[PATCH] usb: dwc2: Fix endless deferral probe

[PATCH] usb: dwc2: Fix endless deferral probe

[Stefan Wahren]

The dwc2 USB driver tries to find a generic PHY first and then look
for an old style USB PHY. In case of a valid generic PHY node without
a PHY driver, the PHY layer will return -EPROBE_DEFER forever. So dwc2
will never tries for an USB PHY.

Fix this issue by finding a generic PHY and an old style USB PHY
at once.

Fixes: 6c2dad69163f ("usb: dwc2: Return errors from PHY")
Link: https://marc.info/?l=linux-usb&m=151518314314753&w=2
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
---
 drivers/usb/dwc2/platform.c | 42 ++++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index 3e26550..5279567 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -225,10 +225,11 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
 	hsotg->phyif = GUSBCFG_PHYIF16;
 
 	/*
-	 * Attempt to find a generic PHY, then look for an old style
-	 * USB PHY and then fall back to pdata
+	 * Attempt to find a generic PHY or an old style USB PHY at once
+	 * otherwise fall back to pdata
 	 */
 	hsotg->phy = devm_phy_get(hsotg->dev, "usb2-phy");
+	hsotg->uphy = devm_usb_get_phy(hsotg->dev, USB_PHY_TYPE_USB2);
 	if (IS_ERR(hsotg->phy)) {
 		ret = PTR_ERR(hsotg->phy);
 		switch (ret) {
@@ -237,29 +238,34 @@ static int dwc2_lowlevel_hw_init(struct dwc2_hsotg *hsotg)
 			hsotg->phy = NULL;
 			break;
 		case -EPROBE_DEFER:
-			return ret;
+			if (IS_ERR(hsotg->uphy))
+				return ret;
+
+			hsotg->phy = NULL;
+			break;
 		default:
 			dev_err(hsotg->dev, "error getting phy %d\n", ret);
 			return ret;
 		}
 	}
 
-	if (!hsotg->phy) {
-		hsotg->uphy = devm_usb_get_phy(hsotg->dev, USB_PHY_TYPE_USB2);
-		if (IS_ERR(hsotg->uphy)) {
-			ret = PTR_ERR(hsotg->uphy);
-			switch (ret) {
-			case -ENODEV:
-			case -ENXIO:
-				hsotg->uphy = NULL;
-				break;
-			case -EPROBE_DEFER:
-				return ret;
-			default:
-				dev_err(hsotg->dev, "error getting usb phy %d\n",
-					ret);
+	if (IS_ERR(hsotg->uphy)) {
+		ret = PTR_ERR(hsotg->uphy);
+		switch (ret) {
+		case -ENODEV:
+		case -ENXIO:
+			hsotg->uphy = NULL;
+			break;
+		case -EPROBE_DEFER:
+			if (!hsotg->phy)
 				return ret;
-			}
+
+			hsotg->uphy = NULL;
+			break;
+		default:
+			dev_err(hsotg->dev, "error getting usb phy %d\n",
+				ret);
+			return ret;
 		}
 	}
 
-- 
2.7.4

[PATCH] usb: dwc2: Fix endless deferral probe

[Arnd Bergmann]

On Tue, Jan 9, 2018 at 8:28 PM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
> The dwc2 USB driver tries to find a generic PHY first and then look
> for an old style USB PHY. In case of a valid generic PHY node without
> a PHY driver, the PHY layer will return -EPROBE_DEFER forever. So dwc2
> will never tries for an USB PHY.
>
> Fix this issue by finding a generic PHY and an old style USB PHY
> at once.

This would fix only one of the USB controllers (dwc2), but not the others
that are affected. As I wrote in my suggested patch, dwc3 appears to be
affected the same way, and all other host drivers that call usb_add_hcd()
without first setting hcd->phy would suffer from this as well.

If we go down the route of addressing it here in the hcd drivers, we should
at least change all three of those, and hope this doesn't regress in
another way.

       Arnd

[PATCH] usb: dwc2: Fix endless deferral probe

[Stefan Wahren]

Hi Arnd,

Am 09.01.2018 um 22:33 schrieb Arnd Bergmann:
> On Tue, Jan 9, 2018 at 8:28 PM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
>> The dwc2 USB driver tries to find a generic PHY first and then look
>> for an old style USB PHY. In case of a valid generic PHY node without
>> a PHY driver, the PHY layer will return -EPROBE_DEFER forever. So dwc2
>> will never tries for an USB PHY.
>>
>> Fix this issue by finding a generic PHY and an old style USB PHY
>> at once.
> This would fix only one of the USB controllers (dwc2), but not the others
> that are affected. As I wrote in my suggested patch, dwc3 appears to be
> affected the same way, and all other host drivers that call usb_add_hcd()
> without first setting hcd->phy would suffer from this as well.
>
> If we go down the route of addressing it here in the hcd drivers, we should
> at least change all three of those, and hope this doesn't regress in
> another way.
>
>         Arnd

i fully unterstand. But we leaving the path of "fixing a critical issue 
on BCM2835" and go to "fixing multiple USB host controller". I do this 
all in my spare time and don't have any of the other USB controller 
available. So before i proceed with any other patch i like so see some 
feedback from John, Greg or Felipe.

