2023-05-12 02:23:53

by Qiang Yu

[permalink] [raw]
Subject: [PATCH v3] bus: mhi: host: Skip MHI reset if device is in RDDM

In RDDM EE, device can not process MHI reset issued by host. In case of MHI
power off, host is issuing MHI reset and polls for it to get cleared until
it times out. Since this timeout can not be avoided in case of RDDM, skip
the MHI reset in this scenarios.

Fixes: a6e2e3522f29 ("bus: mhi: core: Add support for PM state transitions")
Signed-off-by: Qiang Yu <[email protected]>
---
v1->v2: use ~75 columns in commit text, add Fixes tag
v2->v3: update Fixes tag

drivers/bus/mhi/host/pm.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/bus/mhi/host/pm.c b/drivers/bus/mhi/host/pm.c
index 0834590..8a4362d 100644
--- a/drivers/bus/mhi/host/pm.c
+++ b/drivers/bus/mhi/host/pm.c
@@ -470,6 +470,10 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)

/* Trigger MHI RESET so that the device will not access host memory */
if (!MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) {
+ /* Skip MHI RESET if in RDDM state */
+ if (mhi_cntrl->rddm_image && mhi_get_exec_env(mhi_cntrl) == MHI_EE_RDDM)
+ goto skip_mhi_reset;
+
dev_dbg(dev, "Triggering MHI Reset in device\n");
mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);

@@ -495,6 +499,7 @@ static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
}
}

+skip_mhi_reset:
dev_dbg(dev,
"Waiting for all pending event ring processing to complete\n");
mhi_event = mhi_cntrl->mhi_event;
--
2.7.4



2023-05-16 20:05:51

by Jeffrey Hugo

[permalink] [raw]
Subject: Re: [PATCH v3] bus: mhi: host: Skip MHI reset if device is in RDDM

On 5/11/2023 8:05 PM, Qiang Yu wrote:
> In RDDM EE, device can not process MHI reset issued by host. In case of MHI
> power off, host is issuing MHI reset and polls for it to get cleared until
> it times out. Since this timeout can not be avoided in case of RDDM, skip
> the MHI reset in this scenarios.
>
> Fixes: a6e2e3522f29 ("bus: mhi: core: Add support for PM state transitions")
> Signed-off-by: Qiang Yu <[email protected]>

I believe Mani will want you to CC stable.

Assuming that
Reviewed-by: Jeffrey Hugo <[email protected]>