Hi Douglas,
Am 04.03.2016 um 23:54 schrieb Michael Niewoehner <linux@xxxxxxxxxxxxxx>:
> Hi Douglas,
>
> Am 04.03.2016 um 19:23 schrieb Douglas Anderson <dianders@xxxxxxxxxxxx>:
>
>> From testing and trying to make sense of the documentation, it appears
>> that a 10 ms delay is needed after resetting the core to make sure that
>> everything is stable and consistent. Let's add it.
>>
>> In my testing (on rk3288) this allows us to revert commit
>> 192cb07f7928 ("usb: dwc2: Fix probe problem on bcm2835"). Though I
>> could never reproduce the problems on my board, this might also allow us
>> to revert commit bd84f4ae9986 ("usb: dwc2: Add extra delay when forcing
>> dr_mode").
>>
>> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
>
> Tested-by: Michael Niewoehner <linux@xxxxxxxxxxxxxx>
>
>> ---
>> drivers/usb/dwc2/core.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
>> index 5e5a0f135b5a..8710b2d3e770 100644
>> --- a/drivers/usb/dwc2/core.c
>> +++ b/drivers/usb/dwc2/core.c
>> @@ -277,6 +277,26 @@ int dwc2_core_reset(struct dwc2_hsotg *hsotg)
>> }
>> } while (!(greset & GRSTCTL_AHBIDLE));
>>
>> + /*
>> + * Sleep for 10-15 ms after the reset to let it finish.
>> + *
>> + * It's been confirmed on at least one version of the controller
>> + * that this is a requirement that this is a requirement in order for
>> + * everything to settle. Specifically if you:
>> + * - change GNPTXFSIZ or HPTXFSIZ before the reset
>> + * - do the reset
>> + * - read GNPTXFSIZ or HPTXFSIZ in a loop
>> + * ...you'll find that it takes almost exactly 10 ms for the registers
>> + * to return to their reset defaults.
>> + *
>> + * Note that it's possible that this 10 ms is the time referred to
>> + * in "Host Initialization" where it says to "Wait at least 10 ms for
>> + * the reset process to complete". In "Device Initialization" there
>> + * is also talk of a reset lasting 10 ms. That may be the source of
>> + * this delay.
>> + */
>> + usleep_range(10000, 15000);
>> +
>> return 0;
>> }
>>
>> --
>> 2.7.0.rc3.207.g0ac5344
>>
>
> I’m a bit confused since git log says bd84f4ae9986 has been merged in 62718e304aa6 but looking at drivers/usb/dwc2/core.c it seems the patch has not been applied anyways ...
> However, I tested you your two patches with „magically reverted“ bd84f4ae9986 (msleep 50) on rk3188.
> The sdcard keeps being detected and boots just fine.
>
> Best regards
> Michael
I meant usb stick of course… too much sdcards in my head today \o/.
Regards
Michael
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