[PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Adam Ford]

The imx8mm and imx8mn appear compatible with imx7d-usb
flags in the OTG driver.  If the dr_mode is defined as
host or peripheral, the device appears to operate correctly,
however the auto host/peripheral detection results in an error.

The solution isn't just adding checks for imx8mm and imx8mn to
the check for imx7, because the USB clock needs to be running
to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.

Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
so I modified that function to return an unknown state if the
device tree does not explicitly state whether it is a host
or a peripheral.

When the driver probes, it looks to see if it's in the unknown
state, and only then will it read the register to auto-detect.

Signed-off-by: Adam Ford <aford173@gmail.com>
Tested-by: Tim Harvey <tharvey@gateworks.com>
---
V4:  Fix 'err_clk' reference, so it is not encapsulated in
     an ifdef making it available at all times.
V3:  Keep ehci_usb_of_to_plat but add the ability to return
     and unknown state instead of reading the register.
     If the probe determines the states is unknown, it will
     query the register after the clocks have been enabled.
     Because of the slight behavior change, I removed any
     review or tested tags.

V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
     from the probe after t

diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
index 1bd6147c76..060b02accc 100644
--- a/drivers/usb/host/ehci-mx6.c
+++ b/drivers/usb/host/ehci-mx6.c
@@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
 			plat->init_type = USB_INIT_DEVICE;
 		else
 			plat->init_type = USB_INIT_HOST;
-	} else if (is_mx7()) {
+	} else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
 		phy_status = (void __iomem *)(addr +
 					      USBNC_PHY_STATUS_OFFSET);
 		val = readl(phy_status);
@@ -573,9 +573,8 @@ static int ehci_usb_of_to_plat(struct udevice *dev)
 	case USB_DR_MODE_PERIPHERAL:
 		plat->init_type = USB_INIT_DEVICE;
 		break;
-	case USB_DR_MODE_OTG:
-	case USB_DR_MODE_UNKNOWN:
-		return ehci_usb_phy_mode(dev);
+	default:
+		plat->init_type = USB_INIT_UNKNOWN;
 	};
 
 	return 0;
@@ -677,6 +676,20 @@ static int ehci_usb_probe(struct udevice *dev)
 	mdelay(1);
 #endif
 
+	/*
+	 * If the device tree didn't specify host or device,
+	 * the default is USB_INIT_UNKNOWN, so we need to check
+	 * the register. For imx8mm and imx8mn, the clocks need to be
+	 * running first, so we defer the check until they are.
+	 */
+	if (priv->init_type == USB_INIT_UNKNOWN) {
+		ret = ehci_usb_phy_mode(dev);
+		if (ret)
+			goto err_clk;
+		else
+			priv->init_type = plat->init_type;
+	}
+
 #if CONFIG_IS_ENABLED(DM_REGULATOR)
 	ret = device_get_supply_regulator(dev, "vbus-supply",
 					  &priv->vbus_supply);
@@ -741,8 +754,8 @@ err_regulator:
 #if CONFIG_IS_ENABLED(DM_REGULATOR)
 	if (priv->vbus_supply)
 		regulator_set_enable(priv->vbus_supply, false);
-err_clk:
 #endif
+err_clk:
 #if CONFIG_IS_ENABLED(CLK)
 	clk_disable(&priv->clk);
 #else
diff --git a/include/usb.h b/include/usb.h
index f032de8af9..7e3796bd5b 100644
--- a/include/usb.h
+++ b/include/usb.h
@@ -163,7 +163,8 @@ struct int_queue;
  */
 enum usb_init_type {
 	USB_INIT_HOST,
-	USB_INIT_DEVICE
+	USB_INIT_DEVICE,
+	USB_INIT_UNKNOWN,
 };
 
 /**********************************************************************
-- 
2.32.0

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Fabio Estevam]

Hi Adam,

On Thu, Feb 3, 2022 at 6:20 PM Adam Ford <aford173@gmail.com> wrote:
>
> The imx8mm and imx8mn appear compatible with imx7d-usb
> flags in the OTG driver.  If the dr_mode is defined as
> host or peripheral, the device appears to operate correctly,
> however the auto host/peripheral detection results in an error.
>
> The solution isn't just adding checks for imx8mm and imx8mn to
> the check for imx7, because the USB clock needs to be running
> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
>
> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> so I modified that function to return an unknown state if the
> device tree does not explicitly state whether it is a host
> or a peripheral.
>
> When the driver probes, it looks to see if it's in the unknown
> state, and only then will it read the register to auto-detect.
>
> Signed-off-by: Adam Ford <aford173@gmail.com>
> Tested-by: Tim Harvey <tharvey@gateworks.com>

The last time I tried to test your previous version I was having an
issue which is solved by Marcel's patch:
https://lists.denx.de/pipermail/u-boot/2022-February/474006.html

With Marcel's patch applied and your updated version, "ums 0 mmc 0"
works fine on a imx7s-warp, thanks:

Tested-by: Fabio Estevam <festevam@gmail.com>

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Marek Vasut]

On 2/3/22 22:20, Adam Ford wrote:
> The imx8mm and imx8mn appear compatible with imx7d-usb
> flags in the OTG driver.  If the dr_mode is defined as
> host or peripheral, the device appears to operate correctly,
> however the auto host/peripheral detection results in an error.
> 
> The solution isn't just adding checks for imx8mm and imx8mn to
> the check for imx7, because the USB clock needs to be running
> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> 
> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> so I modified that function to return an unknown state if the
> device tree does not explicitly state whether it is a host
> or a peripheral.
> 
> When the driver probes, it looks to see if it's in the unknown
> state, and only then will it read the register to auto-detect.
> 
> Signed-off-by: Adam Ford <aford173@gmail.com>
> Tested-by: Tim Harvey <tharvey@gateworks.com>
> ---
> V4:  Fix 'err_clk' reference, so it is not encapsulated in
>       an ifdef making it available at all times.
> V3:  Keep ehci_usb_of_to_plat but add the ability to return
>       and unknown state instead of reading the register.
>       If the probe determines the states is unknown, it will
>       query the register after the clocks have been enabled.
>       Because of the slight behavior change, I removed any
>       review or tested tags.
> 
> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
>       from the probe after t
> 
> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> index 1bd6147c76..060b02accc 100644
> --- a/drivers/usb/host/ehci-mx6.c
> +++ b/drivers/usb/host/ehci-mx6.c
> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
>   			plat->init_type = USB_INIT_DEVICE;
>   		else
>   			plat->init_type = USB_INIT_HOST;
> -	} else if (is_mx7()) {
> +	} else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
>   		phy_status = (void __iomem *)(addr +
>   					      USBNC_PHY_STATUS_OFFSET);
>   		val = readl(phy_status);

Is the USB GPCv2 power domain always ON at this point ? If it isn't, 
then this access will lock up the whole SoC.

