MODULE,
+	.llseek = NULL,
+	.unlocked_ioctl = &ibioctl,
+	.compat_ioctl = &ibioctl,
+	.open = &ibopen,
+	.release = &ibclose,
+};
+
+struct gpib_board board_array[GPIB_MAX_NUM_BOARDS];
+
+LIST_HEAD(registered_drivers);
+
+void init_gpib_descriptor(struct gpib_descriptor *desc)
+{
+	desc->pad = 0;
+	desc->sad = -1;
+	desc->is_board = 0;
+	desc->autopoll_enabled = 0;
+	atomic_set(&desc->io_in_progress, 0);
+	atomic_set(&desc->descriptor_busy, 0);
+}
+
+int gpib_register_driver(struct gpib_interface *interface, struct module *provider_module)
+{
+	struct gpib_interface_list *entry;
+
+	entry = kmalloc_obj(*entry);
+	if (!entry)
+		return -ENOMEM;
+
+	entry->interface = interface;
+	entry->module = provider_module;
+	list_add(&entry->list, &registered_drivers);
+
+	return 0;
+}
+EXPORT_SYMBOL(gpib_register_driver);
+
+void gpib_unregister_driver(struct gpib_interface *interface)
+{
+	int i;
+	struct list_head *list_ptr;
+
+	for (i = 0; i < GPIB_MAX_NUM_BOARDS; i++) {
+		struct gpib_board *board = &board_array[i];
+
+		if (board->interface == interface) {
+			if (board->use_count > 0)
+				pr_warn("gpib: Warning: deregistered interface %s in use\n",
+					interface->name);
+			iboffline(board);
+			board->interface = NULL;
+		}
+	}
+	for (list_ptr = registered_drivers.next; list_ptr != &registered_drivers;) {
+		struct gpib_interface_list *entry;
+
+		entry = list_entry(list_ptr, struct gpib_interface_list, list);
+		list_ptr = list_ptr->next;
+		if (entry->interface == interface) {
+			list_del(&entry->list);
+			kfree(entry);
+		}
+	}
+}
+EXPORT_SYMBOL(gpib_unregister_driver);
+
+static void init_gpib_board_config(struct gpib_board_config *config)
+{
+	memset(config, 0, sizeof(struct gpib_board_config));
+	config->pci_bus = -1;
+	config->pci_slot = -1;
+}
+
+void init_gpib_board(struct gpib_board *board)
+{
+	board->interface = NULL;
+	board->provider_module = NULL;
+	board->buffer = NULL;
+	board->buffer_length = 0;
+	board->status = 0;
+	init_waitqueue_head(&board->wait);
+	mutex_init(&board->user_mutex);
+	mutex_init(&board->big_gpib_mutex);
+	board->locking_pid = 0;
+	spin_lock_init(&board->locking_pid_spinlock);
+	spin_lock_init(&board->spinlock);
+	timer_setup(&board->timer, NULL, 0);
+	board->dev = NULL;
+	board->gpib_dev = NULL;
+	init_gpib_board_config(&board->config);
+	board->private_data = NULL;
+	board->use_count = 0;
+	INIT_LIST_HEAD(&board->device_list);
+	board->pad = 0;
+	board->sad = -1;
+	board->usec_timeout = 3000000;
+	board->parallel_poll_configuration = 0;
+	board->online = 0;
+	board->autospollers = 0;
+	board->autospoll_task = NULL;
+	init_event_queue(&board->event_queue);
+	board->minor = -1;
+	init_gpib_pseudo_irq(&board->pseudo_irq);
+	board->master = 1;
+	atomic_set(&board->stuck_srq, 0);
+	board->local_ppoll_mode = 0;
+}
+
+int gpib_allocate_board(struct gpib_board *board)
+{
+	if (!board->buffer) {
+		board->buffer_length = 0x4000;
+		board->buffer = vmalloc(board->buffer_length);
+		if (!board->buffer) {
+			board->buffer_length = 0;
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+void gpib_deallocate_board(struct gpib_board *board)
+{
+	short dummy;
+
+	if (board->buffer) {
+		vfree(board->buffer);
+		board->buffer = NULL;
+		board->buffer_length = 0;
+	}
+	while (num_gpib_events(&board->event_queue))
+		pop_gpib_event(board, &board->event_queue, &dummy);
