fbdev: make the best-fit section of fb_find_mode return the closest matching mode
[deliverable/linux.git] / drivers / video / fb_draw.h
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1#ifndef _FB_DRAW_H
2#define _FB_DRAW_H
3
4#include <asm/types.h>
779121e9 5#include <linux/fb.h>
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6
7 /*
8 * Compose two values, using a bitmask as decision value
9 * This is equivalent to (a & mask) | (b & ~mask)
10 */
11
12static inline unsigned long
13comp(unsigned long a, unsigned long b, unsigned long mask)
14{
15 return ((a ^ b) & mask) ^ b;
16}
17
18 /*
19 * Create a pattern with the given pixel's color
20 */
21
22#if BITS_PER_LONG == 64
23static inline unsigned long
24pixel_to_pat( u32 bpp, u32 pixel)
25{
26 switch (bpp) {
27 case 1:
28 return 0xfffffffffffffffful*pixel;
29 case 2:
30 return 0x5555555555555555ul*pixel;
31 case 4:
32 return 0x1111111111111111ul*pixel;
33 case 8:
34 return 0x0101010101010101ul*pixel;
35 case 12:
36 return 0x0001001001001001ul*pixel;
37 case 16:
38 return 0x0001000100010001ul*pixel;
39 case 24:
40 return 0x0000000001000001ul*pixel;
41 case 32:
42 return 0x0000000100000001ul*pixel;
43 default:
44 panic("pixel_to_pat(): unsupported pixelformat\n");
45 }
46}
47#else
48static inline unsigned long
49pixel_to_pat( u32 bpp, u32 pixel)
50{
51 switch (bpp) {
52 case 1:
53 return 0xfffffffful*pixel;
54 case 2:
55 return 0x55555555ul*pixel;
56 case 4:
57 return 0x11111111ul*pixel;
58 case 8:
59 return 0x01010101ul*pixel;
60 case 12:
61 return 0x00001001ul*pixel;
62 case 16:
63 return 0x00010001ul*pixel;
64 case 24:
65 return 0x00000001ul*pixel;
66 case 32:
67 return 0x00000001ul*pixel;
68 default:
69 panic("pixel_to_pat(): unsupported pixelformat\n");
70 }
71}
72#endif
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73
74#ifdef CONFIG_FB_CFB_REV_PIXELS_IN_BYTE
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75#if BITS_PER_LONG == 64
76#define REV_PIXELS_MASK1 0x5555555555555555ul
77#define REV_PIXELS_MASK2 0x3333333333333333ul
78#define REV_PIXELS_MASK4 0x0f0f0f0f0f0f0f0ful
79#else
80#define REV_PIXELS_MASK1 0x55555555ul
81#define REV_PIXELS_MASK2 0x33333333ul
82#define REV_PIXELS_MASK4 0x0f0f0f0ful
83#endif
84
85static inline unsigned long fb_rev_pixels_in_long(unsigned long val,
86 u32 bswapmask)
87{
88 if (bswapmask & 1)
89 val = comp(val >> 1, val << 1, REV_PIXELS_MASK1);
90 if (bswapmask & 2)
91 val = comp(val >> 2, val << 2, REV_PIXELS_MASK2);
92 if (bswapmask & 3)
93 val = comp(val >> 4, val << 4, REV_PIXELS_MASK4);
55850f47 94 return val;
15afdd43 95}
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96
97static inline u32 fb_shifted_pixels_mask_u32(u32 index, u32 bswapmask)
98{
99 u32 mask;
100
101 if (!bswapmask) {
102 mask = FB_SHIFT_HIGH(~(u32)0, index);
103 } else {
104 mask = 0xff << FB_LEFT_POS(8);
105 mask = FB_SHIFT_LOW(mask, index & (bswapmask)) & mask;
106 mask = FB_SHIFT_HIGH(mask, index & ~(bswapmask));
107#if defined(__i386__) || defined(__x86_64__)
108 /* Shift argument is limited to 0 - 31 on x86 based CPU's */
109 if(index + bswapmask < 32)
110#endif
111 mask |= FB_SHIFT_HIGH(~(u32)0,
112 (index + bswapmask) & ~(bswapmask));
113 }
114 return mask;
115}
116
117static inline unsigned long fb_shifted_pixels_mask_long(u32 index, u32 bswapmask)
118{
119 unsigned long mask;
120
121 if (!bswapmask) {
122 mask = FB_SHIFT_HIGH(~0UL, index);
123 } else {
124 mask = 0xff << FB_LEFT_POS(8);
125 mask = FB_SHIFT_LOW(mask, index & (bswapmask)) & mask;
126 mask = FB_SHIFT_HIGH(mask, index & ~(bswapmask));
127#if defined(__i386__) || defined(__x86_64__)
128 /* Shift argument is limited to 0 - 31 on x86 based CPU's */
129 if(index + bswapmask < BITS_PER_LONG)
130#endif
131 mask |= FB_SHIFT_HIGH(~0UL,
132 (index + bswapmask) & ~(bswapmask));
133 }
134 return mask;
135}
136
137
138static inline u32 fb_compute_bswapmask(struct fb_info *info)
139{
140 u32 bswapmask = 0;
141 unsigned bpp = info->var.bits_per_pixel;
142
143 if ((bpp < 8) && (info->var.nonstd & FB_NONSTD_REV_PIX_IN_B)) {
144 /*
145 * Reversed order of pixel layout in bytes
146 * works only for 1, 2 and 4 bpp
147 */
148 bswapmask = 7 - bpp + 1;
149 }
150 return bswapmask;
151}
152
153#else /* CONFIG_FB_CFB_REV_PIXELS_IN_BYTE */
154
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155static inline unsigned long fb_rev_pixels_in_long(unsigned long val,
156 u32 bswapmask)
157{
158 return val;
159}
160
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161#define fb_shifted_pixels_mask_u32(i, b) FB_SHIFT_HIGH(~(u32)0, (i))
162#define fb_shifted_pixels_mask_long(i, b) FB_SHIFT_HIGH(~0UL, (i))
163#define fb_compute_bswapmask(...) 0
164
165#endif /* CONFIG_FB_CFB_REV_PIXELS_IN_BYTE */
166
dc0e6e05 167#endif /* FB_DRAW_H */
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