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1// SPDX-License-Identifier: GPL-2.02/*3 * Address translation interface via ACPI DSM.4 * Copyright (C) 2018 Intel Corporation5 *6 * Specification for this interface is available at:7 *8 * https://cdrdv2.intel.com/v1/dl/getContent/6033549 */10 11#include <linux/acpi.h>12#include <linux/adxl.h>13 14#define ADXL_REVISION 0x115#define ADXL_IDX_GET_ADDR_PARAMS 0x116#define ADXL_IDX_FORWARD_TRANSLATE 0x217#define ACPI_ADXL_PATH "\\_SB.ADXL"18 19/*20 * The specification doesn't provide a limit on how many21 * components are in a memory address. But since we allocate22 * memory based on the number the BIOS tells us, we should23 * defend against insane values.24 */25#define ADXL_MAX_COMPONENTS 50026 27#undef pr_fmt28#define pr_fmt(fmt) "ADXL: " fmt29 30static acpi_handle handle;31static union acpi_object *params;32static const guid_t adxl_guid =33 GUID_INIT(0xAA3C050A, 0x7EA4, 0x4C1F,34 0xAF, 0xDA, 0x12, 0x67, 0xDF, 0xD3, 0xD4, 0x8D);35 36static int adxl_count;37static char **adxl_component_names;38 39static 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 72err:73 ACPI_FREE(obj);74 return NULL;75}76 77/**78 * adxl_get_component_names - get list of memory component names79 * Returns NULL terminated list of string names80 *81 * Give the caller a pointer to the list of memory component names82 * e.g. { "SystemAddress", "ProcessorSocketId", "ChannelId", ... NULL }83 * Caller should count how many strings in order to allocate a buffer84 * for the return from adxl_decode().85 */86const char * const *adxl_get_component_names(void)87{88 return (const char * const *)adxl_component_names;89}90EXPORT_SYMBOL_GPL(adxl_get_component_names);91 92/**93 * adxl_decode - ask BIOS to decode a system address to memory address94 * @addr: the address to decode95 * @component_values: pointer to array of values for each component96 * Returns 0 on success, negative error code otherwise97 *98 * The index of each value returned in the array matches the index of99 * 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 */103int 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}136EXPORT_SYMBOL_GPL(adxl_decode);137 138static 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}192subsys_initcall(adxl_init);193