Date:   Thu, 7 Oct 2021 12:24:51 +0200
From:   Pali Rohár <pali@...nel.org>
To:     Jérôme Pouiller <jerome.pouiller@...abs.com>
Cc:     Kalle Valo <kvalo@...eaurora.org>,
        Ulf Hansson <ulf.hansson@...aro.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 <linux-mmc@...r.kernel.org>
Subject: Re: [PATCH v7 08/24] wfx: add bus_sdio.c

On Thursday 07 October 2021 11:26:42 Kalle Valo wrote:
> Jérôme Pouiller <jerome.pouiller@...abs.com> writes:
> > On Wednesday 6 October 2021 17:02:07 CEST Ulf Hansson wrote:
> >> On Tue, 5 Oct 2021 at 10:14, Jérôme Pouiller <jerome.pouiller@...abs.com> wrote:
> >> > On Friday 1 October 2021 17:23:16 CEST Ulf Hansson wrote:
> >> > > On Thu, 30 Sept 2021 at 19:06, Pali Rohár <pali@...nel.org> wrote:
> >> > > > On Thursday 30 September 2021 18:51:09 Jérôme Pouiller wrote:
> >> > > > > On Thursday 30 September 2021 12:07:55 CEST Ulf Hansson wrote:
> >> > > > > > On Mon, 20 Sept 2021 at 18:12, Jerome Pouiller
> >> > > > > > <Jerome.Pouiller@...abs.com> wrote:
> >> > > > > > >
> >> > > > > > > From: Jérôme Pouiller <jerome.pouiller@...abs.com>
> >> > > > > > >
> >> > > > > > > Signed-off-by: Jérôme Pouiller <jerome.pouiller@...abs.com>
> >> > > > > > > ---
> >> > > > > > >  drivers/net/wireless/silabs/wfx/bus_sdio.c | 261 +++++++++++++++++++++
> >> > > > > > >  1 file changed, 261 insertions(+)
> >> > > > > > >  create mode 100644 drivers/net/wireless/silabs/wfx/bus_sdio.c
> >> > > > > > >
> >> > > > > > > diff --git a/drivers/net/wireless/silabs/wfx/bus_sdio.c
> >> > > > > > > b/drivers/net/wireless/silabs/wfx/bus_sdio.c
> >> > > > > >
> >> > > > > > [...]
> >> > > > > >
> >> > > > > > > +
> >> > > > > > > +static int wfx_sdio_probe(struct sdio_func *func,
> >> > > > > > > +                         const struct sdio_device_id *id)
> >> > > > > > > +{
> >> > > > > > > +       struct device_node *np = func->dev.of_node;
> >> > > > > > > +       struct wfx_sdio_priv *bus;
> >> > > > > > > +       int ret;
> >> > > > > > > +
> >> > > > > > > +       if (func->num != 1) {
> >> > > > > > > + dev_err(&func->dev, "SDIO function number is %d while
> >> > > > > > > it should always be 1 (unsupported chip?)\n",
> >> > > > > > > +                       func->num);
> >> > > > > > > +               return -ENODEV;
> >> > > > > > > +       }
> >> > > > > > > +
> >> > > > > > > +       bus = devm_kzalloc(&func->dev, sizeof(*bus), GFP_KERNEL);
> >> > > > > > > +       if (!bus)
> >> > > > > > > +               return -ENOMEM;
> >> > > > > > > +
> >> > > > > > > +       if (!np || !of_match_node(wfx_sdio_of_match, np)) {
> >> > > > > > > + dev_warn(&func->dev, "no compatible device found in
> >> > > > > > > DT\n");
> >> > > > > > > +               return -ENODEV;
> >> > > > > > > +       }
> >> > > > > > > +
> >> > > > > > > +       bus->func = func;
> >> > > > > > > +       bus->of_irq = irq_of_parse_and_map(np, 0);
> >> > > > > > > +       sdio_set_drvdata(func, bus);
> >> > > > > > > +       func->card->quirks |= MMC_QUIRK_LENIENT_FN0 |
> >> > > > > > > +                             MMC_QUIRK_BLKSZ_FOR_BYTE_MODE |
> >> > > > > > > +                             MMC_QUIRK_BROKEN_BYTE_MODE_512;
> >> > > > > >
> >> > > > > > I would rather see that you add an SDIO_FIXUP for the SDIO card, to
> >> > > > > > the sdio_fixup_methods[], in drivers/mmc/core/quirks.h, instead of
> >> > > > > > this.
> >> > > > >
> >> > > > > In the current patch, these quirks are applied only if the device appears
> >> > > > > in the device tree (see the condition above). If I implement them in
> >> > > > > drivers/mmc/core/quirks.h they will be applied as soon as the device is
> >> > > > > detected. Is it what we want?
> >> > > > >
> >> > > > > Note: we already have had a discussion about the strange VID/PID declared
> >> > > > > by this device:
> >> > > > >   https://www.spinics.net/lists/netdev/msg692577.html
> >> > > >
> >> > > > Yes, vendor id 0x0000 is invalid per SDIO spec. So based on this vendor
> >> > > > id, it is not possible to write any quirk in mmc/sdio generic code.
> >> > > >
> >> > > > Ulf, but maybe it could be possible to write quirk based on OF
> >> > > > compatible string?
> >> > >
> >> > > Yes, that would be better in my opinion.
> >> > >
> >> > > We already have DT bindings to describe embedded SDIO cards (a subnode
> >> > > to the mmc controller node), so we should be able to extend that I
> >> > > think.
> >> >
> >> > So, this feature does not yet exist? Do you consider it is a blocker for
> >> > the current patch?
> >> 
> >> Yes, sorry. I think we should avoid unnecessary hacks in SDIO func
> >> drivers, especially those that deserve to be fixed in the mmc core.
> >> 
> >> Moreover, we already support the similar thing for eMMC cards, plus
> >> that most parts are already done for SDIO too.
> >> 
> >> >
> >> > To be honest, I don't really want to take over this change in mmc/core.
> >> 
> >> I understand. Allow me a couple of days, then I can post a patch to
> >> help you out.
> >
> > Great! Thank you. I apologize for the extra work due to this invalid
> > vendor id.
> 
> BTW please escalate in your company how HORRIBLE it is that you
> manufacture SDIO devices without proper device ids, and make sure that
> all your future devices have officially assigned ids. I cannot stress
> enough how important that is for the Linux community!

Absolutely! Please really escalate this problem in your company and
properly ask USB-IF for assigning PCMCIA vendor ID as USB-IF maintains
PCMCIA vendor database and PCMCIA ids are used in SDIO devices:
https://lore.kernel.org/linux-mmc/20210607140216.64iuprp3siggslrk@pali/

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