Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 616 insertions, 0 deletions

diff --git a/drivers/video/fbdev/arcfb.c b/drivers/video/fbdev/arcfb.c
new file mode 100644
index 000000000..b807cf075
--- /dev/null
+++ b/drivers/video/fbdev/arcfb.c
@@ -0,0 +1,616 @@
+/*
+ * linux/drivers/video/arcfb.c -- FB driver for Arc monochrome LCD board
+ *
+ * Copyright (C) 2005, Jaya Kumar <jayalk@intworks.biz>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ *
+ * Layout is based on skeletonfb.c by James Simmons and Geert Uytterhoeven.
+ *
+ * This driver was written to be used with the Arc LCD board. Arc uses a
+ * set of KS108 chips that control individual 64x64 LCD matrices. The board
+ * can be paneled in a variety of setups such as 2x1=128x64, 4x4=256x256 and
+ * so on. The interface between the board and the host is TTL based GPIO. The
+ * GPIO requirements are 8 writable data lines and 4+n lines for control. On a
+ * GPIO-less system, the board can be tested by connecting the respective sigs
+ * up to a parallel port connector. The driver requires the IO addresses for
+ * data and control GPIO at load time. It is unable to probe for the
+ * existence of the LCD so it must be told at load time whether it should
+ * be enabled or not.
+ *
+ * Todo:
+ * - testing with 4x4
+ * - testing with interrupt hw
+ *
+ * General notes:
+ * - User must set tuhold. It's in microseconds. According to the 108 spec,
+ *   the hold time is supposed to be at least 1 microsecond.
+ * - User must set num_cols=x num_rows=y, eg: x=2 means 128
+ * - User must set arcfb_enable=1 to enable it
+ * - User must set dio_addr=0xIOADDR cio_addr=0xIOADDR
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/fb.h>
+#include <linux/init.h>
+#include <linux/arcfb.h>
+#include <linux/platform_device.h>
+
+#include <linux/uaccess.h>
+
+#define floor8(a) (a&(~0x07))
+#define floorXres(a,xres) (a&(~(xres - 1)))
+#define iceil8(a) (((int)((a+7)/8))*8)
+#define ceil64(a) (a|0x3F)
+#define ceilXres(a,xres) (a|(xres - 1))
+
+/* ks108 chipset specific defines and code */
+
+#define KS_SET_DPY_START_LINE 	0xC0
+#define KS_SET_PAGE_NUM 	0xB8
+#define KS_SET_X 		0x40
+#define KS_CEHI 		0x01
+#define KS_CELO 		0x00
+#define KS_SEL_CMD 		0x08
+#define KS_SEL_DATA 		0x00
+#define KS_DPY_ON 		0x3F
+#define KS_DPY_OFF 		0x3E
+#define KS_INTACK 		0x40
+#define KS_CLRINT		0x02
+
+struct arcfb_par {
+	unsigned long dio_addr;
+	unsigned long cio_addr;
+	unsigned long c2io_addr;
+	atomic_t ref_count;
+	unsigned char cslut[9];
+	struct fb_info *info;
+	unsigned int irq;
+	spinlock_t lock;
+};
+
+static const struct fb_fix_screeninfo arcfb_fix = {
+	.id =		"arcfb",
+	.type =		FB_TYPE_PACKED_PIXELS,
+	.visual =	FB_VISUAL_MONO01,
+	.xpanstep =	0,
+	.ypanstep =	1,
+	.ywrapstep =	0,
+	.accel =	FB_ACCEL_NONE,
+};
+
+static const struct fb_var_screeninfo arcfb_var = {
+	.xres		= 128,
+	.yres		= 64,
+	.xres_virtual	= 128,
+	.yres_virtual	= 64,
+	.bits_per_pixel	= 1,
+	.nonstd		= 1,
+};
+
+static unsigned long num_cols;
+static unsigned long num_rows;
+static unsigned long dio_addr;
+static unsigned long cio_addr;
+static unsigned long c2io_addr;
+static unsigned long splashval;
+static unsigned long tuhold;
+static unsigned int nosplash;
+static unsigned int arcfb_enable;
+static unsigned int irq;
+
+static DECLARE_WAIT_QUEUE_HEAD(arcfb_waitq);
