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Subject[PATCH 1/4] drm: add generic convert_lines() function for format conversions.
Date
Introduce some infrastructure to handle format conversions:

* New struct drm_format_convert containing the cpp for src
and dst with a function pointer to actually convert a
single scanline.
* generic convert_lines() function which uses a struct
drm_format_convert pointer to convert a rectangle.

drm_fb_swab16() has been switched over to the new
convert_lines() function as showcase.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
drivers/gpu/drm/drm_format_helper.c | 84 +++++++++++++++++++++--------
1 file changed, 63 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 00d716f14173..f32e0173600c 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -16,6 +16,61 @@
#include <drm/drm_fourcc.h>
#include <drm/drm_rect.h>

+struct drm_format_convert {
+ u32 dst_cpp;
+ u32 src_cpp;
+ void (*func)(void *dst, void *src, u32 pixels);
+};
+
+static void convert_swab16_fn(void *dst, void *src, u32 pixels)
+{
+ u16 *sbuf = src;
+ u16 *dbuf = dst;
+ u32 x;
+
+ for (x = 0; x < pixels; x++)
+ dbuf[x] = swab16(sbuf[16]);
+}
+
+static struct drm_format_convert convert_swab16 = {
+ .dst_cpp = 2,
+ .src_cpp = 2,
+ .func = convert_swab16_fn,
+};
+
+static void convert_lines(void *dst, unsigned int dst_pitch,
+ void *src, unsigned int src_pitch,
+ unsigned int pixels,
+ unsigned int lines,
+ struct drm_format_convert *conv)
+{
+ u32 src_linelength = pixels * conv->src_cpp;
+ u32 y;
+ void *sbuf;
+
+ /*
+ * The cma memory is write-combined so reads are uncached.
+ * Speed up by fetching one line at a time.
+ */
+ sbuf = kmalloc(src_linelength, GFP_KERNEL);
+ if (!sbuf)
+ return;
+
+ for (y = 0; y < lines; y++) {
+ memcpy(sbuf, src, src_linelength);
+ conv->func(dst, sbuf, pixels);
+ src += src_pitch;
+ dst += dst_pitch;
+ }
+
+ kfree(sbuf);
+}
+
+static u32 clip_offset(struct drm_rect *clip, u32 pitch, u32 cpp)
+{
+ return (clip->y1 * pitch) + (clip->x1 * cpp);
+}
+
static void drm_fb_memcpy_lines(void *dst, unsigned int dst_pitch,
void *src, unsigned int src_pitch,
unsigned int linelength, unsigned int lines)
@@ -85,28 +140,15 @@ EXPORT_SYMBOL(drm_fb_memcpy_dstclip);
void drm_fb_swab16(u16 *dst, void *vaddr, struct drm_framebuffer *fb,
struct drm_rect *clip)
{
- size_t len = (clip->x2 - clip->x1) * sizeof(u16);
- unsigned int x, y;
- u16 *src, *buf;
+ struct drm_format_convert *conv = &convert_swab16;
+ unsigned int src_offset =
+ clip_offset(clip, fb->pitches[0], conv->src_cpp);
+ size_t pixels = (clip->x2 - clip->x1);
+ size_t lines = (clip->y2 - clip->y1);

- /*
- * The cma memory is write-combined so reads are uncached.
- * Speed up by fetching one line at a time.
- */
- buf = kmalloc(len, GFP_KERNEL);
- if (!buf)
- return;
-
- 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 = clip->x1; x < clip->x2; x++)
- *dst++ = swab16(*src++);
- }
-
- kfree(buf);
+ convert_lines(dst, pixels * conv->dst_cpp,
+ vaddr + src_offset, fb->pitches[0],
+ pixels, lines, conv);
}
EXPORT_SYMBOL(drm_fb_swab16);

--
2.18.1
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