+}
+
+static void init_board_array(struct gpib_board *board_array, unsigned int length)
+{
+	int i;
+
+	for (i = 0; i < length; i++) {
+		init_gpib_board(&board_array[i]);
+		board_array[i].minor = i;
+	}
+}
+
+void init_gpib_status_queue(struct gpib_status_queue *device)
+{
+	INIT_LIST_HEAD(&device->list);
+	INIT_LIST_HEAD(&device->status_bytes);
+	device->num_status_bytes = 0;
+	device->reference_count = 0;
+	device->dropped_byte = 0;
+}
+
+static const struct class gpib_class = {
+	.name	= "gpib_common",
+};
+
+static int __init gpib_common_init_module(void)
+{
+	int err;
+	int i;
+
+	pr_info("GPIB core driver\n");
+	init_board_array(board_array, GPIB_MAX_NUM_BOARDS);
+	if (register_chrdev(GPIB_CODE, "gpib", &ib_fops)) {
+		pr_err("gpib: can't get major %d\n", GPIB_CODE);
+		return -EIO;
+	}
+	err = class_register(&gpib_class);
+	if (err) {
+		pr_err("gpib: failed to create gpib class\n");
+		unregister_chrdev(GPIB_CODE, "gpib");
+		return err;
+	}
+	for (i = 0; i < GPIB_MAX_NUM_BOARDS; ++i)
+		board_array[i].gpib_dev = device_create(&gpib_class, NULL,
+							MKDEV(GPIB_CODE, i), NULL, "gpib%i", i);
+
+	return 0;
+}
+
+static void __exit gpib_common_exit_module(void)
+{
+	int i;
+
+	for (i = 0; i < GPIB_MAX_NUM_BOARDS; ++i)
+		device_destroy(&gpib_class, MKDEV(GPIB_CODE, i));
+
+	class_unregister(&gpib_class);
+	unregister_chrdev(GPIB_CODE, "gpib");
+}
+
+int gpib_match_device_path(struct device *dev, const char *device_path_in)
+{
+	if (device_path_in) {
+		char *device_path;
+
+		device_path = kobject_get_path(&dev->kobj, GFP_KERNEL);
+		if (!device_path) {
+			dev_err(dev, "kobject_get_path returned NULL.");
+			return 0;
+		}
+		if (strcmp(device_path_in, device_path) != 0) {
+			kfree(device_path);
+			return 0;
+		}
+		kfree(device_path);
+	}
+	return 1;
+}
+EXPORT_SYMBOL(gpib_match_device_path);
+
+struct pci_dev *gpib_pci_get_device(const struct gpib_board_config *config, unsigned int vendor_id,
+				    unsigned int device_id, struct pci_dev *from)
+{
+	struct pci_dev *pci_device = from;
+
+	while ((pci_device = pci_get_device(vendor_id, device_id, pci_device)))	{
+		if (config->pci_bus >= 0 && config->pci_bus != pci_device->bus->number)
+			continue;
+		if (config->pci_slot >= 0 && config->pci_slot !=
+		    PCI_SLOT(pci_device->devfn))
+			continue;
+		if (gpib_match_device_path(&pci_device->dev, config->device_path) == 0)
+			continue;
+		return pci_device;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(gpib_pci_get_device);
+
+struct pci_dev *gpib_pci_get_subsys(const struct gpib_board_config *config, unsigned int vendor_id,
+				    unsigned int device_id, unsigned int ss_vendor,
+				    unsigned int ss_device,
+				    struct pci_dev *from)
+{
+	struct pci_dev *pci_device = from;
+
+	while ((pci_device = pci_get_subsys(vendor_id, device_id,
+					    ss_vendor, ss_device, pci_device))) {
+		if (config->pci_bus >= 0 && config->pci_bus != pci_device->bus->number)
+			continue;
+		if (config->pci_slot >= 0 && config->pci_slot !=
+		    PCI_SLOT(pci_device->devfn))
+			continue;
+		if (gpib_match_device_path(&pci_device->dev, config->device_path) == 0)
+			continue;
+		return pci_device;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(gpib_pci_get_subsys);
+
+module_init(gpib_common_init_module);
+module_exit(gpib_common_exit_module);
+
