mei: me: add pg exit and entry flow commands

For power gating entry we write hbm pg entry request command and
then we set pg register
For power gating exit we clear pg register and wait for exit request
hbm command.

Exit power gating request might also be initiated by the firmware
w/o explicit driver request

The power gating state is tracked by pg_state member of me_hw

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hw-me.c

@@ -109,9 +109,12 @@ static inline void mei_hcsr_set(struct mei_me_hw *hw, u32 hcsr)
  */
 static void mei_me_hw_config(struct mei_device *dev)
 {
+	struct mei_me_hw *hw = to_me_hw(dev);
 	u32 hcsr = mei_hcsr_read(to_me_hw(dev));
 	/* Doesn't change in runtime */
 	dev->hbuf_depth = (hcsr & H_CBD) >> 24;
+
+	hw->pg_state = MEI_PG_OFF;
 }
 
 /**
@@ -123,7 +126,8 @@ static void mei_me_hw_config(struct mei_device *dev)
  */
 static inline enum mei_pg_state mei_me_pg_state(struct mei_device *dev)
 {
-	return MEI_PG_OFF;
+	struct mei_me_hw *hw = to_me_hw(dev);
+	return hw->pg_state;
 }
 
 /**
@@ -472,6 +476,80 @@ static void mei_me_pg_exit(struct mei_device *dev)
 	mei_me_reg_write(hw, H_HPG_CSR, reg);
 }
 
+/**
+ * mei_me_pg_set_sync - perform pg entry procedure
+ *
+ * @dev: the device structure
+ *
+ * returns 0 on success an error code otherwise
+ */
+int mei_me_pg_set_sync(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+	unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
+	int ret;
+
+	dev->pg_event = MEI_PG_EVENT_WAIT;
+
+	ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_ENTRY_REQ_CMD);
+	if (ret)
+		return ret;
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(dev->wait_pg,
+		dev->pg_event == MEI_PG_EVENT_RECEIVED, timeout);
+	mutex_lock(&dev->device_lock);
+
+	if (dev->pg_event == MEI_PG_EVENT_RECEIVED) {
+		mei_me_pg_enter(dev);
+		ret = 0;
+	} else {
+		ret = -ETIME;
+	}
+
+	dev->pg_event = MEI_PG_EVENT_IDLE;
+	hw->pg_state = MEI_PG_ON;
+
+	return ret;
+}
+
+/**
+ * mei_me_pg_unset_sync - perform pg exit procedure
+ *
+ * @dev: the device structure
+ *
+ * returns 0 on success an error code otherwise
+ */
+int mei_me_pg_unset_sync(struct mei_device *dev)
+{
+	struct mei_me_hw *hw = to_me_hw(dev);
+	unsigned long timeout = mei_secs_to_jiffies(MEI_PGI_TIMEOUT);
+	int ret;
+
+	if (dev->pg_event == MEI_PG_EVENT_RECEIVED)
+		goto reply;
+
+	dev->pg_event = MEI_PG_EVENT_WAIT;
+
+	mei_me_pg_exit(dev);
+
+	mutex_unlock(&dev->device_lock);
+	wait_event_timeout(dev->wait_pg,
+		dev->pg_event == MEI_PG_EVENT_RECEIVED, timeout);
+	mutex_lock(&dev->device_lock);
+
+reply:
+	if (dev->pg_event == MEI_PG_EVENT_RECEIVED)
+		ret = mei_hbm_pg(dev, MEI_PG_ISOLATION_EXIT_RES_CMD);
+	else
+		ret = -ETIME;
+
+	dev->pg_event = MEI_PG_EVENT_IDLE;
+	hw->pg_state = MEI_PG_OFF;
+
+	return ret;
+}
+
 /**
  * mei_me_pg_is_enabled - detect if PG is supported by HW
  *
@@ -601,9 +679,15 @@ irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
 
 	dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
 
-	rets = mei_irq_write_handler(dev, &complete_list);
-
-	dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
+	/*
+	 * During PG handshake only allowed write is the replay to the
+	 * PG exit message, so block calling write function
+	 * if the pg state is not idle
+	 */
+	if (dev->pg_event == MEI_PG_EVENT_IDLE) {
+		rets = mei_irq_write_handler(dev, &complete_list);
+		dev->hbuf_is_ready = mei_hbuf_is_ready(dev);
+	}
 
 	mei_irq_compl_handler(dev, &complete_list);