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staging: udlfb: fbdev character read and write support
Restore fbdev character read and write support Enables access to the framebuffer from simple reads and writes to /dev/fb0 (or fb1, ...). Low performance, because of extra copy and because udlfb must scan every pixel for changes. But very useful for testing and simple image display, etc. Signed-off-by: Bernie Thompson <bernie@plugable.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -602,6 +602,48 @@ int dlfb_handle_damage(struct dlfb_data *dev, int x, int y,
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return 0;
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}
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static ssize_t dlfb_ops_read(struct fb_info *info, char __user *buf,
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size_t count, loff_t *ppos)
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{
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ssize_t result = -ENOSYS;
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#if defined CONFIG_FB_SYS_FOPS || defined CONFIG_FB_SYS_FOPS_MODULE
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result = fb_sys_read(info, buf, count, ppos);
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#endif
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return result;
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}
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/*
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* Path triggered by usermode clients who write to filesystem
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* e.g. cat filename > /dev/fb1
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* Not used by X Windows or text-mode console. But useful for testing.
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* Slow because of extra copy and we must assume all pixels dirty.
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*/
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static ssize_t dlfb_ops_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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ssize_t result = -ENOSYS;
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struct dlfb_data *dev = info->par;
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u32 offset = (u32) *ppos;
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#if defined CONFIG_FB_SYS_FOPS || defined CONFIG_FB_SYS_FOPS_MODULE
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result = fb_sys_write(info, buf, count, ppos);
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if (result > 0) {
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int start = max((int)(offset / info->fix.line_length) - 1, 0);
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int lines = min((u32)((result / info->fix.line_length) + 1),
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(u32)info->var.yres);
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dlfb_handle_damage(dev, 0, start, info->var.xres,
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lines, info->screen_base);
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}
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#endif
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return result;
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}
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/* hardware has native COPY command (see libdlo), but not worth it for fbcon */
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static void dlfb_ops_copyarea(struct fb_info *info,
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const struct fb_copyarea *area)
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@ -924,6 +966,8 @@ static int dlfb_ops_blank(int blank_mode, struct fb_info *info)
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static struct fb_ops dlfb_ops = {
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.owner = THIS_MODULE,
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.fb_read = dlfb_ops_read,
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.fb_write = dlfb_ops_write,
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.fb_setcolreg = dlfb_ops_setcolreg,
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.fb_fillrect = dlfb_ops_fillrect,
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.fb_copyarea = dlfb_ops_copyarea,
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