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[RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

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  [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220 John Stultz <john.stultz@linaro.org> - 2016-10-14 01:40 +0200
    Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 John Stultz <john.stultz@linaro.org> - 2016-10-14 02:00 +0200
    Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 Rob Herring <robh+dt@kernel.org> - 2016-10-14 17:10 +0200
      Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 John Stultz <john.stultz@linaro.org> - 2016-10-14 20:30 +0200
    Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 John Youn <John.Youn@synopsys.com> - 2016-10-14 21:50 +0200
      Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 Chen Yu <chenyu56@huawei.com> - 2016-10-17 04:50 +0200
        Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 John Youn <John.Youn@synopsys.com> - 2016-10-19 00:30 +0200
          Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 Chen Yu <chenyu56@huawei.com> - 2016-10-21 02:50 +0200
            Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 John Youn <John.Youn@synopsys.com> - 2016-10-21 22:10 +0200
              Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed  negotiation for Hisilicon Hi6220 Chen Yu <chenyu56@huawei.com> - 2016-10-22 03:10 +0200

#1500627 — [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

From: Chen Yu <chenyu56@huawei.com>

The Hi6220's usb controller is limited in that it does not
automatically autonegotiate the usb speed. Thus it requires a
quirk so that we can manually negotiate the best usb speed for
the attached device.

Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Guodong Xu <guodong.xu@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: John Youn <johnyoun@synopsys.com>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Chen Yu <chenyu56@huawei.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 arch/arm64/boot/dts/hisilicon/hi6220.dtsi |  1 +
 drivers/usb/dwc2/core.h                   |  7 +++
 drivers/usb/dwc2/hcd.c                    | 75 +++++++++++++++++++++++++++++++
 drivers/usb/dwc2/platform.c               |  3 ++
 4 files changed, 86 insertions(+)

diff --git a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
index 17839db..2c8f435 100644
--- a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
+++ b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
@@ -752,6 +752,7 @@
 			g-np-tx-fifo-size = <128>;
 			g-tx-fifo-size = <128 128 128 128 128 128>;
 			interrupts = <0 77 0x4>;
+			hi6220,change_speed_quirk;
 		};
 
 		mailbox: mailbox@f7510000 {
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 2a21a04..24fea73 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -823,6 +823,10 @@ struct dwc2_hregs_backup {
  * @frame_list_sz:      Frame list size
  * @desc_gen_cache:     Kmem cache for generic descriptors
  * @desc_hsisoc_cache:  Kmem cache for hs isochronous descriptors
+ * @change_speed_quirk: Change speed configuration to DWC2_SPEED_PARAM_FULL
+ *                      while full&low speed device connect. And change speed
+ *                      back to DWC2_SPEED_PARAM_HIGH while device is gone.
+ * @device_count:       Number of devices connect to root hub
  *
  * These are for peripheral mode:
  *
@@ -951,6 +955,9 @@ struct dwc2_hsotg {
 	struct kmem_cache *desc_gen_cache;
 	struct kmem_cache *desc_hsisoc_cache;
 
+	int change_speed_quirk;
+	unsigned int device_count;
+
 #ifdef DEBUG
 	u32 frrem_samples;
 	u64 frrem_accum;
diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index b374e60..663033e 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -4868,6 +4868,75 @@ static void _dwc2_hcd_clear_tt_buffer_complete(struct usb_hcd *hcd,
 	spin_unlock_irqrestore(&hsotg->lock, flags);
 }
 
+/*
+ * HPRT0_SPD_HIGH_SPEED: high speed
+ * HPRT0_SPD_FULL_SPEED: full speed
+ */
+static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
+{
+	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
+
+	if (hsotg->core_params->speed == speed)
+		return;
+
+	hsotg->core_params->speed = speed;
+	queue_work(hsotg->wq_otg, &hsotg->wf_otg);
+}
+
+static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
+
+	if (!hsotg->change_speed_quirk)
+		return 1;
+
+	hsotg->device_count++;
+	dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
+			hsotg->device_count);
+
+	return 1;
+}
+
+static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
+
+	if (!hsotg->change_speed_quirk)
+		return;
+
+	if (hsotg->device_count)
+		hsotg->device_count--;
+
+	dev_info(hsotg->dev, "Device count is %u after free dev\n",
+			hsotg->device_count);
+
+	if (hsotg->device_count == 1 && udev->parent &&
+			udev->parent->speed > USB_SPEED_UNKNOWN &&
+			udev->parent->speed < USB_SPEED_HIGH) {
+		dev_info(hsotg->dev, "Set speed to default high-speed\n");
+		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
+	}
+}
+
+static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
+{
+	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
+
+	if (!hsotg->change_speed_quirk)
+		return 0;
+
+	if (udev->speed == USB_SPEED_HIGH) {
+		dev_info(hsotg->dev, "Set speed to high-speed\n");
+		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
+	} else if (udev->speed == USB_SPEED_FULL
+			|| udev->speed == USB_SPEED_LOW) {
+		dev_info(hsotg->dev, "Set speed to full-speed\n");
+		dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
+	}
+
+	return 0;
+}
+
 static struct hc_driver dwc2_hc_driver = {
 	.description = "dwc2_hsotg",
 	.product_desc = "DWC OTG Controller",
@@ -5023,6 +5092,12 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg, int irq)
 			dev_warn(hsotg->dev, "can't set coherent DMA mask\n");
 	}
 
