iwlwifi: Thermal Throttling Management - Part 1

Part 1 of Thermal Throttling Management -

Thermal Throttling feature is used to put NIC into low power state when
driver detect the Radio temperature reach pre-defined threshold

Two Thermal Throttling Management Methods; this patch introduce the
Legacy Thermal Management:
   IWL_TI_0: normal temperature, system power state
   IWL_TI_1: high temperature detect, low power state
   IWL_TI_2: higher temperature detected, lower power state
   IWL_TI_CT_KILL: critical temperature detected, lowest power state

Once get into CT_KILL state, uCode go into sleep, driver will stop all
the active queues, then move to IWL_TI_CT_KILL state; also set up 5
seconds timer to toggle CSR flag, uCode wake up upon CSR flag change,
then measure the temperature.
If temperature is above CT_KILL exit threshold, uCode go backto sleep;
if temperature is below CT_KILL exit threshold, uCode send Card State
Notification response with appropriate CT_KILL status flag, and uCode
remain awake, Driver receive Card State Notification Response and update
the card temperature to the CT_KILL exit threshold.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 249 insertions, 0 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-power.c b/drivers/net/wireless/iwlwifi/iwl-power.c
index f2ea3f05f6e..d7fdb582545 100644
--- a/drivers/net/wireless/iwlwifi/iwl-power.c
+++ b/drivers/net/wireless/iwlwifi/iwl-power.c
@@ -36,6 +36,7 @@
 #include "iwl-eeprom.h"
 #include "iwl-dev.h"
 #include "iwl-core.h"
+#include "iwl-io.h"
 #include "iwl-commands.h"
 #include "iwl-debug.h"
 #include "iwl-power.h"
@@ -211,6 +212,7 @@ int iwl_power_update_mode(struct iwl_priv *priv, bool force)
 {
 	struct iwl_power_mgr *setting = &(priv->power_data);
 	int ret = 0;
+	struct iwl_tt_mgmt *tt = &priv->power_data.tt;
 	u16 uninitialized_var(final_mode);
 	bool update_chains;
 
@@ -223,6 +225,10 @@ int iwl_power_update_mode(struct iwl_priv *priv, bool force)
 	if (setting->power_disabled)
 		final_mode = IWL_POWER_MODE_CAM;
 
+	if (tt->state >= IWL_TI_1) {
+		/* TT power setting overwrite user & system power setting */
+		final_mode = tt->tt_power_mode;
+	}
 	if (iwl_is_ready_rf(priv) &&
 	    ((setting->power_mode != final_mode) || force)) {
 		struct iwl_powertable_cmd cmd;
@@ -267,6 +273,249 @@ int iwl_power_set_user_mode(struct iwl_priv *priv, u16 mode)
 }
 EXPORT_SYMBOL(iwl_power_set_user_mode);
 
