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Commit 09aaf268 authored by Antonino A. Daplas's avatar Antonino A. Daplas Committed by Linus Torvalds
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fbdev: add fb_read/fb_write functions for framebuffers in system RAM 



The functions fb_read() and fb_write in fbmem.c assume that the framebuffer
is in IO memory.  However, we have 3 drivers (hecubafb, arcfb, and vfb)
where the framebuffer is allocated from system RAM (via vmalloc). Using
__raw_read/__raw_write (fb_readl/fb_writel) for these drivers is
illegal, especially in other platforms.

Create file read and write methods for these types of drivers.  These are
named fb_sys_read() and fb_sys_write().

Signed-off-by: default avatarAntonino Daplas <adaplas@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3f9b0880

drivers/video/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -122,6 +122,11 @@ config FB_SYS_IMAGEBLIT 
	  blitting. This is used by drivers that don't provide their own

	  (accelerated) version and the framebuffer is in system RAM.



config FB_SYS_FOPS

       tristate

       depends on FB

       default n



config FB_DEFERRED_IO

	bool

	depends on FB

drivers/video/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ obj-$(CONFIG_FB_CFB_IMAGEBLIT) += cfbimgblt.o 
obj-$(CONFIG_FB_SYS_FILLRECT)  += sysfillrect.o

obj-$(CONFIG_FB_SYS_COPYAREA)  += syscopyarea.o

obj-$(CONFIG_FB_SYS_IMAGEBLIT) += sysimgblt.o

obj-$(CONFIG_FB_SYS_FOPS)      += fb_sys_fops.o

obj-$(CONFIG_FB_SVGALIB)       += svgalib.o

obj-$(CONFIG_FB_MACMODES)      += macmodes.o

obj-$(CONFIG_FB_DDC)           += fb_ddc.o

drivers/video/fb_sys_fops.c

0 → 100644
+104 −0
Original line number Diff line number Diff line 
/*

 * linux/drivers/video/fb_sys_read.c - Generic file operations where

 * framebuffer is in system RAM

 *

 * Copyright (C) 2007 Antonino Daplas <adaplas@pol.net>

 *

 * 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.

 *

 */

#include <linux/fb.h>

#include <linux/module.h>

#include <asm/uaccess.h>



ssize_t fb_sys_read(struct fb_info *info, char __user *buf, size_t count,

		    loff_t *ppos)

{

	unsigned long p = *ppos;

	void *src;

	int err = 0;

	unsigned long total_size;



	if (info->state != FBINFO_STATE_RUNNING)

		return -EPERM;



	total_size = info->screen_size;



	if (total_size == 0)

		total_size = info->fix.smem_len;



	if (p >= total_size)

		return 0;



	if (count >= total_size)

		count = total_size;



	if (count + p > total_size)

		count = total_size - p;



	src = (void __force *)(info->screen_base + p);



	if (info->fbops->fb_sync)

		info->fbops->fb_sync(info);



	if (copy_to_user(buf, src, count))

		err = -EFAULT;



	if  (!err)

		*ppos += count;



	return (err) ? err : count;

}

EXPORT_SYMBOL_GPL(fb_sys_read);



ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,

		     size_t count, loff_t *ppos)

{

	unsigned long p = *ppos;

	void *dst;

	int err = 0;

	unsigned long total_size;



	if (info->state != FBINFO_STATE_RUNNING)

		return -EPERM;



	total_size = info->screen_size;



	if (total_size == 0)

		total_size = info->fix.smem_len;



	if (p > total_size)

		return -EFBIG;



	if (count > total_size) {

		err = -EFBIG;

		count = total_size;

	}



	if (count + p > total_size) {

		if (!err)

			err = -ENOSPC;



		count = total_size - p;

	}



	dst = (void __force *) (info->screen_base + p);



	if (info->fbops->fb_sync)

		info->fbops->fb_sync(info);



	if (copy_from_user(dst, buf, count))

		err = -EFAULT;



	if  (!err)

		*ppos += count;



	return (err) ? err : count;

}

EXPORT_SYMBOL_GPL(fb_sys_write);



MODULE_AUTHOR("Antonino Daplas <adaplas@pol.net>");

MODULE_DESCRIPTION("Generic file read (fb in system RAM)");

MODULE_LICENSE("GPL");

include/linux/fb.h

+4 −0
Original line number Diff line number Diff line
@@ -903,6 +903,10 @@ extern void cfb_imageblit(struct fb_info *info, const struct fb_image *image); 
extern void sys_fillrect(struct fb_info *info, const struct fb_fillrect *rect);

extern void sys_copyarea(struct fb_info *info, const struct fb_copyarea *area);

extern void sys_imageblit(struct fb_info *info, const struct fb_image *image);

extern ssize_t fb_sys_read(struct fb_info *info, char __user *buf,

			   size_t count, loff_t *ppos);

extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,

			    size_t count, loff_t *ppos);



/* drivers/video/fbmem.c */

extern int register_framebuffer(struct fb_info *fb_info);