wifi: iwlwifi: mvm: Support STEP equalizer settings from BIOS.

Read the STEP equalizer parameters from the BIOS during init
and transfer it to the firmware.

This table provides values to configure an equalizer at the transmitter
that can be used to compensate for PCB channel attenuation.

Signed-off-by: Ayala Barazani <ayala.barazani@intel.com>
Link: https://lore.kernel.org/r/20230127002430.f25f871c5e17.I8390ab916c8f681229433ebc576ed37a594c6d30@changeid
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>

2 files changed, 76 insertions, 2 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
index 6d408cd0f517..0b6f694cf30d 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
- * Copyright(c) 2021 Intel Corporation
+ * Copyright(c) 2021-2022 Intel Corporation
  */
 
 #include "iwl-drv.h"
@@ -246,6 +246,63 @@ void *iwl_uefi_get_reduced_power(struct iwl_trans *trans, size_t *len)
 	return data;
 }
 
+static int iwl_uefi_step_parse(struct uefi_cnv_common_step_data *common_step_data,
+			       struct iwl_trans *trans)
+{
+	if (common_step_data->revision != 1)
+		return -EINVAL;
+
+	trans->mbx_addr_0_step = (u32)common_step_data->revision |
+		(u32)common_step_data->cnvi_eq_channel << 8 |
+		(u32)common_step_data->cnvr_eq_channel << 16 |
+		(u32)common_step_data->radio1 << 24;
+	trans->mbx_addr_1_step = (u32)common_step_data->radio2;
+	return 0;
+}
+
+void iwl_uefi_get_step_table(struct iwl_trans *trans)
+{
+	struct uefi_cnv_common_step_data *data;
+	unsigned long package_size;
+	efi_status_t status;
+	int ret;
+
+	if (trans->trans_cfg->device_family < IWL_DEVICE_FAMILY_AX210)
+		return;
+
+	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
+		return;
+
+	/* TODO: we hardcode a maximum length here, because reading
+	 * from the UEFI is not working.  To implement this properly,
+	 * we have to call efivar_entry_size().
+	 */
+	package_size = IWL_HARDCODED_STEP_SIZE;
+
+	data = kmalloc(package_size, GFP_KERNEL);
+	if (!data)
+		return;
+
+	status = efi.get_variable(IWL_UEFI_STEP_NAME, &IWL_EFI_VAR_GUID,
+				  NULL, &package_size, data);
+	if (status != EFI_SUCCESS) {
+		IWL_DEBUG_FW(trans,
+			     "STEP UEFI variable not found 0x%lx\n", status);
+		goto out_free;
+	}
+
+	IWL_DEBUG_FW(trans, "Read STEP from UEFI with size %lu\n",
+		     package_size);
+
+	ret = iwl_uefi_step_parse(data, trans);
+	if (ret < 0)
+		IWL_DEBUG_FW(trans, "Cannot read STEP tables. rev is invalid\n");
+
+out_free:
+	kfree(data);
+}
+IWL_EXPORT_SYMBOL(iwl_uefi_get_step_table);
+
 #ifdef CONFIG_ACPI
 static int iwl_uefi_sgom_parse(struct uefi_cnv_wlan_sgom_data *sgom_data,
 			       struct iwl_fw_runtime *fwrt)
diff --git a/drivers/net/wireless/intel/iwlwifi/fw/uefi.h b/drivers/net/wireless/intel/iwlwifi/fw/uefi.h
index 09d2a971b3a0..17089bc74cf9 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/uefi.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/uefi.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause */
 /*
- * Copyright(c) 2021 Intel Corporation
+ * Copyright(c) 2021-2022 Intel Corporation
  */
 #ifndef __iwl_fw_uefi__
 #define __iwl_fw_uefi__
@@ -8,6 +8,7 @@
 #define IWL_UEFI_OEM_PNVM_NAME		L"UefiCnvWlanOemSignedPnvm"
 #define IWL_UEFI_REDUCED_POWER_NAME	L"UefiCnvWlanReducedPower"
 #define IWL_UEFI_SGOM_NAME		L"UefiCnvWlanSarGeoOffsetMapping"
+#define IWL_UEFI_STEP_NAME		L"UefiCnvCommonSTEP"
 
 /*
  * TODO: we have these hardcoded values that the caller must pass,
@@ -18,6 +19,7 @@
 #define IWL_HARDCODED_PNVM_SIZE		4096
 #define IWL_HARDCODED_REDUCE_POWER_SIZE	32768
 #define IWL_HARDCODED_SGOM_SIZE		339
+#define IWL_HARDCODED_STEP_SIZE		6
 
 struct pnvm_sku_package {
 	u8 rev;
@@ -32,6 +34,15 @@ struct uefi_cnv_wlan_sgom_data {
 	u8 offset_map[IWL_HARDCODED_SGOM_SIZE - 1];
 } __packed;
 
+struct uefi_cnv_common_step_data {
+	u8 revision;
+	u8 step_mode;
+	u8 cnvi_eq_channel;
+	u8 cnvr_eq_channel;
+	u8 radio1;
+	u8 radio2;
+} __packed;
+
 /*
  * This is known to be broken on v4.19 and to work on v5.4.  Until we
  * figure out why this is the case and how to make it work, simply
@@ -40,6 +51,7 @@ struct uefi_cnv_wlan_sgom_data {
 #ifdef CONFIG_EFI
 void *iwl_uefi_get_pnvm(struct iwl_trans *trans, size_t *len);
 void *iwl_uefi_get_reduced_power(struct iwl_trans *trans, size_t *len);
+void iwl_uefi_get_step_table(struct iwl_trans *trans);
 #else /* CONFIG_EFI */
 static inline
 void *iwl_uefi_get_pnvm(struct iwl_trans *trans, size_t *len)
@@ -52,6 +64,11 @@ void *iwl_uefi_get_reduced_power(struct iwl_trans *trans, size_t *len)
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
+
+static inline
+void iwl_uefi_get_step_table(struct iwl_trans *trans)
+{
+}
 #endif /* CONFIG_EFI */
 
 #if defined(CONFIG_EFI) && defined(CONFIG_ACPI)