1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * framebuffer-coreboot.c
4 *
5 * Memory based framebuffer accessed through coreboot table.
6 *
7 * Copyright 2012-2013 David Herrmann <dh.herrmann@gmail.com>
8 * Copyright 2017 Google Inc.
9 * Copyright 2017 Samuel Holland <samuel@sholland.org>
10 */
11
12 #include <linux/device.h>
13 #include <linux/kernel.h>
14 #include <linux/mm.h>
15 #include <linux/module.h>
16 #include <linux/platform_data/simplefb.h>
17 #include <linux/platform_device.h>
18
19 #include "coreboot_table.h"
20
21 #define CB_TAG_FRAMEBUFFER 0x12
22
23 static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
24
framebuffer_probe(struct coreboot_device * dev)25 static int framebuffer_probe(struct coreboot_device *dev)
26 {
27 int i;
28 u32 length;
29 struct lb_framebuffer *fb = &dev->framebuffer;
30 struct platform_device *pdev;
31 struct resource res;
32 struct simplefb_platform_data pdata = {
33 .width = fb->x_resolution,
34 .height = fb->y_resolution,
35 .stride = fb->bytes_per_line,
36 .format = NULL,
37 };
38
39 for (i = 0; i < ARRAY_SIZE(formats); ++i) {
40 if (fb->bits_per_pixel == formats[i].bits_per_pixel &&
41 fb->red_mask_pos == formats[i].red.offset &&
42 fb->red_mask_size == formats[i].red.length &&
43 fb->green_mask_pos == formats[i].green.offset &&
44 fb->green_mask_size == formats[i].green.length &&
45 fb->blue_mask_pos == formats[i].blue.offset &&
46 fb->blue_mask_size == formats[i].blue.length &&
47 fb->reserved_mask_pos == formats[i].transp.offset &&
48 fb->reserved_mask_size == formats[i].transp.length)
49 pdata.format = formats[i].name;
50 }
51 if (!pdata.format)
52 return -ENODEV;
53
54 memset(&res, 0, sizeof(res));
55 res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
56 res.name = "Coreboot Framebuffer";
57 res.start = fb->physical_address;
58 length = PAGE_ALIGN(fb->y_resolution * fb->bytes_per_line);
59 res.end = res.start + length - 1;
60 if (res.end <= res.start)
61 return -EINVAL;
62
63 pdev = platform_device_register_resndata(&dev->dev,
64 "simple-framebuffer", 0,
65 &res, 1, &pdata,
66 sizeof(pdata));
67 if (IS_ERR(pdev))
68 pr_warn("coreboot: could not register framebuffer\n");
69 else
70 dev_set_drvdata(&dev->dev, pdev);
71
72 return PTR_ERR_OR_ZERO(pdev);
73 }
74
framebuffer_remove(struct coreboot_device * dev)75 static int framebuffer_remove(struct coreboot_device *dev)
76 {
77 struct platform_device *pdev = dev_get_drvdata(&dev->dev);
78
79 platform_device_unregister(pdev);
80
81 return 0;
82 }
83
84 static struct coreboot_driver framebuffer_driver = {
85 .probe = framebuffer_probe,
86 .remove = framebuffer_remove,
87 .drv = {
88 .name = "framebuffer",
89 },
90 .tag = CB_TAG_FRAMEBUFFER,
91 };
92 module_coreboot_driver(framebuffer_driver);
93
94 MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
95 MODULE_LICENSE("GPL");
96