mei: expose hardware power gating state to mei layer

Since the runtime pm and the internal power gating
cannot be in complete sync in regards to I/O
operations, we need to expose the device
hardware internal power gating state to mei layer

2. We add pg_state handler that translate the hw
internal pg state to mei layer

2. We add power gating event variable to keep
power track of power gating transitions
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Reviewed-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/hw-me.c

@@ -113,6 +113,19 @@ static void mei_me_hw_config(struct mei_device *dev)
 	/* Doesn't change in runtime */
 	dev->hbuf_depth = (hcsr & H_CBD) >> 24;
 }
+
+/**
+ * mei_me_pg_state  - translate internal pg state
+ *   to the mei power gating state
+ *
+ * @hw -  me hardware
+ * returns: MEI_PG_OFF if aliveness is on and MEI_PG_ON otherwise
+ */
+static inline enum mei_pg_state mei_me_pg_state(struct mei_device *dev)
+{
+	return MEI_PG_OFF;
+}
+
 /**
  * mei_clear_interrupts - clear and stop interrupts
  *
@@ -601,6 +614,8 @@ irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
 }
 static const struct mei_hw_ops mei_me_hw_ops = {
 
+	.pg_state  = mei_me_pg_state,
+
 	.host_is_ready = mei_me_host_is_ready,
 
 	.hw_is_ready = mei_me_hw_is_ready,

drivers/misc/mei/hw-txe.c

@@ -158,7 +158,7 @@ static bool mei_txe_aliveness_set(struct mei_device *dev, u32 req)
 	dev_dbg(&dev->pdev->dev, "Aliveness current=%d request=%d\n",
 				hw->aliveness, req);
 	if (do_req) {
-		hw->recvd_aliveness = false;
+		dev->pg_event = MEI_PG_EVENT_WAIT;
 		mei_txe_br_reg_write(hw, SICR_HOST_ALIVENESS_REQ_REG, req);
 	}
 	return do_req;
@@ -213,6 +213,7 @@ static int mei_txe_aliveness_poll(struct mei_device *dev, u32 expected)
 	do {
 		hw->aliveness = mei_txe_aliveness_get(dev);
 		if (hw->aliveness == expected) {
+			dev->pg_event = MEI_PG_EVENT_IDLE;
 			dev_dbg(&dev->pdev->dev,
 				"aliveness settled after %d msecs\n", t);
 			return t;
@@ -223,6 +224,7 @@ static int mei_txe_aliveness_poll(struct mei_device *dev, u32 expected)
 		t += MSEC_PER_SEC / 5;
 	} while (t < SEC_ALIVENESS_WAIT_TIMEOUT);
 
+	dev->pg_event = MEI_PG_EVENT_IDLE;
 	dev_err(&dev->pdev->dev, "aliveness timed out\n");
 	return -ETIME;
 }
@@ -249,19 +251,22 @@ static int mei_txe_aliveness_wait(struct mei_device *dev, u32 expected)
 		return 0;
 
 	mutex_unlock(&dev->device_lock);
-	err = wait_event_timeout(hw->wait_aliveness,
-			hw->recvd_aliveness, timeout);
+	err = wait_event_timeout(hw->wait_aliveness_resp,
+			dev->pg_event == MEI_PG_EVENT_RECEIVED, timeout);
 	mutex_lock(&dev->device_lock);
 
 	hw->aliveness = mei_txe_aliveness_get(dev);
 	ret = hw->aliveness == expected ? 0 : -ETIME;
 
 	if (ret)
-		dev_err(&dev->pdev->dev, "aliveness timed out");
+		dev_warn(&dev->pdev->dev, "aliveness timed out = %ld aliveness = %d event = %d\n",
+			err, hw->aliveness, dev->pg_event);
 	else
-		dev_dbg(&dev->pdev->dev, "aliveness settled after %d msecs\n",
-				jiffies_to_msecs(timeout - err));
-	hw->recvd_aliveness = false;
+		dev_dbg(&dev->pdev->dev, "aliveness settled after = %d msec aliveness = %d event = %d\n",
+			jiffies_to_msecs(timeout - err),
+			hw->aliveness, dev->pg_event);
+
+	dev->pg_event = MEI_PG_EVENT_IDLE;
 	return ret;
 }
 
@@ -291,6 +296,20 @@ static bool mei_txe_pg_is_enabled(struct mei_device *dev)
 	return true;
 }
 
+/**
+ * mei_txe_pg_state  - translate aliveness register value
+ *   to the mei power gating state
+ *
+ * @dev: the device structure
+ *
+ * returns: MEI_PG_OFF if aliveness is on and MEI_PG_ON otherwise
+ */
+static inline enum mei_pg_state mei_txe_pg_state(struct mei_device *dev)
+{
+	struct mei_txe_hw *hw = to_txe_hw(dev);
+	return hw->aliveness ? MEI_PG_OFF : MEI_PG_ON;
+}
+
 /**
  * mei_txe_input_ready_interrupt_enable - sets the Input Ready Interrupt
  *
@@ -972,9 +991,9 @@ irqreturn_t mei_txe_irq_thread_handler(int irq, void *dev_id)
 		/* Clear the interrupt cause */
 		dev_dbg(&dev->pdev->dev,
 			"Aliveness Interrupt: Status: %d\n", hw->aliveness);
-		hw->recvd_aliveness = true;
-		if (waitqueue_active(&hw->wait_aliveness))
-			wake_up(&hw->wait_aliveness);
+		dev->pg_event = MEI_PG_EVENT_RECEIVED;
+		if (waitqueue_active(&hw->wait_aliveness_resp))
+			wake_up(&hw->wait_aliveness_resp);
 	}
 
