[3.13.y.z extended stable] Patch "iwlwifi: configure the LTR" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Thu Nov 6 01:28:53 UTC 2014


This is a note to let you know that I have just added a patch titled

    iwlwifi: configure the LTR

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From a2970b43f8841c29b568a420ad31440e9df9b4e9 Mon Sep 17 00:00:00 2001
From: Emmanuel Grumbach <emmanuel.grumbach at intel.com>
Date: Tue, 23 Sep 2014 23:02:41 +0300
Subject: iwlwifi: configure the LTR

commit 9180ac50716a097a407c6d7e7e4589754a922260 upstream.

The LTR is the handshake between the device and the root
complex about the latency allowed when the bus exits power
save. This configuration was missing and this led to high
latency in the link power up. The end user could experience
high latency in the network because of this.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach at intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/wireless/iwlwifi/iwl-trans.h        |  2 ++
 drivers/net/wireless/iwlwifi/mvm/fw-api-power.h | 35 ++++++++++++++++++++++++-
 drivers/net/wireless/iwlwifi/mvm/fw-api.h       |  1 +
 drivers/net/wireless/iwlwifi/mvm/fw.c           |  9 +++++++
 drivers/net/wireless/iwlwifi/mvm/ops.c          |  1 +
 drivers/net/wireless/iwlwifi/pcie/trans.c       | 16 ++++++-----
 6 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index 143292b..2379419 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -484,6 +484,7 @@ enum iwl_trans_state {
  *	Set during transport allocation.
  * @hw_id_str: a string with info about HW ID. Set during transport allocation.
  * @pm_support: set to true in start_hw if link pm is supported
+ * @ltr_enabled: set to true if the LTR is enabled
  * @dev_cmd_pool: pool for Tx cmd allocation - for internal use only.
  *	The user should use iwl_trans_{alloc,free}_tx_cmd.
  * @dev_cmd_headroom: room needed for the transport's private use before the
@@ -508,6 +509,7 @@ struct iwl_trans {
 	u8 rx_mpdu_cmd, rx_mpdu_cmd_hdr_size;

 	bool pm_support;
+	bool ltr_enabled;

 	/* The following fields are internal only */
 	struct kmem_cache *dev_cmd_pool;
diff --git a/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h b/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h
index 5cb93ae..71eee38 100644
--- a/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h
+++ b/drivers/net/wireless/iwlwifi/mvm/fw-api-power.h
@@ -66,13 +66,46 @@

 /* Power Management Commands, Responses, Notifications */

+/**
+ * enum iwl_ltr_config_flags - masks for LTR config command flags
+ * @LTR_CFG_FLAG_FEATURE_ENABLE: Feature operational status
+ * @LTR_CFG_FLAG_HW_DIS_ON_SHADOW_REG_ACCESS: allow LTR change on shadow
+ *	memory access
+ * @LTR_CFG_FLAG_HW_EN_SHRT_WR_THROUGH: allow LTR msg send on ANY LTR
+ *	reg change
+ * @LTR_CFG_FLAG_HW_DIS_ON_D0_2_D3: allow LTR msg send on transition from
+ *	D0 to D3
+ * @LTR_CFG_FLAG_SW_SET_SHORT: fixed static short LTR register
+ * @LTR_CFG_FLAG_SW_SET_LONG: fixed static short LONG register
+ * @LTR_CFG_FLAG_DENIE_C10_ON_PD: allow going into C10 on PD
+ */
+enum iwl_ltr_config_flags {
+	LTR_CFG_FLAG_FEATURE_ENABLE = BIT(0),
+	LTR_CFG_FLAG_HW_DIS_ON_SHADOW_REG_ACCESS = BIT(1),
+	LTR_CFG_FLAG_HW_EN_SHRT_WR_THROUGH = BIT(2),
+	LTR_CFG_FLAG_HW_DIS_ON_D0_2_D3 = BIT(3),
+	LTR_CFG_FLAG_SW_SET_SHORT = BIT(4),
+	LTR_CFG_FLAG_SW_SET_LONG = BIT(5),
+	LTR_CFG_FLAG_DENIE_C10_ON_PD = BIT(6),
+};
+
+/**
+ * struct iwl_ltr_config_cmd - configures the LTR
+ * @flags: See %enum iwl_ltr_config_flags
+ */
+struct iwl_ltr_config_cmd {
+	__le32 flags;
+	__le32 static_long;
+	__le32 static_short;
+} __packed;
+
 /* 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
+ * enum iwl_power_flags - masks for power table command flags
  * @POWER_FLAGS_POWER_SAVE_ENA_MSK: '1' Allow to save power by turning off
  *		receiver and transmitter. '0' - does not allow.
  * @POWER_FLAGS_POWER_MANAGEMENT_ENA_MSK: '0' Driver disables power management,
diff --git a/drivers/net/wireless/iwlwifi/mvm/fw-api.h b/drivers/net/wireless/iwlwifi/mvm/fw-api.h
index bad5a55..c079783 100644
--- a/drivers/net/wireless/iwlwifi/mvm/fw-api.h
+++ b/drivers/net/wireless/iwlwifi/mvm/fw-api.h
@@ -141,6 +141,7 @@ enum {

