bus: mhi: core: Check state before processing power_down

We cannot process a power_down if the power state is DISABLED.  There is
no valid mhi_ctxt in that case, so attepting to process the power_down
will likely result in a null pointer dereference.  If the power state is
DISABLED, there is nothing to do anyways, so just bail early.

Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1615409365-8165-1-git-send-email-jhugo@codeaurora.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index adb0e80974f1f2610330ba1d515ea1703c4b9097..fbe9447304017a48083022225f297d9c4e3b28f7 100644 (file)
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -1134,6 +1134,7 @@ error_setup_irq:
                mhi_deinit_dev_ctxt(mhi_cntrl);
 
 error_dev_ctxt:
+       mhi_cntrl->pm_state = MHI_PM_DISABLE;
        mutex_unlock(&mhi_cntrl->pm_mutex);
 
        return ret;
@@ -1145,12 +1146,19 @@ void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
        enum mhi_pm_state cur_state, transition_state;
        struct device *dev = &mhi_cntrl->mhi_dev->dev;
 
+       mutex_lock(&mhi_cntrl->pm_mutex);
+       write_lock_irq(&mhi_cntrl->pm_lock);
+       cur_state = mhi_cntrl->pm_state;
+       if (cur_state == MHI_PM_DISABLE) {
+               write_unlock_irq(&mhi_cntrl->pm_lock);
+               mutex_unlock(&mhi_cntrl->pm_mutex);
+               return; /* Already powered down */
+       }
+
        /* If it's not a graceful shutdown, force MHI to linkdown state */
        transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS :
                           MHI_PM_LD_ERR_FATAL_DETECT;
 
-       mutex_lock(&mhi_cntrl->pm_mutex);
-       write_lock_irq(&mhi_cntrl->pm_lock);
        cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state);
        if (cur_state != transition_state) {
                dev_err(dev, "Failed to move to state: %s from: %s\n",