On 7/19/2016 5:06 AM, Randy Li wrote:
> From: Doug Anderson <dianders@xxxxxxxxxxxx>
>
> 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). The problem is caused by a design fault in IC, Rockchip
> have confirmed it and fix this problem in the future IC model.
>
> 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), 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: Douglas Anderson <dianders@xxxxxxxxxxxx>
> Signed-off-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx>
> Reviewed-by: Randy Li <randy.li@xxxxxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/usb/dwc2.txt | 7 +++++++
> drivers/usb/dwc2/core.h | 5 +++++
> drivers/usb/dwc2/core_intr.c | 14 ++++++++++++++
> drivers/usb/dwc2/platform.c | 13 +++++++++++++
> 4 files changed, 39 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/usb/dwc2.txt b/Documentation/devicetree/bindings/usb/dwc2.txt
> index 20a68bf..40c63ae 100644
> --- a/Documentation/devicetree/bindings/usb/dwc2.txt
> +++ b/Documentation/devicetree/bindings/usb/dwc2.txt
> @@ -20,6 +20,13 @@ Refer to clk/clock-bindings.txt for generic clock consumer properties
> Optional properties:
> - phys: phy provider specifier
> - phy-names: shall be "usb2-phy"
> +- snps,need-phy-full-reset-on-wake: if present indicates that we need to reset
> + the PHY when we detect a wakeup due to a hardware errata. If present you
> + must specify a "phy-full-reset" reset.
> +
> +Resets:
> +- phy-full-reset (optional): Fully resets the PHY (Only used by rk3288 Soc).
> +
> Refer to phy/phy-bindings.txt for generic phy consumer properties
> - dr_mode: shall be one of "host", "peripheral" and "otg"
> Refer to usb/generic.txt
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index dec0b21..951abe0 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -719,8 +719,11 @@ struct dwc2_hregs_backup {
> * @hcd_enabled Host mode sub-driver initialization indicator.
> * @gadget_enabled Peripheral mode sub-driver initialization indicator.
> * @ll_hw_enabled Status of low-level hardware resources.
> + * @need_phy_full_reset_on_wake: Quirk saying that we should assert
> + * phy_full_reset on a remote wakeup.
> * @phy: The otg phy transceiver structure for phy control.
> * @uphy: The otg phy transceiver structure for old USB phy control.
> + * @phy_full_reset: Reset control for the PHY's "full reset".
> * @plat: The platform specific configuration data. This can be removed once
> * all SoCs support usb transceiver.
> * @supplies: Definition of USB power supplies
> @@ -853,9 +856,11 @@ struct dwc2_hsotg {
> unsigned int hcd_enabled:1;
> unsigned int gadget_enabled:1;
> unsigned int ll_hw_enabled:1;
> + unsigned int need_phy_full_reset_on_wake:1;
>
> struct phy *phy;
> struct usb_phy *uphy;
> + struct reset_control *phy_full_reset;
> struct dwc2_hsotg_plat *plat;
> struct regulator_bulk_data supplies[ARRAY_SIZE(dwc2_hsotg_supply_names)];
> u32 phyif;
> diff --git a/drivers/usb/dwc2/core_intr.c b/drivers/usb/dwc2/core_intr.c
> index d85c5c9..53d8327 100644
> --- a/drivers/usb/dwc2/core_intr.c
> +++ b/drivers/usb/dwc2/core_intr.c
> @@ -45,6 +45,7 @@
> #include <linux/dma-mapping.h>
> #include <linux/io.h>
> #include <linux/slab.h>
> +#include <linux/reset.h>
> #include <linux/usb.h>
>
> #include <linux/usb/hcd.h>
> @@ -379,6 +380,19 @@ static void dwc2_handle_wakeup_detected_intr(struct dwc2_hsotg *hsotg)
> /* Restart the Phy Clock */
> pcgcctl &= ~PCGCTL_STOPPCLK;
> dwc2_writel(pcgcctl, hsotg->regs + PCGCTL);
> +
> + /*
> + * If we've got this quirk then the PHY is stuck upon
> + * wakeup. Assert reset. This will propagate out and
> + * eventually we'll re-enumerate the device. Not great
> + * but the best we can do.
> + */
> + if (hsotg->need_phy_full_reset_on_wake) {
> + reset_control_assert(hsotg->phy_full_reset);
> + udelay(50);
> + reset_control_deassert(hsotg->phy_full_reset);
> + }
> +
> mod_timer(&hsotg->wkp_timer,
> jiffies + msecs_to_jiffies(71));
> } else {
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index fc6f525..d8894a1 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -45,6 +45,7 @@
> #include <linux/platform_device.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_data/s3c-hsotg.h>
> +#include <linux/reset.h>
>
> #include <linux/usb/of.h>
>
> @@ -529,6 +530,18 @@ 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->need_phy_full_reset_on_wake =
> + of_property_read_bool(dev->dev.of_node,
> + "snps,need-phy-full-reset-on-wake");
> + hsotg->phy_full_reset = devm_reset_control_get(hsotg->dev,
> + "phy-full-reset");
> + if (IS_ERR(hsotg->phy_full_reset) &&
> + hsotg->need_phy_full_reset_on_wake) {
Should use the devm_reset_control_get_optional() variant so that we
can check whether it is a legitimate error, or the PHY is not
specified or !CONFIG_OF.
> + dev_warn(hsotg->dev, "Missing phy full reset (%ld); skipping\n",
> + PTR_ERR(hsotg->phy_full_reset));
> + hsotg->need_phy_full_reset_on_wake = false;
> + }
> +
Also this code can go into the dwc2_lowlevel_hw_init() function so as
not to clutter up the probe() function futher.
A similar patch adding a reset was submitted by Dinh which you can use
as a reference:
http://marc.info/?l=linux-usb&m=147085447403019&w=2
Regards,
John
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