You can check that easily by adding printf() into 
drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and 
verify that printf() prints something before this ehci_usb_phy_mode() 
code is called.

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Adam Ford]

On Sun, Feb 6, 2022 at 3:59 PM Marek Vasut <marex@denx.de> wrote:
>
> On 2/3/22 22:20, Adam Ford wrote:
> > The imx8mm and imx8mn appear compatible with imx7d-usb
> > flags in the OTG driver.  If the dr_mode is defined as
> > host or peripheral, the device appears to operate correctly,
> > however the auto host/peripheral detection results in an error.
> >
> > The solution isn't just adding checks for imx8mm and imx8mn to
> > the check for imx7, because the USB clock needs to be running
> > to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> >
> > Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> > so I modified that function to return an unknown state if the
> > device tree does not explicitly state whether it is a host
> > or a peripheral.
> >
> > When the driver probes, it looks to see if it's in the unknown
> > state, and only then will it read the register to auto-detect.
> >
> > Signed-off-by: Adam Ford <aford173@gmail.com>
> > Tested-by: Tim Harvey <tharvey@gateworks.com>
> > ---
> > V4:  Fix 'err_clk' reference, so it is not encapsulated in
> >       an ifdef making it available at all times.
> > V3:  Keep ehci_usb_of_to_plat but add the ability to return
> >       and unknown state instead of reading the register.
> >       If the probe determines the states is unknown, it will
> >       query the register after the clocks have been enabled.
> >       Because of the slight behavior change, I removed any
> >       review or tested tags.
> >
> > V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
> >       from the probe after t
> >
> > diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> > index 1bd6147c76..060b02accc 100644
> > --- a/drivers/usb/host/ehci-mx6.c
> > +++ b/drivers/usb/host/ehci-mx6.c
> > @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
> >                       plat->init_type = USB_INIT_DEVICE;
> >               else
> >                       plat->init_type = USB_INIT_HOST;
> > -     } else if (is_mx7()) {
> > +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
> >               phy_status = (void __iomem *)(addr +
> >                                             USBNC_PHY_STATUS_OFFSET);
> >               val = readl(phy_status);
>
> Is the USB GPCv2 power domain always ON at this point ? If it isn't,
> then this access will lock up the whole SoC.

The GPCv2 needs to be enabled if USB is going to be used, but I would
expect that to happen even without this patch.  I ran into that during
my early testing.

>
> You can check that easily by adding printf() into
> drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and
> verify that printf() prints something before this ehci_usb_phy_mode()
> code is called.

I added a printf to show when a power domain is enabled.  It does
appear that power domains for HSIO, USBOTG1 and USBOTG2 are all
enabled before the scan on the respective USB bus happens, so I think
we're safe from hanging.

U-Boot 2022.01-00678-ge83818c782-dirty (Feb 06 2022 - 18:39:41 -0600)

CPU:   Freescale i.MX8MMQ rev1.0 at 1200 MHz
Reset cause: POR
Model: Beacon EmbeddedWorks i.MX8M Mini Development Kit
DRAM:  2 GiB
Core:  99 devices, 21 uclasses, devicetree: separate
WDT:   Started watchdog@30280000 with servicing (60s timeout)
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... OK
In:    serial@30890000
Out:   serial@30890000
Err:   serial@30890000
Net:   eth0: ethernet@30be0000
Hit any key to stop autoboot:  0
u-boot=> usb start
starting USB...
Bus usb@32e40000: imx8m_power_domain_on 0
imx8m_power_domain_on 2
USB EHCI 1.00
Bus usb@32e50000: imx8m_power_domain_on 0
imx8m_power_domain_on 3
USB EHCI 1.00
scanning bus usb@32e40000 for devices... imx8m_power_domain_on 0
imx8m_power_domain_on 2
1 USB Device(s) found
scanning bus usb@32e50000 for devices... imx8m_power_domain_on 0
imx8m_power_domain_on 3
3 USB Device(s) found
       scanning usb for storage devices... 1 Storage Device(s) found
u-boot=>

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Marek Vasut]

On 2/7/22 01:51, Adam Ford wrote:
> On Sun, Feb 6, 2022 at 3:59 PM Marek Vasut <marex@denx.de> wrote:
>>
>> On 2/3/22 22:20, Adam Ford wrote:
>>> The imx8mm and imx8mn appear compatible with imx7d-usb
>>> flags in the OTG driver.  If the dr_mode is defined as
>>> host or peripheral, the device appears to operate correctly,
>>> however the auto host/peripheral detection results in an error.
>>>
>>> The solution isn't just adding checks for imx8mm and imx8mn to
>>> the check for imx7, because the USB clock needs to be running
>>> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
>>>
>>> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
>>> so I modified that function to return an unknown state if the
>>> device tree does not explicitly state whether it is a host
>>> or a peripheral.
>>>
>>> When the driver probes, it looks to see if it's in the unknown
>>> state, and only then will it read the register to auto-detect.
>>>
>>> Signed-off-by: Adam Ford <aford173@gmail.com>
>>> Tested-by: Tim Harvey <tharvey@gateworks.com>
>>> ---
>>> V4:  Fix 'err_clk' reference, so it is not encapsulated in
>>>        an ifdef making it available at all times.
>>> V3:  Keep ehci_usb_of_to_plat but add the ability to return
>>>        and unknown state instead of reading the register.
>>>        If the probe determines the states is unknown, it will
>>>        query the register after the clocks have been enabled.
>>>        Because of the slight behavior change, I removed any
>>>        review or tested tags.
>>>
>>> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
>>>        from the probe after t
>>>
>>> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
>>> index 1bd6147c76..060b02accc 100644
>>> --- a/drivers/usb/host/ehci-mx6.c
>>> +++ b/drivers/usb/host/ehci-mx6.c
>>> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
>>>                        plat->init_type = USB_INIT_DEVICE;
>>>                else
>>>                        plat->init_type = USB_INIT_HOST;
>>> -     } else if (is_mx7()) {
>>> +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
>>>                phy_status = (void __iomem *)(addr +
>>>                                              USBNC_PHY_STATUS_OFFSET);
>>>                val = readl(phy_status);
>>
>> Is the USB GPCv2 power domain always ON at this point ? If it isn't,
>> then this access will lock up the whole SoC.
> 
> The GPCv2 needs to be enabled if USB is going to be used, but I would
> expect that to happen even without this patch.  I ran into that during
> my early testing.
> 
>>
>> You can check that easily by adding printf() into
>> drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and
>> verify that printf() prints something before this ehci_usb_phy_mode()
>> code is called.
> 
> I added a printf to show when a power domain is enabled.  It does
> appear that power domains for HSIO, USBOTG1 and USBOTG2 are all
> enabled before the scan on the respective USB bus happens, so I think
> we're safe from hanging.

