From: Hemant Kumar <hemantk@codeaurora.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
jhugo@codeaurora.org, bbhatt@codeaurora.org
Subject: Re: [PATCH v1 3/5] bus: mhi: core: Skip handling BHI irq if MHI reg access is not allowed
Date: Wed, 13 May 2020 11:39:40 -0700 [thread overview]
Message-ID: <d8893525-f19d-d839-5ba3-218b5ee2ed20@codeaurora.org> (raw)
In-Reply-To: <20200513070402.GA26866@Mani-XPS-13-9360>
Hi Mani,
On 5/13/20 12:04 AM, Manivannan Sadhasivam wrote:
> On Tue, May 12, 2020 at 05:28:45PM -0700, Hemant Kumar wrote:
>> Hi Mani,
>>
>> On 5/11/20 11:53 PM, Manivannan Sadhasivam wrote:
>>> On Mon, May 11, 2020 at 07:03:07PM -0700, Hemant Kumar wrote:
>>>> Driver continues handling of BHI interrupt even if MHI register access
>>>> is not allowed. By doing so it calls the status call back and performs
>>>> early notification for the MHI client. This is not needed when MHI
>>>> register access is not allowed. Hence skip the handling in this case and
>>>> return. Also add debug log to print device state, local EE and device EE
>>>> when reg access is valid.
>>>>
>>>> Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
>>>> Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
>>>> ---
>>>> drivers/bus/mhi/core/main.c | 21 ++++++++++++++-------
>>>> 1 file changed, 14 insertions(+), 7 deletions(-)
>>>>
>>>> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
>>>> index 9ec9b36..467c0ba 100644
>>>> --- a/drivers/bus/mhi/core/main.c
>>>> +++ b/drivers/bus/mhi/core/main.c
>>>> @@ -369,22 +369,29 @@ irqreturn_t mhi_irq_handler(int irq_number, void *dev)
>>>> return IRQ_HANDLED;
>>>> }
>>>> -irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *dev)
>>>> +irqreturn_t mhi_intvec_threaded_handler(int irq_number, void *priv)
>>>> {
>>>> - struct mhi_controller *mhi_cntrl = dev;
>>>> + struct mhi_controller *mhi_cntrl = priv;
>>>> + struct device *dev = &mhi_cntrl->mhi_dev->dev;
>>>> enum mhi_state state = MHI_STATE_MAX;
>>>> enum mhi_pm_state pm_state = 0;
>>>> enum mhi_ee_type ee = 0;
>>>> write_lock_irq(&mhi_cntrl->pm_lock);
>>>> - if (MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state)) {
>>>> - state = mhi_get_mhi_state(mhi_cntrl);
>>>> - ee = mhi_cntrl->ee;
>>>> - mhi_cntrl->ee = mhi_get_exec_env(mhi_cntrl);
>>>> + if (!MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state)) {
>>>> + write_unlock_irq(&mhi_cntrl->pm_lock);
>>>
>>> write_lock is only used for protecting 'mhi_cntrl->ee' but here we are not
>>> updating it if reg access is not valid. So there is no reason to hold this lock.
>> Original code is using write_lock to protect pm_state as well as
>> mhi_cntrl->ee. This patch is keeping the lock same as original code. Just if
>> condition logic is negated here due to that write_unlock_irq is added under
>> if condition.
>
> 'mhi_cntrl->pm_state' is not always protected by 'pm_lock' and that too
> write_lock is used here but 'pm_state' is not modified. So as like in most of
> the places, locks are abused here as well.
>
> I think after 5.8, you should really think about fixing the usage of locks
> throughout the MHI stack.
>
> So I'll take this patch as it is.
>
Thanks for accepting this patch. Will revisit and review usage of locks
in MHI stack and identify areas of improvement.
> Thanks,
> Mani
>
>>>
>>>> + goto exit_intvec;
>>>> }
>>>> + state = mhi_get_mhi_state(mhi_cntrl);
>>>> + ee = mhi_cntrl->ee;
>>>> + mhi_cntrl->ee = mhi_get_exec_env(mhi_cntrl);
>>>
>>> But it is needed here.
>>>
>>> Thanks,
>>> Mani
>>>
>>>> + dev_dbg(dev, "local ee:%s device ee:%s dev_state:%s\n",
>>>> + TO_MHI_EXEC_STR(mhi_cntrl->ee), TO_MHI_EXEC_STR(ee),
>>>> + TO_MHI_STATE_STR(state));
>>>> +
>>>> if (state == MHI_STATE_SYS_ERR) {
>>>> - dev_dbg(&mhi_cntrl->mhi_dev->dev, "System error detected\n");
>>>> + dev_dbg(dev, "System error detected\n");
>>>> pm_state = mhi_tryset_pm_state(mhi_cntrl,
>>>> MHI_PM_SYS_ERR_DETECT);
>>>> }
>>>> --
>>>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>>>> a Linux Foundation Collaborative Project
>>
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
next prev parent reply other threads:[~2020-05-13 18:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-12 2:03 [PATCH v1 0/5] MHI Misc Fixes Hemant Kumar
2020-05-12 2:03 ` [PATCH v1 1/5] bus: mhi: core: Remove the system error worker thread Hemant Kumar
2020-05-12 6:46 ` Manivannan Sadhasivam
2020-05-12 2:03 ` [PATCH v1 2/5] bus: mhi: core: Handle disable transitions in state worker Hemant Kumar
2020-05-12 6:47 ` Manivannan Sadhasivam
2020-05-12 2:03 ` [PATCH v1 3/5] bus: mhi: core: Skip handling BHI irq if MHI reg access is not allowed Hemant Kumar
2020-05-12 6:53 ` Manivannan Sadhasivam
2020-05-13 0:28 ` Hemant Kumar
2020-05-13 7:04 ` Manivannan Sadhasivam
2020-05-13 18:39 ` Hemant Kumar [this message]
2020-05-13 7:58 ` Manivannan Sadhasivam
2020-05-12 2:03 ` [PATCH v1 4/5] bus: mhi: core: Do not process SYS_ERROR if RDDM is supported Hemant Kumar
2020-05-12 6:55 ` Manivannan Sadhasivam
2020-05-12 2:03 ` [PATCH v1 5/5] bus: mhi: core: Handle write lock properly in mhi_pm_m0_transition Hemant Kumar
2020-05-12 6:57 ` Manivannan Sadhasivam
2020-05-12 7:04 ` [PATCH v1 0/5] MHI Misc Fixes Manivannan Sadhasivam
2020-05-13 10:35 ` Manivannan Sadhasivam
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