+
+static void ks108_writeb_ctl(struct arcfb_par *par,
+				unsigned int chipindex, unsigned char value)
+{
+	unsigned char chipselval = par->cslut[chipindex];
+
+	outb(chipselval|KS_CEHI|KS_SEL_CMD, par->cio_addr);
+	outb(value, par->dio_addr);
+	udelay(tuhold);
+	outb(chipselval|KS_CELO|KS_SEL_CMD, par->cio_addr);
+}
+
+static void ks108_writeb_mainctl(struct arcfb_par *par, unsigned char value)
+{
+
+	outb(value, par->cio_addr);
+	udelay(tuhold);
+}
+
+static unsigned char ks108_readb_ctl2(struct arcfb_par *par)
+{
+	return inb(par->c2io_addr);
+}
+
+static void ks108_writeb_data(struct arcfb_par *par,
+				unsigned int chipindex, unsigned char value)
+{
+	unsigned char chipselval = par->cslut[chipindex];
+
+	outb(chipselval|KS_CEHI|KS_SEL_DATA, par->cio_addr);
+	outb(value, par->dio_addr);
+	udelay(tuhold);
+	outb(chipselval|KS_CELO|KS_SEL_DATA, par->cio_addr);
+}
+
+static void ks108_set_start_line(struct arcfb_par *par,
+				unsigned int chipindex, unsigned char y)
+{
+	ks108_writeb_ctl(par, chipindex, KS_SET_DPY_START_LINE|y);
+}
+
+static void ks108_set_yaddr(struct arcfb_par *par,
+				unsigned int chipindex, unsigned char y)
+{
+	ks108_writeb_ctl(par, chipindex, KS_SET_PAGE_NUM|y);
+}
+
+static void ks108_set_xaddr(struct arcfb_par *par,
+				unsigned int chipindex, unsigned char x)
+{
+	ks108_writeb_ctl(par, chipindex, KS_SET_X|x);
+}
+
+static void ks108_clear_lcd(struct arcfb_par *par, unsigned int chipindex)
+{
+	int i,j;
+
+	for (i = 0; i <= 8; i++) {
+		ks108_set_yaddr(par, chipindex, i);
+		ks108_set_xaddr(par, chipindex, 0);
+		for (j = 0; j < 64; j++) {
+			ks108_writeb_data(par, chipindex,
+				(unsigned char) splashval);
+		}
+	}
+}
+
+/* main arcfb functions */
+
+static int arcfb_open(struct fb_info *info, int user)
+{
+	struct arcfb_par *par = info->par;
+
+	atomic_inc(&par->ref_count);
+	return 0;
+}
+
+static int arcfb_release(struct fb_info *info, int user)
+{
+	struct arcfb_par *par = info->par;
+	int count = atomic_read(&par->ref_count);
+
+	if (!count)
+		return -EINVAL;
+	atomic_dec(&par->ref_count);
+	return 0;
+}
+
+static int arcfb_pan_display(struct fb_var_screeninfo *var,
+				struct fb_info *info)
+{
+	int i;
+	struct arcfb_par *par = info->par;
+
+	if ((var->vmode & FB_VMODE_YWRAP) && (var->yoffset < 64)
+		&& (info->var.yres <= 64)) {
+		for (i = 0; i < num_cols; i++) {
+			ks108_set_start_line(par, i, var->yoffset);
+		}
+		info->var.yoffset = var->yoffset;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static irqreturn_t arcfb_interrupt(int vec, void *dev_instance)
+{
+	struct fb_info *info = dev_instance;
+	unsigned char ctl2status;
+	struct arcfb_par *par = info->par;
+
+	ctl2status = ks108_readb_ctl2(par);
+
+	if (!(ctl2status & KS_INTACK)) /* not arc generated interrupt */
+		return IRQ_NONE;
+
+	ks108_writeb_mainctl(par, KS_CLRINT);
+
+	spin_lock(&par->lock);
+        if (waitqueue_active(&arcfb_waitq)) {
+                wake_up(&arcfb_waitq);
+        }
+	spin_unlock(&par->lock);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * here we handle a specific page on the lcd. the complexity comes from
+ * the fact that the fb is laidout in 8xX vertical columns. we extract
+ * each write of 8 vertical pixels. then we shift out as we move along
+ * X. That's what rightshift does. bitmask selects the desired input bit.
