2020-10-18 14:12:01

by Dejin Zheng

Subject: [PATCH v1] usb: dwc3: core: fix a issue about clear connect state

According to Synopsys Programming Guide chapter 2.2 Register Resets,
it cannot reset the DCTL register by set DCTL.CSFTRST for Core Soft Reset,
if DWC3 controller as a slave device and stay connected with a usb host,
then, reboot linux, it will fail to reinitialize dwc3 as a slave device
when the DWC3 controller did not power off. because the connection status
is incorrect, so we also need clear DCTL.RUN_STOP bit for disable connect
when do core soft reset.

Fixes: f59dcab176293b6 ("usb: dwc3: core: improve reset sequence")
Signed-off-by: Dejin Zheng <[email protected]>
---
drivers/usb/dwc3/core.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 2eb34c8b4065..239636c454c2 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -256,6 +256,7 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)

reg = dwc3_readl(dwc->regs, DWC3_DCTL);
reg |= DWC3_DCTL_CSFTRST;
+ reg &= ~DWC3_DCTL_RUN_STOP;
dwc3_writel(dwc->regs, DWC3_DCTL, reg);

/*
--
2.25.0

2020-10-18 20:32:50

by Sergei Shtylyov

Subject: Re: [PATCH v1] usb: dwc3: core: fix a issue about clear connect state

Hello!

On 10/18/20 4:47 PM, Dejin Zheng wrote:

> According to Synopsys Programming Guide chapter 2.2 Register Resets,
> it cannot reset the DCTL register by set DCTL.CSFTRST for Core Soft Reset,

s/set/setting/.

> if DWC3 controller as a slave device and stay connected with a usb host,
> then, reboot linux, it will fail to reinitialize dwc3 as a slave device

s/reboot/while rebooting/.

> when the DWC3 controller did not power off. because the connection status
> is incorrect, so we also need clear DCTL.RUN_STOP bit for disable connect
^ to ^ ing

> when do core soft reset.
^ ing

> Fixes: f59dcab176293b6 ("usb: dwc3: core: improve reset sequence")
> Signed-off-by: Dejin Zheng <[email protected]>
[...]

MBR, Sergei

2020-10-27 14:24:08

by Felipe Balbi

Subject: Re: [PATCH v1] usb: dwc3: core: fix a issue about clear connect state

Hi,

Dejin Zheng <[email protected]> writes:
> According to Synopsys Programming Guide chapter 2.2 Register Resets,
> it cannot reset the DCTL register by set DCTL.CSFTRST for Core Soft Reset,
> if DWC3 controller as a slave device and stay connected with a usb host,
> then, reboot linux, it will fail to reinitialize dwc3 as a slave device
> when the DWC3 controller did not power off. because the connection status
> is incorrect, so we also need clear DCTL.RUN_STOP bit for disable connect
> when do core soft reset.
>
> Fixes: f59dcab176293b6 ("usb: dwc3: core: improve reset sequence")
> Signed-off-by: Dejin Zheng <[email protected]>
> ---
> drivers/usb/dwc3/core.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 2eb34c8b4065..239636c454c2 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -256,6 +256,7 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
>
> reg = dwc3_readl(dwc->regs, DWC3_DCTL);
> reg |= DWC3_DCTL_CSFTRST;
> + reg &= ~DWC3_DCTL_RUN_STOP;

as I mentioned in the other thread, I would rather figure out why we're
getting to probe() with RUN_STOP already set.

--
balbi