diff --git a/drivers/gpib/common/iblib.c b/drivers/gpib/common/iblib.c
new file mode 100644
index 000000000..511e1d61c
--- /dev/null
+++ b/drivers/gpib/common/iblib.c
@@ -0,0 +1,713 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/***************************************************************************
+ *    copyright            : (C) 2001, 2002 by Frank Mori Hess
+ ***************************************************************************/
+
+#define dev_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "ibsys.h"
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/vmalloc.h>
+
+/*
+ * IBCAC
+ * Return to the controller active state from the
+ * controller standby state, i.e., turn ATN on.  Note
+ * that in order to enter the controller active state
+ * from the controller idle state, ibsic must be called.
+ * If sync is non-zero, attempt to take control synchronously.
+ * If fallback_to_async is non-zero, try to take control asynchronously
+ * if synchronous attempt fails.
+ */
+int ibcac(struct gpib_board *board, int sync, int fallback_to_async)
+{
+	int status = ibstatus(board);
+	int retval;
+
+	if ((status & CIC) == 0)
+		return -EINVAL;
+
+	if (status & ATN)
+		return 0;
+
+	if (sync && (status & LACS) == 0)
+		/*
+		 * tcs (take control synchronously) can only possibly work when
+		 * controller is listener.  Error code also needs to be -ETIMEDOUT
+		 * or it will giveout without doing fallback.
+		 */
+		retval = -ETIMEDOUT;
+	else
+		retval = board->interface->take_control(board, sync);
+
+	if (retval < 0 && fallback_to_async) {
+		if (sync && retval == -ETIMEDOUT)
+			retval = board->interface->take_control(board, 0);
+	}
+	board->interface->update_status(board, 0);
+
+	return retval;
+}
+
+/*
+ * After ATN is asserted, it should cause any connected devices
+ * to start listening for command bytes and leave acceptor idle state.
+ * So if ATN is asserted and neither NDAC or NRFD are asserted,
+ * then there are no devices and ibcmd should error out immediately.
+ * Some gpib hardware sees itself asserting NDAC/NRFD when it
+ * is controller in charge, in which case this check will
+ * do nothing useful (but shouldn't cause any harm either).
+ * Drivers that don't need this check (ni_usb for example) may
+ * set the skip_check_for_command_acceptors flag in their
+ * gpib_interface_struct to avoid useless overhead.
+ */
+static int check_for_command_acceptors(struct gpib_board *board)
+{
+	int lines;
+
+	if (board->interface->skip_check_for_command_acceptors)
+		return 0;
+	if (!board->interface->line_status)
+		return 0;
+
+	udelay(2); // allow time for devices to respond to ATN if it was just asserted
+
+	lines = board->interface->line_status(board);
+	if (lines < 0)
+		return lines;
+
+	if ((lines & VALID_NRFD) && (lines & VALID_NDAC))	{
+		if ((lines & BUS_NRFD) == 0 && (lines & BUS_NDAC) == 0)
+			return -ENOTCONN;
+	}
+
+	return 0;
+}
+
+/*
+ * IBCMD
+ * Write cnt command bytes from buf to the GPIB.  The
+ * command operation terminates only on I/O complete.
+ *
+ * NOTE:
+ *      1.  Prior to beginning the command, the interface is
+ *          placed in the controller active state.
+ *      2.  Before calling ibcmd for the first time, ibsic
+ *          must be called to initialize the GPIB and enable
+ *          the interface to leave the controller idle state.
