Message-ID: <be41bf8a-df36-7f21-7616-b1983f78b5c7@web.de>
Date:   Tue, 22 Jan 2019 17:08:13 +0100
From:   Jan Kiszka <jan.kiszka@....de>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Kalle Valo <kvalo@...eaurora.org>,
        Tony Lindgren <tony@...mide.com>, Eyal Reizer <eyalr@...com>,
        linux-wireless@...r.kernel.org,
        Ricardo Salveti <rsalveti@...lveti.net>,
        Kishon Vijay Abraham I <kishon@...com>,
        Anders Roxell <anders.roxell@...aro.org>,
        John Stultz <john.stultz@...aro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-omap <linux-omap@...r.kernel.org>
Subject: Re: [PATCH V2] wlcore: sdio: Fixup power on/off sequence

On 21.01.19 15:40, Ulf Hansson wrote:
> On Fri, 18 Jan 2019 at 16:09, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>>
>> On Fri, 18 Jan 2019 at 13:09, Jan Kiszka <jan.kiszka@....de> wrote:
>>>
>>> On 17.01.19 10:54, Ulf Hansson wrote:
>>>> On Wed, 16 Jan 2019 at 21:26, Jan Kiszka <jan.kiszka@....de> 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@...aro.org>
>>>>>> ---
>>>>>>
>>>>>> 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.

Jan

View attachment "wlan.log" of type "text/x-log" (23855 bytes)

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