+#define CT_KILL_EXIT_DURATION (5)	/* 5 seconds duration */
+
+/*
+ * toggle the bit to wake up uCode and check the temperature
+ * if the temperature is below CT, uCode will stay awake and send card
+ * state notification with CT_KILL bit clear to inform Thermal Throttling
+ * Management to change state. Otherwise, uCode will go back to sleep
+ * without doing anything, driver should continue the 5 seconds timer
+ * to wake up uCode for temperature check until temperature drop below CT
+ */
+static void iwl_tt_check_exit_ct_kill(unsigned long data)
+{
+	struct iwl_priv *priv = (struct iwl_priv *)data;
+	struct iwl_tt_mgmt *tt = &priv->power_data.tt;
+	unsigned long flags;
+
+	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
+		return;
+
+	if (tt->state == IWL_TI_CT_KILL) {
+		if (priv->power_data.ct_kill_toggle) {
+			iwl_write32(priv, CSR_UCODE_DRV_GP1_CLR,
+				    CSR_UCODE_DRV_GP1_REG_BIT_CT_KILL_EXIT);
+			priv->power_data.ct_kill_toggle = false;
+		} else {
+			iwl_write32(priv, CSR_UCODE_DRV_GP1_SET,
+				    CSR_UCODE_DRV_GP1_REG_BIT_CT_KILL_EXIT);
+			priv->power_data.ct_kill_toggle = true;
+		}
+		iwl_read32(priv, CSR_UCODE_DRV_GP1);
+		spin_lock_irqsave(&priv->reg_lock, flags);
+		if (!iwl_grab_nic_access(priv))
+			iwl_release_nic_access(priv);
+		spin_unlock_irqrestore(&priv->reg_lock, flags);
+
+		/* Reschedule the ct_kill timer to occur in
+		 * CT_KILL_EXIT_DURATION seconds to ensure we get a
+		 * thermal update */
+		mod_timer(&priv->power_data.ct_kill_exit_tm, jiffies +
+			  CT_KILL_EXIT_DURATION * HZ);
+	}
+}
+
+static void iwl_perform_ct_kill_task(struct iwl_priv *priv,
+			   bool stop)
+{
+	if (stop) {
+		IWL_DEBUG_POWER(priv, "Stop all queues\n");
+		if (priv->mac80211_registered)
+			ieee80211_stop_queues(priv->hw);
+		IWL_DEBUG_POWER(priv,
+				"Schedule 5 seconds CT_KILL Timer\n");
+		mod_timer(&priv->power_data.ct_kill_exit_tm, jiffies +
+			  CT_KILL_EXIT_DURATION * HZ);
+	} else {
+		IWL_DEBUG_POWER(priv, "Wake all queues\n");
+		if (priv->mac80211_registered)
+			ieee80211_wake_queues(priv->hw);
+	}
+}
+
+#define IWL_MINIMAL_POWER_THRESHOLD		(CT_KILL_THRESHOLD_LEGACY)
+#define IWL_REDUCED_PERFORMANCE_THRESHOLD_2	(100)
+#define IWL_REDUCED_PERFORMANCE_THRESHOLD_1	(90)
+
+/*
+ * Legacy thermal throttling
+ * 1) Avoid NIC destruction due to high temperatures
+ *	Chip will identify dangerously high temperatures that can
+ *	harm the device and will power down
+ * 2) Avoid the NIC power down due to high temperature
+ *	Throttle early enough to lower the power consumption before
+ *	drastic steps are needed
+ */
+static void iwl_legacy_tt_handler(struct iwl_priv *priv, s32 temp)
+{
+	struct iwl_tt_mgmt *tt = &priv->power_data.tt;
+	enum iwl_tt_state new_state;
+	struct iwl_power_mgr *setting = &priv->power_data;
+
+#ifdef CONFIG_IWLWIFI_DEBUG
+	if ((tt->tt_previous_temp) &&
+	    (temp > tt->tt_previous_temp) &&
+	    ((temp - tt->tt_previous_temp) >
+	    IWL_TT_INCREASE_MARGIN)) {
+		IWL_DEBUG_POWER(priv,
+			"Temperature increase %d degree Celsius\n",
+			(temp - tt->tt_previous_temp));
+	}
+#endif
+	/* in Celsius */
+	if (temp >= IWL_MINIMAL_POWER_THRESHOLD)
+		new_state = IWL_TI_CT_KILL;
+	else if (temp >= IWL_REDUCED_PERFORMANCE_THRESHOLD_2)
+		new_state = IWL_TI_2;
+	else if (temp >= IWL_REDUCED_PERFORMANCE_THRESHOLD_1)
+		new_state = IWL_TI_1;
+	else
+		new_state = IWL_TI_0;
+
+#ifdef CONFIG_IWLWIFI_DEBUG
+	tt->tt_previous_temp = temp;
+#endif
+	if (tt->state != new_state) {
+		if (tt->state == IWL_TI_0) {
+			tt->sys_power_mode = setting->power_mode;
+			IWL_DEBUG_POWER(priv, "current power mode: %u\n",
+				setting->power_mode);
+		}
+		switch (new_state) {
+		case IWL_TI_0:
+			/* when system ready to go back to IWL_TI_0 state
+			 * using system power mode instead of TT power mode
+			 * revert back to the orginal power mode which was saved
+			 * before enter Thermal Throttling state
+			 * update priv->power_data.user_power_setting to the
+			 * required power mode to make sure
