iwlwifi: mvm: read SAR BIOS table from ACPI

Read the SAR BIOS table from the ACPI and parse it into the
iwl_mvm_sar_table structure.  If the table is enabled, send it to the
firmware via REDUCE_TX_POWER_CMD.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
index 510b4c1..4db1d84 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -65,6 +65,7 @@
  *****************************************************************************/
 #include <net/mac80211.h>
 #include <linux/netdevice.h>
+#include <linux/acpi.h>
 
 #include "iwl-trans.h"
 #include "iwl-op-mode.h"
@@ -902,6 +903,174 @@ static int iwl_mvm_config_ltr(struct iwl_mvm *mvm)
                                    sizeof(cmd), &cmd);
 }
 
+#define ACPI_WRDS_METHOD       "WRDS"
+#define ACPI_WRDS_WIFI         (0x07)
+#define ACPI_WRDS_TABLE_SIZE   10
+
+struct iwl_mvm_sar_table {
+       bool enabled;
+       u8 values[ACPI_WRDS_TABLE_SIZE];
+};
+
+#ifdef CONFIG_ACPI
+static int iwl_mvm_sar_get_wrds(struct iwl_mvm *mvm, union acpi_object *wrds,
+                               struct iwl_mvm_sar_table *sar_table)
+{
+       union acpi_object *data_pkg;
+       u32 i;
+
+       /* We need at least two packages, one for the revision and one
+        * for the data itself.  Also check that the revision is valid
+        * (i.e. it is an integer set to 0).
+       */
+       if (wrds->type != ACPI_TYPE_PACKAGE ||
+           wrds->package.count < 2 ||
+           wrds->package.elements[0].type != ACPI_TYPE_INTEGER ||
+           wrds->package.elements[0].integer.value != 0) {
+               IWL_DEBUG_RADIO(mvm, "Unsupported wrds structure\n");
+               return -EINVAL;
+       }
+
+       /* loop through all the packages to find the one for WiFi */
+       for (i = 1; i < wrds->package.count; i++) {
+               union acpi_object *domain;
+
+               data_pkg = &wrds->package.elements[i];
+
+               /* Skip anything that is not a package with the right
+                * amount of elements (i.e. domain_type,
+                * enabled/disabled plus the sar table size.
+                */
+               if (data_pkg->type != ACPI_TYPE_PACKAGE ||
+                   data_pkg->package.count != ACPI_WRDS_TABLE_SIZE + 2)
+                       continue;
+
+               domain = &data_pkg->package.elements[0];
+               if (domain->type == ACPI_TYPE_INTEGER &&
+                   domain->integer.value == ACPI_WRDS_WIFI)
+                       break;
+
+               data_pkg = NULL;
+       }
+
+       if (!data_pkg)
+               return -ENOENT;
+
+       if (data_pkg->package.elements[1].type != ACPI_TYPE_INTEGER)
+               return -EINVAL;
+
+       sar_table->enabled = !!(data_pkg->package.elements[1].integer.value);
+
+       for (i = 0; i < ACPI_WRDS_TABLE_SIZE; i++) {
+               union acpi_object *entry;
+
+               entry = &data_pkg->package.elements[i + 2];
+               if ((entry->type != ACPI_TYPE_INTEGER) ||
+                   (entry->integer.value > U8_MAX))
+                       return -EINVAL;
+
+               sar_table->values[i] = entry->integer.value;
+       }
+
+       return 0;
+}
+
+static int iwl_mvm_sar_get_table(struct iwl_mvm *mvm,
+                                struct iwl_mvm_sar_table *sar_table)
+{
+       acpi_handle root_handle;
+       acpi_handle handle;
+       struct acpi_buffer wrds = {ACPI_ALLOCATE_BUFFER, NULL};
+       acpi_status status;
+       int ret;
+
