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Commit cff38c32 authored by Konstantin Dorfman's avatar Konstantin Dorfman Committed by Gerrit - the friendly Code Review server
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soc:qcom:spcom: free not consumed packet on rx timeout 



Every SPU to hlos spcom data packet should be consumed by userspace
read() context. When spcomlib read() system call exits on timeout,
a packet arrived later will be stuck till next read() context arrives.

This change fixes this by removing not used packet from channel table
in following cases:
 - user character device is closed (no packet expected)
 - packet receive from SPU, by assumption, that the next read()
   belongs to different session

There is sequence number maintained for each spcom session per channel.
It is stored in a channel context and changed as follows:
 - initialized on channel creation and channel destroy
 - incremented by client side, before send new request to spcom server
 - no changes on spcom_device_open/spcom_device_release
 - incremented when timeout on spcom_rx() in order to drop later

txn_id of incoming server response is used to validate that incoming
packet has same sequence number as expected by client channel context.

Also added logic to support detection of communication
role (client/server):
 - for server: first packet is incoming from SPU
 - for client: first packet is send to SPU


Change-Id: Ied52fd6fa41255db817f1aabc2f4acf2616ee75c
Signed-off-by: default avatarKonstantin Dorfman <kdorfman@codeaurora.org>
parent ec0348d9

drivers/soc/qcom/spcom.c

+50 −11
Original line number Diff line number Diff line
@@ -151,6 +151,8 @@ struct spcom_channel { 
	struct mutex lock;

	uint32_t txn_id;           /* incrementing nonce per client request */

	bool is_server;            /* for txn_id and response_timeout_msec  */

	bool comm_role_undefined;  /* is true on channel creation, before   */

				   /* first tx/rx on channel                */

	uint32_t response_timeout_msec; /* for client only */



	/* char dev */
@@ -320,6 +322,7 @@ static int spcom_init_channel(struct spcom_channel *ch, const char *name) 
	ch->pid = 0;

	ch->rpmsg_abort = false;

	ch->rpmsg_rx_buf = NULL;

	ch->comm_role_undefined = true;



	return 0;

}
@@ -381,7 +384,9 @@ static int spcom_rx(struct spcom_channel *ch, 


		mutex_lock(&ch->lock);

		if (timeout_msec && timeleft == 0) {

			pr_err("rx_done timeout expired %d ms\n", timeout_msec);

			ch->txn_id++; /* to drop expired rx packet later */

			pr_err("rx_done timeout expired %d ms, set txn_id=%d\n",

			       timeout_msec, ch->txn_id);

			ret = -ETIMEDOUT;

			goto exit_err;

		} else if (ch->rpmsg_abort) {
@@ -395,16 +400,16 @@ static int spcom_rx(struct spcom_channel *ch, 
				ret = -ERESTARTSYS;

			goto exit_err;

		} else if (ch->actual_rx_size) {

			pr_debug("actual_rx_size is [%zu]\n",

				 ch->actual_rx_size);

			pr_debug("actual_rx_size is [%zu], txn_id %d\n",

				 ch->actual_rx_size, ch->txn_id);

		} else {

			pr_err("actual_rx_size is zero.\n");

			ret = -EFAULT;

			goto exit_err;

		}

	} else {

		pr_debug("pending data size [%zu], requested size [%u]\n",

			 ch->actual_rx_size, size);

		pr_debug("pending data size [%zu], requested size [%zu], ch->txn_id %d\n",

			 ch->actual_rx_size, size, ch->txn_id);

	}

	if (!ch->rpmsg_rx_buf) {

		pr_err("invalid rpmsg_rx_buf.\n");
@@ -624,12 +629,17 @@ static int spcom_handle_send_command(struct spcom_channel *ch, 
	hdr = tx_buf;



	mutex_lock(&ch->lock);

	/* Header */

	hdr->txn_id = ch->txn_id;

	if (ch->comm_role_undefined) {

		pr_debug("ch [%s] send first -> it is client\n", ch->name);

		ch->comm_role_undefined = false;

		ch->is_server = false;

	}



	if (!ch->is_server) {

		ch->txn_id++;   /* client sets the request txn_id */

		ch->response_timeout_msec = timeout_msec;

	}

	hdr->txn_id = ch->txn_id;



