usb: typec: mux: intel_pmc_mux: Add retry logic to a PMC command

There are few scenerio when PMC reports 'busy condition' and command
fail.

If PMC receives a high priority command while servicing a low priority
command then it discards the low priority command and start servicing
the high priority command. The lower priority command fail and driver
returns error. If the same command resend to the PMC then PMC latches
the command and service it accordingly.

Thus adds the retry logic for the PMC command.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Tanveer Alam <tanveer1.alam@intel.com>
Link: https://lore.kernel.org/r/20220328105137.6223-1-tanveer1.alam@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
index 2cdd22130834e3813ac9fc31e38e1f00be6693cc..da6b381ddf0051b18344f0f1fff43b1d5d194d1f 100644 (file)
--- a/drivers/usb/typec/mux/intel_pmc_mux.c
+++ b/drivers/usb/typec/mux/intel_pmc_mux.c
@@ -173,7 +173,7 @@ static int hsl_orientation(struct pmc_usb_port *port)
        return port->orientation - 1;
 }
 
-static int pmc_usb_command(struct pmc_usb_port *port, u8 *msg, u32 len)
+static int pmc_usb_send_command(struct intel_scu_ipc_dev *ipc, u8 *msg, u32 len)
 {
        u8 response[4];
        u8 status_res;
@@ -184,7 +184,7 @@ static int pmc_usb_command(struct pmc_usb_port *port, u8 *msg, u32 len)
         * Status can be checked from the response message if the
         * function intel_scu_ipc_dev_command succeeds.
         */
-       ret = intel_scu_ipc_dev_command(port->pmc->ipc, PMC_USBC_CMD, 0, msg,
+       ret = intel_scu_ipc_dev_command(ipc, PMC_USBC_CMD, 0, msg,
                                        len, response, sizeof(response));
 
        if (ret)
@@ -203,6 +203,23 @@ static int pmc_usb_command(struct pmc_usb_port *port, u8 *msg, u32 len)
        return 0;
 }
 
+static int pmc_usb_command(struct pmc_usb_port *port, u8 *msg, u32 len)
+{
+       int retry_count = 3;
+       int ret;
+
+       /*
+        * If PMC is busy then retry the command once again
+        */
+       while (retry_count--) {
+               ret = pmc_usb_send_command(port->pmc->ipc, msg, len);
+               if (ret != -EBUSY)
+                       break;
+       }
+
+       return ret;
+}
+
 static int
 pmc_usb_mux_dp_hpd(struct pmc_usb_port *port, struct typec_displayport_data *dp)
 {