Isn't the ehci_usb_of_to_plat() called way before you even initiate the 
scan, somewhere during U-Boot startup ? So no, you might end up hanging 
the hardware ?

(you can verify that by adding more printf()s)

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Michael Walle]

Hi Adam,

it's nice to include people who made review comments in the follow-up
patches. I had to pull this out of the mailinglist again.

> The imx8mm and imx8mn appear compatible with imx7d-usb
> flags in the OTG driver.  If the dr_mode is defined as
> host or peripheral, the device appears to operate correctly,
> however the auto host/peripheral detection results in an error.
> 
> The solution isn't just adding checks for imx8mm and imx8mn to
> the check for imx7, because the USB clock needs to be running
> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> 
> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> so I modified that function to return an unknown state if the
> device tree does not explicitly state whether it is a host
> or a peripheral.
> 
> When the driver probes, it looks to see if it's in the unknown
> state, and only then will it read the register to auto-detect.
> 
> Signed-off-by: Adam Ford <aford173@gmail.com>
> Tested-by: Tim Harvey <tharvey@gateworks.com>
> ---
> V4:  Fix 'err_clk' reference, so it is not encapsulated in
>      an ifdef making it available at all times.
> V3:  Keep ehci_usb_of_to_plat but add the ability to return
>      and unknown state instead of reading the register.
>      If the probe determines the states is unknown, it will
>      query the register after the clocks have been enabled.
>      Because of the slight behavior change, I removed any
>      review or tested tags.
> 
> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
>      from the probe after t
> 
> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> index 1bd6147c76..060b02accc 100644
> --- a/drivers/usb/host/ehci-mx6.c
> +++ b/drivers/usb/host/ehci-mx6.c
> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
>  			plat->init_type = USB_INIT_DEVICE;
>  		else
>  			plat->init_type = USB_INIT_HOST;
> -	} else if (is_mx7()) {
> +	} else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
>  		phy_status = (void __iomem *)(addr +
>  					      USBNC_PHY_STATUS_OFFSET);
>  		val = readl(phy_status);
> @@ -573,9 +573,8 @@ static int ehci_usb_of_to_plat(struct udevice *dev)
>  	case USB_DR_MODE_PERIPHERAL:
>  		plat->init_type = USB_INIT_DEVICE;
>  		break;
> -	case USB_DR_MODE_OTG:
> -	case USB_DR_MODE_UNKNOWN:


Don't you want to propagate the OTG mode to the init_type field? Maybe
it will be useful sometime and IMHO makes it easier to read the code...

> -		return ehci_usb_phy_mode(dev);
> +	default:
> +		plat->init_type = USB_INIT_UNKNOWN;
>  	};
>  
>  	return 0;
> @@ -677,6 +676,20 @@ static int ehci_usb_probe(struct udevice *dev)
>  	mdelay(1);
>  #endif
>  
> +	/*
> +	 * If the device tree didn't specify host or device,
> +	 * the default is USB_INIT_UNKNOWN, so we need to check
> +	 * the register. For imx8mm and imx8mn, the clocks need to be
> +	 * running first, so we defer the check until they are.
> +	 */
> +	if (priv->init_type == USB_INIT_UNKNOWN) {

Because this implicitly also contains OTG mode, right? So despite
the comment, if the device tree includes OTG mode, this branch is
also taken.

Otherwise looks good to me:

Reviewed-by: Michael Walle <michael@walle.cc>

> +		ret = ehci_usb_phy_mode(dev);
> +		if (ret)
> +			goto err_clk;
> +		else
> +			priv->init_type = plat->init_type;
> +	}
> +
>  #if CONFIG_IS_ENABLED(DM_REGULATOR)
>  	ret = device_get_supply_regulator(dev, "vbus-supply",
>  					  &priv->vbus_supply);
> @@ -741,8 +754,8 @@ err_regulator:
>  #if CONFIG_IS_ENABLED(DM_REGULATOR)
>  	if (priv->vbus_supply)
>  		regulator_set_enable(priv->vbus_supply, false);
> -err_clk:
>  #endif
> +err_clk:
>  #if CONFIG_IS_ENABLED(CLK)
>  	clk_disable(&priv->clk);
>  #else
> diff --git a/include/usb.h b/include/usb.h
> index f032de8af9..7e3796bd5b 100644
> --- a/include/usb.h
> +++ b/include/usb.h
> @@ -163,7 +163,8 @@ struct int_queue;
>   */
>  enum usb_init_type {
>  	USB_INIT_HOST,
> -	USB_INIT_DEVICE
> +	USB_INIT_DEVICE,
> +	USB_INIT_UNKNOWN,
>  };
>  
>  /**********************************************************************

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Adam Ford]

On Mon, Feb 7, 2022 at 2:47 AM Marek Vasut <marex@denx.de> wrote:
>
> On 2/7/22 01:51, Adam Ford wrote:
> > On Sun, Feb 6, 2022 at 3:59 PM Marek Vasut <marex@denx.de> wrote:
> >>
> >> On 2/3/22 22:20, Adam Ford wrote:
> >>> The imx8mm and imx8mn appear compatible with imx7d-usb
> >>> flags in the OTG driver.  If the dr_mode is defined as
> >>> host or peripheral, the device appears to operate correctly,
> >>> however the auto host/peripheral detection results in an error.
> >>>
> >>> The solution isn't just adding checks for imx8mm and imx8mn to
> >>> the check for imx7, because the USB clock needs to be running
> >>> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> >>>
> >>> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> >>> so I modified that function to return an unknown state if the
> >>> device tree does not explicitly state whether it is a host
> >>> or a peripheral.
> >>>
> >>> When the driver probes, it looks to see if it's in the unknown
> >>> state, and only then will it read the register to auto-detect.
> >>>
> >>> Signed-off-by: Adam Ford <aford173@gmail.com>
> >>> Tested-by: Tim Harvey <tharvey@gateworks.com>
> >>> ---
> >>> V4:  Fix 'err_clk' reference, so it is not encapsulated in
> >>>        an ifdef making it available at all times.
> >>> V3:  Keep ehci_usb_of_to_plat but add the ability to return
> >>>        and unknown state instead of reading the register.
> >>>        If the probe determines the states is unknown, it will
> >>>        query the register after the clocks have been enabled.
> >>>        Because of the slight behavior change, I removed any
> >>>        review or tested tags.
> >>>
> >>> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
> >>>        from the probe after t
> >>>
> >>> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> >>> index 1bd6147c76..060b02accc 100644
> >>> --- a/drivers/usb/host/ehci-mx6.c
> >>> +++ b/drivers/usb/host/ehci-mx6.c
> >>> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
> >>>                        plat->init_type = USB_INIT_DEVICE;
> >>>                else
> >>>                        plat->init_type = USB_INIT_HOST;
> >>> -     } else if (is_mx7()) {
> >>> +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
> >>>                phy_status = (void __iomem *)(addr +
> >>>                                              USBNC_PHY_STATUS_OFFSET);
> >>>                val = readl(phy_status);
> >>
> >> Is the USB GPCv2 power domain always ON at this point ? If it isn't,
> >> then this access will lock up the whole SoC.
> >
> > The GPCv2 needs to be enabled if USB is going to be used, but I would
> > expect that to happen even without this patch.  I ran into that during
> > my early testing.
> >
> >>
> >> You can check that easily by adding printf() into
> >> drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and
> >> verify that printf() prints something before this ehci_usb_phy_mode()
> >> code is called.
> >
> > I added a printf to show when a power domain is enabled.  It does
> > appear that power domains for HSIO, USBOTG1 and USBOTG2 are all
> > enabled before the scan on the respective USB bus happens, so I think
> > we're safe from hanging.
>
> Isn't the ehci_usb_of_to_plat() called way before you even initiate the
> scan, somewhere during U-Boot startup ? So no, you might end up hanging
> the hardware ?