+ */
+static void arcfb_lcd_update_page(struct arcfb_par *par, unsigned int upper,
+		unsigned int left, unsigned int right, unsigned int distance)
+{
+	unsigned char *src;
+	unsigned int xindex, yindex, chipindex, linesize;
+	int i;
+	unsigned char val;
+	unsigned char bitmask, rightshift;
+
+	xindex = left >> 6;
+	yindex = upper >> 6;
+	chipindex = (xindex + (yindex*num_cols));
+
+	ks108_set_yaddr(par, chipindex, upper/8);
+
+	linesize = par->info->var.xres/8;
+	src = (unsigned char *)par->info->screen_buffer + (left/8) +
+		(upper * linesize);
+	ks108_set_xaddr(par, chipindex, left);
+
+	bitmask=1;
+	rightshift=0;
+	while (left <= right) {
+		val = 0;
+		for (i = 0; i < 8; i++) {
+			if ( i > rightshift) {
+				val |= (*(src + (i*linesize)) & bitmask)
+						<< (i - rightshift);
+			} else {
+				val |= (*(src + (i*linesize)) & bitmask)
+						 >> (rightshift - i);
+			}
+		}
+		ks108_writeb_data(par, chipindex, val);
+		left++;
+		if (bitmask == 0x80) {
+			bitmask = 1;
+			src++;
+			rightshift=0;
+		} else {
+			bitmask <<= 1;
+			rightshift++;
+		}
+	}
+}
+
+/*
+ * here we handle the entire vertical page of the update. we write across
+ * lcd chips. update_page uses the upper/left values to decide which
+ * chip to select for the right. upper is needed for setting the page
+ * desired for the write.
+ */
+static void arcfb_lcd_update_vert(struct arcfb_par *par, unsigned int top,
+		unsigned int bottom, unsigned int left, unsigned int right)
+{
+	unsigned int distance, upper, lower;
+
+	distance = (bottom - top) + 1;
+	upper = top;
+	lower = top + 7;
+
+	while (distance > 0) {
+		distance -= 8;
+		arcfb_lcd_update_page(par, upper, left, right, 8);
+		upper = lower + 1;
+		lower = upper + 7;
+	}
+}
+
+/*
+ * here we handle horizontal blocks for the update. update_vert will
+ * handle spaning multiple pages. we break out each horizontal
+ * block in to individual blocks no taller than 64 pixels.
+ */
+static void arcfb_lcd_update_horiz(struct arcfb_par *par, unsigned int left,
+			unsigned int right, unsigned int top, unsigned int h)
+{
+	unsigned int distance, upper, lower;
+
+	distance = h;
+	upper = floor8(top);
+	lower = min(upper + distance - 1, ceil64(upper));
+
+	while (distance > 0) {
+		distance -= ((lower - upper) + 1 );
+		arcfb_lcd_update_vert(par, upper, lower, left, right);
+		upper = lower + 1;
+		lower = min(upper + distance - 1, ceil64(upper));
+	}
+}
+
+/*
+ * here we start the process of splitting out the fb update into
+ * individual blocks of pixels. we end up splitting into 64x64 blocks
+ * and finally down to 64x8 pages.
