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From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: Randy Li <ayaka@soulik.info>, linux-usb@vger.kernel.org
Cc: felipe.balbi@linux.intel.com, John.Youn@synopsys.com,
	mark.rutland@arm.com, devicetree@vger.kernel.org,
	heiko@sntech.de, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	robh+dt@kernel.org, kishon@ti.com, randy.li@rock-chips.com
Subject: Re: [PATCH v7 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform
Date: Sun, 4 Sep 2016 01:08:55 +0300	[thread overview]
Message-ID: <784a905b-61e8-3786-74fa-de1829cf3f59@cogentembedded.com> (raw)
In-Reply-To: <1472939729-15187-4-git-send-email-ayaka@soulik.info>

On 09/04/2016 12:55 AM, Randy Li wrote:

> On the rk3288 USB host-only port (the one that's not the OTG-enabled
> port) the PHY can get into a bad state when a wakeup is asserted (not
> just a wakeup from full system suspend but also a wakeup from
> autosuspend).
>
> We can get the PHY out of its bad state by asserting its "port reset",
> but unfortunately that seems to assert a reset onto the USB bus so it
> could confuse things if we don't actually deenumerate / reenumerate the
> device.
>
> We can also get the PHY out of its bad state by fully resetting it using
> the reset from the CRU (clock reset unit) in chip, which does a more full
> reset.  The CRU-based reset appears to actually cause devices on the bus
> to be removed and reinserted, which fixes the problem (albeit in a hacky
> way).
>
> It's unfortunate that we need to do a full re-enumeration of devices at
> wakeup time, but this is better than alternative of letting the bus get
> wedged.
>
> Signed-off-by: Randy Li <ayaka@soulik.info>
> ---
>  drivers/usb/dwc2/core_intr.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
> index d85c5c9..08485b7 100644
> --- a/drivers/usb/dwc2/core_intr.c
> +++ b/drivers/usb/dwc2/core_intr.c
[...]
> @@ -379,6 +380,17 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>  			/* Restart the Phy Clock */
>  			pcgcctl &= ~PCGCTL_STOPPCLK;
>  			dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
> +
> +			/*
> +			 * It is a quirk in Rockchip RK3288, causing by
> +			 * a hardware bug. This will propagate out and
> +			 * eventually we'll re-enumerate the device.
> +			 * Not great but the best we can do
> +			 */
> +			if (of_device_is_compatible(np, "rockchip,rk3288-usb")
> +					&& (NULL != hsotg->phy->ops->reset))

    Don't reverse the operands of !=, please.

[...]

MBR, Sergei

WARNING: multiple messages have this Message-ID
From: Sergei Shtylyov <sergei.shtylyov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org>
To: Randy Li <ayaka-xPW3/0Ywev/iB9QmIjCX8w@public.gmane.org>,
	linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: mark.rutland-5wv7dgnIgG8@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org,
	felipe.balbi-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
	gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org,
	randy.li-TNX95d0MmH7DzftRWevZcw@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	John.Youn-HKixBCOQz3hWk0Htik3J/w@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	kishon-l0cyMroinI0@public.gmane.org
Subject: Re: [PATCH v7 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform
Date: Sun, 4 Sep 2016 01:08:55 +0300	[thread overview]
Message-ID: <784a905b-61e8-3786-74fa-de1829cf3f59@cogentembedded.com> (raw)
In-Reply-To: <1472939729-15187-4-git-send-email-ayaka-xPW3/0Ywev/iB9QmIjCX8w@public.gmane.org>

On 09/04/2016 12:55 AM, Randy Li wrote:

> On the rk3288 USB host-only port (the one that's not the OTG-enabled
> port) the PHY can get into a bad state when a wakeup is asserted (not
> just a wakeup from full system suspend but also a wakeup from
> autosuspend).
>
> We can get the PHY out of its bad state by asserting its "port reset",
> but unfortunately that seems to assert a reset onto the USB bus so it
> could confuse things if we don't actually deenumerate / reenumerate the
> device.
>
> We can also get the PHY out of its bad state by fully resetting it using
> the reset from the CRU (clock reset unit) in chip, which does a more full
> reset.  The CRU-based reset appears to actually cause devices on the bus
> to be removed and reinserted, which fixes the problem (albeit in a hacky
> way).
>
> It's unfortunate that we need to do a full re-enumeration of devices at
> wakeup time, but this is better than alternative of letting the bus get
> wedged.
>
> Signed-off-by: Randy Li <ayaka-xPW3/0Ywev/iB9QmIjCX8w@public.gmane.org>
> ---
>  drivers/usb/dwc2/core_intr.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
> index d85c5c9..08485b7 100644
> --- a/drivers/usb/dwc2/core_intr.c
> +++ b/drivers/usb/dwc2/core_intr.c
[...]
> @@ -379,6 +380,17 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
>  			/* Restart the Phy Clock */
>  			pcgcctl &= ~PCGCTL_STOPPCLK;
>  			dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
> +
> +			/*
> +			 * It is a quirk in Rockchip RK3288, causing by
> +			 * a hardware bug. This will propagate out and
> +			 * eventually we'll re-enumerate the device.
> +			 * Not great but the best we can do
> +			 */
> +			if (of_device_is_compatible(np, "rockchip,rk3288-usb")
> +					&& (NULL != hsotg->phy->ops->reset))

    Don't reverse the operands of !=, please.

[...]

MBR, Sergei

  reply	other threads:[~2016-09-03 22:37 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-03 21:55 [PATCH v7 0/4] the fix for the USB HOST1 at " Randy Li
2016-09-03 21:55 ` Randy Li
2016-09-03 21:55 ` [PATCH v7 1/4] phy: Add reset callback Randy Li
2016-09-03 21:55   ` Randy Li
2016-09-03 21:55 ` [PATCH v7 2/4] phy: rockchip-usb: use rockchip_usb_phy_reset to reset phy during wakeup Randy Li
2016-09-03 21:55   ` Randy Li
2016-09-03 21:55 ` [PATCH v7 3/4] usb: dwc2: assert phy reset when waking up in rk3288 platform Randy Li
2016-09-03 21:55   ` Randy Li
2016-09-03 22:08   ` Sergei Shtylyov [this message]
2016-09-03 22:08     ` Sergei Shtylyov
2016-09-05 13:35   ` David Laight
2016-09-05 13:35     ` David Laight
2016-09-05 23:38     ` Ayaka
2016-09-05 23:38       ` Ayaka
2016-09-06  5:14   ` Kishon Vijay Abraham I
2016-09-06  5:14     ` Kishon Vijay Abraham I
2016-09-06 18:54     ` John Youn
2016-09-06 18:54       ` John Youn
2016-09-07  1:19       ` Ayaka
2016-09-07  1:19         ` Ayaka
2016-09-07  2:02         ` John Youn
2016-09-07  2:02           ` John Youn
2016-09-03 21:55 ` [PATCH v7 4/4] ARM: dts: rockchip: Point rk3288 dwc2 usb at the full PHY reset Randy Li
2016-09-03 21:55   ` Randy Li

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