If you look at what this patch is doing, ehci_usb_of_to_plat is no
longer making any calls to the USB registers.  ehci_usb_of_to_plat is
just an exercise in reading the device tree for the desired mode.  If
it's not host mode or peripheral mode it returns unknown.  The part
that reads the registers now is delayed until after the clocks are
enabled inside the probe function which is called when USB is started
and the power-domains are available.

adam

>
> (you can verify that by adding more printf()s)

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Adam Ford]

On Mon, Feb 7, 2022 at 5:00 AM Michael Walle <michael@walle.cc> wrote:
>
> Hi Adam,
>
> it's nice to include people who made review comments in the follow-up
> patches. I had to pull this out of the mailinglist again.

Sorry.  I didn't purposefully leave you out.  I have a little script I
run to get the list of people involved, and I forgot to manually add
you back in.

>
> > The imx8mm and imx8mn appear compatible with imx7d-usb
> > flags in the OTG driver.  If the dr_mode is defined as
> > host or peripheral, the device appears to operate correctly,
> > however the auto host/peripheral detection results in an error.
> >
> > The solution isn't just adding checks for imx8mm and imx8mn to
> > the check for imx7, because the USB clock needs to be running
> > to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> >
> > Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> > so I modified that function to return an unknown state if the
> > device tree does not explicitly state whether it is a host
> > or a peripheral.
> >
> > When the driver probes, it looks to see if it's in the unknown
> > state, and only then will it read the register to auto-detect.
> >
> > Signed-off-by: Adam Ford <aford173@gmail.com>
> > Tested-by: Tim Harvey <tharvey@gateworks.com>
> > ---
> > V4:  Fix 'err_clk' reference, so it is not encapsulated in
> >      an ifdef making it available at all times.
> > V3:  Keep ehci_usb_of_to_plat but add the ability to return
> >      and unknown state instead of reading the register.
> >      If the probe determines the states is unknown, it will
> >      query the register after the clocks have been enabled.
> >      Because of the slight behavior change, I removed any
> >      review or tested tags.
> >
> > V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
> >      from the probe after t
> >
> > diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> > index 1bd6147c76..060b02accc 100644
> > --- a/drivers/usb/host/ehci-mx6.c
> > +++ b/drivers/usb/host/ehci-mx6.c
> > @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
> >                       plat->init_type = USB_INIT_DEVICE;
> >               else
> >                       plat->init_type = USB_INIT_HOST;
> > -     } else if (is_mx7()) {
> > +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
> >               phy_status = (void __iomem *)(addr +
> >                                             USBNC_PHY_STATUS_OFFSET);
> >               val = readl(phy_status);
> > @@ -573,9 +573,8 @@ static int ehci_usb_of_to_plat(struct udevice *dev)
> >       case USB_DR_MODE_PERIPHERAL:
> >               plat->init_type = USB_INIT_DEVICE;
> >               break;
> > -     case USB_DR_MODE_OTG:
> > -     case USB_DR_MODE_UNKNOWN:
>
>
> Don't you want to propagate the OTG mode to the init_type field? Maybe
> it will be useful sometime and IMHO makes it easier to read the code...

I was thinking the OTG case was included with the default, since this
function is  really only looking for whether or not we're host or
peripheral.  Every other case is considered unknown since we have to
defer the reading of the USB state until later.

adam
>
> > -             return ehci_usb_phy_mode(dev);
> > +     default:
> > +             plat->init_type = USB_INIT_UNKNOWN;
> >       };
> >
> >       return 0;
> > @@ -677,6 +676,20 @@ static int ehci_usb_probe(struct udevice *dev)
> >       mdelay(1);
> >  #endif
> >
> > +     /*
> > +      * If the device tree didn't specify host or device,
> > +      * the default is USB_INIT_UNKNOWN, so we need to check
> > +      * the register. For imx8mm and imx8mn, the clocks need to be
> > +      * running first, so we defer the check until they are.
> > +      */
> > +     if (priv->init_type == USB_INIT_UNKNOWN) {
>
> Because this implicitly also contains OTG mode, right? So despite
> the comment, if the device tree includes OTG mode, this branch is
> also taken.

Yes, because the device tree didn't specify host or peripheral, all
other instances are assumed to be OTG and deferred until we get here.

