brcm2708: update against latest rpi-3.10.y branch
[openwrt/svn-archive/archive.git] / target / linux / brcm2708 / patches-3.10 / 0068-Speed-up-console-framebuffer-imageblit-function.patch
1 From 42b4a831d77ee33f67142882b2b68e4138cbf13e Mon Sep 17 00:00:00 2001
2 From: Harm Hanemaaijer <fgenfb@yahoo.com>
3 Date: Thu, 20 Jun 2013 20:21:39 +0200
4 Subject: [PATCH 068/174] Speed up console framebuffer imageblit function
5
6 Especially on platforms with a slower CPU but a relatively high
7 framebuffer fill bandwidth, like current ARM devices, the existing
8 console monochrome imageblit function used to draw console text is
9 suboptimal for common pixel depths such as 16bpp and 32bpp. The existing
10 code is quite general and can deal with several pixel depths. By creating
11 special case functions for 16bpp and 32bpp, by far the most common pixel
12 formats used on modern systems, a significant speed-up is attained
13 which can be readily felt on ARM-based devices like the Raspberry Pi
14 and the Allwinner platform, but should help any platform using the
15 fb layer.
16
17 The special case functions allow constant folding, eliminating a number
18 of instructions including divide operations, and allow the use of an
19 unrolled loop, eliminating instructions with a variable shift size,
20 reducing source memory access instructions, and eliminating excessive
21 branching. These unrolled loops also allow much better code optimization
22 by the C compiler. The code that selects which optimized variant is used
23 is also simplified, eliminating integer divide instructions.
24
25 The speed-up, measured by timing 'cat file.txt' in the console, varies
26 between 40% and 70%, when testing on the Raspberry Pi and Allwinner
27 ARM-based platforms, depending on font size and the pixel depth, with
28 the greater benefit for 32bpp.
29
30 Signed-off-by: Harm Hanemaaijer <fgenfb@yahoo.com>
31 ---
32 drivers/video/cfbimgblt.c | 152 ++++++++++++++++++++++++++++++++++++++++++++--
33 1 file changed, 147 insertions(+), 5 deletions(-)
34
35 --- a/drivers/video/cfbimgblt.c
36 +++ b/drivers/video/cfbimgblt.c
37 @@ -28,6 +28,11 @@
38 *
39 * Also need to add code to deal with cards endians that are different than
40 * the native cpu endians. I also need to deal with MSB position in the word.
41 + * Modified by Harm Hanemaaijer (fgenfb@yahoo.com) 2013:
42 + * - Provide optimized versions of fast_imageblit for 16 and 32bpp that are
43 + * significantly faster than the previous implementation.
44 + * - Simplify the fast/slow_imageblit selection code, avoiding integer
45 + * divides.
46 */
47 #include <linux/module.h>
48 #include <linux/string.h>
49 @@ -262,6 +267,133 @@ static inline void fast_imageblit(const
50 }
51 }
52
53 +/*
54 + * Optimized fast_imageblit for bpp == 16. ppw = 2, bit_mask = 3 folded
55 + * into the code, main loop unrolled.
56 + */
57 +
58 +static inline void fast_imageblit16(const struct fb_image *image,
59 + struct fb_info *p, u8 __iomem * dst1,
60 + u32 fgcolor, u32 bgcolor)
61 +{
62 + u32 fgx = fgcolor, bgx = bgcolor;
63 + u32 spitch = (image->width + 7) / 8;
64 + u32 end_mask, eorx;
65 + const char *s = image->data, *src;
66 + u32 __iomem *dst;
67 + const u32 *tab = NULL;
68 + int i, j, k;
69 +
70 + tab = fb_be_math(p) ? cfb_tab16_be : cfb_tab16_le;
71 +
72 + fgx <<= 16;
73 + bgx <<= 16;
74 + fgx |= fgcolor;
75 + bgx |= bgcolor;
76 +
77 + eorx = fgx ^ bgx;
78 + k = image->width / 2;
79 +
80 + for (i = image->height; i--;) {
81 + dst = (u32 __iomem *) dst1;
82 + src = s;
83 +
84 + j = k;
85 + while (j >= 4) {
86 + u8 bits = *src;
87 + end_mask = tab[(bits >> 6) & 3];
88 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
89 + end_mask = tab[(bits >> 4) & 3];
90 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
91 + end_mask = tab[(bits >> 2) & 3];
92 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
93 + end_mask = tab[bits & 3];
94 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
95 + src++;
96 + j -= 4;
97 + }
98 + if (j != 0) {
99 + u8 bits = *src;
100 + end_mask = tab[(bits >> 6) & 3];
101 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
102 + if (j >= 2) {
103 + end_mask = tab[(bits >> 4) & 3];
104 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
105 + if (j == 3) {
106 + end_mask = tab[(bits >> 2) & 3];
107 + FB_WRITEL((end_mask & eorx) ^ bgx, dst);
108 + }
109 + }
110 + }
111 + dst1 += p->fix.line_length;
112 + s += spitch;
113 + }
114 +}
115 +
116 +/*
117 + * Optimized fast_imageblit for bpp == 32. ppw = 1, bit_mask = 1 folded
118 + * into the code, main loop unrolled.
