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