>
> Otherwise looks good to me:
>
> Reviewed-by: Michael Walle <michael@walle.cc>
>
> > +             ret = ehci_usb_phy_mode(dev);
> > +             if (ret)
> > +                     goto err_clk;
> > +             else
> > +                     priv->init_type = plat->init_type;
> > +     }
> > +
> >  #if CONFIG_IS_ENABLED(DM_REGULATOR)
> >       ret = device_get_supply_regulator(dev, "vbus-supply",
> >                                         &priv->vbus_supply);
> > @@ -741,8 +754,8 @@ err_regulator:
> >  #if CONFIG_IS_ENABLED(DM_REGULATOR)
> >       if (priv->vbus_supply)
> >               regulator_set_enable(priv->vbus_supply, false);
> > -err_clk:
> >  #endif
> > +err_clk:
> >  #if CONFIG_IS_ENABLED(CLK)
> >       clk_disable(&priv->clk);
> >  #else
> > diff --git a/include/usb.h b/include/usb.h
> > index f032de8af9..7e3796bd5b 100644
> > --- a/include/usb.h
> > +++ b/include/usb.h
> > @@ -163,7 +163,8 @@ struct int_queue;
> >   */
> >  enum usb_init_type {
> >       USB_INIT_HOST,
> > -     USB_INIT_DEVICE
> > +     USB_INIT_DEVICE,
> > +     USB_INIT_UNKNOWN,
> >  };
> >
> >  /**********************************************************************

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Marek Vasut]

On 2/7/22 12:13, Adam Ford wrote:
> On Mon, Feb 7, 2022 at 2:47 AM Marek Vasut <marex@denx.de> wrote:
>>
>> On 2/7/22 01:51, Adam Ford wrote:
>>> On Sun, Feb 6, 2022 at 3:59 PM Marek Vasut <marex@denx.de> wrote:
>>>>
>>>> On 2/3/22 22:20, Adam Ford wrote:
>>>>> The imx8mm and imx8mn appear compatible with imx7d-usb
>>>>> flags in the OTG driver.  If the dr_mode is defined as
>>>>> host or peripheral, the device appears to operate correctly,
>>>>> however the auto host/peripheral detection results in an error.
>>>>>
>>>>> The solution isn't just adding checks for imx8mm and imx8mn to
>>>>> the check for imx7, because the USB clock needs to be running
>>>>> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
>>>>>
>>>>> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
>>>>> so I modified that function to return an unknown state if the
>>>>> device tree does not explicitly state whether it is a host
>>>>> or a peripheral.
>>>>>
>>>>> When the driver probes, it looks to see if it's in the unknown
>>>>> state, and only then will it read the register to auto-detect.
>>>>>
>>>>> Signed-off-by: Adam Ford <aford173@gmail.com>
>>>>> Tested-by: Tim Harvey <tharvey@gateworks.com>
>>>>> ---
>>>>> V4:  Fix 'err_clk' reference, so it is not encapsulated in
>>>>>         an ifdef making it available at all times.
>>>>> V3:  Keep ehci_usb_of_to_plat but add the ability to return
>>>>>         and unknown state instead of reading the register.
>>>>>         If the probe determines the states is unknown, it will
>>>>>         query the register after the clocks have been enabled.
>>>>>         Because of the slight behavior change, I removed any
>>>>>         review or tested tags.
>>>>>
>>>>> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
>>>>>         from the probe after t
>>>>>
>>>>> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
>>>>> index 1bd6147c76..060b02accc 100644
>>>>> --- a/drivers/usb/host/ehci-mx6.c
>>>>> +++ b/drivers/usb/host/ehci-mx6.c
>>>>> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
>>>>>                         plat->init_type = USB_INIT_DEVICE;
>>>>>                 else
>>>>>                         plat->init_type = USB_INIT_HOST;
>>>>> -     } else if (is_mx7()) {
>>>>> +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
>>>>>                 phy_status = (void __iomem *)(addr +
>>>>>                                               USBNC_PHY_STATUS_OFFSET);
>>>>>                 val = readl(phy_status);
>>>>
>>>> Is the USB GPCv2 power domain always ON at this point ? If it isn't,
>>>> then this access will lock up the whole SoC.
>>>
>>> The GPCv2 needs to be enabled if USB is going to be used, but I would
>>> expect that to happen even without this patch.  I ran into that during
>>> my early testing.
>>>
>>>>
>>>> You can check that easily by adding printf() into
>>>> drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and
>>>> verify that printf() prints something before this ehci_usb_phy_mode()
>>>> code is called.
>>>
>>> I added a printf to show when a power domain is enabled.  It does
>>> appear that power domains for HSIO, USBOTG1 and USBOTG2 are all
>>> enabled before the scan on the respective USB bus happens, so I think
>>> we're safe from hanging.
>>
>> Isn't the ehci_usb_of_to_plat() called way before you even initiate the
>> scan, somewhere during U-Boot startup ? So no, you might end up hanging
>> the hardware ?
> 
> If you look at what this patch is doing, ehci_usb_of_to_plat is no
> longer making any calls to the USB registers.  ehci_usb_of_to_plat is
> just an exercise in reading the device tree for the desired mode.  If
> it's not host mode or peripheral mode it returns unknown.  The part
> that reads the registers now is delayed until after the clocks are
> enabled inside the probe function which is called when USB is started
> and the power-domains are available.

Ah, I missed that part of the change.

One more thing, can you double-check that the "if (ctrl->init == 
USB_INIT_DEVICE)" checks in drivers/usb/host/ehci-hcd.c still work as 
they should ? If so, then this patch is fine.

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Adam Ford]

