mei: me: d0i3: add d0i3 enter/exit state machine

Rework mei power gating state machine to support entry and exit to and
from D0i3 power state.
The choice between legacy and D0i3 routines is conditioned on
d0i3_supported flag.

The patch introduces warning:
drivers/misc/mei/hw-me.c:901:12: warning: ‘mei_me_d0i3_enter’ defined but not used [-Wunused-function]
it will go away in consequent patch
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hbm.c

@@ -901,6 +901,17 @@ static int mei_hbm_pg_enter_res(struct mei_device *dev)
 	return 0;
 }
 
+/**
+ * mei_hbm_pg_resume - process with PG resume
+ *
+ * @dev: the device structure.
+ */
+void mei_hbm_pg_resume(struct mei_device *dev)
+{
+	pm_request_resume(dev->dev);
+}
+EXPORT_SYMBOL_GPL(mei_hbm_pg_resume);
+
 /**
  * mei_hbm_pg_exit_res - PG exit response received
  *
@@ -930,7 +941,7 @@ static int mei_hbm_pg_exit_res(struct mei_device *dev)
 		* Start runtime pm resume sequence to exit from PG.
 		*/
 		dev->pg_event = MEI_PG_EVENT_RECEIVED;
-		pm_request_resume(dev->dev);
+		mei_hbm_pg_resume(dev);
 		break;
 	default:
 		WARN(1, "hbm: pg exit response: unexpected pg event = %d\n",

drivers/misc/mei/hbm.h

@@ -54,6 +54,7 @@ int mei_hbm_cl_disconnect_rsp(struct mei_device *dev, struct mei_cl *cl);
 int mei_hbm_cl_connect_req(struct mei_device *dev, struct mei_cl *cl);
 bool mei_hbm_version_is_supported(struct mei_device *dev);
 int mei_hbm_pg(struct mei_device *dev, u8 pg_cmd);
+void mei_hbm_pg_resume(struct mei_device *dev);
 int mei_hbm_cl_notify_req(struct mei_device *dev,
 			  struct mei_cl *cl, u8 request);
 

drivers/misc/mei/hw-me.c

@@ -138,6 +138,35 @@ static inline void mei_hcsr_set(struct mei_device *dev, u32 reg)
 	mei_hcsr_write(dev, reg);
 }
 
+/**
+ * mei_me_d0i3c_read - Reads 32bit data from the D0I3C register
+ *
+ * @dev: the device structure
+ *
+ * Return: H_D0I3C register value (u32)
+ */
+static inline u32 mei_me_d0i3c_read(const struct mei_device *dev)
+{
+	u32 reg;
+
+	reg = mei_me_reg_read(to_me_hw(dev), H_D0I3C);
+	trace_mei_reg_read(dev->dev, "H_D0I3C", H_CSR, reg);
+
+	return reg;
+}
+
+/**
+ * mei_me_d0i3c_write - writes H_D0I3C register to device
+ *
+ * @dev: the device structure
+ * @reg: new register value
+ */
+static inline void mei_me_d0i3c_write(struct mei_device *dev, u32 reg)
+{
+	trace_mei_reg_write(dev->dev, "H_D0I3C", H_CSR, reg);
+	mei_me_reg_write(to_me_hw(dev), H_D0I3C, reg);
+}
+
 /**
  * mei_me_fw_status - read fw status register from pci config space
  *
@@ -609,13 +638,13 @@ static void mei_me_pg_unset(struct mei_device *dev)
 }
 
 /**
- * mei_me_pg_enter_sync - perform pg entry procedure
+ * mei_me_pg_legacy_enter_sync - perform legacy pg entry procedure
  *
  * @dev: the device structure
  *
  * Return: 0 on success an error code otherwise
  */
-int mei_me_pg_enter_sync(struct mei_device *dev)
+static int mei_me_pg_legacy_enter_sync(struct mei_device *dev)
 {
 	struct mei_me_hw *hw = to_me_hw(dev);
 	unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
@@ -646,13 +675,13 @@ int mei_me_pg_enter_sync(struct mei_device *dev)
 }
 