+ */
+int ibcmd(struct gpib_board *board, u8 *buf, size_t length, size_t *bytes_written)
+{
+	ssize_t ret = 0;
+	int status;
+
+	*bytes_written = 0;
+
+	status = ibstatus(board);
+
+	if ((status & CIC) == 0)
+		return -EINVAL;
+
+	os_start_timer(board, board->usec_timeout);
+
+	ret = ibcac(board, 1, 1);
+	if (ret == 0) {
+		ret = check_for_command_acceptors(board);
+		if (ret == 0)
+			ret = board->interface->command(board, buf, length, bytes_written);
+	}
+
+	os_remove_timer(board);
+
+	if (io_timed_out(board))
+		ret = -ETIMEDOUT;
+
+	return ret;
+}
+
+/*
+ * IBGTS
+ * Go to the controller standby state from the controller
+ * active state, i.e., turn ATN off.
+ */
+
+int ibgts(struct gpib_board *board)
+{
+	int status = ibstatus(board);
+	int retval;
+
+	if ((status & CIC) == 0)
+		return -EINVAL;
+
+	retval = board->interface->go_to_standby(board);    /* go to standby */
+
+	board->interface->update_status(board, 0);
+
+	return retval;
+}
+
+static int autospoll_wait_should_wake_up(struct gpib_board *board)
+{
+	int retval;
+
+	mutex_lock(&board->big_gpib_mutex);
+
+	retval = board->master && board->autospollers > 0 &&
+		!atomic_read(&board->stuck_srq) &&
+		test_and_clear_bit(SRQI_NUM, &board->status);
+
+	mutex_unlock(&board->big_gpib_mutex);
+	return retval;
+}
+
+static int autospoll_thread(void *board_void)
+{
+	struct gpib_board *board = board_void;
+	int retval = 0;
+
+	dev_dbg(board->gpib_dev, "entering autospoll thread\n");
+
+	while (1) {
+		wait_event_interruptible(board->wait,
+					 kthread_should_stop() ||
+					 autospoll_wait_should_wake_up(board));
+		dev_dbg(board->gpib_dev, "autospoll wait satisfied\n");
+		if (kthread_should_stop())
+			break;
+
+		mutex_lock(&board->big_gpib_mutex);
+		/* make sure we are still good after we have lock */
+		if (board->autospollers <= 0 || board->master == 0) {
+			mutex_unlock(&board->big_gpib_mutex);
+			continue;
+		}
+		mutex_unlock(&board->big_gpib_mutex);
+
+		if (try_module_get(board->provider_module)) {
+			retval = autopoll_all_devices(board);
+			module_put(board->provider_module);
+		} else {
+			dev_err(board->gpib_dev, "try_module_get() failed!\n");
+		}
+		if (retval <= 0) {
+			dev_err(board->gpib_dev, "stuck SRQ\n");
+		}
+	}
+	return retval;
+}
+
+int ibonline(struct gpib_board *board)
+{
+	int retval;
+
+	if (board->online)
+		return -EBUSY;
+	if (!board->interface)
+		return -ENODEV;
+	retval = gpib_allocate_board(board);
+	if (retval < 0)
+		return retval;
+
+	board->dev = NULL;
+	board->local_ppoll_mode = 0;
+	retval = board->interface->attach(board, &board->config);
+	if (retval < 0) {
+		board->interface->detach(board);
+		return retval;
+	}
+	/*
+	 * nios2nommu on 2.6.11 uclinux kernel has weird problems
+	 * with autospoll thread causing huge slowdowns
+	 */
+#ifndef CONFIG_NIOS2
+	board->autospoll_task = kthread_run(&autospoll_thread, board,
+					    "gpib%d_autospoll_kthread", board->minor);
+	if (IS_ERR(board->autospoll_task)) {
+		dev_err(board->gpib_dev, "failed to create autospoll thread\n");
+		board->interface->detach(board);
+		return PTR_ERR(board->autospoll_task);
+	}
+#endif
+	board->online = 1;
+	dev_dbg(board->gpib_dev, "board online\n");
+
+	return 0;
+}
+
+/* XXX need to make sure board is generally not in use (grab board lock?) */
+int iboffline(struct gpib_board *board)
+{
+	int retval;
+
+	if (board->online == 0)
+		return 0;
+	if (!board->interface)
+		return -ENODEV;
+
+	if (board->autospoll_task && !IS_ERR(board->autospoll_task)) {
+		retval = kthread_stop(board->autospoll_task);
+		if (retval)
+			dev_err(board->gpib_dev, "kthread_stop returned %i\n", retval);
+		board->autospoll_task = NULL;
+	}
+
+	board->interface->detach(board);
+	gpib_deallocate_board(board);
+	board->online = 0;
+	dev_dbg(board->gpib_dev, "board offline\n");
+
+	return 0;
+}
+
+/*
+ * IBLINES
+ * Poll the GPIB control lines and return their status in buf.
