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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 | /* * 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 <linux/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, c; ssize_t ret; if (!info->screen_buffer) return -ENODEV; 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 = info->screen_buffer + p; if (info->fbops->fb_sync) info->fbops->fb_sync(info); c = copy_to_user(buf, src, count); if (c) err = -EFAULT; ret = count - c; *ppos += ret; return ret ? ret : err; } 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, c; size_t ret; if (!info->screen_buffer) return -ENODEV; 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 = info->screen_buffer + p; if (info->fbops->fb_sync) info->fbops->fb_sync(info); c = copy_from_user(dst, buf, count); if (c) err = -EFAULT; ret = count - c; *ppos += ret; return ret ? ret : err; } 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"); |