bus: mhi: Early MHI resume failure in non M3 state

MHI suspend/resume are symmetric and balanced procedures. If device is
not in M3 state on a resume, that means something happened behind our
back. In this case resume is aborted and error reported, to let the
controller handle the situation.

This is mainly requested for system wide suspend-resume operation in
PCI context which may lead to power-down/reset of the controller which
will then lose its MHI context. In such cases, PCI driver is supposed
to recover and reinitialize the device.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/1614960841-20233-1-git-send-email-loic.poulain@linaro.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 681960c..d61e636 100644 (file)
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -880,6 +880,9 @@ int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
        if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
                return -EIO;
 
+       if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3)
+               return -EINVAL;
+
        /* Notify clients about exiting LPM */
        list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
                mutex_lock(&itr->mutex);