+ *
+ *      LSB (bits 0-7)  -  VALID lines mask (lines that can be monitored).
+ * Next LSB (bits 8-15) - STATUS lines mask (lines that are currently set).
+ *
+ */
+int iblines(const struct gpib_board *board, short *lines)
+{
+	int retval;
+
+	*lines = 0;
+	if (!board->interface->line_status)
+		return 0;
+	retval = board->interface->line_status(board);
+	if (retval < 0)
+		return retval;
+	*lines = retval;
+	return 0;
+}
+
+/*
+ * IBRD
+ * Read up to 'length' bytes of data from the GPIB into buf.  End
+ * on detection of END (EOI and or EOS) and set 'end_flag'.
+ *
+ * NOTE:
+ *      1.  The interface is placed in the controller standby
+ *          state prior to beginning the read.
+ *      2.  Prior to calling ibrd, the intended devices as well
+ *          as the interface board itself must be addressed by
+ *          calling ibcmd.
+ */
+
+int ibrd(struct gpib_board *board, u8 *buf, size_t length, int *end_flag, size_t *nbytes)
+{
+	ssize_t ret = 0;
+	int retval;
+	size_t bytes_read;
+
+	*nbytes = 0;
+	*end_flag = 0;
+	if (length == 0)
+		return 0;
+
+	if (board->master) {
+		retval = ibgts(board);
+		if (retval < 0)
+			return retval;
+	}
+	/*
+	 * XXX resetting timer here could cause timeouts take longer than they should,
+	 * since read_ioctl calls this
+	 * function in a loop, there is probably a similar problem with writes/commands
+	 */
+	os_start_timer(board, board->usec_timeout);
+
+	do {
+		ret = board->interface->read(board, buf, length - *nbytes, end_flag, &bytes_read);
+		if (ret < 0)
+			goto ibrd_out;
+
+		buf += bytes_read;
+		*nbytes += bytes_read;
+		if (need_resched())
+			schedule();
+	} while (ret == 0 && *nbytes > 0 && *nbytes < length && *end_flag == 0);
+ibrd_out:
+	os_remove_timer(board);
+
+	return ret;
+}
+
+/*
+ * IBRPP
+ * Conduct a parallel poll and return the byte in buf.
+ *
+ * NOTE:
+ *	1.  Prior to conducting the poll the interface is placed
+ *	    in the controller active state.