+       root_handle = ACPI_HANDLE(mvm->dev);
+       if (!root_handle) {
+               IWL_DEBUG_RADIO(mvm,
+                               "Could not retrieve root port ACPI handle\n");
+               return -ENOENT;
+       }
+
+       /* Get the method's handle */
+       status = acpi_get_handle(root_handle, (acpi_string)ACPI_WRDS_METHOD,
+                                &handle);
+       if (ACPI_FAILURE(status)) {
+               IWL_DEBUG_RADIO(mvm, "WRDS method not found\n");
+               return -ENOENT;
+       }
+
+       /* Call WRDS with no arguments */
+       status = acpi_evaluate_object(handle, NULL, NULL, &wrds);
+       if (ACPI_FAILURE(status)) {
+               IWL_DEBUG_RADIO(mvm, "WRDS invocation failed (0x%x)\n", status);
+               return -ENOENT;
+       }
+
+       ret = iwl_mvm_sar_get_wrds(mvm, wrds.pointer, sar_table);
+       kfree(wrds.pointer);
+
+       return ret;
+}
+#else /* CONFIG_ACPI */
+static int iwl_mvm_sar_get_table(struct iwl_mvm *mvm,
+                                struct iwl_mvm_sar_table *sar_table)
+{
+       return -ENOENT;
+}
+#endif /* CONFIG_ACPI */
+
+static int iwl_mvm_sar_init(struct iwl_mvm *mvm)
+{
+       struct iwl_mvm_sar_table sar_table;
+       struct iwl_dev_tx_power_cmd cmd = {
+               .v2.set_mode = cpu_to_le32(IWL_TX_POWER_MODE_SET_CHAINS),
+       };
+       int ret, i, j, idx;
+
+       /* we can't do anything with the table if the FW doesn't support it */
+       if (!fw_has_api(&mvm->fw->ucode_capa,
+                       IWL_UCODE_TLV_API_TX_POWER_CHAIN)) {
+               IWL_DEBUG_RADIO(mvm,
+                               "FW doesn't support per-chain TX power settings.\n");
+               return 0;
+       }
+
+       ret = iwl_mvm_sar_get_table(mvm, &sar_table);
+       if (ret < 0) {
+               IWL_DEBUG_RADIO(mvm,
+                               "SAR BIOS table invalid or unavailable. (%d)\n",
+                               ret);
+               /* we don't fail if the table is not available */
+               return 0;
+       }
+
+       if (!sar_table.enabled)
+               return 0;
+
+       IWL_DEBUG_RADIO(mvm, "Sending REDUCE_TX_POWER_CMD per chain\n");
+
+       BUILD_BUG_ON(IWL_NUM_CHAIN_LIMITS * IWL_NUM_SUB_BANDS !=
+                    ACPI_WRDS_TABLE_SIZE);
+
+       for (i = 0; i < IWL_NUM_CHAIN_LIMITS; i++) {
+               IWL_DEBUG_RADIO(mvm, "  Chain[%d]:\n", i);
+               for (j = 0; j < IWL_NUM_SUB_BANDS; j++) {
+                       idx = (i * IWL_NUM_SUB_BANDS) + j;
+                       cmd.per_chain_restriction[i][j] =
+                               cpu_to_le16(sar_table.values[idx]);
+                       IWL_DEBUG_RADIO(mvm, "    Band[%d] = %d * .125dBm\n",
+                                       j, sar_table.values[idx]);
+               }
+       }
+
+       ret = iwl_mvm_send_cmd_pdu(mvm, REDUCE_TX_POWER_CMD, 0,
+                                  sizeof(cmd), &cmd);
+       if (ret)
+               IWL_ERR(mvm, "failed to set per-chain TX power: %d\n", ret);
+
+       return ret;
+}
+
 int iwl_mvm_up(struct iwl_mvm *mvm)
 {
        int ret, i;
@@ -1077,6 +1246,10 @@ int iwl_mvm_up(struct iwl_mvm *mvm)
        if (!test_bit(IWL_MVM_STATUS_IN_HW_RESTART, &mvm->status))
                iwl_mvm_unref(mvm, IWL_MVM_REF_UCODE_DOWN);
 
+       ret = iwl_mvm_sar_init(mvm);
+       if (ret)
+               goto error;
+
        IWL_DEBUG_INFO(mvm, "RT uCode started.\n");
        return 0;
  error: