staging: typec: tcpm: Add timeout when waiting for role swap completion

The Type-C protocol manager state machine could fail, which might result
in role swap requests from user space to hang forever. Add a generous
timeout when waiting for role swaps to complete to avoid this situation.

Originally-from: Badhri Jagan Sridharan <badhri@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/typec/tcpm.c b/drivers/staging/typec/tcpm.c
index ac08364..8d3a9ad 100644 (file)
--- a/drivers/staging/typec/tcpm.c
+++ b/drivers/staging/typec/tcpm.c
@@ -3165,9 +3165,12 @@ static int tcpm_dr_set(const struct typec_capability *cap,
        tcpm_set_state(port, DR_SWAP_SEND, 0);
        mutex_unlock(&port->lock);
 
-       wait_for_completion(&port->swap_complete);
+       if (!wait_for_completion_timeout(&port->swap_complete,
+                               msecs_to_jiffies(PD_ROLE_SWAP_TIMEOUT)))
+               ret = -ETIMEDOUT;
+       else
+               ret = port->swap_status;
 
-       ret = port->swap_status;
        goto swap_unlock;
 
 port_unlock:
@@ -3222,9 +3225,12 @@ static int tcpm_pr_set(const struct typec_capability *cap,
        tcpm_set_state(port, PR_SWAP_SEND, 0);
        mutex_unlock(&port->lock);
 
-       wait_for_completion(&port->swap_complete);
+       if (!wait_for_completion_timeout(&port->swap_complete,
+                               msecs_to_jiffies(PD_ROLE_SWAP_TIMEOUT)))
+               ret = -ETIMEDOUT;
+       else
+               ret = port->swap_status;
 
-       ret = port->swap_status;
        goto swap_unlock;
 
 port_unlock:
@@ -3259,9 +3265,12 @@ static int tcpm_vconn_set(const struct typec_capability *cap,
        tcpm_set_state(port, VCONN_SWAP_SEND, 0);
        mutex_unlock(&port->lock);
 
-       wait_for_completion(&port->swap_complete);
+       if (!wait_for_completion_timeout(&port->swap_complete,
+                               msecs_to_jiffies(PD_ROLE_SWAP_TIMEOUT)))
+               ret = -ETIMEDOUT;
+       else
+               ret = port->swap_status;
 
-       ret = port->swap_status;
        goto swap_unlock;
 
 port_unlock:

diff --git a/drivers/staging/typec/tcpm.h b/drivers/staging/typec/tcpm.h
index 4c6b38c..374cea4 100644 (file)
--- a/drivers/staging/typec/tcpm.h
+++ b/drivers/staging/typec/tcpm.h
@@ -34,7 +34,8 @@ enum typec_cc_polarity {
 };
 
 /* Time to wait for TCPC to complete transmit */
-#define PD_T_TCPC_TX_TIMEOUT  100
+#define PD_T_TCPC_TX_TIMEOUT   100             /* in ms        */
+#define PD_ROLE_SWAP_TIMEOUT   (MSEC_PER_SEC * 10)
 
 enum tcpm_transmit_status {
        TCPC_TX_SUCCESS = 0,