iwlwifi: support loading the reduced power table from UEFI

This new feature allows OEMs to set a special reduced power table in a
UEFI variable, which we use to tell the firmware to change the TX
power tables.

Read the variable and store it in a dram block to pass it to the
firmware.  We do this as part of the PNVM loading flow.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210621103449.259a33ba5074.I2e0bb142d2a9c412547cba89b62dd077b328fdc4@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

1 files changed, 199 insertions, 1 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
index bdcdca178eda..a7c79d814aa4 100644
--- a/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
+++ b/drivers/net/wireless/intel/iwlwifi/fw/uefi.c
@@ -9,6 +9,7 @@
 #include "iwl-io.h"
 
 #include "fw/uefi.h"
+#include "fw/api/alive.h"
 #include <linux/efi.h>
 
 #define IWL_EFI_VAR_GUID EFI_GUID(0x92daaf2f, 0xc02b, 0x455b,	\
@@ -22,6 +23,8 @@ void *iwl_uefi_get_pnvm(struct iwl_trans *trans, size_t *len)
 	unsigned long package_size;
 	int err;
 
+	*len = 0;
+
 	pnvm_efivar = kzalloc(sizeof(*pnvm_efivar), GFP_KERNEL);
 	if (!pnvm_efivar)
 		return ERR_PTR(-ENOMEM);
@@ -40,7 +43,6 @@ void *iwl_uefi_get_pnvm(struct iwl_trans *trans, size_t *len)
 	data = kmalloc(package_size, GFP_KERNEL);
 	if (!data) {
 		data = ERR_PTR(-ENOMEM);
-		*len = 0;
 		goto out;
 	}
 
@@ -62,3 +64,199 @@ out:
 
