shadowacpi.c

  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
 25static int
 26acpi_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 */
 63static u32
 64acpi_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 */
 84static u32
 85acpi_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
104static void *
105acpi_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
125const struct nvbios_source
126nvbios_acpi_fast = {
127	.name = "ACPI",
128	.init = acpi_init,
129	.read = acpi_read_fast,
130	.rw = false,
131	.require_checksum = true,
132};
133
134const struct nvbios_source
135nvbios_acpi_slow = {
136	.name = "ACPI",
137	.init = acpi_init,
138	.read = acpi_read_slow,
139	.rw = false,
140};