 
@@ -1024,6 +1043,8 @@ static const struct mei_hw_ops mei_txe_hw_ops = {
 
 	.host_is_ready = mei_txe_host_is_ready,
 
+	.pg_state = mei_txe_pg_state,
+
 	.hw_is_ready = mei_txe_hw_is_ready,
 	.hw_reset = mei_txe_hw_reset,
 	.hw_config = mei_txe_hw_config,
@@ -1069,7 +1090,7 @@ struct mei_device *mei_txe_dev_init(struct pci_dev *pdev)
 
 	hw = to_txe_hw(dev);
 
-	init_waitqueue_head(&hw->wait_aliveness);
+	init_waitqueue_head(&hw->wait_aliveness_resp);
 
 	dev->ops = &mei_txe_hw_ops;
 

drivers/misc/mei/hw-txe.h

@@ -38,8 +38,7 @@
  * @mem_addr:            SeC and BRIDGE bars
  * @aliveness:           aliveness (power gating) state of the hardware
  * @readiness:           readiness state of the hardware
- * @wait_aliveness:  aliveness wait queue
- * @recvd_aliveness: aliveness interrupt was recived
+ * @wait_aliveness_resp: aliveness wait queue
  * @intr_cause:          translated interrupt cause
  */
 struct mei_txe_hw {
@@ -48,8 +47,7 @@ struct mei_txe_hw {
 	u32 readiness;
 	u32 slots;
 
-	wait_queue_head_t wait_aliveness;
-	bool recvd_aliveness;
+	wait_queue_head_t wait_aliveness_resp;
 
 	unsigned long intr_cause;
 };

drivers/misc/mei/init.c

@@ -341,6 +341,8 @@ void mei_device_init(struct mei_device *dev)
 	 * 0: Reserved for MEI Bus Message communications
 	 */
 	bitmap_set(dev->host_clients_map, 0, 1);
+
+	dev->pg_event = MEI_PG_EVENT_IDLE;
 }
 EXPORT_SYMBOL_GPL(mei_device_init);
 

drivers/misc/mei/mei_dev.h

@@ -220,6 +220,7 @@ struct mei_cl {
  * @hw_start         - start hw after reset
  * @hw_config        - configure hw
 
+ * @pg_state         - power gating state of the device
  * @pg_is_enabled    - is power gating enabled
 
  * @intr_clear       - clear pending interrupts
@@ -246,6 +247,7 @@ struct mei_hw_ops {
 	int (*hw_start)(struct mei_device *dev);
 	void (*hw_config)(struct mei_device *dev);
 
+	enum mei_pg_state (*pg_state)(struct mei_device *dev);
 	bool (*pg_is_enabled)(struct mei_device *dev);
 
 	void (*intr_clear)(struct mei_device *dev);
@@ -335,11 +337,37 @@ struct mei_cl_device {
 	void *priv_data;
 };
 
+
+ /**
+ * enum mei_pg_event - power gating transition events
+ *
+ * @MEI_PG_EVENT_IDLE: the driver is not in power gating transition
+ * @MEI_PG_EVENT_WAIT: the driver is waiting for a pg event to complete
+ * @MEI_PG_EVENT_RECEIVED: the driver received pg event
+ */
+enum mei_pg_event {
+	MEI_PG_EVENT_IDLE,
+	MEI_PG_EVENT_WAIT,
+	MEI_PG_EVENT_RECEIVED,
+};
+
+/**
+ * enum mei_pg_state - device internal power gating state
+ *
+ * @MEI_PG_OFF: device is not power gated - it is active
+ * @MEI_PG_ON:  device is power gated - it is in lower power state
+ */
+enum mei_pg_state {
+	MEI_PG_OFF = 0,
+	MEI_PG_ON =  1,
+};
+
 /**
  * struct mei_device -  MEI private device struct
 
  * @reset_count - limits the number of consecutive resets
  * @hbm_state - state of host bus message protocol
+ * @pg_event - power gating event
  * @mem_addr - mem mapped base register address
 
  * @hbuf_depth - depth of hardware host/write buffer is slots
@@ -387,6 +415,11 @@ struct mei_device {
 	enum mei_hbm_state hbm_state;
 	u16 init_clients_timer;
 
+	/*
+	 * Power Gating support
+	 */
+	enum mei_pg_event pg_event;
+
 	unsigned char rd_msg_buf[MEI_RD_MSG_BUF_SIZE];	/* control messages */
 	u32 rd_msg_hdr;
 
@@ -563,6 +596,11 @@ static inline void mei_hw_config(struct mei_device *dev)
 	dev->ops->hw_config(dev);
 }
 
+static inline enum mei_pg_state mei_pg_state(struct mei_device *dev)
+{
+	return dev->ops->pg_state(dev);
+}
+
 static inline bool mei_pg_is_enabled(struct mei_device *dev)
 {
 	return dev->ops->pg_is_enabled(dev);