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path: root/drivers/video/fb_sys_fops.c
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Diffstat (limited to 'drivers/video/fb_sys_fops.c')
-rw-r--r--drivers/video/fb_sys_fops.c104
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 000000000000..cf2538d669cd
--- /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");