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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
| 2 | +/* |
| 3 | + * Address translation interface via ACPI DSM. |
| 4 | + * Copyright (C) 2018 Intel Corporation |
| 5 | + * |
| 6 | + * Specification for this interface is available at: |
| 7 | + * |
| 8 | + * https://cdrdv2.intel.com/v1/dl/getContent/603354 |
| 9 | + */ |
| 10 | + |
| 11 | +#include <linux/acpi.h> |
| 12 | +#include <linux/adxl.h> |
| 13 | + |
| 14 | +#define ADXL_REVISION 0x1 |
| 15 | +#define ADXL_IDX_GET_ADDR_PARAMS 0x1 |
| 16 | +#define ADXL_IDX_FORWARD_TRANSLATE 0x2 |
| 17 | +#define ACPI_ADXL_PATH "\\_SB.ADXL" |
| 18 | + |
| 19 | +/* |
| 20 | + * The specification doesn't provide a limit on how many |
| 21 | + * components are in a memory address. But since we allocate |
| 22 | + * memory based on the number the BIOS tells us, we should |
| 23 | + * defend against insane values. |
| 24 | + */ |
| 25 | +#define ADXL_MAX_COMPONENTS 500 |
| 26 | + |
| 27 | +#undef pr_fmt |
| 28 | +#define pr_fmt(fmt) "ADXL: " fmt |
| 29 | + |
| 30 | +static acpi_handle handle; |
| 31 | +static union acpi_object *params; |
| 32 | +static const guid_t adxl_guid = |
| 33 | + GUID_INIT(0xAA3C050A, 0x7EA4, 0x4C1F, |
| 34 | + 0xAF, 0xDA, 0x12, 0x67, 0xDF, 0xD3, 0xD4, 0x8D); |
| 35 | + |
| 36 | +static int adxl_count; |
| 37 | +static char **adxl_component_names; |
| 38 | + |
| 39 | +static union acpi_object *adxl_dsm(int cmd, union acpi_object argv[]) |
| 40 | +{ |
| 41 | + union acpi_object *obj, *o; |
| 42 | + |
| 43 | + obj = acpi_evaluate_dsm_typed(handle, &adxl_guid, ADXL_REVISION, |
| 44 | + cmd, argv, ACPI_TYPE_PACKAGE); |
| 45 | + if (!obj) { |
| 46 | + pr_info("DSM call failed for cmd=%d\n", cmd); |
| 47 | + return NULL; |
| 48 | + } |
| 49 | + |
| 50 | + if (obj->package.count != 2) { |
| 51 | + pr_info("Bad pkg count %d\n", obj->package.count); |
| 52 | + goto err; |
| 53 | + } |
| 54 | + |
| 55 | + o = obj->package.elements; |
| 56 | + if (o->type != ACPI_TYPE_INTEGER) { |
| 57 | + pr_info("Bad 1st element type %d\n", o->type); |
| 58 | + goto err; |
| 59 | + } |
| 60 | + if (o->integer.value) { |
| 61 | + pr_info("Bad ret val %llu\n", o->integer.value); |
| 62 | + goto err; |
| 63 | + } |
| 64 | + |
| 65 | + o = obj->package.elements + 1; |
| 66 | + if (o->type != ACPI_TYPE_PACKAGE) { |
| 67 | + pr_info("Bad 2nd element type %d\n", o->type); |
| 68 | + goto err; |
| 69 | + } |
| 70 | + return obj; |
| 71 | + |
| 72 | +err: |
| 73 | + ACPI_FREE(obj); |
| 74 | + return NULL; |
| 75 | +} |
| 76 | + |
| 77 | +/** |
| 78 | + * adxl_get_component_names - get list of memory component names |
| 79 | + * Returns NULL terminated list of string names |
| 80 | + * |
| 81 | + * Give the caller a pointer to the list of memory component names |
| 82 | + * e.g. { "SystemAddress", "ProcessorSocketId", "ChannelId", ... NULL } |
| 83 | + * Caller should count how many strings in order to allocate a buffer |
| 84 | + * for the return from adxl_decode(). |
| 85 | + */ |
| 86 | +const char * const *adxl_get_component_names(void) |
| 87 | +{ |
| 88 | + return (const char * const *)adxl_component_names; |
| 89 | +} |
| 90 | +EXPORT_SYMBOL_GPL(adxl_get_component_names); |
| 91 | + |
| 92 | +/** |
| 93 | + * adxl_decode - ask BIOS to decode a system address to memory address |
| 94 | + * @addr: the address to decode |
| 95 | + * @component_values: pointer to array of values for each component |