 /**
- * mei_me_pg_exit_sync - perform pg exit procedure
+ * mei_me_pg_legacy_exit_sync - perform legacy pg exit procedure
  *
  * @dev: the device structure
  *
  * Return: 0 on success an error code otherwise
  */
-int mei_me_pg_exit_sync(struct mei_device *dev)
+static int mei_me_pg_legacy_exit_sync(struct mei_device *dev)
 {
 	struct mei_me_hw *hw = to_me_hw(dev);
 	unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
@@ -720,8 +749,12 @@ static bool mei_me_pg_in_transition(struct mei_device *dev)
  */
 static bool mei_me_pg_is_enabled(struct mei_device *dev)
 {
+	struct mei_me_hw *hw = to_me_hw(dev);
 	u32 reg = mei_me_mecsr_read(dev);
 
+	if (hw->d0i3_supported)
+		return true;
+
 	if ((reg & ME_PGIC_HRA) == 0)
 		goto notsupported;
 
@@ -731,7 +764,8 @@ static bool mei_me_pg_is_enabled(struct mei_device *dev)
 	return true;
 
 notsupported:
-	dev_dbg(dev->dev, "pg: not supported: HGP = %d hbm version %d.%d ?= %d.%d\n",
+	dev_dbg(dev->dev, "pg: not supported: d0i3 = %d HGP = %d hbm version %d.%d ?= %d.%d\n",
+		hw->d0i3_supported,
 		!!(reg & ME_PGIC_HRA),
 		dev->version.major_version,
 		dev->version.minor_version,
@@ -742,11 +776,211 @@ static bool mei_me_pg_is_enabled(struct mei_device *dev)
 }
 