+	if (hsotg->change_speed_quirk) {
+		dwc2_hc_driver.alloc_dev = dwc2_alloc_dev;
+		dwc2_hc_driver.free_dev = dwc2_free_dev;
+		dwc2_hc_driver.reset_device = dwc2_reset_device;
+	}
+
 	hcd = usb_create_hcd(&dwc2_hc_driver, hsotg->dev, dev_name(hsotg->dev));
 	if (!hcd)
 		goto error1;
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index 8e1728b..21c328b 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -585,6 +585,9 @@ static int dwc2_driver_probe(struct platform_device *dev)
 	dev_dbg(&dev->dev, "mapped PA %08lx to VA %p\n",
 		(unsigned long)res->start, hsotg->regs);
 
+	hsotg->change_speed_quirk = device_property_read_bool(&dev->dev,
+				"hi6220,change_speed_quirk");
+
 	retval = dwc2_lowlevel_hw_init(hsotg);
 	if (retval)
 		return retval;
-- 
2.7.4

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#1500635 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On Thu, Oct 13, 2016 at 4:29 PM, John Stultz <john.stultz@linaro.org> wrote:
> From: Chen Yu <chenyu56@huawei.com>
>
> The Hi6220's usb controller is limited in that it does not
> automatically autonegotiate the usb speed. Thus it requires a
> quirk so that we can manually negotiate the best usb speed for
> the attached device.
>
> Cc: Wei Xu <xuwei5@hisilicon.com>
> Cc: Guodong Xu <guodong.xu@linaro.org>
> Cc: Amit Pundir <amit.pundir@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: John Youn <johnyoun@synopsys.com>
> Cc: Douglas Anderson <dianders@chromium.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-usb@vger.kernel.org
> Signed-off-by: Chen Yu <chenyu56@huawei.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
>  arch/arm64/boot/dts/hisilicon/hi6220.dtsi |  1 +
>  drivers/usb/dwc2/core.h                   |  7 +++
>  drivers/usb/dwc2/hcd.c                    | 75 +++++++++++++++++++++++++++++++
>  drivers/usb/dwc2/platform.c               |  3 ++
>  4 files changed, 86 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> index 17839db..2c8f435 100644
> --- a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> +++ b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> @@ -752,6 +752,7 @@
>                         g-np-tx-fifo-size = <128>;
>                         g-tx-fifo-size = <128 128 128 128 128 128>;
>                         interrupts = <0 77 0x4>;
> +                       hi6220,change_speed_quirk;


I also realize I'm missing the DT binding documentation for this, but
I wanted to get a rough idea if this approach was ok first.
On the next submission (if there aren't major objections to the
approach) I can split the binding documentation and dts change into
different patches.

thanks
-john

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#1501047 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On Thu, Oct 13, 2016 at 6:29 PM, John Stultz <john.stultz@linaro.org> wrote:
> From: Chen Yu <chenyu56@huawei.com>
>
> The Hi6220's usb controller is limited in that it does not
> automatically autonegotiate the usb speed. Thus it requires a
> quirk so that we can manually negotiate the best usb speed for
> the attached device.
>
> Cc: Wei Xu <xuwei5@hisilicon.com>
> Cc: Guodong Xu <guodong.xu@linaro.org>
> Cc: Amit Pundir <amit.pundir@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: John Youn <johnyoun@synopsys.com>
> Cc: Douglas Anderson <dianders@chromium.org>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-usb@vger.kernel.org
> Signed-off-by: Chen Yu <chenyu56@huawei.com>
> Signed-off-by: John Stultz <john.stultz@linaro.org>
> ---
>  arch/arm64/boot/dts/hisilicon/hi6220.dtsi |  1 +
>  drivers/usb/dwc2/core.h                   |  7 +++
>  drivers/usb/dwc2/hcd.c                    | 75 +++++++++++++++++++++++++++++++
>  drivers/usb/dwc2/platform.c               |  3 ++
>  4 files changed, 86 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> index 17839db..2c8f435 100644
> --- a/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> +++ b/arch/arm64/boot/dts/hisilicon/hi6220.dtsi
> @@ -752,6 +752,7 @@
>                         g-np-tx-fifo-size = <128>;
>                         g-tx-fifo-size = <128 128 128 128 128 128>;
>                         interrupts = <0 77 0x4>;
> +                       hi6220,change_speed_quirk;
>                 };
>
>                 mailbox: mailbox@f7510000 {
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 2a21a04..24fea73 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -823,6 +823,10 @@ struct dwc2_hregs_backup {
>   * @frame_list_sz:      Frame list size
>   * @desc_gen_cache:     Kmem cache for generic descriptors
>   * @desc_hsisoc_cache:  Kmem cache for hs isochronous descriptors
> + * @change_speed_quirk: Change speed configuration to DWC2_SPEED_PARAM_FULL
> + *                      while full&low speed device connect. And change speed
> + *                      back to DWC2_SPEED_PARAM_HIGH while device is gone.
> + * @device_count:       Number of devices connect to root hub
>   *
>   * These are for peripheral mode:
>   *
> @@ -951,6 +955,9 @@ struct dwc2_hsotg {
>         struct kmem_cache *desc_gen_cache;
>         struct kmem_cache *desc_hsisoc_cache;
>
> +       int change_speed_quirk;
> +       unsigned int device_count;
> +
>  #ifdef DEBUG
>         u32 frrem_samples;
>         u64 frrem_accum;
> diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
> index b374e60..663033e 100644
> --- a/drivers/usb/dwc2/hcd.c
> +++ b/drivers/usb/dwc2/hcd.c
> @@ -4868,6 +4868,75 @@ static void _dwc2_hcd_clear_tt_buffer_complete(struct usb_hcd *hcd,
>         spin_unlock_irqrestore(&hsotg->lock, flags);
>  }
>
> +/*
> + * HPRT0_SPD_HIGH_SPEED: high speed
> + * HPRT0_SPD_FULL_SPEED: full speed
> + */
> +static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
> +{
> +       struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +       if (hsotg->core_params->speed == speed)
> +               return;
> +
> +       hsotg->core_params->speed = speed;
> +       queue_work(hsotg->wq_otg, &hsotg->wf_otg);
> +}
> +
> +static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
> +{
> +       struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +       if (!hsotg->change_speed_quirk)
> +               return 1;
> +
> +       hsotg->device_count++;
> +       dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
> +                       hsotg->device_count);
> +
> +       return 1;
> +}
> +
> +static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
> +{
> +       struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +       if (!hsotg->change_speed_quirk)
> +               return;
> +
> +       if (hsotg->device_count)
> +               hsotg->device_count--;
> +
> +       dev_info(hsotg->dev, "Device count is %u after free dev\n",
> +                       hsotg->device_count);
> +
> +       if (hsotg->device_count == 1 && udev->parent &&
> +                       udev->parent->speed > USB_SPEED_UNKNOWN &&
> +                       udev->parent->speed < USB_SPEED_HIGH) {
> +               dev_info(hsotg->dev, "Set speed to default high-speed\n");
> +               dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
> +       }
> +}
> +
> +static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
> +{
> +       struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +       if (!hsotg->change_speed_quirk)
> +               return 0;
> +
> +       if (udev->speed == USB_SPEED_HIGH) {
> +               dev_info(hsotg->dev, "Set speed to high-speed\n");
> +               dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
> +       } else if (udev->speed == USB_SPEED_FULL
> +                       || udev->speed == USB_SPEED_LOW) {
> +               dev_info(hsotg->dev, "Set speed to full-speed\n");
> +               dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
> +       }
> +
> +       return 0;
> +}
> +
>  static struct hc_driver dwc2_hc_driver = {
>         .description = "dwc2_hsotg",
>         .product_desc = "DWC OTG Controller",
> @@ -5023,6 +5092,12 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg, int irq)
>                         dev_warn(hsotg->dev, "can't set coherent DMA mask\n");
>         }
>
> +       if (hsotg->change_speed_quirk) {
> +               dwc2_hc_driver.alloc_dev = dwc2_alloc_dev;
> +               dwc2_hc_driver.free_dev = dwc2_free_dev;
> +               dwc2_hc_driver.reset_device = dwc2_reset_device;
> +       }
> +
>         hcd = usb_create_hcd(&dwc2_hc_driver, hsotg->dev, dev_name(hsotg->dev));
>         if (!hcd)
>                 goto error1;
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index 8e1728b..21c328b 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -585,6 +585,9 @@ static int dwc2_driver_probe(struct platform_device *dev)
>         dev_dbg(&dev->dev, "mapped PA %08lx to VA %p\n",
>                 (unsigned long)res->start, hsotg->regs);
>
> +       hsotg->change_speed_quirk = device_property_read_bool(&dev->dev,
> +                               "hi6220,change_speed_quirk");

