--- /dev/null
+// 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);
projects / linux-2.6-block.git / commitdiff