On Mon, Feb 7, 2022 at 5:50 AM Marek Vasut <marex@denx.de> wrote:
>
> On 2/7/22 12:13, Adam Ford wrote:
> > On Mon, Feb 7, 2022 at 2:47 AM Marek Vasut <marex@denx.de> wrote:
> >>
> >> On 2/7/22 01:51, Adam Ford wrote:
> >>> On Sun, Feb 6, 2022 at 3:59 PM Marek Vasut <marex@denx.de> wrote:
> >>>>
> >>>> On 2/3/22 22:20, Adam Ford wrote:
> >>>>> The imx8mm and imx8mn appear compatible with imx7d-usb
> >>>>> flags in the OTG driver.  If the dr_mode is defined as
> >>>>> host or peripheral, the device appears to operate correctly,
> >>>>> however the auto host/peripheral detection results in an error.
> >>>>>
> >>>>> The solution isn't just adding checks for imx8mm and imx8mn to
> >>>>> the check for imx7, because the USB clock needs to be running
> >>>>> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> >>>>>
> >>>>> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> >>>>> so I modified that function to return an unknown state if the
> >>>>> device tree does not explicitly state whether it is a host
> >>>>> or a peripheral.
> >>>>>
> >>>>> When the driver probes, it looks to see if it's in the unknown
> >>>>> state, and only then will it read the register to auto-detect.
> >>>>>
> >>>>> Signed-off-by: Adam Ford <aford173@gmail.com>
> >>>>> Tested-by: Tim Harvey <tharvey@gateworks.com>
> >>>>> ---
> >>>>> V4:  Fix 'err_clk' reference, so it is not encapsulated in
> >>>>>         an ifdef making it available at all times.
> >>>>> V3:  Keep ehci_usb_of_to_plat but add the ability to return
> >>>>>         and unknown state instead of reading the register.
> >>>>>         If the probe determines the states is unknown, it will
> >>>>>         query the register after the clocks have been enabled.
> >>>>>         Because of the slight behavior change, I removed any
> >>>>>         review or tested tags.
> >>>>>
> >>>>> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
> >>>>>         from the probe after t
> >>>>>
> >>>>> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> >>>>> index 1bd6147c76..060b02accc 100644
> >>>>> --- a/drivers/usb/host/ehci-mx6.c
> >>>>> +++ b/drivers/usb/host/ehci-mx6.c
> >>>>> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
> >>>>>                         plat->init_type = USB_INIT_DEVICE;
> >>>>>                 else
> >>>>>                         plat->init_type = USB_INIT_HOST;
> >>>>> -     } else if (is_mx7()) {
> >>>>> +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
> >>>>>                 phy_status = (void __iomem *)(addr +
> >>>>>                                               USBNC_PHY_STATUS_OFFSET);
> >>>>>                 val = readl(phy_status);
> >>>>
> >>>> Is the USB GPCv2 power domain always ON at this point ? If it isn't,
> >>>> then this access will lock up the whole SoC.
> >>>
> >>> The GPCv2 needs to be enabled if USB is going to be used, but I would
> >>> expect that to happen even without this patch.  I ran into that during
> >>> my early testing.
> >>>
> >>>>
> >>>> You can check that easily by adding printf() into
> >>>> drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and
> >>>> verify that printf() prints something before this ehci_usb_phy_mode()
> >>>> code is called.
> >>>
> >>> I added a printf to show when a power domain is enabled.  It does
> >>> appear that power domains for HSIO, USBOTG1 and USBOTG2 are all
> >>> enabled before the scan on the respective USB bus happens, so I think
> >>> we're safe from hanging.
> >>
> >> Isn't the ehci_usb_of_to_plat() called way before you even initiate the
> >> scan, somewhere during U-Boot startup ? So no, you might end up hanging
> >> the hardware ?
> >
> > If you look at what this patch is doing, ehci_usb_of_to_plat is no
> > longer making any calls to the USB registers.  ehci_usb_of_to_plat is
> > just an exercise in reading the device tree for the desired mode.  If
> > it's not host mode or peripheral mode it returns unknown.  The part
> > that reads the registers now is delayed until after the clocks are
> > enabled inside the probe function which is called when USB is started
> > and the power-domains are available.
>
> Ah, I missed that part of the change.
>
> One more thing, can you double-check that the "if (ctrl->init ==
> USB_INIT_DEVICE)" checks in drivers/usb/host/ehci-hcd.c still work as
> they should ? If so, then this patch is fine.

Sure.  If I run ums 0 mmc 2, I see the peripheral is enumerating on
the U-Boot side:

U-Boot 2022.01-00678-ge83818c782-dirty (Feb 06 2022 - 18:55:39 -0600)

CPU:   Freescale i.MX8MMQ rev1.0 at 1200 MHz
Reset cause: POR
Model: Beacon EmbeddedWorks i.MX8M Mini Development Kit
DRAM:  2 GiB
Core:  99 devices, 21 uclasses, devicetree: separate
WDT:   Started watchdog@30280000 with servicing (60s timeout)
MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
Loading Environment from MMC... OK
In:    serial@30890000
Out:   serial@30890000
Err:   serial@30890000
Net:   eth0: ethernet@30be0000
Hit any key to stop autoboot:  0
u-boot=> ums 0 mmc 2
UMS: LUN 0, dev mmc 2, hwpart 0, sector 0x0, count 0x3a3e000
imx8m_power_domain_on 0
imx8m_power_domain_on 2
-

And the power domains enable in the right order.

On the host side, I see:

usb 3-2: new high-speed USB device number 24 using xhci_hcd
usb 3-2: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice= 2.21
usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 3-2: Product: USB download gadget
 usb 3-2: Manufacturer: U-Boot
usb-storage 3-2:1.0: USB Mass Storage device detected
 usb-storage 3-2:1.0: Quirks match for vid 0525 pid a4a5: 10000
scsi host6: usb-storage 3-2:1.0
 scsi 6:0:0:0: Direct-Access     Linux    UMS disk 0       ffff PQ: 0 ANSI: 2
sd 6:0:0:0: Attached scsi generic sg2 type 0
sd 6:0:0:0: [sdb] 61071360 512-byte logical blocks: (31.3 GB/29.1 GiB)
sd 6:0:0:0: [sdb] Write Protect is off
sd 6:0:0:0: [sdb] Mode Sense: 0f 00 00 00
sd 6:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't
support DPO or FUA
sd 6:0:0:0: [sdb] Attached SCSI removable disk

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Adam Ford]

