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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e3263ab3 | 2 | /* |
8633ef82 | 3 | * Generic System Framebuffers |
e3263ab3 | 4 | * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com> |
e3263ab3 DH |
5 | */ |
6 | ||
7 | /* | |
8 | * simple-framebuffer probing | |
9 | * Try to convert "screen_info" into a "simple-framebuffer" compatible mode. | |
10 | * If the mode is incompatible, we return "false" and let the caller create | |
11 | * legacy nodes instead. | |
12 | */ | |
13 | ||
14 | #include <linux/err.h> | |
15 | #include <linux/init.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/platform_data/simplefb.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/screen_info.h> | |
d391c582 | 21 | #include <linux/sysfb.h> |
e3263ab3 DH |
22 | |
23 | static const char simplefb_resname[] = "BOOTFB"; | |
24 | static const struct simplefb_format formats[] = SIMPLEFB_FORMATS; | |
25 | ||
8633ef82 JMC |
26 | /* try parsing screen_info into a simple-framebuffer mode struct */ |
27 | __init bool sysfb_parse_mode(const struct screen_info *si, | |
28 | struct simplefb_platform_data *mode) | |
e3263ab3 | 29 | { |
e3263ab3 | 30 | __u8 type; |
f35cd3fa | 31 | u32 bits_per_pixel; |
e3263ab3 DH |
32 | unsigned int i; |
33 | ||
34 | type = si->orig_video_isVGA; | |
35 | if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI) | |
36 | return false; | |
37 | ||
f35cd3fa TZ |
38 | /* |
39 | * The meaning of depth and bpp for direct-color formats is | |
40 | * inconsistent: | |
41 | * | |
42 | * - DRM format info specifies depth as the number of color | |
43 | * bits; including alpha, but not including filler bits. | |
44 | * - Linux' EFI platform code computes lfb_depth from the | |
45 | * individual color channels, including the reserved bits. | |
46 | * - VBE 1.1 defines lfb_depth for XRGB1555 as 16, but later | |
47 | * versions use 15. | |
48 | * - On the kernel command line, 'bpp' of 32 is usually | |
49 | * XRGB8888 including the filler bits, but 15 is XRGB1555 | |
50 | * not including the filler bit. | |
51 | * | |
52 | * It's not easily possible to fix this in struct screen_info, | |
53 | * as this could break UAPI. The best solution is to compute | |
1b617bc9 PA |
54 | * bits_per_pixel from the color bits, reserved bits and |
55 | * reported lfb_depth, whichever is highest. In the loop below, | |
f35cd3fa TZ |
56 | * ignore simplefb formats with alpha bits, as EFI and VESA |
57 | * don't specify alpha channels. | |
58 | */ | |
59 | if (si->lfb_depth > 8) { | |
60 | bits_per_pixel = max(max3(si->red_size + si->red_pos, | |
61 | si->green_size + si->green_pos, | |
62 | si->blue_size + si->blue_pos), | |
63 | si->rsvd_size + si->rsvd_pos); | |
1b617bc9 | 64 | bits_per_pixel = max_t(u32, bits_per_pixel, si->lfb_depth); |
f35cd3fa TZ |
65 | } else { |
66 | bits_per_pixel = si->lfb_depth; | |
67 | } | |
68 | ||
e3263ab3 | 69 | for (i = 0; i < ARRAY_SIZE(formats); ++i) { |
f35cd3fa TZ |
70 | const struct simplefb_format *f = &formats[i]; |
71 | ||
72 | if (f->transp.length) | |
73 | continue; /* transparent formats are unsupported by VESA/EFI */ | |
74 | ||
75 | if (bits_per_pixel == f->bits_per_pixel && | |
e3263ab3 DH |
76 | si->red_size == f->red.length && |
77 | si->red_pos == f->red.offset && | |
78 | si->green_size == f->green.length && | |
79 | si->green_pos == f->green.offset && | |
80 | si->blue_size == f->blue.length && | |
