// 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);