On Mon, Feb 7, 2022 at 6:15 AM Adam Ford <aford173@gmail.com> wrote:
>
> On Mon, Feb 7, 2022 at 5:50 AM Marek Vasut <marex@denx.de> wrote:
> >
> > On 2/7/22 12:13, Adam Ford wrote:
> > > On Mon, Feb 7, 2022 at 2:47 AM Marek Vasut <marex@denx.de> wrote:
> > >>
> > >> On 2/7/22 01:51, Adam Ford wrote:
> > >>> On Sun, Feb 6, 2022 at 3:59 PM Marek Vasut <marex@denx.de> wrote:
> > >>>>
> > >>>> On 2/3/22 22:20, Adam Ford wrote:
> > >>>>> The imx8mm and imx8mn appear compatible with imx7d-usb
> > >>>>> flags in the OTG driver.  If the dr_mode is defined as
> > >>>>> host or peripheral, the device appears to operate correctly,
> > >>>>> however the auto host/peripheral detection results in an error.
> > >>>>>
> > >>>>> The solution isn't just adding checks for imx8mm and imx8mn to
> > >>>>> the check for imx7, because the USB clock needs to be running
> > >>>>> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
> > >>>>>
> > >>>>> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
> > >>>>> so I modified that function to return an unknown state if the
> > >>>>> device tree does not explicitly state whether it is a host
> > >>>>> or a peripheral.
> > >>>>>
> > >>>>> When the driver probes, it looks to see if it's in the unknown
> > >>>>> state, and only then will it read the register to auto-detect.
> > >>>>>
> > >>>>> Signed-off-by: Adam Ford <aford173@gmail.com>
> > >>>>> Tested-by: Tim Harvey <tharvey@gateworks.com>
> > >>>>> ---
> > >>>>> V4:  Fix 'err_clk' reference, so it is not encapsulated in
> > >>>>>         an ifdef making it available at all times.
> > >>>>> V3:  Keep ehci_usb_of_to_plat but add the ability to return
> > >>>>>         and unknown state instead of reading the register.
> > >>>>>         If the probe determines the states is unknown, it will
> > >>>>>         query the register after the clocks have been enabled.
> > >>>>>         Because of the slight behavior change, I removed any
> > >>>>>         review or tested tags.
> > >>>>>
> > >>>>> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
> > >>>>>         from the probe after t
> > >>>>>
> > >>>>> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
> > >>>>> index 1bd6147c76..060b02accc 100644
> > >>>>> --- a/drivers/usb/host/ehci-mx6.c
> > >>>>> +++ b/drivers/usb/host/ehci-mx6.c
> > >>>>> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
> > >>>>>                         plat->init_type = USB_INIT_DEVICE;
> > >>>>>                 else
> > >>>>>                         plat->init_type = USB_INIT_HOST;
> > >>>>> -     } else if (is_mx7()) {
> > >>>>> +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
> > >>>>>                 phy_status = (void __iomem *)(addr +
> > >>>>>                                               USBNC_PHY_STATUS_OFFSET);
> > >>>>>                 val = readl(phy_status);
> > >>>>
> > >>>> Is the USB GPCv2 power domain always ON at this point ? If it isn't,
> > >>>> then this access will lock up the whole SoC.
> > >>>
> > >>> The GPCv2 needs to be enabled if USB is going to be used, but I would
> > >>> expect that to happen even without this patch.  I ran into that during
> > >>> my early testing.
> > >>>
> > >>>>
> > >>>> You can check that easily by adding printf() into
> > >>>> drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and
> > >>>> verify that printf() prints something before this ehci_usb_phy_mode()
> > >>>> code is called.
> > >>>
> > >>> I added a printf to show when a power domain is enabled.  It does
> > >>> appear that power domains for HSIO, USBOTG1 and USBOTG2 are all
> > >>> enabled before the scan on the respective USB bus happens, so I think
> > >>> we're safe from hanging.
> > >>
> > >> Isn't the ehci_usb_of_to_plat() called way before you even initiate the
> > >> scan, somewhere during U-Boot startup ? So no, you might end up hanging
> > >> the hardware ?
> > >
> > > If you look at what this patch is doing, ehci_usb_of_to_plat is no
> > > longer making any calls to the USB registers.  ehci_usb_of_to_plat is
> > > just an exercise in reading the device tree for the desired mode.  If
> > > it's not host mode or peripheral mode it returns unknown.  The part
> > > that reads the registers now is delayed until after the clocks are
> > > enabled inside the probe function which is called when USB is started
> > > and the power-domains are available.
> >
> > Ah, I missed that part of the change.
> >
> > One more thing, can you double-check that the "if (ctrl->init ==
> > USB_INIT_DEVICE)" checks in drivers/usb/host/ehci-hcd.c still work as
> > they should ? If so, then this patch is fine.
>
> Sure.  If I run ums 0 mmc 2, I see the peripheral is enumerating on
> the U-Boot side:
>
> U-Boot 2022.01-00678-ge83818c782-dirty (Feb 06 2022 - 18:55:39 -0600)
>
> CPU:   Freescale i.MX8MMQ rev1.0 at 1200 MHz
> Reset cause: POR
> Model: Beacon EmbeddedWorks i.MX8M Mini Development Kit
> DRAM:  2 GiB
> Core:  99 devices, 21 uclasses, devicetree: separate
> WDT:   Started watchdog@30280000 with servicing (60s timeout)
> MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
> Loading Environment from MMC... OK
> In:    serial@30890000
> Out:   serial@30890000
> Err:   serial@30890000
> Net:   eth0: ethernet@30be0000
> Hit any key to stop autoboot:  0
> u-boot=> ums 0 mmc 2
> UMS: LUN 0, dev mmc 2, hwpart 0, sector 0x0, count 0x3a3e000
> imx8m_power_domain_on 0
> imx8m_power_domain_on 2
> -
>
> And the power domains enable in the right order.
>
> On the host side, I see:
>
> usb 3-2: new high-speed USB device number 24 using xhci_hcd
> usb 3-2: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice= 2.21
> usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> usb 3-2: Product: USB download gadget
>  usb 3-2: Manufacturer: U-Boot
> usb-storage 3-2:1.0: USB Mass Storage device detected
>  usb-storage 3-2:1.0: Quirks match for vid 0525 pid a4a5: 10000
> scsi host6: usb-storage 3-2:1.0
>  scsi 6:0:0:0: Direct-Access     Linux    UMS disk 0       ffff PQ: 0 ANSI: 2
> sd 6:0:0:0: Attached scsi generic sg2 type 0
> sd 6:0:0:0: [sdb] 61071360 512-byte logical blocks: (31.3 GB/29.1 GiB)
> sd 6:0:0:0: [sdb] Write Protect is off
> sd 6:0:0:0: [sdb] Mode Sense: 0f 00 00 00
> sd 6:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't
> support DPO or FUA
> sd 6:0:0:0: [sdb] Attached SCSI removable disk

Marek,

Is this sufficient, or do you need explicit printf's inside the driver
to show the device is in peripheral mode?

adam

Re: [PATCH V4] usb: ehci-mx6: Enable OTG detection on imx8mm and imx8mn

[Marek Vasut]