	/* user buf */

	memcpy(hdr->buf, buf, buf_size);
@@ -818,12 +828,16 @@ static int spcom_handle_send_modified_command(struct spcom_channel *ch, 
	hdr = tx_buf;



	mutex_lock(&ch->lock);

	/* Header */

	hdr->txn_id = ch->txn_id;

	if (ch->comm_role_undefined) {

		pr_debug("ch [%s] send first -> it is client\n", ch->name);

		ch->comm_role_undefined = false;

		ch->is_server = false;

	}

	if (!ch->is_server) {

		ch->txn_id++;   /* client sets the request txn_id */

		ch->response_timeout_msec = timeout_msec;

	}

	hdr->txn_id = ch->txn_id;



	/* user buf */

	memcpy(hdr->buf, buf, buf_size);
@@ -1308,7 +1322,6 @@ static int spcom_device_open(struct inode *inode, struct file *filp) 


	ch->is_busy = true;

	ch->pid = pid;

	ch->txn_id = INITIAL_TXN_ID;

	mutex_unlock(&ch->lock);



	filp->private_data = ch;
@@ -1363,7 +1376,13 @@ static int spcom_device_release(struct inode *inode, struct file *filp) 


	ch->is_busy = false;

	ch->pid = 0;

	ch->txn_id = INITIAL_TXN_ID; /* use non-zero nonce for debug */

	if (ch->rpmsg_rx_buf) {

		pr_debug("ch [%s] discarting unconsumed rx packet actual_rx_size=%d\n",

		       name, ch->actual_rx_size);

		kfree(ch->rpmsg_rx_buf);

		ch->rpmsg_rx_buf = NULL;

	}

	ch->actual_rx_size = 0;

	mutex_unlock(&ch->lock);

	filp->private_data = NULL;
@@ -1844,6 +1863,7 @@ static void spcom_signal_rx_done(struct work_struct *ignored) 
{

	struct spcom_channel *ch;

	struct rx_buff_list *rx_item;

	struct spcom_msg_hdr *hdr;

	unsigned long flags;



	spin_lock_irqsave(&spcom_dev->rx_lock, flags);
@@ -1860,7 +1880,17 @@ static void spcom_signal_rx_done(struct work_struct *ignored) 
			continue;

		}

		ch = rx_item->ch;

		hdr = (struct spcom_msg_hdr *)rx_item->rpmsg_rx_buf;

		mutex_lock(&ch->lock);



		if (ch->comm_role_undefined) {

			ch->comm_role_undefined = false;

			ch->is_server = true;

			ch->txn_id = hdr->txn_id;

			pr_debug("ch [%s] first packet txn_id=%d, it is server\n",

				 ch->name, ch->txn_id);

		}



		if (ch->rpmsg_abort) {

			if (ch->rpmsg_rx_buf) {

				pr_debug("ch [%s] rx aborted free %d bytes\n",
@@ -1873,6 +1903,13 @@ static void spcom_signal_rx_done(struct work_struct *ignored) 
		if (ch->rpmsg_rx_buf) {

			pr_err("ch [%s] previous buffer not consumed %lu bytes\n",

			       ch->name, ch->actual_rx_size);

			kfree(ch->rpmsg_rx_buf);

			ch->rpmsg_rx_buf = NULL;

			ch->actual_rx_size = 0;

		}

		if (!ch->is_server && (hdr->txn_id != ch->txn_id)) {

			pr_err("ch [%s] rx dropped txn_id %d, ch->txn_id %d\n",

				ch->name, hdr->txn_id, ch->txn_id);

			goto rx_aborted;

		}

		ch->rpmsg_rx_buf = rx_item->rpmsg_rx_buf;
@@ -1959,6 +1996,7 @@ static int spcom_rpdev_probe(struct rpmsg_device *rpdev) 
	mutex_lock(&ch->lock);

	ch->rpdev = rpdev;

	ch->rpmsg_abort = false;

	ch->txn_id = INITIAL_TXN_ID;

	complete_all(&ch->connect);

	mutex_unlock(&ch->lock);
@@ -2005,6 +2043,7 @@ static void spcom_rpdev_remove(struct rpmsg_device *rpdev) 


	ch->rpdev = NULL;

	ch->rpmsg_abort = true;

	ch->txn_id = 0;

	complete_all(&ch->rx_done);

	mutex_unlock(&ch->lock);