Can't this be determined from the hi6220's compatible string?

In any case, "hi6220" is not a vendor. This should be
hisilicon,change... and don't use '_'. And to bikeshed things,
"no-speed-change-quirk".

Rob

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#1501124 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On Fri, Oct 14, 2016 at 8:00 AM, Rob Herring <robh+dt@kernel.org> wrote:
> On Thu, Oct 13, 2016 at 6:29 PM, John Stultz <john.stultz@linaro.org> wrote:
>> From: Chen Yu <chenyu56@huawei.com>
>>
>> The Hi6220's usb controller is limited in that it does not
>> automatically autonegotiate the usb speed. Thus it requires a
>> quirk so that we can manually negotiate the best usb speed for
>> the attached device.
>>
>> Cc: Wei Xu <xuwei5@hisilicon.com>
>> Cc: Guodong Xu <guodong.xu@linaro.org>
>> Cc: Amit Pundir <amit.pundir@linaro.org>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: John Youn <johnyoun@synopsys.com>
>> Cc: Douglas Anderson <dianders@chromium.org>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: linux-usb@vger.kernel.org
>> Signed-off-by: Chen Yu <chenyu56@huawei.com>
>> Signed-off-by: John Stultz <john.stultz@linaro.org>
>> ---
>>  arch/arm64/boot/dts/hisilicon/hi6220.dtsi |  1 +
>>  drivers/usb/dwc2/core.h                   |  7 +++
>>  drivers/usb/dwc2/hcd.c                    | 75 +++++++++++++++++++++++++++++++
>>  drivers/usb/dwc2/platform.c               |  3 ++
>>  4 files changed, 86 insertions(+)
>>
[snip]
>> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
>> index 8e1728b..21c328b 100644
>> --- a/drivers/usb/dwc2/platform.c
>> +++ b/drivers/usb/dwc2/platform.c
>> @@ -585,6 +585,9 @@ static int dwc2_driver_probe(struct platform_device *dev)
>>         dev_dbg(&dev->dev, "mapped PA %08lx to VA %p\n",
>>                 (unsigned long)res->start, hsotg->regs);
>>
>> +       hsotg->change_speed_quirk = device_property_read_bool(&dev->dev,
>> +                               "hi6220,change_speed_quirk");
>
> Can't this be determined from the hi6220's compatible string?

Ah. Good suggestion! I'm moving the quirk field to the core_params.
Should avoid any dts or binding changes.

thanks
-john

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#1501172 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On 10/13/2016 4:36 PM, John Stultz wrote:
> From: Chen Yu <chenyu56@huawei.com>
> 
> The Hi6220's usb controller is limited in that it does not
> automatically autonegotiate the usb speed. Thus it requires a
> quirk so that we can manually negotiate the best usb speed for
> the attached device.