After finalizing this patch i think the chance is little that this would 
be applied to 4.15. So i seems to me that we still revert my DT clean up 
patch.

Stefan

[PATCH] usb: dwc2: Fix endless deferral probe

[Arnd Bergmann]

On Wed, Jan 10, 2018 at 1:15 PM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
> Hi Arnd,
>
>
> Am 09.01.2018 um 22:33 schrieb Arnd Bergmann:
>>
>> On Tue, Jan 9, 2018 at 8:28 PM, Stefan Wahren <stefan.wahren@i2se.com>
>> wrote:
>>>
>>> The dwc2 USB driver tries to find a generic PHY first and then look
>>> for an old style USB PHY. In case of a valid generic PHY node without
>>> a PHY driver, the PHY layer will return -EPROBE_DEFER forever. So dwc2
>>> will never tries for an USB PHY.
>>>
>>> Fix this issue by finding a generic PHY and an old style USB PHY
>>> at once.
>>
>> This would fix only one of the USB controllers (dwc2), but not the others
>> that are affected. As I wrote in my suggested patch, dwc3 appears to be
>> affected the same way, and all other host drivers that call usb_add_hcd()
>> without first setting hcd->phy would suffer from this as well.
>>
>> If we go down the route of addressing it here in the hcd drivers, we
>> should
>> at least change all three of those, and hope this doesn't regress in
>> another way.
>>
>>         Arnd
>
>
> i fully unterstand. But we leaving the path of "fixing a critical issue on
> BCM2835" and go to "fixing multiple USB host controller". I do this all in
> my spare time and don't have any of the other USB controller available. So
> before i proceed with any other patch i like so see some feedback from John,
> Greg or Felipe.
>
> After finalizing this patch i think the chance is little that this would be
> applied to 4.15. So i seems to me that we still revert my DT clean up patch.

Could you confirm that this simpler patch fixes the problem for  you?
My feeling right now is that this would be the least invasive variant.
This is obviously a critical regression for BCM2835, but I'm fairly sure
it's just as critical for a lot of other SoCs that haven't done as much
testing on linux-next.

Hans has already verified the earlier (more complex) version, but my
analysis today has made it very likely that this one is fully sufficient
to fix all affected platforms.

Reverting all nine patches that add #phy-cells would still be an option,
but seems way more invasive at this point.

       Arnd

diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index b4964b067aec..93b55fb71d54 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -410,6 +410,10 @@ static struct phy *_of_phy_get(struct device_node
*np, int index)
        if (ret)
                return ERR_PTR(-ENODEV);

+       /* This phy type handled by the usb-phy subsystem for now */
+       if (of_device_is_compatible(np, "usb-nop-xceiv"))
+               return ERR_PTR(-ENODEV);
+
        mutex_lock(&phy_provider_mutex);
        phy_provider = of_phy_provider_lookup(args.np);
        if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner)) {

[PATCH] usb: dwc2: Fix endless deferral probe

[Stefan Wahren]

Am 12.01.2018 um 00:32 schrieb Arnd Bergmann:
> On Wed, Jan 10, 2018 at 1:15 PM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
>> Hi Arnd,
>>
>>
>> Am 09.01.2018 um 22:33 schrieb Arnd Bergmann:
>>> On Tue, Jan 9, 2018 at 8:28 PM, Stefan Wahren <stefan.wahren@i2se.com>
>>> wrote:
>>>> The dwc2 USB driver tries to find a generic PHY first and then look
>>>> for an old style USB PHY. In case of a valid generic PHY node without
>>>> a PHY driver, the PHY layer will return -EPROBE_DEFER forever. So dwc2
>>>> will never tries for an USB PHY.
>>>>
>>>> Fix this issue by finding a generic PHY and an old style USB PHY
>>>> at once.
>>> This would fix only one of the USB controllers (dwc2), but not the others
>>> that are affected. As I wrote in my suggested patch, dwc3 appears to be
>>> affected the same way, and all other host drivers that call usb_add_hcd()
>>> without first setting hcd->phy would suffer from this as well.
>>>
>>> If we go down the route of addressing it here in the hcd drivers, we
>>> should
>>> at least change all three of those, and hope this doesn't regress in
>>> another way.
>>>
>>>          Arnd
>>
>> i fully unterstand. But we leaving the path of "fixing a critical issue on
>> BCM2835" and go to "fixing multiple USB host controller". I do this all in
>> my spare time and don't have any of the other USB controller available. So
>> before i proceed with any other patch i like so see some feedback from John,
>> Greg or Felipe.
>>
>> After finalizing this patch i think the chance is little that this would be
>> applied to 4.15. So i seems to me that we still revert my DT clean up patch.
> Could you confirm that this simpler patch fixes the problem for  you?
> My feeling right now is that this would be the least invasive variant.
> This is obviously a critical regression for BCM2835, but I'm fairly sure
> it's just as critical for a lot of other SoCs that haven't done as much
> testing on linux-next.