+ */
+int ibrpp(struct gpib_board *board, u8 *result)
+{
+	int retval = 0;
+
+	os_start_timer(board, board->usec_timeout);
+	retval = ibcac(board, 1, 1);
+	if (retval)
+		return -1;
+
+	retval =  board->interface->parallel_poll(board, result);
+
+	os_remove_timer(board);
+	return retval;
+}
+
+int ibppc(struct gpib_board *board, u8 configuration)
+{
+	configuration &= 0x1f;
+	board->interface->parallel_poll_configure(board, configuration);
+	board->parallel_poll_configuration = configuration;
+
+	return 0;
+}
+
+int ibrsv2(struct gpib_board *board, u8 status_byte, int new_reason_for_service)
+{
+	int board_status = ibstatus(board);
+	const unsigned int MSS = status_byte & request_service_bit;
+
+	if ((board_status & CIC))
+		return -EINVAL;
+
+	if (MSS == 0 && new_reason_for_service)
+		return -EINVAL;
+
+	if (board->interface->serial_poll_response2)	{
+		board->interface->serial_poll_response2(board, status_byte, new_reason_for_service);
+		// fall back on simpler serial_poll_response if the behavior would be the same
+	} else if (board->interface->serial_poll_response &&
+		   (MSS == 0 || (MSS && new_reason_for_service))) {
+		board->interface->serial_poll_response(board, status_byte);
+	} else {
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+/*
+ * IBSIC
+ * Send IFC for at least 100 microseconds.
+ *
+ * NOTE:
+ *	1.  Ibsic must be called prior to the first call to
+ *	    ibcmd in order to initialize the bus and enable the
+ *	    interface to leave the controller idle state.
+ */
+int ibsic(struct gpib_board *board, unsigned int usec_duration)
+{
+	if (board->master == 0)
+		return -EINVAL;
+
+	if (usec_duration < 100)
+		usec_duration = 100;
+	if (usec_duration > 1000)
+		usec_duration = 1000;
+
+	dev_dbg(board->gpib_dev, "sending interface clear, delay = %ius\n", usec_duration);
+	board->interface->interface_clear(board, 1);
+	udelay(usec_duration);
+	board->interface->interface_clear(board, 0);
+
+	return 0;
+}
+
+int ibrsc(struct gpib_board *board, int request_control)
+{
+	int retval;
+
+	if (!board->interface->request_system_control)
+		return -EPERM;
+
+	retval = board->interface->request_system_control(board, request_control);
+
+	if (retval)
+		return retval;
+
+	board->master = request_control != 0;
+
+	return  0;
+}
+
+/*
+ * IBSRE
+ * Send REN true if v is non-zero or false if v is zero.
+ */
+int ibsre(struct gpib_board *board, int enable)
+{
+	if (board->master == 0)
+		return -EINVAL;
+
+	board->interface->remote_enable(board, enable);	/* set or clear REN */
+	if (!enable)
+		usleep_range(100, 150);
+
+	return 0;
+}
+
+/*
+ * IBPAD
+ * change the GPIB address of the interface board.  The address
+ * must be 0 through 30.  ibonl resets the address to PAD.
+ */
+int ibpad(struct gpib_board *board, unsigned int addr)
+{
+	if (addr > MAX_GPIB_PRIMARY_ADDRESS)
+		return -EINVAL;
+
+	board->pad = addr;
+	if (board->online)
+		board->interface->primary_address(board, board->pad);
+	dev_dbg(board->gpib_dev, "set primary addr to %i\n", board->pad);
+	return 0;
+}
+
+/*
+ * IBSAD
+ * change the secondary GPIB address of the interface board.
+ * The address must be 0 through 30, or negative disables.  ibonl resets the
+ * address to SAD.
+ */
+int ibsad(struct gpib_board *board, int addr)
+{
+	if (addr > MAX_GPIB_SECONDARY_ADDRESS)
+		return -EINVAL;
+	board->sad = addr;
+	if (board->online) {
+		if (board->sad >= 0)
+			board->interface->secondary_address(board, board->sad, 1);
+		else
+			board->interface->secondary_address(board, 0, 0);
+	}
+	dev_dbg(board->gpib_dev, "set secondary addr to %i\n", board->sad);
+
+	return 0;
+}
+
+/*
+ * IBEOS
+ * Set the end-of-string modes for I/O operations to v.
