Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 248 insertions, 0 deletions

diff --git a/drivers/char/nwbutton.c b/drivers/char/nwbutton.c
new file mode 100644
index 000000000..92cee5717
--- /dev/null
+++ b/drivers/char/nwbutton.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 	NetWinder Button Driver-
+ *	Copyright (C) Alex Holden <alex@linuxhacker.org> 1998, 1999.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/timer.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+
+#include <linux/uaccess.h>
+#include <asm/irq.h>
+#include <asm/mach-types.h>
+
+#define __NWBUTTON_C		/* Tell the header file who we are */
+#include "nwbutton.h"
+
+static void button_sequence_finished(struct timer_list *unused);
+
+static int button_press_count;		/* The count of button presses */
+/* Times for the end of a sequence */
+static DEFINE_TIMER(button_timer, button_sequence_finished);
+static DECLARE_WAIT_QUEUE_HEAD(button_wait_queue); /* Used for blocking read */
+static char button_output_buffer[32];	/* Stores data to write out of device */
+static int bcount;			/* The number of bytes in the buffer */
+static int bdelay = BUTTON_DELAY;	/* The delay, in jiffies */
+static struct button_callback button_callback_list[32]; /* The callback list */
+static int callback_count;		/* The number of callbacks registered */
+static int reboot_count = NUM_PRESSES_REBOOT; /* Number of presses to reboot */
+
+/*
+ * This function is called by other drivers to register a callback function
+ * to be called when a particular number of button presses occurs.
+ * The callback list is a static array of 32 entries (I somehow doubt many
+ * people are ever going to want to register more than 32 different actions
+ * to be performed by the kernel on different numbers of button presses ;).
+ * However, if an attempt to register a 33rd entry (perhaps a stuck loop
+ * somewhere registering the same entry over and over?) it will fail to
+ * do so and return -ENOMEM. If an attempt is made to register a null pointer,
+ * it will fail to do so and return -EINVAL.
+ * Because callbacks can be unregistered at random the list can become
+ * fragmented, so we need to search through the list until we find the first
+ * free entry.
+ *
+ * FIXME: Has anyone spotted any locking functions int his code recently ??
+ */
+
+int button_add_callback (void (*callback) (void), int count)
+{
+	int lp = 0;
+	if (callback_count == 32) {
+		return -ENOMEM;
+	}
+	if (!callback) {
+		return -EINVAL;
+	}
+	callback_count++;
+	for (; (button_callback_list [lp].callback); lp++);
+	button_callback_list [lp].callback = callback;
+	button_callback_list [lp].count = count;
+	return 0;
+}
+
+/*
+ * This function is called by other drivers to deregister a callback function.
+ * If you attempt to unregister a callback which does not exist, it will fail
+ * with -EINVAL. If there is more than one entry with the same address,
+ * because it searches the list from end to beginning, it will unregister the
+ * last one to be registered first (FILO- First In Last Out).
+ * Note that this is not necessarily true if the entries are not submitted
+ * at the same time, because another driver could have unregistered a callback
+ * between the submissions creating a gap earlier in the list, which would
+ * be filled first at submission time.
+ */
+
+int button_del_callback (void (*callback) (void))
+{
+	int lp = 31;
+	if (!callback) {
+		return -EINVAL;
+	}
+	while (lp >= 0) {
+		if ((button_callback_list [lp].callback) == callback) {
+			button_callback_list [lp].callback = NULL;
+			button_callback_list [lp].count = 0;
+			callback_count--;
+			return 0;
+		}
+		lp--;
+	}
+	return -EINVAL;
+}
+
+/*
+ * This function is called by button_sequence_finished to search through the
+ * list of callback functions, and call any of them whose count argument
+ * matches the current count of button presses. It starts at the beginning
+ * of the list and works up to the end. It will refuse to follow a null
+ * pointer (which should never happen anyway).
+ */
+
+static void button_consume_callbacks (int bpcount)
+{
+	int lp = 0;
+	for (; lp <= 31; lp++) {
+		if ((button_callback_list [lp].count) == bpcount) {
+			if (button_callback_list [lp].callback) {
+				button_callback_list[lp].callback();
+			}
+		}
+	}
+}
+
+/* 
+ * This function is called when the button_timer times out.