 /**
- * mei_me_pg_intr - perform pg processing in interrupt thread handler
+ * mei_me_d0i3_set - write d0i3 register bit on mei device.
+ *
+ * @dev: the device structure
+ * @intr: ask for interrupt
+ *
+ * Return: D0I3C register value
+ */
+static u32 mei_me_d0i3_set(struct mei_device *dev, bool intr)
+{
+	u32 reg = mei_me_d0i3c_read(dev);
+
+	reg |= H_D0I3C_I3;
+	if (intr)
+		reg |= H_D0I3C_IR;
+	else
+		reg &= ~H_D0I3C_IR;
+	mei_me_d0i3c_write(dev, reg);
+	/* read it to ensure HW consistency */
+	reg = mei_me_d0i3c_read(dev);
+	return reg;
+}
+
+/**
+ * mei_me_d0i3_unset - clean d0i3 register bit on mei device.
  *
  * @dev: the device structure
+ *
+ * Return: D0I3C register value
  */
-static void mei_me_pg_intr(struct mei_device *dev)
+static u32 mei_me_d0i3_unset(struct mei_device *dev)
+{
+	u32 reg = mei_me_d0i3c_read(dev);
+
+	reg &= ~H_D0I3C_I3;
+	reg |= H_D0I3C_IR;
+	mei_me_d0i3c_write(dev, reg);
+	/* read it to ensure HW consistency */
+	reg = mei_me_d0i3c_read(dev);
+	return reg;
+}
+
+/**
+ * mei_me_d0i3_enter_sync - perform d0i3 entry procedure
+ *
+ * @dev: the device structure
+ *
+ * Return: 0 on success an error code otherwise
+ */
+static int mei_me_d0i3_enter_sync(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+	unsigned long d0i3_timeout = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
+	unsigned long pgi_timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
+	int ret;
+	u32 reg;
+
+	reg = mei_me_d0i3c_read(dev);
+	if (reg & H_D0I3C_I3) {
+		/* we are in d0i3, nothing to do */
+		dev_dbg(dev->dev, "d0i3 set not needed\n");
+		ret = 0;
+		goto on;
+	}
+
+	/* PGI entry procedure */
+	dev->pg_event = MEI_PG_EVENT_WAIT;
+
+	ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_ENTRY_REQ_CMD);
+	if (ret)
+		/* FIXME: should we reset here? */
+		goto out;
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(dev->wait_pg,
+		dev->pg_event == MEI_PG_EVENT_RECEIVED, pgi_timeout);
+	mutex_lock(&dev->device_lock);
+
+	if (dev->pg_event != MEI_PG_EVENT_RECEIVED) {
+		ret = -ETIME;
+		goto out;
+	}
+	/* end PGI entry procedure */
+
+	dev->pg_event = MEI_PG_EVENT_INTR_WAIT;
+
+	reg = mei_me_d0i3_set(dev, true);
+	if (!(reg & H_D0I3C_CIP)) {
+		dev_dbg(dev->dev, "d0i3 enter wait not needed\n");
+		ret = 0;
+		goto on;
+	}
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(dev->wait_pg,
+		dev->pg_event == MEI_PG_EVENT_INTR_RECEIVED, d0i3_timeout);
+	mutex_lock(&dev->device_lock);
+
+	if (dev->pg_event != MEI_PG_EVENT_INTR_RECEIVED) {
+		reg = mei_me_d0i3c_read(dev);
+		if (!(reg & H_D0I3C_I3)) {
+			ret = -ETIME;
+			goto out;
+		}
+	}
+
+	ret = 0;
+on:
+	hw->pg_state = MEI_PG_ON;
+out:
+	dev->pg_event = MEI_PG_EVENT_IDLE;
+	dev_dbg(dev->dev, "d0i3 enter ret = %d\n", ret);
+	return ret;
+}
+
+/**
+ * mei_me_d0i3_enter - perform d0i3 entry procedure
+ *   no hbm PG handshake
+ *   no waiting for confirmation; runs with interrupts
+ *   disabled
+ *
+ * @dev: the device structure
+ *
+ * Return: 0 on success an error code otherwise
+ */
+static int mei_me_d0i3_enter(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+	u32 reg;
+
+	reg = mei_me_d0i3c_read(dev);
+	if (reg & H_D0I3C_I3) {
+		/* we are in d0i3, nothing to do */
+		dev_dbg(dev->dev, "already d0i3 : set not needed\n");
+		goto on;
+	}
+
+	mei_me_d0i3_set(dev, false);
+on:
+	hw->pg_state = MEI_PG_ON;
+	dev->pg_event = MEI_PG_EVENT_IDLE;
+	dev_dbg(dev->dev, "d0i3 enter\n");
+	return 0;
+}
+
+/**
+ * mei_me_d0i3_exit_sync - perform d0i3 exit procedure
+ *
+ * @dev: the device structure
+ *
+ * Return: 0 on success an error code otherwise
+ */
+static int mei_me_d0i3_exit_sync(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+	unsigned long timeout = mei_secs_to_jiffies(MEI_D0I3_TIMEOUT);
+	int ret;
+	u32 reg;
+
+	dev->pg_event = MEI_PG_EVENT_INTR_WAIT;
+
+	reg = mei_me_d0i3c_read(dev);
+	if (!(reg & H_D0I3C_I3)) {
+		/* we are not in d0i3, nothing to do */
+		dev_dbg(dev->dev, "d0i3 exit not needed\n");
+		ret = 0;
+		goto off;
+	}
+
+	reg = mei_me_d0i3_unset(dev);
+	if (!(reg & H_D0I3C_CIP)) {
+		dev_dbg(dev->dev, "d0i3 exit wait not needed\n");
+		ret = 0;
+		goto off;
+	}
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(dev->wait_pg,
+		dev->pg_event == MEI_PG_EVENT_INTR_RECEIVED, timeout);
+	mutex_lock(&dev->device_lock);
+
+	if (dev->pg_event != MEI_PG_EVENT_INTR_RECEIVED) {
+		reg = mei_me_d0i3c_read(dev);
+		if (reg & H_D0I3C_I3) {
+			ret = -ETIME;
+			goto out;
+		}
+	}
+
+	ret = 0;
+off:
+	hw->pg_state = MEI_PG_OFF;
+out:
+	dev->pg_event = MEI_PG_EVENT_IDLE;
+
+	dev_dbg(dev->dev, "d0i3 exit ret = %d\n", ret);
+	return ret;
+}
+
+/**
+ * mei_me_pg_legacy_intr - perform legacy pg processing
+ *			   in interrupt thread handler
+ *
+ * @dev: the device structure
+ */
+static void mei_me_pg_legacy_intr(struct mei_device *dev)
 {
 	struct mei_me_hw *hw = to_me_hw(dev);
 