| 96 | + * Returns 0 on success, negative error code otherwise |
| 97 | + * |
| 98 | + * The index of each value returned in the array matches the index of |
| 99 | + * each component name returned by adxl_get_component_names(). |
| 100 | + * Components that are not defined for this address translation (e.g. |
| 101 | + * mirror channel number for a non-mirrored address) are set to ~0ull. |
| 102 | + */ |
| 103 | +int adxl_decode(u64 addr, u64 component_values[]) |
| 104 | +{ |
| 105 | + union acpi_object argv4[2], *results, *r; |
| 106 | + int i, cnt; |
| 107 | + |
| 108 | + if (!adxl_component_names) |
| 109 | + return -EOPNOTSUPP; |
| 110 | + |
| 111 | + argv4[0].type = ACPI_TYPE_PACKAGE; |
| 112 | + argv4[0].package.count = 1; |
| 113 | + argv4[0].package.elements = &argv4[1]; |
| 114 | + argv4[1].integer.type = ACPI_TYPE_INTEGER; |
| 115 | + argv4[1].integer.value = addr; |
| 116 | + |
| 117 | + results = adxl_dsm(ADXL_IDX_FORWARD_TRANSLATE, argv4); |
| 118 | + if (!results) |
| 119 | + return -EINVAL; |
| 120 | + |
| 121 | + r = results->package.elements + 1; |
| 122 | + cnt = r->package.count; |
| 123 | + if (cnt != adxl_count) { |
| 124 | + ACPI_FREE(results); |
| 125 | + return -EINVAL; |
| 126 | + } |
| 127 | + r = r->package.elements; |
| 128 | + |
| 129 | + for (i = 0; i < cnt; i++) |
| 130 | + component_values[i] = r[i].integer.value; |
| 131 | + |
| 132 | + ACPI_FREE(results); |
| 133 | + |
| 134 | + return 0; |
| 135 | +} |
| 136 | +EXPORT_SYMBOL_GPL(adxl_decode); |
| 137 | + |
| 138 | +static int __init adxl_init(void) |
| 139 | +{ |
| 140 | + char *path = ACPI_ADXL_PATH; |
| 141 | + union acpi_object *p; |
| 142 | + acpi_status status; |
| 143 | + int i; |
| 144 | + |
| 145 | + status = acpi_get_handle(NULL, path, &handle); |
| 146 | + if (ACPI_FAILURE(status)) { |
| 147 | + pr_debug("No ACPI handle for path %s\n", path); |
| 148 | + return -ENODEV; |
| 149 | + } |
| 150 | + |
| 151 | + if (!acpi_has_method(handle, "_DSM")) { |
| 152 | + pr_info("No DSM method\n"); |
| 153 | + return -ENODEV; |
| 154 | + } |
| 155 | + |
| 156 | + if (!acpi_check_dsm(handle, &adxl_guid, ADXL_REVISION, |
| 157 | + ADXL_IDX_GET_ADDR_PARAMS | |
| 158 | + ADXL_IDX_FORWARD_TRANSLATE)) { |
| 159 | + pr_info("DSM method does not support forward translate\n"); |
| 160 | + return -ENODEV; |
| 161 | + } |
| 162 | + |
| 163 | + params = adxl_dsm(ADXL_IDX_GET_ADDR_PARAMS, NULL); |
| 164 | + if (!params) { |
| 165 | + pr_info("Failed to get component names\n"); |
| 166 | + return -ENODEV; |
| 167 | + } |
| 168 | + |
| 169 | + p = params->package.elements + 1; |
| 170 | + adxl_count = p->package.count; |
| 171 | + if (adxl_count > ADXL_MAX_COMPONENTS) { |
| 172 | + pr_info("Insane number of address component names %d\n", adxl_count); |
| 173 | + ACPI_FREE(params); |
| 174 | + return -ENODEV; |
| 175 | + } |
| 176 | + p = p->package.elements; |
| 177 | + |
| 178 | + /* |
| 179 | + * Allocate one extra for NULL termination. |
| 180 | + */ |
| 181 | + adxl_component_names = kcalloc(adxl_count + 1, sizeof(char *), GFP_KERNEL); |
| 182 | + if (!adxl_component_names) { |
| 183 | + ACPI_FREE(params); |
| 184 | + return -ENOMEM; |
| 185 | + } |
| 186 | + |
| 187 | + for (i = 0; i < adxl_count; i++) |
| 188 | + adxl_component_names[i] = p[i].string.pointer; |
| 189 | + |
| 190 | + return 0; |
| 191 | +} |
| 192 | +subsys_initcall(adxl_init); |
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