+ * ie. When you don't press the button for bdelay jiffies, this is taken to
+ * mean you have ended the sequence of key presses, and this function is
+ * called to wind things up (write the press_count out to /dev/button, call
+ * any matching registered function callbacks, initiate reboot, etc.).
+ */
+
+static void button_sequence_finished(struct timer_list *unused)
+{
+	if (IS_ENABLED(CONFIG_NWBUTTON_REBOOT) &&
+	    button_press_count == reboot_count)
+		kill_cad_pid(SIGINT, 1);	/* Ask init to reboot us */
+	button_consume_callbacks (button_press_count);
+	bcount = sprintf (button_output_buffer, "%d\n", button_press_count);
+	button_press_count = 0;		/* Reset the button press counter */
+	wake_up_interruptible (&button_wait_queue);
+}
+
+/* 
+ *  This handler is called when the orange button is pressed (GPIO 10 of the
+ *  SuperIO chip, which maps to logical IRQ 26). If the press_count is 0,
+ *  this is the first press, so it starts a timer and increments the counter.
+ *  If it is higher than 0, it deletes the old timer, starts a new one, and
+ *  increments the counter.
+ */ 
+
+static irqreturn_t button_handler (int irq, void *dev_id)
+{
+	button_press_count++;
+	mod_timer(&button_timer, jiffies + bdelay);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * This function is called when a user space program attempts to read
+ * /dev/nwbutton. It puts the device to sleep on the wait queue until
+ * button_sequence_finished writes some data to the buffer and flushes
+ * the queue, at which point it writes the data out to the device and
+ * returns the number of characters it has written. This function is
+ * reentrant, so that many processes can be attempting to read from the
+ * device at any one time.
+ */
+
+static int button_read (struct file *filp, char __user *buffer,
+			size_t count, loff_t *ppos)
+{
+	DEFINE_WAIT(wait);
+	prepare_to_wait(&button_wait_queue, &wait, TASK_INTERRUPTIBLE);
+	schedule();
+	finish_wait(&button_wait_queue, &wait);
+	return (copy_to_user (buffer, &button_output_buffer, bcount))
+		 ? -EFAULT : bcount;
+}
+
+/* 
+ * This structure is the file operations structure, which specifies what
+ * callbacks functions the kernel should call when a user mode process
+ * attempts to perform these operations on the device.
+ */
+
+static const struct file_operations button_fops = {
+	.owner		= THIS_MODULE,
+	.read		= button_read,
+	.llseek		= noop_llseek,
+};
+
+/* 
+ * This structure is the misc device structure, which specifies the minor
+ * device number (158 in this case), the name of the device (for /proc/misc),
+ * and the address of the above file operations structure.
+ */
+
+static struct miscdevice button_misc_device = {
+	BUTTON_MINOR,
+	"nwbutton",
+	&button_fops,
+};
+
+/*
+ * This function is called to initialise the driver, either from misc.c at
+ * bootup if the driver is compiled into the kernel, or from init_module
+ * below at module insert time. It attempts to register the device node
+ * and the IRQ and fails with a warning message if either fails, though
+ * neither ever should because the device number and IRQ are unique to
+ * this driver.
+ */
+
+static int __init nwbutton_init(void)
+{
+	if (!machine_is_netwinder())
+		return -ENODEV;
+
+	printk (KERN_INFO "NetWinder Button Driver Version %s (C) Alex Holden "
+			"<alex@linuxhacker.org> 1998.\n", VERSION);
+
+	if (misc_register (&button_misc_device)) {
+		printk (KERN_WARNING "nwbutton: Couldn't register device 10, "
+				"%d.\n", BUTTON_MINOR);
+		return -EBUSY;
+	}
+
+	if (request_irq (IRQ_NETWINDER_BUTTON, button_handler, 0,
+			"nwbutton", NULL)) {
+		printk (KERN_WARNING "nwbutton: IRQ %d is not free.\n",
+				IRQ_NETWINDER_BUTTON);
+		misc_deregister (&button_misc_device);
+		return -EIO;
+	}
+	return 0;
+}
+
+static void __exit nwbutton_exit (void) 
+{
+	free_irq (IRQ_NETWINDER_BUTTON, NULL);
+	misc_deregister (&button_misc_device);
+}
+
+
+MODULE_AUTHOR("Alex Holden");
+MODULE_DESCRIPTION("NetWinder button driver");
+MODULE_LICENSE("GPL");
+
+module_init(nwbutton_init);
+module_exit(nwbutton_exit);