diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.14/950-0057-Speed-up-console-framebuffer-imageblit-function.patch')
-rw-r--r-- | target/linux/brcm2708/patches-4.14/950-0057-Speed-up-console-framebuffer-imageblit-function.patch | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.14/950-0057-Speed-up-console-framebuffer-imageblit-function.patch b/target/linux/brcm2708/patches-4.14/950-0057-Speed-up-console-framebuffer-imageblit-function.patch new file mode 100644 index 0000000000..a6d3234f26 --- /dev/null +++ b/target/linux/brcm2708/patches-4.14/950-0057-Speed-up-console-framebuffer-imageblit-function.patch @@ -0,0 +1,209 @@ +From 0b3eb7b8f3ac701b27253ce407041ed69784306e Mon Sep 17 00:00:00 2001 +From: Harm Hanemaaijer <fgenfb@yahoo.com> +Date: Thu, 20 Jun 2013 20:21:39 +0200 +Subject: [PATCH 057/454] Speed up console framebuffer imageblit function + +Especially on platforms with a slower CPU but a relatively high +framebuffer fill bandwidth, like current ARM devices, the existing +console monochrome imageblit function used to draw console text is +suboptimal for common pixel depths such as 16bpp and 32bpp. The existing +code is quite general and can deal with several pixel depths. By creating +special case functions for 16bpp and 32bpp, by far the most common pixel +formats used on modern systems, a significant speed-up is attained +which can be readily felt on ARM-based devices like the Raspberry Pi +and the Allwinner platform, but should help any platform using the +fb layer. + +The special case functions allow constant folding, eliminating a number +of instructions including divide operations, and allow the use of an +unrolled loop, eliminating instructions with a variable shift size, +reducing source memory access instructions, and eliminating excessive +branching. These unrolled loops also allow much better code optimization +by the C compiler. The code that selects which optimized variant is used +is also simplified, eliminating integer divide instructions. + +The speed-up, measured by timing 'cat file.txt' in the console, varies +between 40% and 70%, when testing on the Raspberry Pi and Allwinner +ARM-based platforms, depending on font size and the pixel depth, with +the greater benefit for 32bpp. + +Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com> +--- + drivers/video/fbdev/core/cfbimgblt.c | 152 ++++++++++++++++++++++++++- + 1 file changed, 147 insertions(+), 5 deletions(-) + +--- a/drivers/video/fbdev/core/cfbimgblt.c ++++ b/drivers/video/fbdev/core/cfbimgblt.c +@@ -28,6 +28,11 @@ + * + * Also need to add code to deal with cards endians that are different than + * the native cpu endians. I also need to deal with MSB position in the word. ++ * Modified by Harm Hanemaaijer (fgenfb@yahoo.com) 2013: ++ * - Provide optimized versions of fast_imageblit for 16 and 32bpp that are ++ * significantly faster than the previous implementation. ++ * - Simplify the fast/slow_imageblit selection code, avoiding integer ++ * divides. + */ + #include <linux/module.h> + #include <linux/string.h> +@@ -262,6 +267,133 @@ static inline void fast_imageblit(const + } + } + ++/* ++ * Optimized fast_imageblit for bpp == 16. ppw = 2, bit_mask = 3 folded ++ * into the code, main loop unrolled. ++ */ ++ ++static inline void fast_imageblit16(const struct fb_image *image, ++ struct fb_info *p, u8 __iomem * dst1, ++ u32 fgcolor, u32 bgcolor) ++{ ++ u32 fgx = fgcolor, bgx = bgcolor; ++ u32 spitch = (image->width + 7) / 8; ++ u32 end_mask, eorx; ++ const char *s = image->data, *src; ++ u32 __iomem *dst; ++ const u32 *tab = NULL; ++ int i, j, k; ++ ++ tab = fb_be_math(p) ? cfb_tab16_be : cfb_tab16_le; ++ ++ fgx <<= 16; ++ bgx <<= 16; ++ fgx |= fgcolor; ++ bgx |= bgcolor; ++ ++ eorx = fgx ^ bgx; ++ k = image->width / 2; ++ ++ for (i = image->height; i--;) { ++ dst = (u32 __iomem *) dst1; ++ src = s; ++ ++ j = k; ++ while (j >= 4) { ++ u8 bits = *src; ++ end_mask = tab[(bits >> 6) & 3]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 4) & 3]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 2) & 3]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[bits & 3]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ src++; ++ j -= 4; ++ } ++ if (j != 0) { ++ u8 bits = *src; ++ end_mask = tab[(bits >> 6) & 3]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ if (j >= 2) { ++ end_mask = tab[(bits >> 4) & 3]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ if (j == 3) { ++ end_mask = tab[(bits >> 2) & 3]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst); ++ } ++ } ++ } ++ dst1 += p->fix.line_length; ++ s += spitch; ++ } ++} ++ ++/* ++ * Optimized fast_imageblit for bpp == 32. ppw = 1, bit_mask = 1 folded ++ * into the code, main loop unrolled. ++ */ ++ ++static inline void fast_imageblit32(const struct fb_image *image, ++ struct fb_info *p, u8 __iomem * dst1, ++ u32 fgcolor, u32 bgcolor) ++{ ++ u32 fgx = fgcolor, bgx = bgcolor; ++ u32 spitch = (image->width + 7) / 8; ++ u32 end_mask, eorx; ++ const char *s = image->data, *src; ++ u32 __iomem *dst; ++ const u32 *tab = NULL; ++ int i, j, k; ++ ++ tab = cfb_tab32; ++ ++ eorx = fgx ^ bgx; ++ k = image->width; ++ ++ for (i = image->height; i--;) { ++ dst = (u32 __iomem *) dst1; ++ src = s; ++ ++ j = k; ++ while (j >= 8) { ++ u8 bits = *src; ++ end_mask = tab[(bits >> 7) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 6) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 5) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 4) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 3) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 2) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[(bits >> 1) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ end_mask = tab[bits & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ src++; ++ j -= 8; ++ } ++ if (j != 0) { ++ u32 bits = (u32) * src; ++ while (j > 1) { ++ end_mask = tab[(bits >> 7) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst++); ++ bits <<= 1; ++ j--; ++ } ++ end_mask = tab[(bits >> 7) & 1]; ++ FB_WRITEL((end_mask & eorx) ^ bgx, dst); ++ } ++ dst1 += p->fix.line_length; ++ s += spitch; ++ } ++} ++ + void cfb_imageblit(struct fb_info *p, const struct fb_image *image) + { + u32 fgcolor, bgcolor, start_index, bitstart, pitch_index = 0; +@@ -294,11 +426,21 @@ void cfb_imageblit(struct fb_info *p, co + bgcolor = image->bg_color; + } + +- if (32 % bpp == 0 && !start_index && !pitch_index && +- ((width & (32/bpp-1)) == 0) && +- bpp >= 8 && bpp <= 32) +- fast_imageblit(image, p, dst1, fgcolor, bgcolor); +- else ++ if (!start_index && !pitch_index) { ++ if (bpp == 32) ++ fast_imageblit32(image, p, dst1, fgcolor, ++ bgcolor); ++ else if (bpp == 16 && (width & 1) == 0) ++ fast_imageblit16(image, p, dst1, fgcolor, ++ bgcolor); ++ else if (bpp == 8 && (width & 3) == 0) ++ fast_imageblit(image, p, dst1, fgcolor, ++ bgcolor); ++ else ++ slow_imageblit(image, p, dst1, fgcolor, ++ bgcolor, ++ start_index, pitch_index); ++ } else + slow_imageblit(image, p, dst1, fgcolor, bgcolor, + start_index, pitch_index); + } else |