diff options
Diffstat (limited to 'drivers/video/fbdev/core/fb_io_fops.c')
-rw-r--r-- | drivers/video/fbdev/core/fb_io_fops.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/drivers/video/fbdev/core/fb_io_fops.c b/drivers/video/fbdev/core/fb_io_fops.c new file mode 100644 index 000000000000..5985e5e1b040 --- /dev/null +++ b/drivers/video/fbdev/core/fb_io_fops.c @@ -0,0 +1,133 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/fb.h> +#include <linux/module.h> +#include <linux/uaccess.h> + +ssize_t fb_io_read(struct fb_info *info, char __user *buf, size_t count, loff_t *ppos) +{ + unsigned long p = *ppos; + u8 *buffer, *dst; + u8 __iomem *src; + int c, cnt = 0, err = 0; + unsigned long total_size, trailing; + + if (!info->screen_base) + 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; + + buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, + GFP_KERNEL); + if (!buffer) + return -ENOMEM; + + src = (u8 __iomem *) (info->screen_base + p); + + if (info->fbops->fb_sync) + info->fbops->fb_sync(info); + + while (count) { + c = (count > PAGE_SIZE) ? PAGE_SIZE : count; + dst = buffer; + fb_memcpy_fromio(dst, src, c); + dst += c; + src += c; + + trailing = copy_to_user(buf, buffer, c); + if (trailing == c) { + err = -EFAULT; + break; + } + c -= trailing; + + *ppos += c; + buf += c; + cnt += c; + count -= c; + } + + kfree(buffer); + + return cnt ? cnt : err; +} +EXPORT_SYMBOL(fb_io_read); + +ssize_t fb_io_write(struct fb_info *info, const char __user *buf, size_t count, loff_t *ppos) +{ + unsigned long p = *ppos; + u8 *buffer, *src; + u8 __iomem *dst; + int c, cnt = 0, err = 0; + unsigned long total_size, trailing; + + if (!info->screen_base) + 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; + } + + buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, + GFP_KERNEL); + if (!buffer) + return -ENOMEM; + + dst = (u8 __iomem *) (info->screen_base + p); + + if (info->fbops->fb_sync) + info->fbops->fb_sync(info); + + while (count) { + c = (count > PAGE_SIZE) ? PAGE_SIZE : count; + src = buffer; + + trailing = copy_from_user(src, buf, c); + if (trailing == c) { + err = -EFAULT; + break; + } + c -= trailing; + + fb_memcpy_toio(dst, src, c); + dst += c; + src += c; + *ppos += c; + buf += c; + cnt += c; + count -= c; + } + + kfree(buffer); + + return (cnt) ? cnt : err; +} +EXPORT_SYMBOL(fb_io_write); |