iwlwifi: mvm: Add support for Low Power RX

To improve power consumption in idle associated mode FW may lower
RX power. This low linearity mode is acceptable for listening low rate
RX such as beacons and groupcast. The driver enables LPRX only if PM
is enabled and associated AP's beacon TX rate is 1Mbps or 6Mbps.
LPRX RSSI threshold is used to limit a range where LPRX is applied.

Signed-off-by: Alexander Bondar <alexander.bondar@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/mvm/debugfs.c b/drivers/net/wireless/iwlwifi/mvm/debugfs.c
index 63d19d9..e56ed2a 100644
--- a/drivers/net/wireless/iwlwifi/mvm/debugfs.c
+++ b/drivers/net/wireless/iwlwifi/mvm/debugfs.c
@@ -344,6 +344,13 @@
 	case MVM_DEBUGFS_PM_DISABLE_POWER_OFF:
 		IWL_DEBUG_POWER(mvm, "disable_power_off=%d\n", val);
 		dbgfs_pm->disable_power_off = val;
+	case MVM_DEBUGFS_PM_LPRX_ENA:
+		IWL_DEBUG_POWER(mvm, "lprx %s\n", val ? "enabled" : "disabled");
+		dbgfs_pm->lprx_ena = val;
+		break;
+	case MVM_DEBUGFS_PM_LPRX_RSSI_THRESHOLD:
+		IWL_DEBUG_POWER(mvm, "lprx_rssi_threshold=%d\n", val);
+		dbgfs_pm->lprx_rssi_threshold = val;
 		break;
 	}
 }
@@ -387,6 +394,17 @@
 		if (sscanf(buf + 18, "%d", &val) != 1)
 			return -EINVAL;
 		param = MVM_DEBUGFS_PM_DISABLE_POWER_OFF;
+	} else if (!strncmp("lprx=", buf, 5)) {
+		if (sscanf(buf + 5, "%d", &val) != 1)
+			return -EINVAL;
+		param = MVM_DEBUGFS_PM_LPRX_ENA;
+	} else if (!strncmp("lprx_rssi_threshold=", buf, 20)) {
+		if (sscanf(buf + 20, "%d", &val) != 1)
+			return -EINVAL;
+		if (val > POWER_LPRX_RSSI_THRESHOLD_MAX || val <
+		    POWER_LPRX_RSSI_THRESHOLD_MIN)
+			return -EINVAL;
+		param = MVM_DEBUGFS_PM_LPRX_RSSI_THRESHOLD;
 	} else {
 		return -EINVAL;
 	}
@@ -421,7 +439,7 @@
 			 le32_to_cpu(cmd.skip_dtim_periods));
 	pos += scnprintf(buf+pos, bufsz-pos, "power_scheme = %d\n",
 			 iwlmvm_mod_params.power_scheme);
-	pos += scnprintf(buf+pos, bufsz-pos, "flags = %d\n",
+	pos += scnprintf(buf+pos, bufsz-pos, "flags = 0x%x\n",
 			 le16_to_cpu(cmd.flags));
 	pos += scnprintf(buf+pos, bufsz-pos, "keep_alive = %d\n",
 			 cmd.keep_alive_seconds);
@@ -435,6 +453,10 @@
 				 le32_to_cpu(cmd.rx_data_timeout));
 		pos += scnprintf(buf+pos, bufsz-pos, "tx_data_timeout = %d\n",
 				 le32_to_cpu(cmd.tx_data_timeout));
+		if (cmd.flags & cpu_to_le16(POWER_FLAGS_LPRX_ENA_MSK))
+			pos += scnprintf(buf+pos, bufsz-pos,
+					 "lprx_rssi_threshold = %d\n",
+					 le32_to_cpu(cmd.lprx_rssi_threshold));
 	}
 
 	return simple_read_from_buffer(user_buf, count, ppos, buf, pos);
diff --git a/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h b/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h
index d8e1929..a6da359 100644
--- a/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h
+++ b/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h
@@ -66,6 +66,11 @@
 
