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SubjectRe: [PATCH v1 3/5] bus: mhi: core: Skip handling BHI irq if MHI reg access is not allowed
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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.
>
>> + 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

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