Re: [PATCH V2] wlcore: sdio: Fixup power on/off sequence

[Ulf Hansson]

On Tue, 22 Jan 2019 at 17:08, Jan Kiszka <jan.kiszka@xxxxxx> wrote:
>
> On 21.01.19 15:40, Ulf Hansson wrote:
> > On Fri, 18 Jan 2019 at 16:09, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
> >>
> >> On Fri, 18 Jan 2019 at 13:09, Jan Kiszka <jan.kiszka@xxxxxx> wrote:
> >>>
> >>> On 17.01.19 10:54, Ulf Hansson wrote:
> >>>> On Wed, 16 Jan 2019 at 21:26, Jan Kiszka <jan.kiszka@xxxxxx> wrote:
> >>>>>
> >>>>> On 16.01.19 12:37, Ulf Hansson wrote:
> >>>>>> During "wlan-up", we are programming the FW into the WiFi-chip. However,
> >>>>>> re-programming the FW doesn't work, unless a power cycle of the WiFi-chip
> >>>>>> is made in-between the programmings.
> >>>>>>
> >>>>>> To conform to this requirement and to fix the regression in a simple way,
> >>>>>> let's start by allowing that the SDIO card (WiFi-chip) may stay powered on
> >>>>>> (runtime resumed) when wl12xx_sdio_power_off() returns. The intent with the
> >>>>>> current code is to treat this scenario as an error, but unfortunate this
> >>>>>> doesn't work as expected, so let's fix this.
> >>>>>>
> >>>>>> The other part is to guarantee that a power cycle of the SDIO card has been
> >>>>>> completed when wl12xx_sdio_power_on() returns, as to allow the FW
> >>>>>> programming to succeed. However, relying solely on runtime PM to deal with
> >>>>>> this isn't sufficient. For example, userspace may prevent runtime suspend
> >>>>>> via sysfs for the device that represents the SDIO card, leading to that the
> >>>>>> mmc core also keeps it powered on. For this reason, let's instead do a
> >>>>>> brute force power cycle in wl12xx_sdio_power_on().
> >>>>>>
> >>>>>> Fixes: 728a9dc61f13 ("wlcore: sdio: Fix flakey SDIO runtime PM handling")
> >>>>>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> >>>>>> ---
> >>>>>>
> >>>>>> Changes in v2:
> >>>>>>         - Keep the SDIO host claimed when calling mmc_hw_reset().
> >>>>>>         - Add a fixes tag.
> >>>>>> ---
> >>>>>>     drivers/net/wireless/ti/wlcore/sdio.c | 15 +++++++--------
> >>>>>>     1 file changed, 7 insertions(+), 8 deletions(-)
> >>>>>>
> >>>>>> diff --git a/drivers/net/wireless/ti/wlcore/sdio.c b/drivers/net/wireless/ti/wlcore/sdio.c
> >>>>>> index bd10165d7eec..4d4b07701149 100644
> >>>>>> --- a/drivers/net/wireless/ti/wlcore/sdio.c
> >>>>>> +++ b/drivers/net/wireless/ti/wlcore/sdio.c
> >>>>>> @@ -164,6 +164,12 @@ static int wl12xx_sdio_power_on(struct wl12xx_sdio_glue *glue)
> >>>>>>         }
> >>>>>>
> >>>>>>         sdio_claim_host(func);
> >>>>>> +     /*
> >>>>>> +      * To guarantee that the SDIO card is power cycled, as required to make
> >>>>>> +      * the FW programming to succeed, let's do a brute force HW reset.
> >>>>>> +      */
> >>>>>> +     mmc_hw_reset(card->host);
> >>>>>> +
> >>>>>>         sdio_enable_func(func);
> >>>>>>         sdio_release_host(func);
> >>>>>>
> >>>>>> @@ -174,20 +180,13 @@ static int wl12xx_sdio_power_off(struct wl12xx_sdio_glue *glue)
> >>>>>>     {
> >>>>>>         struct sdio_func *func = dev_to_sdio_func(glue->dev);
> >>>>>>         struct mmc_card *card = func->card;
> >>>>>> -     int error;
> >>>>>>
> >>>>>>         sdio_claim_host(func);
> >>>>>>         sdio_disable_func(func);
> >>>>>>         sdio_release_host(func);
> >>>>>>
> >>>>>>         /* Let runtime PM know the card is powered off */
> >>>>>> -     error = pm_runtime_put(&card->dev);
> >>>>>> -     if (error < 0 && error != -EBUSY) {
> >>>>>> -             dev_err(&card->dev, "%s failed: %i\n", __func__, error);
> >>>>>> -
> >>>>>> -             return error;
> >>>>>> -     }
> >>>>>> -
> >>>>>> +     pm_runtime_put(&card->dev);
> >>>>>>         return 0;
> >>>>>>     }
> >>>>>>
> >>>>>>
> >>>>>
> >>>>> Just tested on both HiKey (620) and Ultra96 but it fails to fix the issue on
> >>>>> both. I'm getting
> >>>>>
> >>>>> wl1271_sdio: probe of mmc2:0001:1 failed with error -16
> >>>>>
> >>>>> during boot again, and the interface is not available.
> >>>>
> >>>> Okay, sounds like this may be a different problem then. Can you share
> >>>> the complete log and the kernel config?
> >>>
> >>> You can find the config here [1], log from the HiKey boot attached.
> >>>
> >>>> I can prepare a debug patch as well, if you are willing to re-run the test?
> >>>
> >>> Sure, send it over, I can run it.
> >>
> >> Alright, sounds great. However, I need to defer that to Monday/Tuesday
> >> next week.
> >>
> >>>
> >>>>
> >>>> Adding a post-power-on-delay-ms of 1 ms as you suggested [1], doesn't
> >>>> sounds like the correct solution to me, unless I am overlooking some
> >>>> things. The point is, since the mmc core succeeds to detect and
> >>>> initialize the SDIO card, the power sequence seems to be correct.
> >>>
> >>> Yeah, I'm not claiming at all I know what I'm doing there, just that it happens
> >>> to work.
> >>
> >> I see. Good to know, thanks!
> >>
> >>>
> >>> Jan
> >>>
> >>> [1]
> >>> https://github.com/siemens/jailhouse-images/blob/next/recipes-kernel/linux/files/arm64_defconfig_4.19
> >>
> >> I have looked through the log and the defconfig. No obvious things
> >> found at this point. Thanks for sharing them!
> >>
> >
> > So, I have put together a debug patch, mostly to verify that things
> > seems to be correct in regards to runtime PM. It should produce some
> > prints to the log, particular during power on/off of the SDIO card and
> > during probe of the wifi driver. Please re-run the test on top of the
> > v2 version of the $subject patch.
> >
>
> Log attached.

Thanks! Okay, so the re-initialization of the SDIO card is failing,
that's very valuable information.

I noticed one difference while comparing your log with the one I
received (offlist) from Anders... In your case the initialization
frequency that works the first time is 300KHz, while in Anders case
it's 100KHz. This sounds a bit fishy to me, so maybe there are some
problems with the pwrseq after all.

Let me think a bit and see what I can come up with as a possible solution.

In the meantime, can you re-run the test with same debug patch, but
change the post-power-on-delay-ms to let's say 10 ms in the DTS? I am
going to ask Anders to do the same test on his side, as to see if we
get different values of the found initialization frequency.

Kind regards
Uffe