Even worse arm64 and mips could be affected, too.

>
> Hans has already verified the earlier (more complex) version, but my
> analysis today has made it very likely that this one is fully sufficient
> to fix all affected platforms.
>
> Reverting all nine patches that add #phy-cells would still be an option,
> but seems way more invasive at this point.
>
>         Arnd
>
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index b4964b067aec..93b55fb71d54 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -410,6 +410,10 @@ static struct phy *_of_phy_get(struct device_node
> *np, int index)
>          if (ret)
>                  return ERR_PTR(-ENODEV);
>
> +       /* This phy type handled by the usb-phy subsystem for now */
> +       if (of_device_is_compatible(np, "usb-nop-xceiv"))
> +               return ERR_PTR(-ENODEV);
> +
>          mutex_lock(&phy_provider_mutex);
>          phy_provider = of_phy_provider_lookup(args.np);
>          if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner)) {

I tried this, but it doesn't work. "np" is the node of the USB 
controller, not of the phy?

[PATCH] usb: dwc2: Fix endless deferral probe

[Arnd Bergmann]

On Fri, Jan 12, 2018 at 9:06 AM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
> Am 12.01.2018 um 00:32 schrieb Arnd Bergmann:
>> On Wed, Jan 10, 2018 at 1:15 PM, Stefan Wahren <stefan.wahren@i2se.com>

>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>> index b4964b067aec..93b55fb71d54 100644
>> --- a/drivers/phy/phy-core.c
>> +++ b/drivers/phy/phy-core.c
>> @@ -410,6 +410,10 @@ static struct phy *_of_phy_get(struct device_node
>> *np, int index)
>>          if (ret)
>>                  return ERR_PTR(-ENODEV);
>>
>> +       /* This phy type handled by the usb-phy subsystem for now */
>> +       if (of_device_is_compatible(np, "usb-nop-xceiv"))
>> +               return ERR_PTR(-ENODEV);
>> +
>>          mutex_lock(&phy_provider_mutex);
>>          phy_provider = of_phy_provider_lookup(args.np);
>>          if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner))
>> {
>
>
> I tried this, but it doesn't work. "np" is the node of the USB controller,
> not of the phy?

Correct, that was a really dumb mistake on my end, I'm glad I asked
you to try it first.

I'll fix it up and send the right version with a proper changelog right away.

Thanks for bearing with me,

       Arnd

[PATCH] usb: dwc2: Fix endless deferral probe

[Mauro Carvalho Chehab]

Em Fri, 12 Jan 2018 10:18:59 +0100
Arnd Bergmann <arnd@arndb.de> escreveu:

> On Fri, Jan 12, 2018 at 9:06 AM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
> > Am 12.01.2018 um 00:32 schrieb Arnd Bergmann:  
> >> On Wed, Jan 10, 2018 at 1:15 PM, Stefan Wahren <stefan.wahren@i2se.com>  
> 
> >> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> >> index b4964b067aec..93b55fb71d54 100644
> >> --- a/drivers/phy/phy-core.c
> >> +++ b/drivers/phy/phy-core.c
> >> @@ -410,6 +410,10 @@ static struct phy *_of_phy_get(struct device_node
> >> *np, int index)
> >>          if (ret)
> >>                  return ERR_PTR(-ENODEV);
> >>
> >> +       /* This phy type handled by the usb-phy subsystem for now */
> >> +       if (of_device_is_compatible(np, "usb-nop-xceiv"))
> >> +               return ERR_PTR(-ENODEV);
> >> +
> >>          mutex_lock(&phy_provider_mutex);
> >>          phy_provider = of_phy_provider_lookup(args.np);
> >>          if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner))
> >> {  
> >
> >
> > I tried this, but it doesn't work. "np" is the node of the USB controller,
> > not of the phy?  
> 
> Correct, that was a really dumb mistake on my end, I'm glad I asked
> you to try it first.
> 
> I'll fix it up and send the right version with a proper changelog right away.