On 2/10/22 15:49, Adam Ford wrote:
> On Mon, Feb 7, 2022 at 6:15 AM Adam Ford <aford173@gmail.com> wrote:
>>
>> On Mon, Feb 7, 2022 at 5:50 AM Marek Vasut <marex@denx.de> wrote:
>>>
>>> On 2/7/22 12:13, Adam Ford wrote:
>>>> On Mon, Feb 7, 2022 at 2:47 AM Marek Vasut <marex@denx.de> wrote:
>>>>>
>>>>> On 2/7/22 01:51, Adam Ford wrote:
>>>>>> On Sun, Feb 6, 2022 at 3:59 PM Marek Vasut <marex@denx.de> wrote:
>>>>>>>
>>>>>>> On 2/3/22 22:20, Adam Ford wrote:
>>>>>>>> The imx8mm and imx8mn appear compatible with imx7d-usb
>>>>>>>> flags in the OTG driver.  If the dr_mode is defined as
>>>>>>>> host or peripheral, the device appears to operate correctly,
>>>>>>>> however the auto host/peripheral detection results in an error.
>>>>>>>>
>>>>>>>> The solution isn't just adding checks for imx8mm and imx8mn to
>>>>>>>> the check for imx7, because the USB clock needs to be running
>>>>>>>> to read from the USBNC_PHY_STATUS_OFFSET register or it will hang.
>>>>>>>>
>>>>>>>> Marek requested that I not enable the clocks in ehci_usb_of_to_plat,
>>>>>>>> so I modified that function to return an unknown state if the
>>>>>>>> device tree does not explicitly state whether it is a host
>>>>>>>> or a peripheral.
>>>>>>>>
>>>>>>>> When the driver probes, it looks to see if it's in the unknown
>>>>>>>> state, and only then will it read the register to auto-detect.
>>>>>>>>
>>>>>>>> Signed-off-by: Adam Ford <aford173@gmail.com>
>>>>>>>> Tested-by: Tim Harvey <tharvey@gateworks.com>
>>>>>>>> ---
>>>>>>>> V4:  Fix 'err_clk' reference, so it is not encapsulated in
>>>>>>>>          an ifdef making it available at all times.
>>>>>>>> V3:  Keep ehci_usb_of_to_plat but add the ability to return
>>>>>>>>          and unknown state instead of reading the register.
>>>>>>>>          If the probe determines the states is unknown, it will
>>>>>>>>          query the register after the clocks have been enabled.
>>>>>>>>          Because of the slight behavior change, I removed any
>>>>>>>>          review or tested tags.
>>>>>>>>
>>>>>>>> V2:  Rename ehci_usb_of_to_plat to ehci_usb_dr_mode and call it
>>>>>>>>          from the probe after t
>>>>>>>>
>>>>>>>> diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
>>>>>>>> index 1bd6147c76..060b02accc 100644
>>>>>>>> --- a/drivers/usb/host/ehci-mx6.c
>>>>>>>> +++ b/drivers/usb/host/ehci-mx6.c
>>>>>>>> @@ -543,7 +543,7 @@ static int ehci_usb_phy_mode(struct udevice *dev)
>>>>>>>>                          plat->init_type = USB_INIT_DEVICE;
>>>>>>>>                  else
>>>>>>>>                          plat->init_type = USB_INIT_HOST;
>>>>>>>> -     } else if (is_mx7()) {
>>>>>>>> +     } else if (is_mx7() || is_imx8mm() || is_imx8mn()) {
>>>>>>>>                  phy_status = (void __iomem *)(addr +
>>>>>>>>                                                USBNC_PHY_STATUS_OFFSET);
>>>>>>>>                  val = readl(phy_status);
>>>>>>>
>>>>>>> Is the USB GPCv2 power domain always ON at this point ? If it isn't,
>>>>>>> then this access will lock up the whole SoC.
>>>>>>
>>>>>> The GPCv2 needs to be enabled if USB is going to be used, but I would
>>>>>> expect that to happen even without this patch.  I ran into that during
>>>>>> my early testing.
>>>>>>
>>>>>>>
>>>>>>> You can check that easily by adding printf() into
>>>>>>> drivers/power/domain/imx8m-power-domain.c imx8m_power_domain_on() , and
>>>>>>> verify that printf() prints something before this ehci_usb_phy_mode()
>>>>>>> code is called.
>>>>>>
>>>>>> I added a printf to show when a power domain is enabled.  It does
>>>>>> appear that power domains for HSIO, USBOTG1 and USBOTG2 are all
>>>>>> enabled before the scan on the respective USB bus happens, so I think
>>>>>> we're safe from hanging.
>>>>>
>>>>> Isn't the ehci_usb_of_to_plat() called way before you even initiate the
>>>>> scan, somewhere during U-Boot startup ? So no, you might end up hanging
>>>>> the hardware ?
>>>>
>>>> If you look at what this patch is doing, ehci_usb_of_to_plat is no
>>>> longer making any calls to the USB registers.  ehci_usb_of_to_plat is
>>>> just an exercise in reading the device tree for the desired mode.  If
>>>> it's not host mode or peripheral mode it returns unknown.  The part
>>>> that reads the registers now is delayed until after the clocks are
>>>> enabled inside the probe function which is called when USB is started
>>>> and the power-domains are available.
>>>
>>> Ah, I missed that part of the change.
>>>
>>> One more thing, can you double-check that the "if (ctrl->init ==
>>> USB_INIT_DEVICE)" checks in drivers/usb/host/ehci-hcd.c still work as
>>> they should ? If so, then this patch is fine.
>>
>> Sure.  If I run ums 0 mmc 2, I see the peripheral is enumerating on
>> the U-Boot side:
>>
>> U-Boot 2022.01-00678-ge83818c782-dirty (Feb 06 2022 - 18:55:39 -0600)
>>
>> CPU:   Freescale i.MX8MMQ rev1.0 at 1200 MHz
>> Reset cause: POR
>> Model: Beacon EmbeddedWorks i.MX8M Mini Development Kit
>> DRAM:  2 GiB
>> Core:  99 devices, 21 uclasses, devicetree: separate
>> WDT:   Started watchdog@30280000 with servicing (60s timeout)
>> MMC:   FSL_SDHC: 0, FSL_SDHC: 1, FSL_SDHC: 2
>> Loading Environment from MMC... OK
>> In:    serial@30890000
>> Out:   serial@30890000
>> Err:   serial@30890000
>> Net:   eth0: ethernet@30be0000
>> Hit any key to stop autoboot:  0
>> u-boot=> ums 0 mmc 2
>> UMS: LUN 0, dev mmc 2, hwpart 0, sector 0x0, count 0x3a3e000
>> imx8m_power_domain_on 0
>> imx8m_power_domain_on 2
>> -
>>
>> And the power domains enable in the right order.
>>
>> On the host side, I see:
>>
>> usb 3-2: new high-speed USB device number 24 using xhci_hcd
>> usb 3-2: New USB device found, idVendor=0525, idProduct=a4a5, bcdDevice= 2.21
>> usb 3-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
>> usb 3-2: Product: USB download gadget
>>   usb 3-2: Manufacturer: U-Boot
>> usb-storage 3-2:1.0: USB Mass Storage device detected
>>   usb-storage 3-2:1.0: Quirks match for vid 0525 pid a4a5: 10000
>> scsi host6: usb-storage 3-2:1.0
>>   scsi 6:0:0:0: Direct-Access     Linux    UMS disk 0       ffff PQ: 0 ANSI: 2
>> sd 6:0:0:0: Attached scsi generic sg2 type 0
>> sd 6:0:0:0: [sdb] 61071360 512-byte logical blocks: (31.3 GB/29.1 GiB)
>> sd 6:0:0:0: [sdb] Write Protect is off
>> sd 6:0:0:0: [sdb] Mode Sense: 0f 00 00 00
>> sd 6:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't
>> support DPO or FUA
>> sd 6:0:0:0: [sdb] Attached SCSI removable disk
> 
> Marek,
> 
> Is this sufficient, or do you need explicit printf's inside the driver
> to show the device is in peripheral mode?

It's in the MR queue.