Hi,

Could you expand more on this by explaining what exactly is the
limitation and the workaround?

[snip]

> +/*
> + * HPRT0_SPD_HIGH_SPEED: high speed
> + * HPRT0_SPD_FULL_SPEED: full speed
> + */
> +static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
> +{
> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +	if (hsotg->core_params->speed == speed)
> +		return;
> +
> +	hsotg->core_params->speed = speed;
> +	queue_work(hsotg->wq_otg, &hsotg->wf_otg);
> +}
> +
> +static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
> +{
> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +	if (!hsotg->change_speed_quirk)
> +		return 1;
> +
> +	hsotg->device_count++;

Why do you need to track the device count?

> +	dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
> +			hsotg->device_count);
> +
> +	return 1;
> +}
> +
> +static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
> +{
> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +	if (!hsotg->change_speed_quirk)
> +		return;
> +
> +	if (hsotg->device_count)
> +		hsotg->device_count--;
> +
> +	dev_info(hsotg->dev, "Device count is %u after free dev\n",
> +			hsotg->device_count);
> +
> +	if (hsotg->device_count == 1 && udev->parent &&
> +			udev->parent->speed > USB_SPEED_UNKNOWN &&
> +			udev->parent->speed < USB_SPEED_HIGH) {
> +		dev_info(hsotg->dev, "Set speed to default high-speed\n");
> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
> +	}
> +}
> +
> +static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
> +{
> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
> +
> +	if (!hsotg->change_speed_quirk)
> +		return 0;
> +
> +	if (udev->speed == USB_SPEED_HIGH) {
> +		dev_info(hsotg->dev, "Set speed to high-speed\n");
> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
> +	} else if (udev->speed == USB_SPEED_FULL
> +			|| udev->speed == USB_SPEED_LOW) {
> +		dev_info(hsotg->dev, "Set speed to full-speed\n");
> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
> +	}

It seems you are reinitializing the core every time a device is reset
and the udev->speed does not match the core_param speed. But how is
the udev->speed being set correctly if the hw cannot negotiate the
speed in the first place?

Also should it be for every device? What about if a device gets
plugged in behind a hub? I don't think you want to execute this code
in that case.

This should only affect devices plugged into the root hub, correct?
And the hsotg controller only has one root hub port. It seems things
could be simplified a bit.

Regards,
John

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#1501605 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On 2016/10/15 3:37, John Youn wrote:
> On 10/13/2016 4:36 PM, John Stultz wrote:
>> From: Chen Yu <chenyu56@huawei.com>
>>
>> The Hi6220's usb controller is limited in that it does not
>> automatically autonegotiate the usb speed. Thus it requires a
>> quirk so that we can manually negotiate the best usb speed for
>> the attached device.
> 
> Hi,
> 
> Could you expand more on this by explaining what exactly is the
> limitation and the workaround?
> 

The USB host limitation of Hisilicon Hi6220 is full-speed and low-speed
devices can not be enumerated when gets plugged behind a hub.

> [snip]
> 
>> +/*
>> + * HPRT0_SPD_HIGH_SPEED: high speed
>> + * HPRT0_SPD_FULL_SPEED: full speed
>> + */
>> +static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
>> +{
>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>> +
>> +	if (hsotg->core_params->speed == speed)
>> +		return;
>> +
>> +	hsotg->core_params->speed = speed;
>> +	queue_work(hsotg->wq_otg, &hsotg->wf_otg);
>> +}
>> +
>> +static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
>> +{
>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>> +
>> +	if (!hsotg->change_speed_quirk)
>> +		return 1;
>> +
>> +	hsotg->device_count++;
> 
> Why do you need to track the device count?
> 
>> +	dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
>> +			hsotg->device_count);
>> +
>> +	return 1;
>> +}
>> +
>> +static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
>> +{
>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>> +
>> +	if (!hsotg->change_speed_quirk)
>> +		return;
>> +
>> +	if (hsotg->device_count)
>> +		hsotg->device_count--;
>> +
>> +	dev_info(hsotg->dev, "Device count is %u after free dev\n",
>> +			hsotg->device_count);
>> +
>> +	if (hsotg->device_count == 1 && udev->parent &&
>> +			udev->parent->speed > USB_SPEED_UNKNOWN &&
>> +			udev->parent->speed < USB_SPEED_HIGH) {
>> +		dev_info(hsotg->dev, "Set speed to default high-speed\n");
>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>> +	}
>> +}
>> +
>> +static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
>> +{
>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>> +
>> +	if (!hsotg->change_speed_quirk)
>> +		return 0;
>> +
>> +	if (udev->speed == USB_SPEED_HIGH) {
>> +		dev_info(hsotg->dev, "Set speed to high-speed\n");
>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>> +	} else if (udev->speed == USB_SPEED_FULL
>> +			|| udev->speed == USB_SPEED_LOW) {
>> +		dev_info(hsotg->dev, "Set speed to full-speed\n");
>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
>> +	}
> 
> It seems you are reinitializing the core every time a device is reset
> and the udev->speed does not match the core_param speed. But how is
> the udev->speed being set correctly if the hw cannot negotiate the
> speed in the first place?
> 

The hardware can negotiate the speed, but communication with a full-speed or
low-speed device behind a hub is the problem.

> Also should it be for every device? What about if a device gets
> plugged in behind a hub? I don't think you want to execute this code
> in that case.
> 
> This should only affect devices plugged into the root hub, correct?
> And the hsotg controller only has one root hub port. It seems things
> could be simplified a bit.
> 

The patch is initially written for Hikey Hi6220 board, and there is a
hub always connected to root hub, so the patch sets the configuration to
HPRT0_SPD_HIGH_SPEED when there is only one device(the hub).

