[RFC,v1,1/3] drivers: soc: add support for soc_device_match returning -EPROBE_DEFER

Message ID 20210419042722.27554-2-alice.guo@oss.nxp.com
State New
Headers show
Series
  • [RFC,v1,1/3] drivers: soc: add support for soc_device_match returning -EPROBE_DEFER
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Commit Message

Alice Guo (OSS) April 19, 2021, 4:27 a.m.
From: Alice Guo <alice.guo@nxp.com>

In i.MX8M boards, the registration of SoC device is later than caam
driver which needs it. Caam driver needs soc_device_match to provide
-EPROBE_DEFER when no SoC device is registered and no
early_soc_dev_attr.

Signed-off-by: Alice Guo <alice.guo@nxp.com>
---
 drivers/base/soc.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Alice Guo (OSS) April 19, 2021, 6:40 a.m. | #1
> -----Original Message-----

> From: Dominique MARTINET <dominique.martinet@atmark-techno.com>

> Sent: 2021年4月19日 12:49

> To: Alice Guo (OSS) <alice.guo@oss.nxp.com>

> Cc: gregkh@linuxfoundation.org; rafael@kernel.org; Horia Geanta

> <horia.geanta@nxp.com>; Aymen Sghaier <aymen.sghaier@nxp.com>;

> herbert@gondor.apana.org.au; davem@davemloft.net; tony@atomide.com;

> geert+renesas@glider.be; mturquette@baylibre.com; sboyd@kernel.org;

> vkoul@kernel.org; peter.ujfalusi@gmail.com; a.hajda@samsung.com;

> narmstrong@baylibre.com; robert.foss@linaro.org; airlied@linux.ie;

> daniel@ffwll.ch; khilman@baylibre.com; tomba@kernel.org; jyri.sarha@iki.fi;

> joro@8bytes.org; will@kernel.org; mchehab@kernel.org;

> ulf.hansson@linaro.org; adrian.hunter@intel.com; kishon@ti.com;

> kuba@kernel.org; linus.walleij@linaro.org; Roy Pledge <roy.pledge@nxp.com>;

> Leo Li <leoyang.li@nxp.com>; ssantosh@kernel.org; matthias.bgg@gmail.com;

> edubezval@gmail.com; j-keerthy@ti.com; balbi@kernel.org;

> linux@prisktech.co.nz; stern@rowland.harvard.edu; wim@linux-watchdog.org;

> linux@roeck-us.net; linux-kernel@vger.kernel.org; linux-crypto@vger.kernel.org;

> linux-omap@vger.kernel.org; linux-renesas-soc@vger.kernel.org;

> linux-clk@vger.kernel.org; dmaengine@vger.kernel.org;

> dri-devel@lists.freedesktop.org; linux-amlogic@lists.infradead.org;

> linux-arm-kernel@lists.infradead.org; iommu@lists.linux-foundation.org;

> linux-media@vger.kernel.org; linux-mmc@vger.kernel.org;

> netdev@vger.kernel.org; linux-phy@lists.infradead.org;

> linux-gpio@vger.kernel.org; linuxppc-dev@lists.ozlabs.org;

> linux-staging@lists.linux.dev; linux-mediatek@lists.infradead.org;

> linux-pm@vger.kernel.org; linux-usb@vger.kernel.org;

> linux-watchdog@vger.kernel.org

> Subject: Re: [RFC v1 PATCH 1/3] drivers: soc: add support for soc_device_match

> returning -EPROBE_DEFER

> 

> First comment overall for the whole serie:

> Since it is the solution I had suggested when I reported the problem[1] I have no

> qualm on the approach, comments for individual patches follow.

> 

> [1] http://lore.kernel.org/r/YGGZJjAxA1IO+/VU@atmark-techno.com

> 

> 

> Alice Guo (OSS) wrote on Mon, Apr 19, 2021 at 12:27:20PM +0800:

> > From: Alice Guo <alice.guo@nxp.com>

> >

> > In i.MX8M boards, the registration of SoC device is later than caam

> > driver which needs it. Caam driver needs soc_device_match to provide

> > -EPROBE_DEFER when no SoC device is registered and no

> > early_soc_dev_attr.