+ */
+static void arcfb_lcd_update(struct arcfb_par *par, unsigned int dx,
+			unsigned int dy, unsigned int w, unsigned int h)
+{
+	unsigned int left, right, distance, y;
+
+	/* align the request first */
+	y = floor8(dy);
+	h += dy - y;
+	h = iceil8(h);
+
+	distance = w;
+	left = dx;
+	right = min(left + w - 1, ceil64(left));
+
+	while (distance > 0) {
+		arcfb_lcd_update_horiz(par, left, right, y, h);
+		distance -= ((right - left) + 1);
+		left = right + 1;
+		right = min(left + distance - 1, ceil64(left));
+	}
+}
+
+static int arcfb_ioctl(struct fb_info *info,
+			  unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	struct arcfb_par *par = info->par;
+	unsigned long flags;
+
+	switch (cmd) {
+		case FBIO_WAITEVENT:
+		{
+			DEFINE_WAIT(wait);
+			/* illegal to wait on arc if no irq will occur */
+			if (!par->irq)
+				return -EINVAL;
+
+			/* wait until the Arc has generated an interrupt
+			 * which will wake us up */
+			spin_lock_irqsave(&par->lock, flags);
+			prepare_to_wait(&arcfb_waitq, &wait,
+					TASK_INTERRUPTIBLE);
+			spin_unlock_irqrestore(&par->lock, flags);
+			schedule();
+			finish_wait(&arcfb_waitq, &wait);
+		}
+		fallthrough;
+
+		case FBIO_GETCONTROL2:
+		{
+			unsigned char ctl2;
+
+			ctl2 = ks108_readb_ctl2(info->par);
+			if (copy_to_user(argp, &ctl2, sizeof(ctl2)))
+				return -EFAULT;
+			return 0;
+		}
+		default:
+			return -EINVAL;
+	}
+}
+
+static void arcfb_damage_range(struct fb_info *info, off_t off, size_t len)
+{
+	struct arcfb_par *par = info->par;
+	unsigned int xres = info->var.xres;
+	unsigned int bitppos, startpos, endpos, bitcount;
+	unsigned int x, y, width, height;
+
+	bitppos = off * 8;
+	startpos = floorXres(bitppos, xres);
+	endpos = ceilXres((bitppos + (len * 8)), xres);
+	bitcount = endpos - startpos;
+
+	x = startpos % xres;
+	y = startpos / xres;
+	width = xres;
+	height = bitcount / xres;
+
+	arcfb_lcd_update(par, x, y, width, height);
+}
+
+static void arcfb_damage_area(struct fb_info *info, u32 x, u32 y,
+			      u32 width, u32 height)
+{
+	struct arcfb_par *par = info->par;
+
+	/* update the physical lcd */
+	arcfb_lcd_update(par, x, y, width, height);
+}
+
+FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(arcfb,
+				   arcfb_damage_range,
+				   arcfb_damage_area)
+
+static const struct fb_ops arcfb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_open	= arcfb_open,
+	__FB_DEFAULT_DEFERRED_OPS_RDWR(arcfb),
+	.fb_release	= arcfb_release,
+	.fb_pan_display	= arcfb_pan_display,
+	__FB_DEFAULT_DEFERRED_OPS_DRAW(arcfb),
+	.fb_ioctl 	= arcfb_ioctl,
+	// .fb_mmap reqires deferred I/O
+};
+
+static int arcfb_probe(struct platform_device *dev)
+{
+	struct fb_info *info;
+	int retval = -ENOMEM;
+	int videomemorysize;
+	unsigned char *videomemory;
+	struct arcfb_par *par;
+	int i;
+
+	videomemorysize = (((64*64)*num_cols)*num_rows)/8;
+
+	/* We need a flat backing store for the Arc's
+	   less-flat actual paged framebuffer */
+	videomemory = vzalloc(videomemorysize);
+	if (!videomemory)
+		return retval;
+
+	info = framebuffer_alloc(sizeof(struct arcfb_par), &dev->dev);
+	if (!info)
+		goto err_fb_alloc;
+
+	info->flags |= FBINFO_VIRTFB;
+	info->screen_buffer = videomemory;
+	info->fbops = &arcfb_ops;
+
+	info->var = arcfb_var;
+	info->fix = arcfb_fix;
+	par = info->par;
+	par->info = info;
+
+	if (!dio_addr || !cio_addr || !c2io_addr) {
+		printk(KERN_WARNING "no IO addresses supplied\n");
+		goto err_addr;
+	}
+	par->dio_addr = dio_addr;
+	par->cio_addr = cio_addr;
+	par->c2io_addr = c2io_addr;
