Commit 25794e30 authored by Hans de Goede's avatar Hans de Goede Committed by Greg Kroah-Hartman
Browse files

usb: typec: ucsi: Rework ppm_lock handling 



The ppm_lock really only needs to be hold during 2 functions:
ucsi_reset_ppm() and ucsi_run_command().

Push the taking of the lock down into these 2 functions, renaming
ucsi_run_command() to ucsi_send_command() which was an existing
wrapper already taking the lock for its callers.

This simplifies things for the callers and removes the difference
between ucsi_send_command() and ucsi_run_command() which has led
to various locking bugs in the past.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Acked-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200809141904.4317-4-hdegoede@redhat.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7e90057f

drivers/usb/typec/ucsi/ucsi.c

+22 −34
Original line number Diff line number Diff line
@@ -146,42 +146,33 @@ static int ucsi_exec_command(struct ucsi *ucsi, u64 cmd) 
	return UCSI_CCI_LENGTH(cci);

}



static int ucsi_run_command(struct ucsi *ucsi, u64 command,

int ucsi_send_command(struct ucsi *ucsi, u64 command,

		      void *data, size_t size)

{

	u8 length;

	int ret;



	WARN_ON(!mutex_is_locked(&ucsi->ppm_lock));

	mutex_lock(&ucsi->ppm_lock);



	ret = ucsi_exec_command(ucsi, command);

	if (ret < 0)

		return ret;

		goto out;



	length = ret;



	if (data) {

		ret = ucsi->ops->read(ucsi, UCSI_MESSAGE_IN, data, size);

		if (ret)

			return ret;

			goto out;

	}



	ret = ucsi_acknowledge_command(ucsi);

	if (ret)

		return ret;



	return length;

}



int ucsi_send_command(struct ucsi *ucsi, u64 command,

		      void *retval, size_t size)

{

	int ret;

		goto out;



	mutex_lock(&ucsi->ppm_lock);

	ret = ucsi_run_command(ucsi, command, retval, size);

	ret = length;

out:

	mutex_unlock(&ucsi->ppm_lock);



	return ret;

}

EXPORT_SYMBOL_GPL(ucsi_send_command);
@@ -738,20 +729,24 @@ static int ucsi_reset_ppm(struct ucsi *ucsi) 
	u32 cci;

	int ret;



	mutex_lock(&ucsi->ppm_lock);



	ret = ucsi->ops->async_write(ucsi, UCSI_CONTROL, &command,

				     sizeof(command));

	if (ret < 0)

		return ret;

		goto out;



	tmo = jiffies + msecs_to_jiffies(UCSI_TIMEOUT_MS);



	do {

		if (time_is_before_jiffies(tmo))

			return -ETIMEDOUT;

		if (time_is_before_jiffies(tmo)) {

			ret = -ETIMEDOUT;

			goto out;

		}



		ret = ucsi->ops->read(ucsi, UCSI_CCI, &cci, sizeof(cci));

		if (ret)

			return ret;

			goto out;



		/* If the PPM is still doing something else, reset it again. */

		if (cci & ~UCSI_CCI_RESET_COMPLETE) {
@@ -759,13 +754,15 @@ static int ucsi_reset_ppm(struct ucsi *ucsi) 
						     &command,

						     sizeof(command));

			if (ret < 0)

				return ret;

				goto out;

		}



		msleep(20);

	} while (!(cci & UCSI_CCI_RESET_COMPLETE));



	return 0;

out:

	mutex_unlock(&ucsi->ppm_lock);

	return ret;

}



static int ucsi_role_cmd(struct ucsi_connector *con, u64 command)
@@ -777,9 +774,7 @@ static int ucsi_role_cmd(struct ucsi_connector *con, u64 command) 
		u64 c;



		/* PPM most likely stopped responding. Resetting everything. */

		mutex_lock(&con->ucsi->ppm_lock);

		ucsi_reset_ppm(con->ucsi);

		mutex_unlock(&con->ucsi->ppm_lock);



		c = UCSI_SET_NOTIFICATION_ENABLE | con->ucsi->ntfy;

		ucsi_send_command(con->ucsi, c, NULL, 0);
@@ -1010,8 +1005,6 @@ static int ucsi_init(struct ucsi *ucsi) 
	int ret;

	int i;



	mutex_lock(&ucsi->ppm_lock);



	/* Reset the PPM */

	ret = ucsi_reset_ppm(ucsi);

	if (ret) {
@@ -1022,13 +1015,13 @@ static int ucsi_init(struct ucsi *ucsi) 
	/* Enable basic notifications */

	ucsi->ntfy = UCSI_ENABLE_NTFY_CMD_COMPLETE | UCSI_ENABLE_NTFY_ERROR;

	command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy;

	ret = ucsi_run_command(ucsi, command, NULL, 0);

	ret = ucsi_send_command(ucsi, command, NULL, 0);

	if (ret < 0)

		goto err_reset;



	/* Get PPM capabilities */

	command = UCSI_GET_CAPABILITY;

	ret = ucsi_run_command(ucsi, command, &ucsi->cap, sizeof(ucsi->cap));

	ret = ucsi_send_command(ucsi, command, &ucsi->cap, sizeof(ucsi->cap));

	if (ret < 0)

		goto err_reset;
@@ -1045,8 +1038,6 @@ static int ucsi_init(struct ucsi *ucsi) 
		goto err_reset;

	}



	mutex_unlock(&ucsi->ppm_lock);



	/* Register all connectors */

	for (i = 0; i < ucsi->cap.num_connectors; i++) {

		ret = ucsi_register_port(ucsi, i);
@@ -1072,12 +1063,9 @@ err_unregister: 
		con->port = NULL;

	}



	mutex_lock(&ucsi->ppm_lock);

err_reset:

	ucsi_reset_ppm(ucsi);

err:

	mutex_unlock(&ucsi->ppm_lock);



	return ret;

}

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