| Antonino A. Daplas | 09aaf26 | 2007-05-08 00:39:03 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * linux/drivers/video/fb_sys_read.c - Generic file operations where |
| 3 | * framebuffer is in system RAM |
| 4 | * |
| 5 | * Copyright (C) 2007 Antonino Daplas <adaplas@pol.net> |
| 6 | * |
| 7 | * This file is subject to the terms and conditions of the GNU General Public |
| 8 | * License. See the file COPYING in the main directory of this archive |
| 9 | * for more details. |
| 10 | * |
| 11 | */ |
| 12 | #include <linux/fb.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <asm/uaccess.h> |
| 15 | |
| 16 | ssize_t fb_sys_read(struct fb_info *info, char __user *buf, size_t count, |
| 17 | loff_t *ppos) |
| 18 | { |
| 19 | unsigned long p = *ppos; |
| 20 | void *src; |
| 21 | int err = 0; |
| 22 | unsigned long total_size; |
| 23 | |
| 24 | if (info->state != FBINFO_STATE_RUNNING) |
| 25 | return -EPERM; |
| 26 | |
| 27 | total_size = info->screen_size; |
| 28 | |
| 29 | if (total_size == 0) |
| 30 | total_size = info->fix.smem_len; |
| 31 | |
| 32 | if (p >= total_size) |
| 33 | return 0; |
| 34 | |
| 35 | if (count >= total_size) |
| 36 | count = total_size; |
| 37 | |
| 38 | if (count + p > total_size) |
| 39 | count = total_size - p; |
| 40 | |
| 41 | src = (void __force *)(info->screen_base + p); |
| 42 | |
| 43 | if (info->fbops->fb_sync) |
| 44 | info->fbops->fb_sync(info); |
| 45 | |
| 46 | if (copy_to_user(buf, src, count)) |
| 47 | err = -EFAULT; |
| 48 | |
| 49 | if (!err) |
| 50 | *ppos += count; |
| 51 | |
| 52 | return (err) ? err : count; |
| 53 | } |
| 54 | EXPORT_SYMBOL_GPL(fb_sys_read); |
| 55 | |
| 56 | ssize_t fb_sys_write(struct fb_info *info, const char __user *buf, |
| 57 | size_t count, loff_t *ppos) |
| 58 | { |
| 59 | unsigned long p = *ppos; |
| 60 | void *dst; |
| 61 | int err = 0; |
| 62 | unsigned long total_size; |
| 63 | |
| 64 | if (info->state != FBINFO_STATE_RUNNING) |
| 65 | return -EPERM; |
| 66 | |
| 67 | total_size = info->screen_size; |
| 68 | |
| 69 | if (total_size == 0) |
| 70 | total_size = info->fix.smem_len; |
| 71 | |
| 72 | if (p > total_size) |
| 73 | return -EFBIG; |
| 74 | |
| 75 | if (count > total_size) { |
| 76 | err = -EFBIG; |
| 77 | count = total_size; |
| 78 | } |
| 79 | |
| 80 | if (count + p > total_size) { |
| 81 | if (!err) |
| 82 | err = -ENOSPC; |
| 83 | |
| 84 | count = total_size - p; |
| 85 | } |
| 86 | |
| 87 | dst = (void __force *) (info->screen_base + p); |
| 88 | |
| 89 | if (info->fbops->fb_sync) |
| 90 | info->fbops->fb_sync(info); |
| 91 | |
| 92 | if (copy_from_user(dst, buf, count)) |
| 93 | err = -EFAULT; |
| 94 | |
| 95 | if (!err) |
| 96 | *ppos += count; |
| 97 | |
| 98 | return (err) ? err : count; |
| 99 | } |
| 100 | EXPORT_SYMBOL_GPL(fb_sys_write); |
| 101 | |
| 102 | MODULE_AUTHOR("Antonino Daplas <adaplas@pol.net>"); |
| 103 | MODULE_DESCRIPTION("Generic file read (fb in system RAM)"); |
| 104 | MODULE_LICENSE("GPL"); |