Re: [PATCH 3/3] usb: cdns3: Enable workaround for USB2.0 PHY Rx compliance test PHY lockup

Peter Chen
2020-08-26T07:16:29Z

On 20-08-26 04:04:01, Pawel Laszczak wrote:
> >On 20-08-25 15:00:59, Roger Quadros wrote:
> >> From: Pawel Laszczak <pawell@cadence.com>
> >>
> >> USB2.0 PHY hangs in Rx Compliance test when the incoming packet
> >> amplitude is varied below and above the Squelch Level of
> >> Receiver during the active packet multiple times.
> >>
> >> Version 1 of the controller allows PHY to be reset when RX fail condition
> >> is detected to work around the above issue. This feature is
> >> disabled by default and needs to be enabled using a bit from
> >> the newly added PHYRST_CFG register. This patch enables the workaround.
> >>
> >> As there is no way to distinguish between the controller version
> >> before the device controller is started we need to rely on a
> >> DT property to decide when to apply the workaround.
> >
> >Pawel, it could know the controller version at cdns3_gadget_start,
> >but the controller starts when it tries to bind gadget driver, at that
> >time, it has already known the controller version.
> >
> >For me, the device controller starts is using USB_CONF.DEVEN (Device
> >Enable) through usb_gadget_connect, I am not sure if it is the same
> >with yours.
> >
>
> Yes in device mode driver knows controller version but this workaround
> Must be enabled also in host mode. In host mode the controller
> doesn't have access to device registers. The controller version is
> placed in device register.
>

You may suggest your design team adding CHIP_VER register at global
register region, it will easy the software engineer life.

From what I read, this register is only enabling USB2 PHY reset software
control, it needs for all chips with rev 0x0002450D, and the place you
current change is only for 0x0002450D, right?

Peter

> Pawel
>
> >Peter
> >
> >
> >>
> >> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
> >> Signed-off-by: Roger Quadros <rogerq@ti.com>
> >> ---
> >> drivers/usb/cdns3/core.c | 2 ++
> >> drivers/usb/cdns3/core.h | 1 +
> >> drivers/usb/cdns3/drd.c | 12 ++++++++++++
> >> drivers/usb/cdns3/drd.h | 5 ++++-
> >> 4 files changed, 19 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
> >> index 5c1586ec7824..34b36487682b 100644
> >> --- a/drivers/usb/cdns3/core.c
> >> +++ b/drivers/usb/cdns3/core.c
> >> @@ -443,6 +443,8 @@ static int cdns3_probe(struct platform_device *pdev)
> >> return -ENXIO;
> >> }
> >>
> >> + cdns->phyrst_a_enable = device_property_read_bool(dev, "cdns,phyrst-a-enable");
> >> +
> >> cdns->otg_res = *res;
> >>
> >> mutex_init(&cdns->mutex);
> >> diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
> >> index 1ad1f1fe61e9..24cf0f1b5726 100644
> >> --- a/drivers/usb/cdns3/core.h
> >> +++ b/drivers/usb/cdns3/core.h
> >> @@ -76,6 +76,7 @@ struct cdns3 {
> >> #define CDNS3_CONTROLLER_V0 0
> >> #define CDNS3_CONTROLLER_V1 1
> >> u32 version;
> >> + bool phyrst_a_enable;
> >>
> >> int otg_irq;
> >> int dev_irq;
> >> diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
> >> index 6234bcd6158a..b74803e9703d 100644
> >> --- a/drivers/usb/cdns3/drd.c
> >> +++ b/drivers/usb/cdns3/drd.c
> >> @@ -42,6 +42,18 @@ int cdns3_set_mode(struct cdns3 *cdns, enum usb_dr_mode mode)
> >> reg = readl(&cdns->otg_v1_regs->override);
> >> reg |= OVERRIDE_IDPULLUP;
> >> writel(reg, &cdns->otg_v1_regs->override);
> >> +
> >> + /*
> >> + * Enable work around feature built into the
> >> + * controller to address issue with RX Sensitivity
> >> + * est (EL_17) for USB2 PHY. The issue only occures
> >> + * for 0x0002450D controller version.
> >> + */
> >> + if (cdns->phyrst_a_enable) {
> >> + reg = readl(&cdns->otg_v1_regs->phyrst_cfg);
> >> + reg |= PHYRST_CFG_PHYRST_A_ENABLE;
> >> + writel(reg, &cdns->otg_v1_regs->phyrst_cfg);
> >> + }
> >> } else {
> >> reg = readl(&cdns->otg_v0_regs->ctrl1);
> >> reg |= OVERRIDE_IDPULLUP_V0;
> >> diff --git a/drivers/usb/cdns3/drd.h b/drivers/usb/cdns3/drd.h
> >> index 7e7cf7fa2dd3..f1ccae285a16 100644
> >> --- a/drivers/usb/cdns3/drd.h
> >> +++ b/drivers/usb/cdns3/drd.h
> >> @@ -31,7 +31,7 @@ struct cdns3_otg_regs {
> >> __le32 simulate;
> >> __le32 override;
> >> __le32 susp_ctrl;
> >> - __le32 reserved4;
> >> + __le32 phyrst_cfg;
> >> __le32 anasts;
> >> __le32 adp_ramp_time;
> >> __le32 ctrl1;
> >> @@ -153,6 +153,9 @@ struct cdns3_otg_common_regs {
> >> /* Only for CDNS3_CONTROLLER_V0 version */
> >> #define OVERRIDE_IDPULLUP_V0 BIT(24)
> >>
> >> +/* PHYRST_CFG - bitmasks */
> >> +#define PHYRST_CFG_PHYRST_A_ENABLE BIT(0)
> >> +
> >> #define CDNS3_ID_PERIPHERAL 1
> >> #define CDNS3_ID_HOST 0
> >>
> >> --
> >> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> >> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> >>
> >
> >--
> >
> >Thanks,
> >Peter Chen

--

Thanks,
Peter Chen