PCI/switchtec: Fix a MRPC error status handling issue

If an error is encountered when executing a MRPC command, the firmware
will set the status register to SWITCHTEC_MRPC_STATUS_ERROR and return
the error code in the return value register.

Add handling of SWITCHTEC_MRPC_STATUS_ERROR on status register when
completing a MRPC command.

Link: https://lore.kernel.org/r/20211014141859.11444-3-kelvin.cao@microchip.com
Signed-off-by: Kelvin Cao <kelvin.cao@microchip.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index e5bb2ac0e7bb06650bd9422570fba437b3cc3c51..5c300ff3921daeb9185b95b9b9d739184af76e07 100644 (file)
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -238,7 +238,8 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev)
        stuser_set_state(stuser, MRPC_DONE);
        stuser->return_code = 0;
 
-       if (stuser->status != SWITCHTEC_MRPC_STATUS_DONE)
+       if (stuser->status != SWITCHTEC_MRPC_STATUS_DONE &&
+           stuser->status != SWITCHTEC_MRPC_STATUS_ERROR)
                goto out;
 
        if (stdev->dma_mrpc)
@@ -622,7 +623,8 @@ static ssize_t switchtec_dev_read(struct file *filp, char __user *data,
 out:
        mutex_unlock(&stdev->mrpc_mutex);
 
-       if (stuser->status == SWITCHTEC_MRPC_STATUS_DONE)
+       if (stuser->status == SWITCHTEC_MRPC_STATUS_DONE ||
+           stuser->status == SWITCHTEC_MRPC_STATUS_ERROR)
                return size;
        else if (stuser->status == SWITCHTEC_MRPC_STATUS_INTERRUPTED)
                return -ENXIO;