// SPDX-License-Identifier: GPL-2.0 /* * Address translation interface via ACPI DSM. * Copyright (C) 2018 Intel Corporation * * Specification for this interface is available at: * * https://cdrdv2.intel.com/v1/dl/getContent/603354 */ #include <linux/acpi.h> #include <linux/adxl.h> #define ADXL_REVISION 0x1 #define ADXL_IDX_GET_ADDR_PARAMS 0x1 #define ADXL_IDX_FORWARD_TRANSLATE 0x2 #define ACPI_ADXL_PATH "\\_SB.ADXL" /* * The specification doesn't provide a limit on how many * components are in a memory address. But since we allocate * memory based on the number the BIOS tells us, we should * defend against insane values. */ #define ADXL_MAX_COMPONENTS 500 #undef pr_fmt #define pr_fmt(fmt) "ADXL: " fmt static acpi_handle handle; static union acpi_object *params; static const guid_t adxl_guid = GUID_INIT(0xAA3C050A, 0x7EA4, 0x4C1F, 0xAF, 0xDA, 0x12, 0x67, 0xDF, 0xD3, 0xD4, 0x8D); static int adxl_count; static char **adxl_component_names; static union acpi_object *adxl_dsm(int cmd, union acpi_object argv[]) { union acpi_object *obj, *o; obj = acpi_evaluate_dsm_typed(handle, &adxl_guid, ADXL_REVISION, cmd, argv, ACPI_TYPE_PACKAGE); if (!obj) { pr_info("DSM call failed for cmd=%d\n", cmd); return NULL; } if (obj->package.count != 2) { pr_info("Bad pkg count %d\n", obj->package.count); goto err; } o = obj->package.elements; if (o->type != ACPI_TYPE_INTEGER) { pr_info("Bad 1st element type %d\n", o->type); goto err; } if (o->integer.value) { pr_info("Bad ret val %llu\n", o->integer.value); goto err; } o = obj->package.elements + 1; if (o->type != ACPI_TYPE_PACKAGE) { pr_info("Bad 2nd element type %d\n", o->type); goto err; } return obj; err: ACPI_FREE(obj); return NULL; } /** * adxl_get_component_names - get list of memory component names * Returns NULL terminated list of string names * * Give the caller a pointer to the list of memory component names * e.g. { "SystemAddress", "ProcessorSocketId", "ChannelId", ... NULL } * Caller should count how many strings in order to allocate a buffer * for the return from adxl_decode(). */ const char * const *adxl_get_component_names(void) { return (const char * const *)adxl_component_names; } EXPORT_SYMBOL_GPL(adxl_get_component_names); /** * adxl_decode - ask BIOS to decode a system address to memory address * @addr: the address to decode * @component_values: pointer to array of values for each component * Returns 0 on success, negative error code otherwise * * The index of each value returned in the array matches the index of * each component name returned by adxl_get_component_names(). * Components that are not defined for this address translation (e.g. * mirror channel number for a non-mirrored address) are set to ~0ull. */ int adxl_decode(u64 addr, u64 component_values[]) { union acpi_object argv4[2], *results, *r; int i, cnt; if (!adxl_component_names) return -EOPNOTSUPP; argv4[0].type = ACPI_TYPE_PACKAGE; argv4[0].package.count = 1; argv4[0].package.elements = &argv4[1]; argv4[1].integer.type = ACPI_TYPE_INTEGER; argv4[1].integer.value = addr; results = adxl_dsm(ADXL_IDX_FORWARD_TRANSLATE, argv4); if (!results) return -EINVAL; r = results->package.elements + 1; cnt = r->package.count; if (cnt != adxl_count) { ACPI_FREE(results); return -EINVAL; } r = r->package.elements; for (i = 0; i < cnt; i++) component_values[i] = r[i].integer.value; ACPI_FREE(results); return 0; } EXPORT_SYMBOL_GPL(adxl_decode); static int __init adxl_init(void) { char *path = ACPI_ADXL_PATH; union acpi_object *p; acpi_status status; int i; status = acpi_get_handle(NULL, path, &handle); if (ACPI_FAILURE(status)) { pr_debug("No ACPI handle for path %s\n", path); return -ENODEV; } if (!acpi_has_method(handle, "_DSM")) { pr_info("No DSM method\n"); return -ENODEV; } if (!acpi_check_dsm(handle, &adxl_guid, ADXL_REVISION, ADXL_IDX_GET_ADDR_PARAMS | ADXL_IDX_FORWARD_TRANSLATE)) { pr_info("DSM method does not support forward translate\n"); return -ENODEV; } params = adxl_dsm(ADXL_IDX_GET_ADDR_PARAMS, NULL); if (!params) { pr_info("Failed to get component names\n"); return -ENODEV; } p = params->package.elements + 1; adxl_count = p->package.count; if (adxl_count > ADXL_MAX_COMPONENTS) { pr_info("Insane number of address component names %d\n", adxl_count); ACPI_FREE(params); return -ENODEV; } p = p->package.elements; /* * Allocate one extra for NULL termination. */ adxl_component_names = kcalloc(adxl_count + 1, sizeof(char *), GFP_KERNEL); if (!adxl_component_names) { ACPI_FREE(params); return -ENOMEM; } for (i = 0; i < adxl_count; i++) adxl_component_names[i] = p[i].string.pointer; return 0; } subsys_initcall(adxl_init);