 	return data;
 }
+
+static void *iwl_uefi_reduce_power_section(struct iwl_trans *trans,
+					   const u8 *data, size_t len)
+{
+	struct iwl_ucode_tlv *tlv;
+	u8 *reduce_power_data = NULL, *tmp;
+	u32 size = 0;
+
+	IWL_DEBUG_FW(trans, "Handling REDUCE_POWER section\n");
+
+	while (len >= sizeof(*tlv)) {
+		u32 tlv_len, tlv_type;
+
+		len -= sizeof(*tlv);
+		tlv = (void *)data;
+
+		tlv_len = le32_to_cpu(tlv->length);
+		tlv_type = le32_to_cpu(tlv->type);
+
+		if (len < tlv_len) {
+			IWL_ERR(trans, "invalid TLV len: %zd/%u\n",
+				len, tlv_len);
+			reduce_power_data = ERR_PTR(-EINVAL);
+			goto out;
+		}
+
+		data += sizeof(*tlv);
+
+		switch (tlv_type) {
+		case IWL_UCODE_TLV_MEM_DESC: {
+			IWL_DEBUG_FW(trans,
+				     "Got IWL_UCODE_TLV_MEM_DESC len %d\n",
+				     tlv_len);
+
+			IWL_DEBUG_FW(trans, "Adding data (size %d)\n", tlv_len);
+
+			tmp = krealloc(reduce_power_data, size + tlv_len, GFP_KERNEL);
+			if (!tmp) {
+				IWL_DEBUG_FW(trans,
+					     "Couldn't allocate (more) reduce_power_data\n");
+
+				reduce_power_data = ERR_PTR(-ENOMEM);
+				goto out;
+			}
+
+			reduce_power_data = tmp;
+
+			memcpy(reduce_power_data + size, data, tlv_len);
+
+			size += tlv_len;
+
+			break;
+		}
+		case IWL_UCODE_TLV_PNVM_SKU:
+			IWL_DEBUG_FW(trans,
+				     "New REDUCE_POWER section started, stop parsing.\n");
+			goto done;
+		default:
+			IWL_DEBUG_FW(trans, "Found TLV 0x%0x, len %d\n",
+				     tlv_type, tlv_len);
+			break;
+		}
+
+		len -= ALIGN(tlv_len, 4);
+		data += ALIGN(tlv_len, 4);
+	}
+
+done:
+	if (!size) {
+		IWL_DEBUG_FW(trans, "Empty REDUCE_POWER, skipping.\n");
+		reduce_power_data = ERR_PTR(-ENOENT);
+		goto out;
+	}
+
+	IWL_INFO(trans, "loaded REDUCE_POWER\n");
+
+out:
+	return reduce_power_data;
+}
+
+static void *iwl_uefi_reduce_power_parse(struct iwl_trans *trans,
+					 const u8 *data, size_t len)
+{
+	struct iwl_ucode_tlv *tlv;
+	void *sec_data;
+
+	IWL_DEBUG_FW(trans, "Parsing REDUCE_POWER data\n");
+
+	while (len >= sizeof(*tlv)) {
+		u32 tlv_len, tlv_type;
+
+		len -= sizeof(*tlv);
+		tlv = (void *)data;
+
+		tlv_len = le32_to_cpu(tlv->length);
+		tlv_type = le32_to_cpu(tlv->type);
+
+		if (len < tlv_len) {
+			IWL_ERR(trans, "invalid TLV len: %zd/%u\n",
+				len, tlv_len);
+			return ERR_PTR(-EINVAL);
+		}
+
+		if (tlv_type == IWL_UCODE_TLV_PNVM_SKU) {
+			struct iwl_sku_id *sku_id =
+				(void *)(data + sizeof(*tlv));
+
+			IWL_DEBUG_FW(trans,
+				     "Got IWL_UCODE_TLV_PNVM_SKU len %d\n",
+				     tlv_len);
+			IWL_DEBUG_FW(trans, "sku_id 0x%0x 0x%0x 0x%0x\n",
+				     le32_to_cpu(sku_id->data[0]),
+				     le32_to_cpu(sku_id->data[1]),
+				     le32_to_cpu(sku_id->data[2]));
+
+			data += sizeof(*tlv) + ALIGN(tlv_len, 4);
+			len -= ALIGN(tlv_len, 4);
+
+			if (trans->sku_id[0] == le32_to_cpu(sku_id->data[0]) &&
+			    trans->sku_id[1] == le32_to_cpu(sku_id->data[1]) &&
+			    trans->sku_id[2] == le32_to_cpu(sku_id->data[2])) {
+				sec_data = iwl_uefi_reduce_power_section(trans,
+									 data,
+									 len);
+				if (!IS_ERR(sec_data))
+					return sec_data;
+			} else {
+				IWL_DEBUG_FW(trans, "SKU ID didn't match!\n");
+			}
+		} else {
+			data += sizeof(*tlv) + ALIGN(tlv_len, 4);
+			len -= ALIGN(tlv_len, 4);
+		}
+	}
+
+	return ERR_PTR(-ENOENT);
+}
+
+void *iwl_uefi_get_reduced_power(struct iwl_trans *trans, size_t *len)
+{
+	struct efivar_entry *reduce_power_efivar;
+	struct pnvm_sku_package *package;
+	void *data = NULL;
+	unsigned long package_size;
+	int err;
+
+	*len = 0;
+
+	reduce_power_efivar = kzalloc(sizeof(*reduce_power_efivar), GFP_KERNEL);
+	if (!reduce_power_efivar)
+		return ERR_PTR(-ENOMEM);
+
+	memcpy(&reduce_power_efivar->var.VariableName, IWL_UEFI_REDUCED_POWER_NAME,
+	       sizeof(IWL_UEFI_REDUCED_POWER_NAME));
+	reduce_power_efivar->var.VendorGuid = IWL_EFI_VAR_GUID;
+
+	/*
+	 * 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_REDUCE_POWER_SIZE;
+
+	package = kmalloc(package_size, GFP_KERNEL);
+	if (!package) {
+		package = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	err = efivar_entry_get(reduce_power_efivar, NULL, &package_size, package);
+	if (err) {
+		IWL_DEBUG_FW(trans,
+			     "Reduced Power UEFI variable not found %d (len %lu)\n",
+			     err, package_size);
+		kfree(package);
+		data = ERR_PTR(err);
+		goto out;
+	}
+
+	IWL_DEBUG_FW(trans, "Read reduced power from UEFI with size %lu\n",
+		     package_size);
+	*len = package_size;
+
+	IWL_DEBUG_FW(trans, "rev %d, total_size %d, n_skus %d\n",
+		     package->rev, package->total_size, package->n_skus);
+
+	data = iwl_uefi_reduce_power_parse(trans, package->data,
+					   *len - sizeof(*package));
+
+	kfree(package);
+
+out:
+	kfree(reduce_power_efivar);
+
+	return data;
+}