projects/linux·blob uaccess-cleanups · refs

140 lines · 3.7 KiB

1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic System Framebuffers
4 * Copyright (c) 2012-2013 David Herrmann <[email protected]>
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>
21#include <linux/sysfb.h>
22
23static const char simplefb_resname[] = "BOOTFB";
24static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
25
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)
29{
30 __u8 type;
31 u32 bits_per_pixel;
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
38 bits_per_pixel = __screen_info_lfb_bits_per_pixel(si);
39
40 for (i = 0; i < ARRAY_SIZE(formats); ++i) {
41 const struct simplefb_format *f = &formats[i];
42
43 if (f->transp.length)
44 continue; /* transparent formats are unsupported by VESA/EFI */
45
46 if (bits_per_pixel == f->bits_per_pixel &&
47 si->red_size == f->red.length &&
48 si->red_pos == f->red.offset &&
49 si->green_size == f->green.length &&
50 si->green_pos == f->green.offset &&
51 si->blue_size == f->blue.length &&
52 si->blue_pos == f->blue.offset) {
53 mode->format = f->name;
54 mode->width = si->lfb_width;
55 mode->height = si->lfb_height;
56 mode->stride = si->lfb_linelength;
57 return true;
58 }
59 }
60
61 return false;
62}
63
64__init struct platform_device *sysfb_create_simplefb(const struct screen_info *si,
65 const struct simplefb_platform_data *mode,
66 struct device *parent)
67{
68 struct platform_device *pd;
69 struct resource res;
70 u64 base, size;
71 u32 length;
72 int ret;
73
74 /*
75 * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
76 * upper half of the base address. Assemble the address, then make sure
77 * it is valid and we can actually access it.
78 */
79 base = si->lfb_base;
80 if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
81 base |= (u64)si->ext_lfb_base << 32;
82 if (!base || (u64)(resource_size_t)base != base) {
83 printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
84 return ERR_PTR(-EINVAL);
85 }
86
87 /*
88 * Don't use lfb_size as IORESOURCE size, since it may contain the
89 * entire VMEM, and thus require huge mappings. Use just the part we
90 * need, that is, the part where the framebuffer is located. But verify
91 * that it does not exceed the advertised VMEM.
92 * Note that in case of VBE, the lfb_size is shifted by 16 bits for
93 * historical reasons.
94 */
95 size = si->lfb_size;
96 if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
97 size <<= 16;
98 length = mode->height * mode->stride;
99 if (length > size) {
100 printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
101 return ERR_PTR(-EINVAL);
102 }
103 length = PAGE_ALIGN(length);
104
105 /* setup IORESOURCE_MEM as framebuffer memory */
106 memset(&res, 0, sizeof(res));
107 res.flags = IORESOURCE_MEM;
108 res.name = simplefb_resname;
109 res.start = base;
110 res.end = res.start + length - 1;
111 if (res.end <= res.start)
112 return ERR_PTR(-EINVAL);
113
114 pd = platform_device_alloc("simple-framebuffer", 0);
115 if (!pd)
116 return ERR_PTR(-ENOMEM);
117
118 pd->dev.parent = parent;
119
120 sysfb_set_efifb_fwnode(si, pd);
121
122 ret = platform_device_add_resources(pd, &res, 1);
123 if (ret)
124 goto err_put_device;
125
126 ret = platform_device_add_data(pd, mode, sizeof(*mode));
127 if (ret)
128 goto err_put_device;
129
130 ret = platform_device_add(pd);
131 if (ret)
132 goto err_put_device;
133
134 return pd;
135
136err_put_device:
137 platform_device_put(pd);
138
139 return ERR_PTR(ret);
140}