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: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Antonino A. Daplas 2007-05-08 00:39:03 -07:00 committed by Linus Torvalds
parent 3f9b0880e4
commit 09aaf268eb
4 changed files with 114 additions and 0 deletions

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@ -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

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@ -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

104
drivers/video/fb_sys_fops.c Normal file
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@ -0,0 +1,104 @@
/*
* 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");

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@ -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);