f35cd3fa | 81 | si->blue_pos == f->blue.offset) { |
e3263ab3 DH |
82 | mode->format = f->name; |
83 | mode->width = si->lfb_width; | |
84 | mode->height = si->lfb_height; | |
85 | mode->stride = si->lfb_linelength; | |
86 | return true; | |
87 | } | |
88 | } | |
89 | ||
90 | return false; | |
91 | } | |
92 | ||
0949ee75 | 93 | __init struct platform_device *sysfb_create_simplefb(const struct screen_info *si, |
9eac534d TZ |
94 | const struct simplefb_platform_data *mode, |
95 | struct device *parent) | |
e3263ab3 DH |
96 | { |
97 | struct platform_device *pd; | |
98 | struct resource res; | |
f96acec8 DH |
99 | u64 base, size; |
100 | u32 length; | |
8633ef82 | 101 | int ret; |
9164b4ce DH |
102 | |
103 | /* | |
104 | * If the 64BIT_BASE capability is set, ext_lfb_base will contain the | |
105 | * upper half of the base address. Assemble the address, then make sure | |
106 | * it is valid and we can actually access it. | |
107 | */ | |
108 | base = si->lfb_base; | |
109 | if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE) | |
110 | base |= (u64)si->ext_lfb_base << 32; | |
111 | if (!base || (u64)(resource_size_t)base != base) { | |
112 | printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n"); | |
0949ee75 | 113 | return ERR_PTR(-EINVAL); |
9164b4ce | 114 | } |
e3263ab3 | 115 | |
f96acec8 DH |
116 | /* |
117 | * Don't use lfb_size as IORESOURCE size, since it may contain the | |
118 | * entire VMEM, and thus require huge mappings. Use just the part we | |
119 | * need, that is, the part where the framebuffer is located. But verify | |
120 | * that it does not exceed the advertised VMEM. | |
121 | * Note that in case of VBE, the lfb_size is shifted by 16 bits for | |
122 | * historical reasons. | |
123 | */ | |
124 | size = si->lfb_size; | |
125 | if (si->orig_video_isVGA == VIDEO_TYPE_VLFB) | |
126 | size <<= 16; | |
127 | length = mode->height * mode->stride; | |
f96acec8 | 128 | if (length > size) { |
e3263ab3 | 129 | printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n"); |
0949ee75 | 130 | return ERR_PTR(-EINVAL); |
e3263ab3 | 131 | } |
dacc9092 | 132 | length = PAGE_ALIGN(length); |
e3263ab3 DH |
133 | |
134 | /* setup IORESOURCE_MEM as framebuffer memory */ | |
135 | memset(&res, 0, sizeof(res)); | |
c9689834 | 136 | res.flags = IORESOURCE_MEM; |
e3263ab3 | 137 | res.name = simplefb_resname; |
9164b4ce | 138 | res.start = base; |
f96acec8 | 139 | res.end = res.start + length - 1; |
e3263ab3 | 140 | if (res.end <= res.start) |
0949ee75 | 141 | return ERR_PTR(-EINVAL); |
e3263ab3 | 142 | |
8633ef82 JMC |
143 | pd = platform_device_alloc("simple-framebuffer", 0); |
144 | if (!pd) | |
0949ee75 | 145 | return ERR_PTR(-ENOMEM); |
8633ef82 | 146 | |
9eac534d TZ |
147 | pd->dev.parent = parent; |
148 | ||
3615c786 | 149 | sysfb_set_efifb_fwnode(pd); |
8633ef82 JMC |
150 | |
151 | ret = platform_device_add_resources(pd, &res, 1); | |
202c0891 JH |
152 | if (ret) |
153 | goto err_put_device; | |
8633ef82 JMC |
154 | |
155 | ret = platform_device_add_data(pd, mode, sizeof(*mode)); | |
202c0891 JH |
156 | if (ret) |
157 | goto err_put_device; | |
158 | ||
159 | ret = platform_device_add(pd); | |
160 | if (ret) | |
161 | goto err_put_device; | |
162 | ||
0949ee75 | 163 | return pd; |
202c0891 JH |
164 | |
165 | err_put_device: | |
166 | platform_device_put(pd); | |
8633ef82 | 167 | |
0949ee75 | 168 | return ERR_PTR(ret); |
e3263ab3 | 169 | } |