Date:   Mon, 02 Nov 2020 18:02:22 +0200
From:   Kalle Valo <kvalo@...eaurora.org>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Jérôme Pouiller <jerome.pouiller@...abs.com>,
        Pali Rohár <pali@...nel.org>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        netdev <netdev@...r.kernel.org>,
        driverdevel <devel@...verdev.osuosl.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "David S . Miller" <davem@...emloft.net>,
        DTML <devicetree@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        "linux-mmc\@vger.kernel.org" <linux-mmc@...r.kernel.org>
Subject: Re: [PATCH 07/23] wfx: add bus_sdio.c

Ulf Hansson <ulf.hansson@...aro.org> writes:

> On Thu, 15 Oct 2020 at 16:03, Jérôme Pouiller
> <jerome.pouiller@...abs.com> wrote:
>>
>> On Wednesday 14 October 2020 14:43:34 CEST Pali Rohár wrote:
>> > On Wednesday 14 October 2020 13:52:15 Jérôme Pouiller wrote:
>> > > On Tuesday 13 October 2020 22:11:56 CEST Pali Rohár wrote:
>> > > > On Monday 12 October 2020 12:46:32 Jerome Pouiller wrote:
>> > > > > +#define SDIO_VENDOR_ID_SILABS        0x0000
>> > > > > +#define SDIO_DEVICE_ID_SILABS_WF200  0x1000
>> > > > > +static const struct sdio_device_id wfx_sdio_ids[] = {
>> > > > > +     { SDIO_DEVICE(SDIO_VENDOR_ID_SILABS, SDIO_DEVICE_ID_SILABS_WF200) },
>> > > >
>> > > > Please move ids into common include file include/linux/mmc/sdio_ids.h
>> > > > where are all SDIO ids. Now all drivers have ids defined in that file.
>> > > >
>> > > > > +     // FIXME: ignore VID/PID and only rely on device tree
>> > > > > +     // { SDIO_DEVICE(SDIO_ANY_ID, SDIO_ANY_ID) },
>> > > >
>> > > > What is the reason for ignoring vendor and device ids?
>> > >
>> > > The device has a particularity, its VID/PID is 0000:1000 (as you can see
>> > > above). This value is weird. The risk of collision with another device is
>> > > high.
>> >
>> > Those ids looks strange. You are from Silabs, can you check internally
>> > in Silabs if ids are really correct? And which sdio vendor id you in
>> > Silabs got assigned for your products?
>>
>> I confirm these ids are the ones burned in the WF200. We have to deal with
>> that :( .
>
> Yep. Unfortunately this isn't so uncommon when targeting the embedded
> types of devices.
>
> The good thing is, that we already have bindings allowing us to specify this.
>
>>
>>
>> > I know that sdio devices with multiple functions may have different sdio
>> > vendor/device id particular function and in common CIS (function 0).
>> >
>> > Could not be a problem that on one place is vendor/device id correct and
>> > on other place is that strange value?
>> >
>> > I have sent following patch (now part of upstream kernel) which exports
>> > these ids to userspace:
>> > https://lore.kernel.org/linux-mmc/20200527110858.17504-2-pali@kernel.org/T/#u
>> >
>> > Also for debugging ids and information about sdio cards, I sent another
>> > patch which export additional data:
>> > https://lore.kernel.org/linux-mmc/20200727133837.19086-1-pali@kernel.org/T/#u
>> >
>> > Could you try them and look at /sys/class/mmc_host/ attribute outputs?
>>
>> Here is:
>>
>>     # cd /sys/class/mmc_host/ && grep -r . mmc1/
>>     mmc1/power/runtime_suspended_time:0
>>     grep: mmc1/power/autosuspend_delay_ms: Input/output error
>>     mmc1/power/runtime_active_time:0
>>     mmc1/power/control:auto
>>     mmc1/power/runtime_status:unsupported
>>     mmc1/mmc1:0001/vendor:0x0000
