/*
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* linux/drivers/video/fb_sys_read.c - Generic file operations where
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* framebuffer is in system RAM
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*
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* Copyright (C) 2007 Antonino Daplas <adaplas@pol.net>
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of this archive
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* for more details.
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*
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*/
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#include <linux/fb.h>
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#include <linux/module.h>
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#include <linux/uaccess.h>
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ssize_t fb_sys_read(struct fb_info *info, char __user *buf, size_t count,
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loff_t *ppos)
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{
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unsigned long p = *ppos;
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void *src;
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int err = 0;
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unsigned long total_size;
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if (info->state != FBINFO_STATE_RUNNING)
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return -EPERM;
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total_size = info->screen_size;
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if (total_size == 0)
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total_size = info->fix.smem_len;
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if (p >= total_size)
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return 0;
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if (count >= total_size)
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count = total_size;
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if (count + p > total_size)
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count = total_size - p;
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src = (void __force *)(info->screen_base + p);
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if (info->fbops->fb_sync)
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info->fbops->fb_sync(info);
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if (copy_to_user(buf, src, count))
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err = -EFAULT;
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if (!err)
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*ppos += count;
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return (err) ? err : count;
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}
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EXPORT_SYMBOL_GPL(fb_sys_read);
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ssize_t fb_sys_write(struct fb_info *info, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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unsigned long p = *ppos;
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void *dst;
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int err = 0;
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unsigned long total_size;
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if (info->state != FBINFO_STATE_RUNNING)
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return -EPERM;
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total_size = info->screen_size;
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if (total_size == 0)
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total_size = info->fix.smem_len;
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if (p > total_size)
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return -EFBIG;
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if (count > total_size) {
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err = -EFBIG;
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count = total_size;
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}
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if (count + p > total_size) {
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if (!err)
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err = -ENOSPC;
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count = total_size - p;
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}
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dst = (void __force *) (info->screen_base + p);
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if (info->fbops->fb_sync)
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info->fbops->fb_sync(info);
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if (copy_from_user(dst, buf, count))
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err = -EFAULT;
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if (!err)
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*ppos += count;
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return (err) ? err : count;
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}
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EXPORT_SYMBOL_GPL(fb_sys_write);
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MODULE_AUTHOR("Antonino Daplas <adaplas@pol.net>");
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MODULE_DESCRIPTION("Generic file read (fb in system RAM)");
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MODULE_LICENSE("GPL");
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