 	/* Power - legacy power table command */
 	POWER_TABLE_CMD = 0x77,
+	LTR_CONFIG = 0xee,

 	/* Thermal Throttling*/
 	REPLY_THERMAL_MNG_BACKOFF = 0x7e,
diff --git a/drivers/net/wireless/iwlwifi/mvm/fw.c b/drivers/net/wireless/iwlwifi/mvm/fw.c
index 70e5297..d6de231 100644
--- a/drivers/net/wireless/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/iwlwifi/mvm/fw.c
@@ -431,6 +431,15 @@ int iwl_mvm_up(struct iwl_mvm *mvm)
 			goto error;
 	}

+	if (mvm->trans->ltr_enabled) {
+		struct iwl_ltr_config_cmd cmd = {
+			.flags = cpu_to_le32(LTR_CFG_FLAG_FEATURE_ENABLE),
+		};
+
+		WARN_ON(iwl_mvm_send_cmd_pdu(mvm, LTR_CONFIG, 0,
+					     sizeof(cmd), &cmd));
+	}
+
 	ret = iwl_mvm_power_update_device_mode(mvm);
 	if (ret)
 		goto error;
diff --git a/drivers/net/wireless/iwlwifi/mvm/ops.c b/drivers/net/wireless/iwlwifi/mvm/ops.c
index bb58342..50620a7 100644
--- a/drivers/net/wireless/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/iwlwifi/mvm/ops.c
@@ -310,6 +310,7 @@ static const char *iwl_mvm_cmd_strings[REPLY_MAX] = {
 	CMD(REPLY_BEACON_FILTERING_CMD),
 	CMD(REPLY_THERMAL_MNG_BACKOFF),
 	CMD(MAC_PM_POWER_TABLE),
+	CMD(LTR_CONFIG),
 	CMD(BT_COEX_CI),
 };
 #undef CMD
diff --git a/drivers/net/wireless/iwlwifi/pcie/trans.c b/drivers/net/wireless/iwlwifi/pcie/trans.c
index f69aeb3..e7b2565 100644
--- a/drivers/net/wireless/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/iwlwifi/pcie/trans.c
@@ -121,6 +121,7 @@ static void iwl_pcie_apm_config(struct iwl_trans *trans)
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 	u16 lctl;
+	u16 cap;

 	/*
 	 * HW bug W/A for instability in PCIe bus L0S->L1 transition.
@@ -131,16 +132,17 @@ static void iwl_pcie_apm_config(struct iwl_trans *trans)
 	 *    power savings, even without L1.
 	 */
 	pcie_capability_read_word(trans_pcie->pci_dev, PCI_EXP_LNKCTL, &lctl);
-	if (lctl & PCI_EXP_LNKCTL_ASPM_L1) {
-		/* L1-ASPM enabled; disable(!) L0S */
+	if (lctl & PCI_EXP_LNKCTL_ASPM_L1)
 		iwl_set_bit(trans, CSR_GIO_REG, CSR_GIO_REG_VAL_L0S_ENABLED);
-		dev_info(trans->dev, "L1 Enabled; Disabling L0S\n");
-	} else {
-		/* L1-ASPM disabled; enable(!) L0S */
+	else
 		iwl_clear_bit(trans, CSR_GIO_REG, CSR_GIO_REG_VAL_L0S_ENABLED);
-		dev_info(trans->dev, "L1 Disabled; Enabling L0S\n");
-	}
 	trans->pm_support = !(lctl & PCI_EXP_LNKCTL_ASPM_L0S);
+
+	pcie_capability_read_word(trans_pcie->pci_dev, PCI_EXP_DEVCTL2, &cap);
+	trans->ltr_enabled = cap & PCI_EXP_DEVCTL2_LTR_EN;
+	dev_info(trans->dev, "L1 %sabled - LTR %sabled\n",
+		 (lctl & PCI_EXP_LNKCTL_ASPM_L1) ? "En" : "Dis",
+		 trans->ltr_enabled ? "En" : "Dis");
 }

 /*
--
1.9.1





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