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- // 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);
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