+			 * iwl_power_update_mode() will update power correctly.
+			 */
+			priv->power_data.user_power_setting =
+				tt->sys_power_mode;
+			tt->tt_power_mode = tt->sys_power_mode;
+			break;
+		case IWL_TI_1:
+			tt->tt_power_mode = IWL_POWER_INDEX_3;
+			break;
+		case IWL_TI_2:
+			tt->tt_power_mode = IWL_POWER_INDEX_4;
+			break;
+		default:
+			tt->tt_power_mode = IWL_POWER_INDEX_5;
+			break;
+		}
+		if (iwl_power_update_mode(priv, true)) {
+			/* TT state not updated
+			 * try again during next temperature read
+			 */
+			IWL_ERR(priv, "Cannot update power mode, "
+					"TT state not updated\n");
+		} else {
+			if (new_state == IWL_TI_CT_KILL)
+				iwl_perform_ct_kill_task(priv, true);
+			else if (tt->state == IWL_TI_CT_KILL &&
+				 new_state != IWL_TI_CT_KILL)
+				iwl_perform_ct_kill_task(priv, false);
+			tt->state = new_state;
+			IWL_DEBUG_POWER(priv, "Temperature state changed %u\n",
+					tt->state);
+			IWL_DEBUG_POWER(priv, "Power Index change to %u\n",
+					tt->tt_power_mode);
+		}
+	}
+}
+
+/* Card State Notification indicated reach critical temperature
+ * if PSP not enable, no Thermal Throttling function will be performed
+ * just set the GP1 bit to acknowledge the event
+ * otherwise, go into IWL_TI_CT_KILL state
+ * since Card State Notification will not provide any temperature reading
+ * so just pass the CT_KILL temperature to iwl_legacy_tt_handler()
+ */
+void iwl_tt_enter_ct_kill(struct iwl_priv *priv)
+{
+	struct iwl_tt_mgmt *tt = &priv->power_data.tt;
+
+	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
+		return;
+
+	if (tt->state != IWL_TI_CT_KILL) {
+		IWL_ERR(priv, "Device reached critical temperature "
+			      "- ucode going to sleep!\n");
+		iwl_legacy_tt_handler(priv, IWL_MINIMAL_POWER_THRESHOLD);
+	}
+}
+EXPORT_SYMBOL(iwl_tt_enter_ct_kill);
+
+/* Card State Notification indicated out of critical temperature
+ * since Card State Notification will not provide any temperature reading
+ * so pass the IWL_REDUCED_PERFORMANCE_THRESHOLD_2 temperature
+ * to iwl_legacy_tt_handler() to get out of IWL_CT_KILL state
+ */
+void iwl_tt_exit_ct_kill(struct iwl_priv *priv)
+{
+	struct iwl_tt_mgmt *tt = &priv->power_data.tt;
+
+	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
+		return;
+
+	/* stop ct_kill_exit_tm timer */
+	del_timer_sync(&priv->power_data.ct_kill_exit_tm);
+
+	if (tt->state == IWL_TI_CT_KILL) {
+		IWL_ERR(priv,
+			"Device temperature below critical"
+			"- ucode awake!\n");
+		iwl_legacy_tt_handler(priv,
+			IWL_REDUCED_PERFORMANCE_THRESHOLD_2);
+	}
+}
+EXPORT_SYMBOL(iwl_tt_exit_ct_kill);
+
+void iwl_tt_handler(struct iwl_priv *priv)
+{
+	s32 temp = priv->temperature; /* degrees CELSIUS except 4965 */
+
+	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
+		return;
+
+	if ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) == CSR_HW_REV_TYPE_4965)
+		temp = KELVIN_TO_CELSIUS(priv->temperature);
+
+	iwl_legacy_tt_handler(priv, temp);
+}
+EXPORT_SYMBOL(iwl_tt_handler);
+
+/* Thermal throttling initialization
+ */
+void iwl_tt_initialize(struct iwl_priv *priv)
+{
+	struct iwl_tt_mgmt *tt = &priv->power_data.tt;
+	struct iwl_power_mgr *setting = &priv->power_data;
+
+	IWL_DEBUG_POWER(priv, "Initialize Thermal Throttling \n");
+
+	memset(tt, 0, sizeof(struct iwl_tt_mgmt));
+
+	tt->state = IWL_TI_0;
+	tt->sys_power_mode = setting->power_mode;
+	tt->tt_power_mode = tt->sys_power_mode;
+	init_timer(&priv->power_data.ct_kill_exit_tm);
+	priv->power_data.ct_kill_exit_tm.data = (unsigned long)priv;
+	priv->power_data.ct_kill_exit_tm.function = iwl_tt_check_exit_ct_kill;
+}
+EXPORT_SYMBOL(iwl_tt_initialize);
+
+/* cleanup thermal throttling management related memory and timer */
+void iwl_tt_exit(struct iwl_priv *priv)
+{
+	/* stop ct_kill_exit_tm timer if activated */
+	del_timer_sync(&priv->power_data.ct_kill_exit_tm);
+}
+EXPORT_SYMBOL(iwl_tt_exit);
+
 /* initialize to default */
 void iwl_power_initialize(struct iwl_priv *priv)
 {