> 

> This patch should be last in the set: you can't have soc_device_match return an

> error before its callers handle it.

> 

> > Signed-off-by: Alice Guo <alice.guo@nxp.com>

> 

> As the one who reported the problem I would have been appreciated being at

> least added to Ccs... I only happened to notice you posted this by chance.


Sorry. I will Cc you next time.

> There is also not a single Fixes tag -- I believe this commit should have Fixes:

> 7d981405d0fd ("soc: imx8m: change to use platform driver") but I'm not sure

> how such tags should be handled in case of multiple patches fixing something.


I only mentioned "soc: imx8m: change to use platform driver" in cover letter.
If it is acceptable to make such a modification, I will send non-RFC and add Fixes tag.

Best Regards,
Alice

> --

> Dominique
Dan Carpenter April 20, 2021, 11:21 a.m. | #2
On Mon, Apr 19, 2021 at 10:20:13AM +0200, Geert Uytterhoeven wrote:
> Hi Alice,
> 
> CC Arnd (soc_device_match() author)
> 
> On Mon, Apr 19, 2021 at 6:28 AM Alice Guo (OSS) <alice.guo@oss.nxp.com> wrote:
> > From: Alice Guo <alice.guo@nxp.com>
> >
> > In i.MX8M boards, the registration of SoC device is later than caam
> > driver which needs it. Caam driver needs soc_device_match to provide
> > -EPROBE_DEFER when no SoC device is registered and no
> > early_soc_dev_attr.
> 
> I'm wondering if this is really a good idea: soc_device_match() is a
> last-resort low-level check, and IMHO should be made available early on,
> so there is no need for -EPROBE_DEFER.
> 
> >
> > Signed-off-by: Alice Guo <alice.guo@nxp.com>
> 
> Thanks for your patch!
> 
> > --- a/drivers/base/soc.c
> > +++ b/drivers/base/soc.c
> > @@ -110,6 +110,7 @@ static void soc_release(struct device *dev)
> >  }
> >
> >  static struct soc_device_attribute *early_soc_dev_attr;
> > +static bool soc_dev_attr_init_done = false;
> 
> Do you need this variable?
> 
> >
> >  struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
> >  {
> > @@ -157,6 +158,7 @@ struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr
> >                 return ERR_PTR(ret);
> >         }
> >
> > +       soc_dev_attr_init_done = true;
> >         return soc_dev;
> >
> >  out3:
> > @@ -246,6 +248,9 @@ const struct soc_device_attribute *soc_device_match(
> >         if (!matches)
> >                 return NULL;
> >
> > +       if (!soc_dev_attr_init_done && !early_soc_dev_attr)
> 
> if (!soc_bus_type.p && !early_soc_dev_attr)

There is one place checking this already.  We could wrap it in a helper
function:

static bool device_init_done(void)
{
	return soc_bus_type.p ? true : false;
}

regards,
dan carpenter

Patch

diff --git a/drivers/base/soc.c b/drivers/base/soc.c
index 0af5363a582c..12a22f9cf5c8 100644
--- a/drivers/base/soc.c
+++ b/drivers/base/soc.c
@@ -110,6 +110,7 @@  static void soc_release(struct device *dev)
 }
 
 static struct soc_device_attribute *early_soc_dev_attr;
+static bool soc_dev_attr_init_done = false;
 
 struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
 {
@@ -157,6 +158,7 @@  struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr
 		return ERR_PTR(ret);
 	}
 
+	soc_dev_attr_init_done = true;
 	return soc_dev;
 
 out3:
@@ -246,6 +248,9 @@  const struct soc_device_attribute *soc_device_match(
 	if (!matches)
 		return NULL;
 
+	if (!soc_dev_attr_init_done && !early_soc_dev_attr)
+		return ERR_PTR(-EPROBE_DEFER);
+
 	while (!ret) {
 		if (!(matches->machine || matches->family ||
 		      matches->revision || matches->soc_id))