mei: iamthif: use regular client read functions

Reduce code duplication in amthif by reusing
regular client read functions.

The change also removes the need for amthif
own buffering
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/amthif.c

@@ -49,8 +49,6 @@ void mei_amthif_reset_params(struct mei_device *dev)
 {
 	/* reset iamthif parameters. */
 	dev->iamthif_current_cb = NULL;
-	dev->iamthif_msg_buf_size = 0;
-	dev->iamthif_msg_buf_index = 0;
 	dev->iamthif_canceled = false;
 	dev->iamthif_state = MEI_IAMTHIF_IDLE;
 	dev->iamthif_timer = 0;
@@ -69,7 +67,6 @@ int mei_amthif_host_init(struct mei_device *dev)
 {
 	struct mei_cl *cl = &dev->iamthif_cl;
 	struct mei_me_client *me_cl;
-	unsigned char *msg_buf;
 	int ret;
 
 	dev->iamthif_state = MEI_IAMTHIF_IDLE;
@@ -90,18 +87,6 @@ int mei_amthif_host_init(struct mei_device *dev)
 	dev->iamthif_mtu = me_cl->props.max_msg_length;
 	dev_dbg(dev->dev, "IAMTHIF_MTU = %d\n", dev->iamthif_mtu);
 
-	kfree(dev->iamthif_msg_buf);
-	dev->iamthif_msg_buf = NULL;
-
-	/* allocate storage for ME message buffer */
-	msg_buf = kcalloc(dev->iamthif_mtu,
-			sizeof(unsigned char), GFP_KERNEL);
-	if (!msg_buf) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	dev->iamthif_msg_buf = msg_buf;
 
 	ret = mei_cl_link(cl, MEI_IAMTHIF_HOST_CLIENT_ID);
 	if (ret < 0) {
@@ -282,9 +267,6 @@ static int mei_amthif_read_start(struct mei_cl *cl, struct file *file)
 	cb->fop_type = MEI_FOP_READ;
 	list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
 
-	dev->iamthif_msg_buf_index = 0;
-	dev->iamthif_msg_buf_size = 0;
-
 	dev->iamthif_state = MEI_IAMTHIF_READING;
 	dev->iamthif_file_object = cb->file_object;
 	dev->iamthif_current_cb = cb;
@@ -340,8 +322,6 @@ int mei_amthif_run_next_cmd(struct mei_device *dev)
 	struct mei_cl *cl = &dev->iamthif_cl;
 	struct mei_cl_cb *cb;
 
-	dev->iamthif_msg_buf_size = 0;
-	dev->iamthif_msg_buf_index = 0;
 	dev->iamthif_canceled = false;
 	dev->iamthif_state = MEI_IAMTHIF_IDLE;
 	dev->iamthif_timer = 0;
@@ -440,67 +420,34 @@ int mei_amthif_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
  *
  * @cl: mei client
  * @mei_hdr: header of amthif message
- * @complete_list: completed callbacks list
+ * @cmpl_list: completed callbacks list
  *
- * Return: Always 0; error message is in cb->status
+ * Return: -ENODEV if cb is NULL 0 otherwise; error message is in cb->status
  */
 int mei_amthif_irq_read_msg(struct mei_cl *cl,
 			    struct mei_msg_hdr *mei_hdr,
-			    struct mei_cl_cb *complete_list)
+			    struct mei_cl_cb *cmpl_list)
 {
 	struct mei_device *dev;
-	struct mei_cl_cb *cb;
-	unsigned char *buffer;
+	int ret;
 
 	dev = cl->dev;
 
-	if (cl->state != MEI_FILE_CONNECTED)
-		goto err;
-
 	if (dev->iamthif_state != MEI_IAMTHIF_READING)
-		goto err;
-
-	list_for_each_entry(cb, &dev->read_list.list, list) {
-		if (cl == cb->cl)
-			break;
-	}
-
-	if (&cb->list == &dev->read_list.list) {
-		dev_err(dev->dev, "no reader found\n");
-		goto err;
-	}
-
-	if (dev->iamthif_mtu < dev->iamthif_msg_buf_index + mei_hdr->length) {
-		cb->status = -ERANGE;
-		goto err;
-	}
-
-	buffer = dev->iamthif_msg_buf + dev->iamthif_msg_buf_index;
-	mei_read_slots(dev, buffer, mei_hdr->length);
+		return 0;
 
-	dev->iamthif_msg_buf_index += mei_hdr->length;
+	ret = mei_cl_irq_read_msg(cl, mei_hdr, cmpl_list);
+	if (ret)
+		return ret;
 
 	if (!mei_hdr->msg_complete)
 		return 0;
 
 	dev_dbg(dev->dev, "completed amthif read.\n ");
-
 	dev->iamthif_current_cb = NULL;
-
 	dev->iamthif_stall_timer = 0;
-	cb->buf_idx = dev->iamthif_msg_buf_index;
-	cb->read_time = jiffies;
-
-	dev_dbg(dev->dev, "complete the amthif read cb.\n ");
-	list_move_tail(&cb->list, &complete_list->list);
 
 	return 0;
-
-err:
-	mei_read_slots(dev, dev->rd_msg_buf, mei_hdr->length);
-	dev_dbg(dev->dev, "discarding message " MEI_HDR_FMT "\n",
-				MEI_HDR_PRM(mei_hdr));
-	return 0;
 }
 
