On 2021-03-05 08:14 AM, Loic Poulain wrote:
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 aborded and error reported, to let the
s/aborded/aborted
controller handling 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@xxxxxxxxxx>
---
drivers/bus/mhi/core/pm.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
index 0cd6445..725a0b2 100644
--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -916,6 +916,9 @@ 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);
We've had this check internally in the past but instead of reading the
register,
we just used if (mhi_cntrl->pm_state != MHI_PM_M3) to panic.
I like this version better. No reason why we shouldn't attempt to access
the
link due to read_reg being defined in the controller.
Reviewed-by: Bhaumik Bhatt <bbhatt@xxxxxxxxxxxxxx>
Thanks,
Bhaumik
---
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