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author | Antonino A. Daplas <adaplas@gmail.com> | 2007-05-08 00:39:03 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 11:15:30 -0700 |
commit | 09aaf268eb1d22eee690d26a913f660e2081597f (patch) | |
tree | 9179447608d1c7ee23af266d2bae2eef6d05a1c9 /drivers/video/fb_sys_fops.c | |
parent | 3f9b0880e4a96b02bc0131451f2f6231cd90bd94 (diff) | |
download | kernel_goldelico_gta04-09aaf268eb1d22eee690d26a913f660e2081597f.zip kernel_goldelico_gta04-09aaf268eb1d22eee690d26a913f660e2081597f.tar.gz kernel_goldelico_gta04-09aaf268eb1d22eee690d26a913f660e2081597f.tar.bz2 |
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>
Diffstat (limited to 'drivers/video/fb_sys_fops.c')
-rw-r--r-- | drivers/video/fb_sys_fops.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/drivers/video/fb_sys_fops.c b/drivers/video/fb_sys_fops.c new file mode 100644 index 0000000..cf2538d --- /dev/null +++ b/drivers/video/fb_sys_fops.c @@ -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"); |