[PATCH 01/23] drm/format-helper: Add struct drm_pixmap

[Thomas Zimmermann]

Add struct drm_pixmap to wrap the source parameters for all drawing
operations. This consists of the format, the clipping rectangle, the
line pitch and source data buffers. Also add a helper that creates a
pixmap from a framebuffer.

Existing code uses struct drm_framebuffer for drawing. Converting the
drawing interfaces to struct drm_pixmap will allow for other types of
source buffers, such as plain memory buffers or font data from struct
font_desc.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
---
 drivers/gpu/drm/drm_format_helper.c | 49 +++++++++++++++++++++++++++++
 include/drm/drm_format_helper.h     | 36 ++++++++++++++++++---
 2 files changed, 81 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index b1be458ed4dda..0b69b16d5802a 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -132,6 +132,55 @@ unsigned int drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info
 }
 EXPORT_SYMBOL(drm_fb_clip_offset);
 
+static void drm_pixmap_init(struct drm_pixmap *pix, const struct drm_format_info *format,
+			    const struct iosys_map *data, const unsigned int *pitches,
+			    const struct drm_rect *clip)
+{
+	size_t i;
+
+	pix->format = format;
+
+	/*
+	 * TODO: Set the size and data pointers from the
+	 * clipping rectangle and remove their computation
+	 * from the xfrm helpers.
+	 */
+	memcpy(&pix->clip, clip, sizeof(pix->clip));
+
+	for (i = 0; i < format->num_planes; ++i)
+		pix->pitches[i] = pitches[i];
+	for (; i < ARRAY_SIZE(pix->pitches); ++i)
+		pix->pitches[i] = 0;
+
+	for (i = 0; i < format->num_planes; ++i)
+		pix->data[i] = data[i];
+	for (; i < ARRAY_SIZE(pix->data); ++i)
+		iosys_map_clear(&pix->data[i]);
+}
+
+/**
+ * drm_pixmap_init_from_framebuffer - Initializes a pixmap from a DRM framebuffer
+ * @pix: The pixmap to initialize
+ * @fb: DRM framebuffer
+ * @data: Array of source buffers
+ * @clip: Clip rectangle area to copy
+ *
+ * The parameter @data refers to an array with least as many entries as
+ * there are planes in @fb's format. Each entry stores the value for the
+ * format's respective color plane at the same index.
+ */
+void drm_pixmap_init_from_framebuffer(struct drm_pixmap *pix, const struct drm_framebuffer *fb,
+				      const struct iosys_map *data, const struct drm_rect *clip)
+{
+	const struct drm_rect full_clip = DRM_RECT_INIT(0, 0, fb->width, fb->height);
+
+	if (!clip)
+		clip = &full_clip;
+
+	drm_pixmap_init(pix, fb->format, data, fb->pitches, clip);
+}
+EXPORT_SYMBOL(drm_pixmap_init_from_framebuffer);
+
 /* TODO: Make this function work with multi-plane formats. */
 static int __drm_fb_xfrm(void *dst, unsigned long dst_pitch, unsigned long dst_pixsize,
 			 const void *vaddr, const struct drm_framebuffer *fb,
diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
index f13b34e0b752b..56a98999503e2 100644
--- a/include/drm/drm_format_helper.h
+++ b/include/drm/drm_format_helper.h
@@ -6,14 +6,14 @@
 #ifndef __LINUX_DRM_FORMAT_HELPER_H
 #define __LINUX_DRM_FORMAT_HELPER_H
 
+#include <linux/iosys-map.h>
 #include <linux/types.h>
 
+#include <drm/drm_fourcc.h>
+#include <drm/drm_rect.h>
+
 struct drm_device;
-struct drm_format_info;
 struct drm_framebuffer;
-struct drm_rect;
-
-struct iosys_map;
 
 /**
  * struct drm_format_conv_state - Stores format-conversion state
@@ -66,6 +66,34 @@ void *drm_format_conv_state_reserve(struct drm_format_conv_state *state,
 				    size_t new_size, gfp_t flags);
 void drm_format_conv_state_release(struct drm_format_conv_state *state);
 
+/**
+ * struct drm_pixmap - source pixmap for format-conversion helpers
+ *
+ * A pixmap represents the source data for drawing operations. All
+ * fields are considered private.
+ */
+struct drm_pixmap {
+	/**
+	 * @format: The pixmap's color format
+	 */
+	const struct drm_format_info *format;
+	/**
+	 * @clip: The cliping rectangle.
+	 */
+	struct drm_rect clip;
+	/**
+	 * @pitches: Per-plane offset between two consecutive rows of pixels in Bytes
+	 */
+	unsigned int pitches[DRM_FORMAT_MAX_PLANES];
+	/**
+	 * @data: Per-plane source buffer
+	 */
+	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
+};
+
+void drm_pixmap_init_from_framebuffer(struct drm_pixmap *pix, const struct drm_framebuffer *fb,
+				      const struct iosys_map *data, const struct drm_rect *clip);
+
 unsigned int drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info *format,
 				const struct drm_rect *clip);
 
-- 
2.43.0