From 65931bbc5177f8192a48a0aa5bdb9b95b9f6e87f Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Fri, 28 Mar 2025 15:15:04 +0100 Subject: [PATCH 2854/5403] drm/format-helper: Optimize 32-to-8-bpp conversion For ease of implementation, existing line-conversion functions for 8-bit formats write each pixel individually. Optimize the performance by writing multiple pixels in a single 32-bit store. v2: - simplify address calculation (Jani) - fix typo in commit message (Jocelyn) Signed-off-by: Thomas Zimmermann Reviewed-by: Jocelyn Falempe Link: https://lore.kernel.org/r/20250328141709.217283-9-tzimmermann@suse.de --- drivers/gpu/drm/drm_format_helper.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index 5098a00803d2..fc7347caf600 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -253,10 +253,29 @@ static __always_inline void drm_fb_xfrm_line_32to8(void *dbuf, const void *sbuf, unsigned int pixels, u32 (*xfrm_pixel)(u32)) { - u8 *dbuf8 = dbuf; + __le32 *dbuf32 = dbuf; + u8 *dbuf8; const __le32 *sbuf32 = sbuf; const __le32 *send32 = sbuf32 + pixels; + /* write 4 pixels at once */ + while (sbuf32 < ALIGN_DOWN_PIXELS(send32, pixels, 4)) { + u32 pix[4] = { + le32_to_cpup(sbuf32++), + le32_to_cpup(sbuf32++), + le32_to_cpup(sbuf32++), + le32_to_cpup(sbuf32++), + }; + /* write output bytes in reverse order for little endianness */ + u32 val32 = xfrm_pixel(pix[0]) | + (xfrm_pixel(pix[1]) << 8) | + (xfrm_pixel(pix[2]) << 16) | + (xfrm_pixel(pix[3]) << 24); + *dbuf32++ = cpu_to_le32(val32); + } + + /* write trailing pixels */ + dbuf8 = (u8 __force *)dbuf32; while (sbuf32 < send32) *dbuf8++ = xfrm_pixel(le32_to_cpup(sbuf32++)); } -- 2.54.0