I suspect you meant to do, instead:


diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
index b4964b067aec..584cc1469f7d 100644
--- a/drivers/phy/phy-core.c
+++ b/drivers/phy/phy-core.c
@@ -410,6 +410,10 @@ static struct phy *_of_phy_get(struct device_node *np, int index)
 	if (ret)
 		return ERR_PTR(-ENODEV);
 
+       /* This phy type handled by the usb-phy subsystem for now */
+       if (of_device_is_compatible(args.np, "usb-nop-xceiv"))
+		return ERR_PTR(-ENODEV);
+
 	mutex_lock(&phy_provider_mutex);
 	phy_provider = of_phy_provider_lookup(args.np);
 	if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner)) {


(e. g. args.np, instead of np).

The above works for me on RPi3:

$ uname -a
Linux raspberrypi 4.15.0-rc7-mcc+ #28 SMP Fri Jan 12 12:35:19 EST 2018 armv7l GNU/Linux

$ lsusb
Bus 001 Device 005: ID 045e:0750 Microsoft Corp. Wired Keyboard 600
Bus 001 Device 004: ID 0572:960c Conexant Systems (Rockwell), Inc. DVBSky S960C DVB-S2 tuner
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

So, if you change np -> args.np, feel free to add my:

Tested-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Regards,
Mauro

[PATCH] usb: dwc2: Fix endless deferral probe

[Arnd Bergmann]

On Fri, Jan 12, 2018 at 6:51 PM, Mauro Carvalho Chehab
<mchehab@s-opensource.com> wrote:
> Em Fri, 12 Jan 2018 10:18:59 +0100
> Arnd Bergmann <arnd@arndb.de> escreveu:
>
>> On Fri, Jan 12, 2018 at 9:06 AM, Stefan Wahren <stefan.wahren@i2se.com> wrote:
>> > Am 12.01.2018 um 00:32 schrieb Arnd Bergmann:
>> >> On Wed, Jan 10, 2018 at 1:15 PM, Stefan Wahren <stefan.wahren@i2se.com>
>>
>> >> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>> >> index b4964b067aec..93b55fb71d54 100644
>> >> --- a/drivers/phy/phy-core.c
>> >> +++ b/drivers/phy/phy-core.c
>> >> @@ -410,6 +410,10 @@ static struct phy *_of_phy_get(struct device_node
>> >> *np, int index)
>> >>          if (ret)
>> >>                  return ERR_PTR(-ENODEV);
>> >>
>> >> +       /* This phy type handled by the usb-phy subsystem for now */
>> >> +       if (of_device_is_compatible(np, "usb-nop-xceiv"))
>> >> +               return ERR_PTR(-ENODEV);
>> >> +
>> >>          mutex_lock(&phy_provider_mutex);
>> >>          phy_provider = of_phy_provider_lookup(args.np);
>> >>          if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner))
>> >> {
>> >
>> >
>> > I tried this, but it doesn't work. "np" is the node of the USB controller,
>> > not of the phy?
>>
>> Correct, that was a really dumb mistake on my end, I'm glad I asked
>> you to try it first.
>>
>> I'll fix it up and send the right version with a proper changelog right away.
>
> I suspect you meant to do, instead:
>
>
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index b4964b067aec..584cc1469f7d 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -410,6 +410,10 @@ static struct phy *_of_phy_get(struct device_node *np, int index)
>         if (ret)
>                 return ERR_PTR(-ENODEV);
>
> +       /* This phy type handled by the usb-phy subsystem for now */
> +       if (of_device_is_compatible(args.np, "usb-nop-xceiv"))
> +               return ERR_PTR(-ENODEV);
> +
>         mutex_lock(&phy_provider_mutex);
>         phy_provider = of_phy_provider_lookup(args.np);
>         if (IS_ERR(phy_provider) || !try_module_get(phy_provider->owner)) {
>
>
> (e. g. args.np, instead of np).
>
> The above works for me on RPi3:
>
> $ uname -a
> Linux raspberrypi 4.15.0-rc7-mcc+ #28 SMP Fri Jan 12 12:35:19 EST 2018 armv7l GNU/Linux
>
> $ lsusb
> Bus 001 Device 005: ID 045e:0750 Microsoft Corp. Wired Keyboard 600
> Bus 001 Device 004: ID 0572:960c Conexant Systems (Rockwell), Inc. DVBSky S960C DVB-S2 tuner
> Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
> Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>
> So, if you change np -> args.np, feel free to add my:
>
> Tested-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Thanks a lot for testing, args.np is what the version I sent today has after
Stefan pointed out the mistake earlier.

         Arnd