Thanks for your suggestions, the patch needs modified in these aspect:
1. Change the speed setting only when the device is behind a hub in dwc2_reset_device.
2. Change the speed to HPRT0_SPD_HIGH_SPEED only when the last device is a hub.

What do you think about the fix? Any suggestions will be appreciate!

thanks
- Chen Yu

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#1503401 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On 10/16/2016 7:42 PM, Chen Yu wrote:
> 
> 
> On 2016/10/15 3:37, John Youn wrote:
>> On 10/13/2016 4:36 PM, John Stultz wrote:
>>> From: Chen Yu <chenyu56@huawei.com>
>>>
>>> The Hi6220's usb controller is limited in that it does not
>>> automatically autonegotiate the usb speed. Thus it requires a
>>> quirk so that we can manually negotiate the best usb speed for
>>> the attached device.
>>
>> Hi,
>>
>> Could you expand more on this by explaining what exactly is the
>> limitation and the workaround?
>>
> 
> The USB host limitation of Hisilicon Hi6220 is full-speed and low-speed
> devices can not be enumerated when gets plugged behind a hub.
> 
>> [snip]
>>
>>> +/*
>>> + * HPRT0_SPD_HIGH_SPEED: high speed
>>> + * HPRT0_SPD_FULL_SPEED: full speed
>>> + */
>>> +static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
>>> +{
>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>> +
>>> +	if (hsotg->core_params->speed == speed)
>>> +		return;
>>> +
>>> +	hsotg->core_params->speed = speed;
>>> +	queue_work(hsotg->wq_otg, &hsotg->wf_otg);
>>> +}
>>> +
>>> +static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>> +{
>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>> +
>>> +	if (!hsotg->change_speed_quirk)
>>> +		return 1;
>>> +
>>> +	hsotg->device_count++;
>>
>> Why do you need to track the device count?
>>
>>> +	dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
>>> +			hsotg->device_count);
>>> +
>>> +	return 1;
>>> +}
>>> +
>>> +static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>> +{
>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>> +
>>> +	if (!hsotg->change_speed_quirk)
>>> +		return;
>>> +
>>> +	if (hsotg->device_count)
>>> +		hsotg->device_count--;
>>> +
>>> +	dev_info(hsotg->dev, "Device count is %u after free dev\n",
>>> +			hsotg->device_count);
>>> +
>>> +	if (hsotg->device_count == 1 && udev->parent &&
>>> +			udev->parent->speed > USB_SPEED_UNKNOWN &&
>>> +			udev->parent->speed < USB_SPEED_HIGH) {
>>> +		dev_info(hsotg->dev, "Set speed to default high-speed\n");
>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>> +	}
>>> +}
>>> +
>>> +static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
>>> +{
>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>> +
>>> +	if (!hsotg->change_speed_quirk)
>>> +		return 0;
>>> +
>>> +	if (udev->speed == USB_SPEED_HIGH) {
>>> +		dev_info(hsotg->dev, "Set speed to high-speed\n");
>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>> +	} else if (udev->speed == USB_SPEED_FULL
>>> +			|| udev->speed == USB_SPEED_LOW) {
>>> +		dev_info(hsotg->dev, "Set speed to full-speed\n");
>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
>>> +	}
>>
>> It seems you are reinitializing the core every time a device is reset
>> and the udev->speed does not match the core_param speed. But how is
>> the udev->speed being set correctly if the hw cannot negotiate the
>> speed in the first place?
>>
> 
> The hardware can negotiate the speed, but communication with a full-speed or
> low-speed device behind a hub is the problem.
> 
>> Also should it be for every device? What about if a device gets
>> plugged in behind a hub? I don't think you want to execute this code
>> in that case.
>>
>> This should only affect devices plugged into the root hub, correct?
>> And the hsotg controller only has one root hub port. It seems things
>> could be simplified a bit.
>>
> 
> The patch is initially written for Hikey Hi6220 board, and there is a
> hub always connected to root hub, so the patch sets the configuration to
> HPRT0_SPD_HIGH_SPEED when there is only one device(the hub).

Ok, I see.

> 
> Thanks for your suggestions, the patch needs modified in these aspect:
> 1. Change the speed setting only when the device is behind a hub in dwc2_reset_device.

I still think you will have issues with multiple devices. Since you
have a built-in hub after root hub, it will always be behind the
hub. So whenver you need to change speeds, it will always reset every
device in the tree. Have you tested with multiple devices and also
multiple levels of hubs?

> 2. Change the speed to HPRT0_SPD_HIGH_SPEED only when the last device is a hub.
> 
> What do you think about the fix? Any suggestions will be appreciate!

I'm not sure if any fix can work for all cases. Has this problem
always been there?

