drm/tinydrm: Generalize tinydrm_xrgb8888_to_gray8()

This adds parameters for vaddr and clip to tinydrm_xrgb8888_to_gray8() to
make it more generic.

dma_buf_{begin,end}_cpu_access() are moved out to the repaper driver.

Return type is change to void to simplify error handling by callers.
Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1502127581-10517-2-git-send-email-david@lechnology.com

drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c

@@ -185,7 +185,9 @@ EXPORT_SYMBOL(tinydrm_xrgb8888_to_rgb565);
 /**
  * tinydrm_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
  * @dst: 8-bit grayscale destination buffer
+ * @vaddr: XRGB8888 source buffer
  * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
  *
  * Drm doesn't have native monochrome or grayscale support.
  * Such drivers can announce the commonly supported XR24 format to userspace
@@ -195,41 +197,31 @@ EXPORT_SYMBOL(tinydrm_xrgb8888_to_rgb565);
  * where 1 means foreground color and 0 background color.
  *
  * ITU BT.601 is used for the RGB -> luma (brightness) conversion.
- *
- * Returns:
- * Zero on success, negative error code on failure.
  */
-int tinydrm_xrgb8888_to_gray8(u8 *dst, struct drm_framebuffer *fb)
+void tinydrm_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb,
+			       struct drm_clip_rect *clip)
 {
-	struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
-	struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
-	unsigned int x, y, pitch = fb->pitches[0];
-	int ret = 0;
+	unsigned int len = (clip->x2 - clip->x1) * sizeof(u32);
+	unsigned int x, y;
 	void *buf;
 	u32 *src;
 
 	if (WARN_ON(fb->format->format != DRM_FORMAT_XRGB8888))
-		return -EINVAL;
+		return;
 	/*
 	 * The cma memory is write-combined so reads are uncached.
 	 * Speed up by fetching one line at a time.
 	 */
-	buf = kmalloc(pitch, GFP_KERNEL);
+	buf = kmalloc(len, GFP_KERNEL);
 	if (!buf)
-		return -ENOMEM;
-
-	if (import_attach) {
-		ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
-					       DMA_FROM_DEVICE);
-		if (ret)
-			goto err_free;
-	}
+		return;
 
-	for (y = 0; y < fb->height; y++) {
-		src = cma_obj->vaddr + (y * pitch);
-		memcpy(buf, src, pitch);
+	for (y = clip->y1; y < clip->y2; y++) {
+		src = vaddr + (y * fb->pitches[0]);
+		src += clip->x1;
+		memcpy(buf, src, len);
 		src = buf;
-		for (x = 0; x < fb->width; x++) {
+		for (x = clip->x1; x < clip->x2; x++) {
 			u8 r = (*src & 0x00ff0000) >> 16;
 			u8 g = (*src & 0x0000ff00) >> 8;
 			u8 b =  *src & 0x000000ff;
@@ -240,13 +232,7 @@ int tinydrm_xrgb8888_to_gray8(u8 *dst, struct drm_framebuffer *fb)
 		}
 	}
 
-	if (import_attach)
-		ret = dma_buf_end_cpu_access(import_attach->dmabuf,
-					     DMA_FROM_DEVICE);
-err_free:
 	kfree(buf);
-
-	return ret;
 }
 EXPORT_SYMBOL(tinydrm_xrgb8888_to_gray8);
 

drivers/gpu/drm/tinydrm/repaper.c

@@ -18,6 +18,7 @@
  */
 
 #include <linux/delay.h>
+#include <linux/dma-buf.h>
 #include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
@@ -525,11 +526,20 @@ static int repaper_fb_dirty(struct drm_framebuffer *fb,
 			    struct drm_clip_rect *clips,
 			    unsigned int num_clips)
 {
+	struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
+	struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
 	struct tinydrm_device *tdev = fb->dev->dev_private;
 	struct repaper_epd *epd = epd_from_tinydrm(tdev);
+	struct drm_clip_rect clip;
 	u8 *buf = NULL;
 	int ret = 0;
 
+	/* repaper can't do partial updates */
+	clip.x1 = 0;
+	clip.x2 = fb->width;
+	clip.y1 = 0;
+	clip.y2 = fb->height;
+
 	mutex_lock(&tdev->dirty_lock);
 
 	if (!epd->enabled)
@@ -550,9 +560,21 @@ static int repaper_fb_dirty(struct drm_framebuffer *fb,
 		goto out_unlock;
 	}
 
-	ret = tinydrm_xrgb8888_to_gray8(buf, fb);
-	if (ret)
-		goto out_unlock;
+	if (import_attach) {
+		ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
+					       DMA_FROM_DEVICE);
+		if (ret)
+			goto out_unlock;
+	}
+
+	tinydrm_xrgb8888_to_gray8(buf, cma_obj->vaddr, fb, &clip);
+
+	if (import_attach) {
+		ret = dma_buf_end_cpu_access(import_attach->dmabuf,
+					     DMA_FROM_DEVICE);
+		if (ret)
+			goto out_unlock;
+	}
 
 	repaper_gray8_to_mono_reversed(buf, fb->width, fb->height);
 

include/drm/tinydrm/tinydrm-helpers.h

@@ -43,7 +43,8 @@ void tinydrm_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
 void tinydrm_xrgb8888_to_rgb565(u16 *dst, void *vaddr,
 				struct drm_framebuffer *fb,
 				struct drm_clip_rect *clip, bool swap);
-int tinydrm_xrgb8888_to_gray8(u8 *dst, struct drm_framebuffer *fb);
+void tinydrm_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb,
+			       struct drm_clip_rect *clip);
 
 struct backlight_device *tinydrm_of_find_backlight(struct device *dev);
 int tinydrm_enable_backlight(struct backlight_device *backlight);