+	par->cslut[0] = 0x00;
+	par->cslut[1] = 0x06;
+	spin_lock_init(&par->lock);
+	if (irq) {
+		par->irq = irq;
+		if (request_irq(par->irq, &arcfb_interrupt, IRQF_SHARED,
+				"arcfb", info)) {
+			printk(KERN_INFO
+				"arcfb: Failed req IRQ %d\n", par->irq);
+			retval = -EBUSY;
+			goto err_addr;
+		}
+	}
+	retval = register_framebuffer(info);
+	if (retval < 0)
+		goto err_register_fb;
+	platform_set_drvdata(dev, info);
+	fb_info(info, "Arc frame buffer device, using %dK of video memory\n",
+		videomemorysize >> 10);
+
+	/* this inits the lcd but doesn't clear dirty pixels */
+	for (i = 0; i < num_cols * num_rows; i++) {
+		ks108_writeb_ctl(par, i, KS_DPY_OFF);
+		ks108_set_start_line(par, i, 0);
+		ks108_set_yaddr(par, i, 0);
+		ks108_set_xaddr(par, i, 0);
+		ks108_writeb_ctl(par, i, KS_DPY_ON);
+	}
+
+	/* if we were told to splash the screen, we just clear it */
+	if (!nosplash) {
+		for (i = 0; i < num_cols * num_rows; i++) {
+			fb_info(info, "splashing lcd %d\n", i);
+			ks108_set_start_line(par, i, 0);
+			ks108_clear_lcd(par, i);
+		}
+	}
+
+	return 0;
+
+err_register_fb:
+	free_irq(par->irq, info);
+err_addr:
+	framebuffer_release(info);
+err_fb_alloc:
+	vfree(videomemory);
+	return retval;
+}
+
+static void arcfb_remove(struct platform_device *dev)
+{
+	struct fb_info *info = platform_get_drvdata(dev);
+
+	if (info) {
+		unregister_framebuffer(info);
+		if (irq)
+			free_irq(((struct arcfb_par *)(info->par))->irq, info);
+		vfree(info->screen_buffer);
+		framebuffer_release(info);
+	}
+}
+
+static struct platform_driver arcfb_driver = {
+	.probe	= arcfb_probe,
+	.remove	= arcfb_remove,
+	.driver	= {
+		.name	= "arcfb",
+	},
+};
+
+static struct platform_device *arcfb_device;
+
+static int __init arcfb_init(void)
+{
+	int ret;
+
+	if (!arcfb_enable)
+		return -ENXIO;
+
+	ret = platform_driver_register(&arcfb_driver);
+	if (!ret) {
+		arcfb_device = platform_device_alloc("arcfb", 0);
+		if (arcfb_device) {
+			ret = platform_device_add(arcfb_device);
+		} else {
+			ret = -ENOMEM;
+		}
+		if (ret) {
+			platform_device_put(arcfb_device);
+			platform_driver_unregister(&arcfb_driver);
+		}
+	}
+	return ret;
+
+}
+
+static void __exit arcfb_exit(void)
+{
+	platform_device_unregister(arcfb_device);
+	platform_driver_unregister(&arcfb_driver);
+}
+
+module_param(num_cols, ulong, 0);
+MODULE_PARM_DESC(num_cols, "Num horiz panels, eg: 2 = 128 bit wide");
+module_param(num_rows, ulong, 0);
+MODULE_PARM_DESC(num_rows, "Num vert panels, eg: 1 = 64 bit high");
+module_param(nosplash, uint, 0);
+MODULE_PARM_DESC(nosplash, "Disable doing the splash screen");
+module_param(arcfb_enable, uint, 0);
+MODULE_PARM_DESC(arcfb_enable, "Enable communication with Arc board");
+module_param_hw(dio_addr, ulong, ioport, 0);
+MODULE_PARM_DESC(dio_addr, "IO address for data, eg: 0x480");
+module_param_hw(cio_addr, ulong, ioport, 0);
+MODULE_PARM_DESC(cio_addr, "IO address for control, eg: 0x400");
+module_param_hw(c2io_addr, ulong, ioport, 0);
+MODULE_PARM_DESC(c2io_addr, "IO address for secondary control, eg: 0x408");
+module_param(splashval, ulong, 0);
+MODULE_PARM_DESC(splashval, "Splash pattern: 0xFF is black, 0x00 is green");
+module_param(tuhold, ulong, 0);
+MODULE_PARM_DESC(tuhold, "Time to hold between strobing data to Arc board");
+module_param_hw(irq, uint, irq, 0);
+MODULE_PARM_DESC(irq, "IRQ for the Arc board");
+
+module_init(arcfb_init);
+module_exit(arcfb_exit);
+
+MODULE_DESCRIPTION("fbdev driver for Arc monochrome LCD board");
+MODULE_AUTHOR("Jaya Kumar");
+MODULE_LICENSE("GPL");
+