 /* Power Management Commands, Responses, Notifications */
 
+/* Radio LP RX Energy Threshold measured in dBm */
+#define POWER_LPRX_RSSI_THRESHOLD	75
+#define POWER_LPRX_RSSI_THRESHOLD_MAX	94
+#define POWER_LPRX_RSSI_THRESHOLD_MIN	30
+
 /**
  * enum iwl_scan_flags - masks for power table command flags
  * @POWER_FLAGS_POWER_SAVE_ENA_MSK: '1' Allow to save power by turning off
diff --git a/drivers/net/wireless/iwlwifi/mvm/mvm.h b/drivers/net/wireless/iwlwifi/mvm/mvm.h
index c6ba553..d40d7db 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/iwlwifi/mvm/mvm.h
@@ -158,6 +158,8 @@
 	MVM_DEBUGFS_PM_RX_DATA_TIMEOUT = BIT(3),
 	MVM_DEBUGFS_PM_TX_DATA_TIMEOUT = BIT(4),
 	MVM_DEBUGFS_PM_DISABLE_POWER_OFF = BIT(5),
+	MVM_DEBUGFS_PM_LPRX_ENA = BIT(6),
+	MVM_DEBUGFS_PM_LPRX_RSSI_THRESHOLD = BIT(7),
 };
 
 struct iwl_dbgfs_pm {
@@ -167,6 +169,8 @@
 	bool skip_over_dtim;
 	u8 skip_dtim_periods;
 	bool disable_power_off;
+	bool lprx_ena;
+	u32 lprx_rssi_threshold;
 	int mask;
 };
 
diff --git a/drivers/net/wireless/iwlwifi/mvm/power.c b/drivers/net/wireless/iwlwifi/mvm/power.c
index 3760a33..e7ca965 100644
--- a/drivers/net/wireless/iwlwifi/mvm/power.c
+++ b/drivers/net/wireless/iwlwifi/mvm/power.c
@@ -137,11 +137,12 @@
 				le32_to_cpu(cmd->rx_data_timeout));
 		IWL_DEBUG_POWER(mvm, "Tx timeout = %u usec\n",
 				le32_to_cpu(cmd->tx_data_timeout));
-		IWL_DEBUG_POWER(mvm, "LP RX RSSI threshold = %u\n",
-				cmd->lprx_rssi_threshold);
 		if (cmd->flags & cpu_to_le16(POWER_FLAGS_SKIP_OVER_DTIM_MSK))
 			IWL_DEBUG_POWER(mvm, "DTIM periods to skip = %u\n",
 					le32_to_cpu(cmd->skip_dtim_periods));
+		if (cmd->flags & cpu_to_le16(POWER_FLAGS_LPRX_ENA_MSK))
+			IWL_DEBUG_POWER(mvm, "LP RX RSSI threshold = %u\n",
+					le32_to_cpu(cmd->lprx_rssi_threshold));
 	}
 }
 
@@ -181,6 +182,14 @@
 
 	cmd->flags |= cpu_to_le16(POWER_FLAGS_POWER_MANAGEMENT_ENA_MSK);
 
+	if (vif->bss_conf.beacon_rate &&
+	    (vif->bss_conf.beacon_rate->bitrate == 10 ||
+	     vif->bss_conf.beacon_rate->bitrate == 60)) {
+		cmd->flags |= cpu_to_le16(POWER_FLAGS_LPRX_ENA_MSK);
+		cmd->lprx_rssi_threshold =
+			cpu_to_le32(POWER_LPRX_RSSI_THRESHOLD);
+	}
+
 	dtimper = hw->conf.ps_dtim_period ?: 1;
 
 	/* Check if radar detection is required on current channel */
@@ -236,6 +245,15 @@
 	if (mvmvif->dbgfs_pm.mask & MVM_DEBUGFS_PM_SKIP_DTIM_PERIODS)
 		cmd->skip_dtim_periods =
 			cpu_to_le32(mvmvif->dbgfs_pm.skip_dtim_periods);
+	if (mvmvif->dbgfs_pm.mask & MVM_DEBUGFS_PM_LPRX_ENA) {
+		if (mvmvif->dbgfs_pm.lprx_ena)
+			cmd->flags |= cpu_to_le16(POWER_FLAGS_LPRX_ENA_MSK);
+		else
+			cmd->flags &= cpu_to_le16(~POWER_FLAGS_LPRX_ENA_MSK);
+	}
+	if (mvmvif->dbgfs_pm.mask & MVM_DEBUGFS_PM_LPRX_RSSI_THRESHOLD)
+		cmd->lprx_rssi_threshold =
+			cpu_to_le32(mvmvif->dbgfs_pm.lprx_rssi_threshold);
 #endif /* CONFIG_IWLWIFI_DEBUGFS */
 }