diff options
Diffstat (limited to 'drivers/acpi/acpi_adxl.c')
| -rw-r--r-- | drivers/acpi/acpi_adxl.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_adxl.c b/drivers/acpi/acpi_adxl.c new file mode 100644 index 000000000..13c8f7b50 --- /dev/null +++ b/drivers/acpi/acpi_adxl.c @@ -0,0 +1,192 @@ +// 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); |