+ *
+ */
+int ibeos(struct gpib_board *board, int eos, int eosflags)
+{
+	int retval;
+
+	if (eosflags & ~EOS_MASK)
+		return -EINVAL;
+	if (eosflags & REOS) {
+		retval = board->interface->enable_eos(board, eos, eosflags & BIN);
+	} else {
+		board->interface->disable_eos(board);
+		retval = 0;
+	}
+	return retval;
+}
+
+int ibstatus(struct gpib_board *board)
+{
+	return general_ibstatus(board, NULL, 0, 0, NULL);
+}
+
+int general_ibstatus(struct gpib_board *board, const struct gpib_status_queue *device,
+		     int clear_mask, int set_mask, struct gpib_descriptor *desc)
+{
+	int status = 0;
+	short line_status;
+
+	if (board->private_data) {
+		status = board->interface->update_status(board, clear_mask);
+		/*
+		 * XXX should probably stop having drivers use TIMO bit in
+		 * board->status to avoid confusion
+		 */
+		status &= ~TIMO;
+		/* get real SRQI status if we can */
+		if (iblines(board, &line_status) == 0) {
+			if ((line_status & VALID_SRQ)) {
+				if ((line_status & BUS_SRQ))
+					status |= SRQI;
+				else
+					status &= ~SRQI;
+			}
+		}
+	}
+	if (device)
+		if (num_status_bytes(device))
+			status |= RQS;
+
+	if (desc) {
+		if (set_mask & CMPL)
+			atomic_set(&desc->io_in_progress, 0);
+		else if (clear_mask & CMPL)
+			atomic_set(&desc->io_in_progress, 1);
+
+		if (atomic_read(&desc->io_in_progress))
+			status &= ~CMPL;
+		else
+			status |= CMPL;
+	}
+	if (num_gpib_events(&board->event_queue))
+		status |= EVENT;
+	else
+		status &= ~EVENT;
+
+	return status;
+}
+
+struct wait_info {
+	struct gpib_board *board;
+	struct timer_list timer;
+	int timed_out;
+	unsigned long usec_timeout;
+};
+
+static void wait_timeout(struct timer_list *t)
+{
+	struct wait_info *winfo = timer_container_of(winfo, t, timer);
+
+	winfo->timed_out = 1;
+	wake_up_interruptible(&winfo->board->wait);
+}
+
+static void init_wait_info(struct wait_info *winfo)
+{
+	winfo->board = NULL;
+	winfo->timed_out = 0;
+	timer_setup_on_stack(&winfo->timer, wait_timeout, 0);
+}
+
+static int wait_satisfied(struct wait_info *winfo, struct gpib_status_queue *status_queue,
+			  int wait_mask, int *status, struct gpib_descriptor *desc)
+{
+	struct gpib_board *board = winfo->board;
+	int temp_status;
+
+	if (mutex_lock_interruptible(&board->big_gpib_mutex))
+		return -ERESTARTSYS;
+
+	temp_status = general_ibstatus(board, status_queue, 0, 0, desc);
+
+	mutex_unlock(&board->big_gpib_mutex);
+
+	if (winfo->timed_out)
+		temp_status |= TIMO;
+	else
+		temp_status &= ~TIMO;
+	if (wait_mask & temp_status) {
+		*status = temp_status;
+		return 1;
+	}
+// XXX does wait for END work?
+	return 0;
+}
+
+/* install timer interrupt handler */
+static void start_wait_timer(struct wait_info *winfo)
+/* Starts the timeout task  */
+{
+	winfo->timed_out = 0;
+
+	if (winfo->usec_timeout > 0)
+		mod_timer(&winfo->timer, jiffies + usec_to_jiffies(winfo->usec_timeout));
+}
+
+static void remove_wait_timer(struct wait_info *winfo)
+{
+	timer_delete_sync(&winfo->timer);
+	timer_destroy_on_stack(&winfo->timer);
+}
+
+/*
+ * IBWAIT
+ * Check or wait for a GPIB event to occur.  The mask argument
+ * is a bit vector corresponding to the status bit vector.  It
+ * has a bit set for each condition which can terminate the wait
+ * If the mask is 0 then
+ * no condition is waited for.
