Hi Minas,
Am 11.12.2017 um 11:45 schrieb Minas Harutyunyan:
> Hi Stefan,
> On 12/8/2017 8:25 PM, Stefan Wahren wrote:
>> Hi Minas,
>>
>> Am 07.12.2017 um 17:51 schrieb Stefan Wahren:
>>> Hi Minas,
>>>
>>> Am 07.12.2017 um 09:40 schrieb Stefan Wahren:
>>>> Before flushing fifos required to check AHB master state and
>>>> flush when AHB master is in IDLE state.
>>>>
>>>> Signed-off-by: Minas Harutyunyan <hminas@xxxxxxxxxxxx>
>>>> ---
>>>> drivers/usb/dwc2/core.c | 27 +++++++++++++++++++++++++++
>>>> 1 file changed, 27 insertions(+)
>>>>
>>>> diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
>>>> index dbca3b8890da..cbc7c562477f 100644
>>>> --- a/drivers/usb/dwc2/core.c
>>>> +++ b/drivers/usb/dwc2/core.c
>>>> @@ -670,10 +670,23 @@ void dwc2_flush_tx_fifo(struct dwc2_hsotg *hsotg, const int num)
>>>>
>>>> dev_vdbg(hsotg->dev, "Flush Tx FIFO %d\n", num);
>>>>
>>>> + /* Wait for AHB master IDLE state */
>>>> + do {
>>>> + udelay(1);
>>> is this delay always necessary before reading GRSTCTL?
>>>
>>> If yes please add a comment why.
>>> If no please rework the loop in order to avoid this delay in case the
>>> AHB master is already idle.
>>>
>> i've seen your Patch V2, but it isn't what i thought of. How about:
>>
>>
>> while (1) {
>> greset = dwc2_readl(hsotg->regs + GRSTCTL);
>> if (greset & GRSTCTL_AHBIDLE)
>> break;
>>
>> if (++count > 10000) {
>> dev_warn(hsotg->dev,
>> "%s() HANG! AHB Idle GRSTCTL=%0x\n",
>> __func__, greset);
>> return;
>> }
> udelay(1);
>> }
>>
> I'm Ok with above loop, just think to add udelay(1) in bottom of loop.
> udelay() required to allow AHB go to idle, if not yet.
sorry my fault, i forgot the udelay in my suggestion. I'm fine with your
addition.
>
> Actually in core.c lot of similar code: to wait for set or clear some
> bits which should be fully updated. BTW, my first patch just copied from
> dwc_core_reset() function.
>
>
>> Btw: Please provide a change history, so the maintainers can keep track
>> of your changes.
>>
>> Regards
>> Stefan
>>
> Thanks,
> Minas
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
