1 /*
2  * Copyright 2012 Red Hat Inc.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20  * OTHER DEALINGS IN THE SOFTWARE.
21  *
22  */
23 #include "priv.h"
24 
25 static int
26 acpi_read_bios(acpi_handle rom_handle, u8 *bios, u32 offset, u32 length)
27 {
28 #if defined(CONFIG_ACPI) && defined(CONFIG_X86)
29 	acpi_status status;
30 	union acpi_object rom_arg_elements[2], *obj;
31 	struct acpi_object_list rom_arg;
32 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL};
33 
34 	rom_arg.count = 2;
35 	rom_arg.pointer = &rom_arg_elements[0];
36 
37 	rom_arg_elements[0].type = ACPI_TYPE_INTEGER;
38 	rom_arg_elements[0].integer.value = offset;
39 
40 	rom_arg_elements[1].type = ACPI_TYPE_INTEGER;
41 	rom_arg_elements[1].integer.value = length;
42 
43 	status = acpi_evaluate_object(rom_handle, NULL, &rom_arg, &buffer);
44 	if (ACPI_FAILURE(status)) {
45 		pr_info("failed to evaluate ROM got %s\n",
46 			acpi_format_exception(status));
47 		return -ENODEV;
48 	}
49 	obj = (union acpi_object *)buffer.pointer;
50 	length = min(length, obj->buffer.length);
51 	memcpy(bios+offset, obj->buffer.pointer, length);
52 	kfree(buffer.pointer);
53 	return length;
54 #else
55 	return -EINVAL;
56 #endif
57 }
58 
59 /* This version of the shadow function disobeys the ACPI spec and tries
60  * to fetch in units of more than 4KiB at a time.  This is a LOT faster
61  * on some systems, such as Lenovo W530.
62  */
63 static u32
64 acpi_read_fast(void *data, u32 offset, u32 length, struct nvkm_bios *bios)
65 {
66 	u32 limit = (offset + length + 0xfff) & ~0xfff;
67 	u32 start = offset & ~0x00000fff;
68 	u32 fetch = limit - start;
69 
70 	if (nvbios_extend(bios, limit) >= 0) {
71 		int ret = acpi_read_bios(data, bios->data, start, fetch);
72 		if (ret == fetch)
73 			return fetch;
74 	}
75 
76 	return 0;
77 }
78 
79 /* Other systems, such as the one in fdo#55948, will report a success
80  * but only return 4KiB of data.  The common bios fetching logic will
81  * detect an invalid image, and fall back to this version of the read
82  * function.
83  */
84 static u32
85 acpi_read_slow(void *data, u32 offset, u32 length, struct nvkm_bios *bios)
86 {
87 	u32 limit = (offset + length + 0xfff) & ~0xfff;
88 	u32 start = offset & ~0xfff;
89 	u32 fetch = 0;
90 
91 	if (nvbios_extend(bios, limit) >= 0) {
92 		while (start + fetch < limit) {
93 			int ret = acpi_read_bios(data, bios->data,
94 						 start + fetch, 0x1000);
95 			if (ret != 0x1000)
96 				break;
97 			fetch += 0x1000;
98 		}
99 	}
100 
101 	return fetch;
102 }
103 
104 static void *
105 acpi_init(struct nvkm_bios *bios, const char *name)
106 {
107 #if defined(CONFIG_ACPI) && defined(CONFIG_X86)
108 	acpi_status status;
109 	acpi_handle dhandle, rom_handle;
110 
111 	dhandle = ACPI_HANDLE(bios->subdev.device->dev);
112 	if (!dhandle)
113 		return ERR_PTR(-ENODEV);
114 
115 	status = acpi_get_handle(dhandle, "_ROM", &rom_handle);
116 	if (ACPI_FAILURE(status))
117 		return ERR_PTR(-ENODEV);
118 
119 	return rom_handle;
120 #else
121 	return ERR_PTR(-ENODEV);
122 #endif
123 }
124 
125 const struct nvbios_source
126 nvbios_acpi_fast = {
127 	.name = "ACPI",
128 	.init = acpi_init,
129 	.read = acpi_read_fast,
130 	.rw = false,
131 	.require_checksum = true,
132 };
133 
134 const struct nvbios_source
135 nvbios_acpi_slow = {
136 	.name = "ACPI",
137 	.init = acpi_init,
138 	.read = acpi_read_slow,
139 	.rw = false,
140 };
141