119 + */
120 +
121 +static inline void fast_imageblit32(const struct fb_image *image,
122 + struct fb_info *p, u8 __iomem * dst1,
123 + u32 fgcolor, u32 bgcolor)
124 +{
125 + u32 fgx = fgcolor, bgx = bgcolor;
126 + u32 spitch = (image->width + 7) / 8;
127 + u32 end_mask, eorx;
128 + const char *s = image->data, *src;
129 + u32 __iomem *dst;
130 + const u32 *tab = NULL;
131 + int i, j, k;
132 +
133 + tab = cfb_tab32;
134 +
135 + eorx = fgx ^ bgx;
136 + k = image->width;
137 +
138 + for (i = image->height; i--;) {
139 + dst = (u32 __iomem *) dst1;
140 + src = s;
141 +
142 + j = k;
143 + while (j >= 8) {
144 + u8 bits = *src;
145 + end_mask = tab[(bits >> 7) & 1];
146 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
147 + end_mask = tab[(bits >> 6) & 1];
148 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
149 + end_mask = tab[(bits >> 5) & 1];
150 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
151 + end_mask = tab[(bits >> 4) & 1];
152 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
153 + end_mask = tab[(bits >> 3) & 1];
154 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
155 + end_mask = tab[(bits >> 2) & 1];
156 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
157 + end_mask = tab[(bits >> 1) & 1];
158 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
159 + end_mask = tab[bits & 1];
160 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
161 + src++;
162 + j -= 8;
163 + }
164 + if (j != 0) {
165 + u32 bits = (u32) * src;
166 + while (j > 1) {
167 + end_mask = tab[(bits >> 7) & 1];
168 + FB_WRITEL((end_mask & eorx) ^ bgx, dst++);
169 + bits <<= 1;
170 + j--;
171 + }
172 + end_mask = tab[(bits >> 7) & 1];
173 + FB_WRITEL((end_mask & eorx) ^ bgx, dst);
174 + }
175 + dst1 += p->fix.line_length;
176 + s += spitch;
177 + }
178 +}
179 +
180 void cfb_imageblit(struct fb_info *p, const struct fb_image *image)
181 {
182 u32 fgcolor, bgcolor, start_index, bitstart, pitch_index = 0;
183 @@ -294,11 +426,21 @@ void cfb_imageblit(struct fb_info *p, co
184 bgcolor = image->bg_color;
185 }
186
187 - if (32 % bpp == 0 && !start_index && !pitch_index &&
188 - ((width & (32/bpp-1)) == 0) &&
189 - bpp >= 8 && bpp <= 32)
190 - fast_imageblit(image, p, dst1, fgcolor, bgcolor);
191 - else
192 + if (!start_index && !pitch_index) {
193 + if (bpp == 32)
194 + fast_imageblit32(image, p, dst1, fgcolor,
195 + bgcolor);
196 + else if (bpp == 16 && (width & 1) == 0)
197 + fast_imageblit16(image, p, dst1, fgcolor,
198 + bgcolor);
199 + else if (bpp == 8 && (width & 3) == 0)
200 + fast_imageblit(image, p, dst1, fgcolor,
201 + bgcolor);
202 + else
203 + slow_imageblit(image, p, dst1, fgcolor,
204 + bgcolor,
205 + start_index, pitch_index);
206 + } else
207 slow_imageblit(image, p, dst1, fgcolor, bgcolor,
208 start_index, pitch_index);
209 } else