Regards,
John

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#1505362 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On 2016/10/19 6:21, John Youn wrote:
> On 10/16/2016 7:42 PM, Chen Yu wrote:
>>
>>
>> On 2016/10/15 3:37, John Youn wrote:
>>> On 10/13/2016 4:36 PM, John Stultz wrote:
>>>> From: Chen Yu <chenyu56@huawei.com>
>>>>
>>>> The Hi6220's usb controller is limited in that it does not
>>>> automatically autonegotiate the usb speed. Thus it requires a
>>>> quirk so that we can manually negotiate the best usb speed for
>>>> the attached device.
>>>
>>> Hi,
>>>
>>> Could you expand more on this by explaining what exactly is the
>>> limitation and the workaround?
>>>
>>
>> The USB host limitation of Hisilicon Hi6220 is full-speed and low-speed
>> devices can not be enumerated when gets plugged behind a hub.
>>
>>> [snip]
>>>
>>>> +/*
>>>> + * HPRT0_SPD_HIGH_SPEED: high speed
>>>> + * HPRT0_SPD_FULL_SPEED: full speed
>>>> + */
>>>> +static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
>>>> +{
>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>> +
>>>> +	if (hsotg->core_params->speed == speed)
>>>> +		return;
>>>> +
>>>> +	hsotg->core_params->speed = speed;
>>>> +	queue_work(hsotg->wq_otg, &hsotg->wf_otg);
>>>> +}
>>>> +
>>>> +static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>>> +{
>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>> +
>>>> +	if (!hsotg->change_speed_quirk)
>>>> +		return 1;
>>>> +
>>>> +	hsotg->device_count++;
>>>
>>> Why do you need to track the device count?
>>>
>>>> +	dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
>>>> +			hsotg->device_count);
>>>> +
>>>> +	return 1;
>>>> +}
>>>> +
>>>> +static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>>> +{
>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>> +
>>>> +	if (!hsotg->change_speed_quirk)
>>>> +		return;
>>>> +
>>>> +	if (hsotg->device_count)
>>>> +		hsotg->device_count--;
>>>> +
>>>> +	dev_info(hsotg->dev, "Device count is %u after free dev\n",
>>>> +			hsotg->device_count);
>>>> +
>>>> +	if (hsotg->device_count == 1 && udev->parent &&
>>>> +			udev->parent->speed > USB_SPEED_UNKNOWN &&
>>>> +			udev->parent->speed < USB_SPEED_HIGH) {
>>>> +		dev_info(hsotg->dev, "Set speed to default high-speed\n");
>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>>> +	}
>>>> +}
>>>> +
>>>> +static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
>>>> +{
>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>> +
>>>> +	if (!hsotg->change_speed_quirk)
>>>> +		return 0;
>>>> +
>>>> +	if (udev->speed == USB_SPEED_HIGH) {
>>>> +		dev_info(hsotg->dev, "Set speed to high-speed\n");
>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>>> +	} else if (udev->speed == USB_SPEED_FULL
>>>> +			|| udev->speed == USB_SPEED_LOW) {
>>>> +		dev_info(hsotg->dev, "Set speed to full-speed\n");
>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
>>>> +	}
>>>
>>> It seems you are reinitializing the core every time a device is reset
>>> and the udev->speed does not match the core_param speed. But how is
>>> the udev->speed being set correctly if the hw cannot negotiate the
>>> speed in the first place?
>>>
>>
>> The hardware can negotiate the speed, but communication with a full-speed or
>> low-speed device behind a hub is the problem.
>>
>>> Also should it be for every device? What about if a device gets
>>> plugged in behind a hub? I don't think you want to execute this code
>>> in that case.
>>>
>>> This should only affect devices plugged into the root hub, correct?
>>> And the hsotg controller only has one root hub port. It seems things
>>> could be simplified a bit.
>>>
>>
>> The patch is initially written for Hikey Hi6220 board, and there is a
>> hub always connected to root hub, so the patch sets the configuration to
>> HPRT0_SPD_HIGH_SPEED when there is only one device(the hub).
> 
> Ok, I see.
> 
>>
>> Thanks for your suggestions, the patch needs modified in these aspect:
>> 1. Change the speed setting only when the device is behind a hub in dwc2_reset_device.
> 
> I still think you will have issues with multiple devices. Since you
> have a built-in hub after root hub, it will always be behind the
> hub. So whenver you need to change speeds, it will always reset every
> device in the tree. Have you tested with multiple devices and also
> multiple levels of hubs?
> 

Yes, a full-speed device or low-speed device being plugged in will reset other devices
if current speed setting is not full-speed.
I have tested with multiple devices and also two levels of high-speed hubs,
the patch was working well for enumerating full-speed device and low-speed device.
Also it changed the speed to high when there was only one hub connected to root hub.


>> 2. Change the speed to HPRT0_SPD_HIGH_SPEED only when the last device is a hub.
>>
>> What do you think about the fix? Any suggestions will be appreciate!
> 
> I'm not sure if any fix can work for all cases. Has this problem
> always been there?

Yes, the problem is always there because Hi6220 can not support "Split Transaction".