+ */
+int ibwait(struct gpib_board *board, int wait_mask, int clear_mask, int set_mask,
+	   int *status, unsigned long usec_timeout, struct gpib_descriptor *desc)
+{
+	int retval = 0;
+	struct gpib_status_queue *status_queue;
+	struct wait_info winfo;
+
+	if (desc->is_board)
+		status_queue = NULL;
+	else
+		status_queue = get_gpib_status_queue(board, desc->pad, desc->sad);
+
+	if (wait_mask == 0) {
+		*status = general_ibstatus(board, status_queue, clear_mask, set_mask, desc);
+		return 0;
+	}
+
+	mutex_unlock(&board->big_gpib_mutex);
+
+	init_wait_info(&winfo);
+	winfo.board = board;
+	winfo.usec_timeout = usec_timeout;
+	start_wait_timer(&winfo);
+
+	if (wait_event_interruptible(board->wait, wait_satisfied(&winfo, status_queue,
+								 wait_mask, status, desc))) {
+		dev_dbg(board->gpib_dev, "wait interrupted\n");
+		retval = -ERESTARTSYS;
+	}
+	remove_wait_timer(&winfo);
+
+	if (retval)
+		return retval;
+	if (mutex_lock_interruptible(&board->big_gpib_mutex))
+		return -ERESTARTSYS;
+
+	/* make sure we only clear status bits that we are reporting */
+	if (*status & clear_mask || set_mask)
+		general_ibstatus(board, status_queue, *status & clear_mask, set_mask, NULL);
+
+	return 0;
+}
+
+/*
+ * IBWRT
+ * Write cnt bytes of data from buf to the GPIB.  The write
+ * operation terminates only on I/O complete.
+ *
+ * NOTE:
+ *      1.  Prior to beginning the write, the interface is
+ *          placed in the controller standby state.
+ *      2.  Prior to calling ibwrt, the intended devices as
+ *          well as the interface board itself must be
+ *          addressed by calling ibcmd.
+ */
+int ibwrt(struct gpib_board *board, u8 *buf, size_t cnt, int send_eoi, size_t *bytes_written)
+{
+	int ret = 0;
+	int retval;
+
+	if (cnt == 0)
+		return 0;
+
+	if (board->master) {
+		retval = ibgts(board);
+		if (retval < 0)
+			return retval;
+	}
+	os_start_timer(board, board->usec_timeout);
+	ret = board->interface->write(board, buf, cnt, send_eoi, bytes_written);
+
+	if (io_timed_out(board))
+		ret = -ETIMEDOUT;
+
+	os_remove_timer(board);
+
+	return ret;
+}
+
diff --git a/drivers/gpib/common/ibsys.h b/drivers/gpib/common/ibsys.h
new file mode 100644
index 000000000..e5a148f51
--- /dev/null
+++ b/drivers/gpib/common/ibsys.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include "gpibP.h"
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/major.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/timer.h>
+
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <asm/irq.h>
+#include <asm/dma.h>
+
+#define MAX_GPIB_PRIMARY_ADDRESS 30
+#define MAX_GPIB_SECONDARY_ADDRESS 31
+
+int gpib_allocate_board(struct gpib_board *board);
+void gpib_deallocate_board(struct gpib_board *board);
+
+unsigned int num_status_bytes(const struct gpib_status_queue *dev);
+int push_status_byte(struct gpib_board *board, struct gpib_status_queue *device,
+		     u8 poll_byte);
+int pop_status_byte(struct gpib_board *board, struct gpib_status_queue *device,
+		    u8 *poll_byte);
+struct gpib_status_queue *get_gpib_status_queue(struct gpib_board *board,
+						unsigned int pad, int sad);
+int get_serial_poll_byte(struct gpib_board *board, unsigned int pad, int sad,
+			 unsigned int usec_timeout, u8 *poll_byte);
+int autopoll_all_devices(struct gpib_board *board);