>>     mmc1/mmc1:0001/rca:0x0001
>>     mmc1/mmc1:0001/device:0x1000
>>     mmc1/mmc1:0001/mmc1:0001:1/vendor:0x0000
>>     mmc1/mmc1:0001/mmc1:0001:1/device:0x1000
>>     grep: mmc1/mmc1:0001/mmc1:0001:1/info4: No data available
>>     mmc1/mmc1:0001/mmc1:0001:1/power/runtime_suspended_time:0
>>     grep: mmc1/mmc1:0001/mmc1:0001:1/power/autosuspend_delay_ms: Input/output error
>>     mmc1/mmc1:0001/mmc1:0001:1/power/runtime_active_time:0
>>     mmc1/mmc1:0001/mmc1:0001:1/power/control:auto
>>     mmc1/mmc1:0001/mmc1:0001:1/power/runtime_status:unsupported
>>     mmc1/mmc1:0001/mmc1:0001:1/class:0x00
>>     grep: mmc1/mmc1:0001/mmc1:0001:1/info2: No data available
>>     mmc1/mmc1:0001/mmc1:0001:1/modalias:sdio:c00v0000d1000
>>     mmc1/mmc1:0001/mmc1:0001:1/revision:0.0
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:OF_NAME=mmc
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:OF_FULLNAME=/soc/sdhci@...00000/mmc@1
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:OF_COMPATIBLE_0=silabs,wfx-sdio
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:OF_COMPATIBLE_N=1
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:SDIO_CLASS=00
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:SDIO_ID=0000:1000
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:SDIO_REVISION=0.0
>>     mmc1/mmc1:0001/mmc1:0001:1/uevent:MODALIAS=sdio:c00v0000d1000
>>     grep: mmc1/mmc1:0001/mmc1:0001:1/info3: No data available
>>     grep: mmc1/mmc1:0001/mmc1:0001:1/info1: No data available
>>     mmc1/mmc1:0001/ocr:0x00200000
>>     grep: mmc1/mmc1:0001/info4: No data available
>>     mmc1/mmc1:0001/power/runtime_suspended_time:0
>>     grep: mmc1/mmc1:0001/power/autosuspend_delay_ms: Input/output error
>>     mmc1/mmc1:0001/power/runtime_active_time:0
>>     mmc1/mmc1:0001/power/control:auto
>>     mmc1/mmc1:0001/power/runtime_status:unsupported
>>     grep: mmc1/mmc1:0001/info2: No data available
>>     mmc1/mmc1:0001/type:SDIO
>>     mmc1/mmc1:0001/revision:0.0
>>     mmc1/mmc1:0001/uevent:MMC_TYPE=SDIO
>>     mmc1/mmc1:0001/uevent:SDIO_ID=0000:1000
>>     mmc1/mmc1:0001/uevent:SDIO_REVISION=0.0
>>     grep: mmc1/mmc1:0001/info3: No data available
>>     grep: mmc1/mmc1:0001/info1: No data available
>>
>>
>
> Please have a look at the
> Documentation/devicetree/bindings/mmc/mmc-controller.yaml, there you
> find that from a child node of the mmc host's node, we can specify an
> embedded SDIO functional device.
>
> In sdio_add_func(), which calls sdio_set_of_node() - we assign the
> func->dev.of_node its corresponding child node for the SDIO func.
> Allowing the sdio functional driver to be matched with the SDIO func
> device.
>
> Perhaps what is missing, is that we may want to avoid probing an
> in-correct sdio driver, based upon buggy SDIO ids. I don't think we
> take some actions in the mmc core to prevent this, but maybe it's not
> a big problem anyway.
>
> When it comes to documenting the buggy SDIO ids, please add some
> information about this in the common SDIO headers. It's nice to have a
> that information, if any issue comes up later on.

And if there's some special setup (DT etc) needed to get the wireless
driver working that should be documented in the driver side as well. The
expectation is that an upstream driver is just plug and play, and if
it's not there should be clear documentation how to enable the driver.

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