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#1506257 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On 10/20/2016 5:43 PM, Chen Yu wrote:
> On 2016/10/19 6:21, John Youn wrote:
>> On 10/16/2016 7:42 PM, Chen Yu wrote:
>>>
>>>
>>> On 2016/10/15 3:37, John Youn wrote:
>>>> On 10/13/2016 4:36 PM, John Stultz wrote:
>>>>> From: Chen Yu <chenyu56@huawei.com>
>>>>>
>>>>> The Hi6220's usb controller is limited in that it does not
>>>>> automatically autonegotiate the usb speed. Thus it requires a
>>>>> quirk so that we can manually negotiate the best usb speed for
>>>>> the attached device.
>>>>
>>>> Hi,
>>>>
>>>> Could you expand more on this by explaining what exactly is the
>>>> limitation and the workaround?
>>>>
>>>
>>> The USB host limitation of Hisilicon Hi6220 is full-speed and low-speed
>>> devices can not be enumerated when gets plugged behind a hub.
>>>
>>>> [snip]
>>>>
>>>>> +/*
>>>>> + * HPRT0_SPD_HIGH_SPEED: high speed
>>>>> + * HPRT0_SPD_FULL_SPEED: full speed
>>>>> + */
>>>>> +static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
>>>>> +{
>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>> +
>>>>> +	if (hsotg->core_params->speed == speed)
>>>>> +		return;
>>>>> +
>>>>> +	hsotg->core_params->speed = speed;
>>>>> +	queue_work(hsotg->wq_otg, &hsotg->wf_otg);
>>>>> +}
>>>>> +
>>>>> +static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>>>> +{
>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>> +
>>>>> +	if (!hsotg->change_speed_quirk)
>>>>> +		return 1;
>>>>> +
>>>>> +	hsotg->device_count++;
>>>>
>>>> Why do you need to track the device count?
>>>>
>>>>> +	dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
>>>>> +			hsotg->device_count);
>>>>> +
>>>>> +	return 1;
>>>>> +}
>>>>> +
>>>>> +static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>>>> +{
>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>> +
>>>>> +	if (!hsotg->change_speed_quirk)
>>>>> +		return;
>>>>> +
>>>>> +	if (hsotg->device_count)
>>>>> +		hsotg->device_count--;
>>>>> +
>>>>> +	dev_info(hsotg->dev, "Device count is %u after free dev\n",
>>>>> +			hsotg->device_count);
>>>>> +
>>>>> +	if (hsotg->device_count == 1 && udev->parent &&
>>>>> +			udev->parent->speed > USB_SPEED_UNKNOWN &&
>>>>> +			udev->parent->speed < USB_SPEED_HIGH) {
>>>>> +		dev_info(hsotg->dev, "Set speed to default high-speed\n");
>>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>>>> +	}
>>>>> +}
>>>>> +
>>>>> +static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
>>>>> +{
>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>> +
>>>>> +	if (!hsotg->change_speed_quirk)
>>>>> +		return 0;
>>>>> +
>>>>> +	if (udev->speed == USB_SPEED_HIGH) {
>>>>> +		dev_info(hsotg->dev, "Set speed to high-speed\n");
>>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>>>> +	} else if (udev->speed == USB_SPEED_FULL
>>>>> +			|| udev->speed == USB_SPEED_LOW) {
>>>>> +		dev_info(hsotg->dev, "Set speed to full-speed\n");
>>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
>>>>> +	}
>>>>
>>>> It seems you are reinitializing the core every time a device is reset
>>>> and the udev->speed does not match the core_param speed. But how is
>>>> the udev->speed being set correctly if the hw cannot negotiate the
>>>> speed in the first place?
>>>>
>>>
>>> The hardware can negotiate the speed, but communication with a full-speed or
>>> low-speed device behind a hub is the problem.
>>>
>>>> Also should it be for every device? What about if a device gets
>>>> plugged in behind a hub? I don't think you want to execute this code
>>>> in that case.
>>>>
>>>> This should only affect devices plugged into the root hub, correct?
>>>> And the hsotg controller only has one root hub port. It seems things
>>>> could be simplified a bit.
>>>>
>>>
>>> The patch is initially written for Hikey Hi6220 board, and there is a
>>> hub always connected to root hub, so the patch sets the configuration to
>>> HPRT0_SPD_HIGH_SPEED when there is only one device(the hub).
>>
>> Ok, I see.
>>
>>>
>>> Thanks for your suggestions, the patch needs modified in these aspect:
>>> 1. Change the speed setting only when the device is behind a hub in dwc2_reset_device.
>>
>> I still think you will have issues with multiple devices. Since you
>> have a built-in hub after root hub, it will always be behind the
>> hub. So whenver you need to change speeds, it will always reset every
>> device in the tree. Have you tested with multiple devices and also
>> multiple levels of hubs?
>>
> 
> Yes, a full-speed device or low-speed device being plugged in will reset other devices
> if current speed setting is not full-speed.
> I have tested with multiple devices and also two levels of high-speed hubs,
> the patch was working well for enumerating full-speed device and low-speed device.
> Also it changed the speed to high when there was only one hub connected to root hub.
> 
> 
>>> 2. Change the speed to HPRT0_SPD_HIGH_SPEED only when the last device is a hub.
>>>
>>> What do you think about the fix? Any suggestions will be appreciate!
>>
>> I'm not sure if any fix can work for all cases. Has this problem
>> always been there?
> 
> Yes, the problem is always there because Hi6220 can not support "Split Transaction".

So the problem is actually that the on board hub doesn't support
splits? That's much different than your initial description and the
workaround makes more sense in this context.

But why can't it support splits?

And how can an FS device pass enumeration if the hub doesn't support
splits? I feel like there is still something missing.

Also, if you plug in a HS hub, and then an FS device behind that. That
should work fine, no? So you wouldn't want to reset anything in that
case.

Regards,
John

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#1506366 — Re: [RFC][PATCH 2/2] usb: dwc2: Add a quirk to allow speed negotiation for Hisilicon Hi6220

