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  
dev_to_coreboot_device(struct device * dev)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