From: Bhaumik Bhatt <bbhatt@codeaurora.org>
To: Loic Poulain <loic.poulain@linaro.org>
Cc: manivannan.sadhasivam@linaro.org, hemantk@codeaurora.org,
linux-arm-msm@vger.kernel.org, jhugo@codeaurora.org
Subject: Re: [PATCH] bus: mhi: Early MHI resume failure in non M3 state
Date: Fri, 05 Mar 2021 09:26:57 -0800 [thread overview]
Message-ID: <59a13660c4177299e036baa9e1f219ea@codeaurora.org> (raw)
In-Reply-To: <1614960841-20233-1-git-send-email-loic.poulain@linaro.org>
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@linaro.org>
> ---
> 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@codeaurora.org>
Thanks,
Bhaumik
---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2021-03-05 17:27 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-05 16:14 [PATCH] bus: mhi: Early MHI resume failure in non M3 state Loic Poulain
2021-03-05 17:26 ` Bhaumik Bhatt [this message]
2021-03-10 13:58 ` Manivannan Sadhasivam
2021-05-26 19:03 ` patchwork-bot+linux-arm-msm
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