@@ -759,6 +993,95 @@ static void mei_me_pg_intr(struct mei_device *dev)
 		wake_up(&dev->wait_pg);
 }
 
+/**
+ * mei_me_d0i3_intr - perform d0i3 processing in interrupt thread handler
+ *
+ * @dev: the device structure
+ */
+static void mei_me_d0i3_intr(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+
+	if (dev->pg_event == MEI_PG_EVENT_INTR_WAIT &&
+	    (hw->intr_source & H_D0I3C_IS)) {
+		dev->pg_event = MEI_PG_EVENT_INTR_RECEIVED;
+		if (hw->pg_state == MEI_PG_ON) {
+			hw->pg_state = MEI_PG_OFF;
+			if (dev->hbm_state != MEI_HBM_IDLE) {
+				/*
+				 * force H_RDY because it could be
+				 * wiped off during PG
+				 */
+				dev_dbg(dev->dev, "d0i3 set host ready\n");
+				mei_me_host_set_ready(dev);
+			}
+		} else {
+			hw->pg_state = MEI_PG_ON;
+		}
+
+		wake_up(&dev->wait_pg);
+	}
+
+	if (hw->pg_state == MEI_PG_ON && (hw->intr_source & H_IS)) {
+		/*
+		 * HW sent some data and we are in D0i3, so
+		 * we got here because of HW initiated exit from D0i3.
+		 * Start runtime pm resume sequence to exit low power state.
+		 */
+		dev_dbg(dev->dev, "d0i3 want resume\n");
+		mei_hbm_pg_resume(dev);
+	}
+}
+
+/**
+ * mei_me_pg_intr - perform pg processing in interrupt thread handler
+ *
+ * @dev: the device structure
+ */
+static void mei_me_pg_intr(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+
+	if (hw->d0i3_supported)
+		mei_me_d0i3_intr(dev);
+	else
+		mei_me_pg_legacy_intr(dev);
+}
+
+/**
+ * mei_me_pg_enter_sync - perform runtime pm entry procedure
+ *
+ * @dev: the device structure
+ *
+ * Return: 0 on success an error code otherwise
+ */
+int mei_me_pg_enter_sync(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+
+	if (hw->d0i3_supported)
+		return mei_me_d0i3_enter_sync(dev);
+	else
+		return mei_me_pg_legacy_enter_sync(dev);
+}
+
+/**
+ * mei_me_pg_exit_sync - perform runtime pm exit procedure
+ *
+ * @dev: the device structure
+ *
+ * Return: 0 on success an error code otherwise
+ */
+int mei_me_pg_exit_sync(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+
+	if (hw->d0i3_supported)
+		return mei_me_d0i3_exit_sync(dev);
+	else
+		return mei_me_pg_legacy_exit_sync(dev);
+}
+
 /**
  * mei_me_irq_quick_handler - The ISR of the MEI device
  *

drivers/misc/mei/hw.h

@@ -32,6 +32,7 @@
 #define MEI_IAMTHIF_READ_TIMER     10  /* HPS */
 
 #define MEI_PGI_TIMEOUT             1  /* PG Isolation time response 1 sec */
+#define MEI_D0I3_TIMEOUT            5  /* D0i3 set/unset max response time */
 #define MEI_HBM_TIMEOUT             1  /* 1 second */
 
 /*