xref: /linux/drivers/firmware/google/coreboot_table.h (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * coreboot_table.h
4  *
5  * Internal header for coreboot table access.
6  *
7  * Copyright 2014 Gerd Hoffmann <kraxel@redhat.com>
8  * Copyright 2017 Google Inc.
9  * Copyright 2017 Samuel Holland <samuel@sholland.org>
10  */
11 
12 #ifndef __COREBOOT_TABLE_H
13 #define __COREBOOT_TABLE_H
14 
15 #include <linux/device.h>
16 #include <linux/mod_devicetable.h>
17 
18 /* Coreboot table header structure */
19 struct coreboot_table_header {
20 	char signature[4];
21 	u32 header_bytes;
22 	u32 header_checksum;
23 	u32 table_bytes;
24 	u32 table_checksum;
25 	u32 table_entries;
26 };
27 
28 /* List of coreboot entry structures that is used */
29 /* Generic */
30 struct coreboot_table_entry {
31 	u32 tag;
32 	u32 size;
33 };
34 
35 /* Points to a CBMEM entry */
36 struct lb_cbmem_ref {
37 	u32 tag;
38 	u32 size;
39 
40 	u64 cbmem_addr;
41 };
42 
43 #define LB_TAG_CBMEM_ENTRY 0x31
44 
45 /* Corresponds to LB_TAG_CBMEM_ENTRY */
46 struct lb_cbmem_entry {
47 	u32 tag;
48 	u32 size;
49 
50 	u64 address;
51 	u32 entry_size;
52 	u32 id;
53 };
54 
55 /* Describes framebuffer setup by coreboot */
56 struct lb_framebuffer {
57 	u32 tag;
58 	u32 size;
59 
60 	u64 physical_address;
61 	u32 x_resolution;
62 	u32 y_resolution;
63 	u32 bytes_per_line;
64 	u8  bits_per_pixel;
65 	u8  red_mask_pos;
66 	u8  red_mask_size;
67 	u8  green_mask_pos;
68 	u8  green_mask_size;
69 	u8  blue_mask_pos;
70 	u8  blue_mask_size;
71 	u8  reserved_mask_pos;
72 	u8  reserved_mask_size;
73 };
74 
75 /* A device, additionally with information from coreboot. */
76 struct coreboot_device {
77 	struct device dev;
78 	union {
79 		struct coreboot_table_entry entry;
80 		struct lb_cbmem_ref cbmem_ref;
81 		struct lb_cbmem_entry cbmem_entry;
82 		struct lb_framebuffer framebuffer;
83 		DECLARE_FLEX_ARRAY(u8, raw);
84 	};
85 };
86 
87 static inline struct coreboot_device *dev_to_coreboot_device(struct device *dev)
88 {
89 	return container_of(dev, struct coreboot_device, dev);
90 }
91 
92 /* A driver for handling devices described in coreboot tables. */
93 struct coreboot_driver {
94 	int (*probe)(struct coreboot_device *);
95 	void (*remove)(struct coreboot_device *);
96 	struct device_driver drv;
97 	const struct coreboot_device_id *id_table;
98 };
99 
100 /* use a macro to avoid include chaining to get THIS_MODULE */
101 #define coreboot_driver_register(driver) \
102 	__coreboot_driver_register(driver, THIS_MODULE)
103 /* Register a driver that uses the data from a coreboot table. */
104 int __coreboot_driver_register(struct coreboot_driver *driver,
105 			       struct module *owner);
106 
107 /* Unregister a driver that uses the data from a coreboot table. */
108 void coreboot_driver_unregister(struct coreboot_driver *driver);
109 
110 /* module_coreboot_driver() - Helper macro for drivers that don't do
111  * anything special in module init/exit.  This eliminates a lot of
112  * boilerplate.  Each module may only use this macro once, and
113  * calling it replaces module_init() and module_exit()
114  */
115 #define module_coreboot_driver(__coreboot_driver) \
116 	module_driver(__coreboot_driver, coreboot_driver_register, \
117 			coreboot_driver_unregister)
118 
119 #endif /* __COREBOOT_TABLE_H */
120