 /**
@@ -530,8 +477,6 @@ void mei_amthif_complete(struct mei_device *dev, struct mei_cl_cb *cb)
 	if (dev->iamthif_canceled != 1) {
 		dev->iamthif_state = MEI_IAMTHIF_READ_COMPLETE;
 		dev->iamthif_stall_timer = 0;
-		memcpy(cb->response_buffer.data,
-			dev->iamthif_msg_buf, dev->iamthif_msg_buf_index);
 		list_add_tail(&cb->list, &dev->amthif_rd_complete_list.list);
 		dev_dbg(dev->dev, "amthif read completed\n");
 		dev->iamthif_timer = jiffies;

drivers/misc/mei/client.h

@@ -102,6 +102,8 @@ bool mei_cl_is_other_connecting(struct mei_cl *cl);
 int mei_cl_disconnect(struct mei_cl *cl);
 int mei_cl_connect(struct mei_cl *cl, struct file *file);
 int mei_cl_read_start(struct mei_cl *cl, size_t length);
+int mei_cl_irq_read_msg(struct mei_cl *cl, struct mei_msg_hdr *hdr,
+			struct mei_cl_cb *cmpl_list);
 int mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, bool blocking);
 int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
 		     struct mei_cl_cb *cmpl_list);

drivers/misc/mei/interrupt.c

@@ -81,6 +81,24 @@ static bool mei_cl_is_reading(struct mei_cl *cl)
 		cl->reading_state != MEI_READ_COMPLETE;
 }
 
+/**
+ * mei_irq_discard_msg  - discard received message
+ *
+ * @dev: mei device
+ * @hdr: message header
+ */
+static inline
+void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr)
+{
+	/*
+	 * no need to check for size as it is guarantied
+	 * that length fits into rd_msg_buf
+	 */
+	mei_read_slots(dev, dev->rd_msg_buf, hdr->length);
+	dev_dbg(dev->dev, "discarding message " MEI_HDR_FMT "\n",
+		MEI_HDR_PRM(hdr));
+}
+
 /**
  * mei_cl_irq_read_msg - process client message
  *
@@ -90,9 +108,9 @@ static bool mei_cl_is_reading(struct mei_cl *cl)
  *
  * Return: always 0
  */
-static int mei_cl_irq_read_msg(struct mei_cl *cl,
-			       struct mei_msg_hdr *mei_hdr,
-			       struct mei_cl_cb *complete_list)
+int mei_cl_irq_read_msg(struct mei_cl *cl,
+		       struct mei_msg_hdr *mei_hdr,
+		       struct mei_cl_cb *complete_list)
 {
 	struct mei_device *dev = cl->dev;
 	struct mei_cl_cb *cb;
@@ -144,20 +162,17 @@ static int mei_cl_irq_read_msg(struct mei_cl *cl,
 	mei_read_slots(dev, buffer, mei_hdr->length);
 
 	cb->buf_idx += mei_hdr->length;
+
 	if (mei_hdr->msg_complete) {
+		cb->read_time = jiffies;
 		cl_dbg(dev, cl, "completed read length = %lu\n",
 			cb->buf_idx);
 		list_move_tail(&cb->list, &complete_list->list);
 	}
 
 out:
-	if (!buffer) {
-		/* assume that mei_hdr->length <= MEI_RD_MSG_BUF_SIZE */
-		BUG_ON(mei_hdr->length > MEI_RD_MSG_BUF_SIZE);
-		mei_read_slots(dev, dev->rd_msg_buf, mei_hdr->length);
-		dev_dbg(dev->dev, "discarding message " MEI_HDR_FMT "\n",
-				MEI_HDR_PRM(mei_hdr));
-	}
+	if (!buffer)
+		mei_irq_discard_msg(dev, mei_hdr);
 
 	return 0;
 }
@@ -569,8 +584,6 @@ void mei_timer(struct work_struct *work)
 		if (--dev->iamthif_stall_timer == 0) {
 			dev_err(dev->dev, "timer: amthif  hanged.\n");
 			mei_reset(dev);
-			dev->iamthif_msg_buf_size = 0;
-			dev->iamthif_msg_buf_index = 0;
 			dev->iamthif_canceled = false;
 			dev->iamthif_state = MEI_IAMTHIF_IDLE;
 			dev->iamthif_timer = 0;

drivers/misc/mei/mei_dev.h

@@ -485,9 +485,6 @@ const char *mei_pg_state_str(enum mei_pg_state state);
  * @iamthif_mtu : amthif client max message length
  * @iamthif_timer : time stamp of current amthif command completion
  * @iamthif_stall_timer : timer to detect amthif hang
- * @iamthif_msg_buf : amthif current message buffer
- * @iamthif_msg_buf_size : size of current amthif message request buffer
- * @iamthif_msg_buf_index : current index in amthif message request buffer
  * @iamthif_state : amthif processor state
  * @iamthif_canceled : current amthif command is canceled
  *
@@ -583,9 +580,6 @@ struct mei_device {
 	int iamthif_mtu;
 	unsigned long iamthif_timer;
 	u32 iamthif_stall_timer;
-	unsigned char *iamthif_msg_buf; /* Note: memory has to be allocated */
-	u32 iamthif_msg_buf_size;
-	u32 iamthif_msg_buf_index;
 	enum iamthif_states iamthif_state;
 	bool iamthif_canceled;