On 2016/10/22 4:00, John Youn wrote:
> On 10/20/2016 5:43 PM, Chen Yu wrote:
>> On 2016/10/19 6:21, John Youn wrote:
>>> On 10/16/2016 7:42 PM, Chen Yu wrote:
>>>>
>>>>
>>>> On 2016/10/15 3:37, John Youn wrote:
>>>>> On 10/13/2016 4:36 PM, John Stultz wrote:
>>>>>> From: Chen Yu <chenyu56@huawei.com>
>>>>>>
>>>>>> The Hi6220's usb controller is limited in that it does not
>>>>>> automatically autonegotiate the usb speed. Thus it requires a
>>>>>> quirk so that we can manually negotiate the best usb speed for
>>>>>> the attached device.
>>>>>
>>>>> Hi,
>>>>>
>>>>> Could you expand more on this by explaining what exactly is the
>>>>> limitation and the workaround?
>>>>>
>>>>
>>>> The USB host limitation of Hisilicon Hi6220 is full-speed and low-speed
>>>> devices can not be enumerated when gets plugged behind a hub.
>>>>
>>>>> [snip]
>>>>>
>>>>>> +/*
>>>>>> + * HPRT0_SPD_HIGH_SPEED: high speed
>>>>>> + * HPRT0_SPD_FULL_SPEED: full speed
>>>>>> + */
>>>>>> +static void dwc2_change_bus_speed(struct usb_hcd *hcd, int speed)
>>>>>> +{
>>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>>> +
>>>>>> +	if (hsotg->core_params->speed == speed)
>>>>>> +		return;
>>>>>> +
>>>>>> +	hsotg->core_params->speed = speed;
>>>>>> +	queue_work(hsotg->wq_otg, &hsotg->wf_otg);
>>>>>> +}
>>>>>> +
>>>>>> +static int dwc2_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>>>>> +{
>>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>>> +
>>>>>> +	if (!hsotg->change_speed_quirk)
>>>>>> +		return 1;
>>>>>> +
>>>>>> +	hsotg->device_count++;
>>>>>
>>>>> Why do you need to track the device count?
>>>>>
>>>>>> +	dev_info(hsotg->dev, "Device count is %u after alloc dev\n",
>>>>>> +			hsotg->device_count);
>>>>>> +
>>>>>> +	return 1;
>>>>>> +}
>>>>>> +
>>>>>> +static void dwc2_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
>>>>>> +{
>>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>>> +
>>>>>> +	if (!hsotg->change_speed_quirk)
>>>>>> +		return;
>>>>>> +
>>>>>> +	if (hsotg->device_count)
>>>>>> +		hsotg->device_count--;
>>>>>> +
>>>>>> +	dev_info(hsotg->dev, "Device count is %u after free dev\n",
>>>>>> +			hsotg->device_count);
>>>>>> +
>>>>>> +	if (hsotg->device_count == 1 && udev->parent &&
>>>>>> +			udev->parent->speed > USB_SPEED_UNKNOWN &&
>>>>>> +			udev->parent->speed < USB_SPEED_HIGH) {
>>>>>> +		dev_info(hsotg->dev, "Set speed to default high-speed\n");
>>>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>>>>> +	}
>>>>>> +}
>>>>>> +
>>>>>> +static int dwc2_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
>>>>>> +{
>>>>>> +	struct dwc2_hsotg *hsotg = dwc2_hcd_to_hsotg(hcd);
>>>>>> +
>>>>>> +	if (!hsotg->change_speed_quirk)
>>>>>> +		return 0;
>>>>>> +
>>>>>> +	if (udev->speed == USB_SPEED_HIGH) {
>>>>>> +		dev_info(hsotg->dev, "Set speed to high-speed\n");
>>>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_HIGH_SPEED);
>>>>>> +	} else if (udev->speed == USB_SPEED_FULL
>>>>>> +			|| udev->speed == USB_SPEED_LOW) {
>>>>>> +		dev_info(hsotg->dev, "Set speed to full-speed\n");
>>>>>> +		dwc2_change_bus_speed(hcd, HPRT0_SPD_FULL_SPEED);
>>>>>> +	}
>>>>>
>>>>> It seems you are reinitializing the core every time a device is reset
>>>>> and the udev->speed does not match the core_param speed. But how is
>>>>> the udev->speed being set correctly if the hw cannot negotiate the
>>>>> speed in the first place?
>>>>>
>>>>
>>>> The hardware can negotiate the speed, but communication with a full-speed or
>>>> low-speed device behind a hub is the problem.
>>>>
>>>>> Also should it be for every device? What about if a device gets
>>>>> plugged in behind a hub? I don't think you want to execute this code
>>>>> in that case.
>>>>>
>>>>> This should only affect devices plugged into the root hub, correct?
>>>>> And the hsotg controller only has one root hub port. It seems things
>>>>> could be simplified a bit.
>>>>>
>>>>
>>>> The patch is initially written for Hikey Hi6220 board, and there is a
>>>> hub always connected to root hub, so the patch sets the configuration to
>>>> HPRT0_SPD_HIGH_SPEED when there is only one device(the hub).
>>>
>>> Ok, I see.
>>>
>>>>
>>>> Thanks for your suggestions, the patch needs modified in these aspect:
>>>> 1. Change the speed setting only when the device is behind a hub in dwc2_reset_device.
>>>
>>> I still think you will have issues with multiple devices. Since you
>>> have a built-in hub after root hub, it will always be behind the
>>> hub. So whenver you need to change speeds, it will always reset every
>>> device in the tree. Have you tested with multiple devices and also
>>> multiple levels of hubs?
>>>
>>
>> Yes, a full-speed device or low-speed device being plugged in will reset other devices
>> if current speed setting is not full-speed.
>> I have tested with multiple devices and also two levels of high-speed hubs,
>> the patch was working well for enumerating full-speed device and low-speed device.
>> Also it changed the speed to high when there was only one hub connected to root hub.
>>
>>
>>>> 2. Change the speed to HPRT0_SPD_HIGH_SPEED only when the last device is a hub.
>>>>
>>>> What do you think about the fix? Any suggestions will be appreciate!
>>>
>>> I'm not sure if any fix can work for all cases. Has this problem
>>> always been there?
>>
>> Yes, the problem is always there because Hi6220 can not support "Split Transaction".
> 
> So the problem is actually that the on board hub doesn't support
> splits? That's much different than your initial description and the
> workaround makes more sense in this context.
> 
> But why can't it support splits?
> 
> And how can an FS device pass enumeration if the hub doesn't support
> splits? I feel like there is still something missing.
> 
> Also, if you plug in a HS hub, and then an FS device behind that. That
> should work fine, no? So you wouldn't want to reset anything in that
> case.
> 

Hi6220 is a SOC of Hisilicon, not the board. The hub on board is a HS hub and support splits.
The limitation is from the Hi6220 chip.

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