Hi John, Yu, Felipe,
On Mon, Oct 07, 2019 at 05:55:50PM +0000, John Stultz wrote:
> From: Yu Chen <cheny...@huawei.com>
>
> A GCTL soft reset should be executed when switch mode for dwc3 core
> of Hisilicon Kirin Soc.
>
> Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
> Cc: Felipe Balbi <ba...@kernel.org>
> Cc: Andy Shevchenko <andy.shevche...@gmail.com>
> Cc: Rob Herring <robh...@kernel.org>
> Cc: Mark Rutland <mark.rutl...@arm.com>
> Cc: Yu Chen <cheny...@huawei.com>
> Cc: Matthias Brugger <matthias....@gmail.com>
> Cc: Chunfeng Yun <chunfeng....@mediatek.com>
> Cc: linux-...@vger.kernel.org
> Cc: devicet...@vger.kernel.org
> Signed-off-by: Yu Chen <cheny...@huawei.com>
> Signed-off-by: John Stultz <john.stu...@linaro.org>
> ---
> drivers/usb/dwc3/core.c | 20 ++++++++++++++++++++
> drivers/usb/dwc3/core.h | 3 +++
> 2 files changed, 23 insertions(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 999ce5e84d3c..440261432421 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -112,6 +112,19 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode)
> dwc->current_dr_role = mode;
> }
>
> +static void dwc3_gctl_core_soft_reset(struct dwc3 *dwc)
> +{
> + u32 reg;
> +
> + reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> + reg |= DWC3_GCTL_CORESOFTRESET;
> + dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> +
> + reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> + reg &= ~DWC3_GCTL_CORESOFTRESET;
> + dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> +}
> +
> static void __dwc3_set_mode(struct work_struct *work)
> {
> struct dwc3 *dwc = work_to_dwc(work);
> @@ -156,6 +169,10 @@ static void __dwc3_set_mode(struct work_struct *work)
>
> dwc3_set_prtcap(dwc, dwc->desired_dr_role);
>
> + /* Execute a GCTL Core Soft Reset when switch mode */
> + if (dwc->gctl_reset_quirk)
> + dwc3_gctl_core_soft_reset(dwc);
> +
In fact it is mentioned in the Synopsys databook to perform a GCTL
CoreSoftReset when changing the PrtCapDir between device & host modes.
So I think this should apply generally without a quirk. Further, it
states to do this *prior* to writing PrtCapDir, so should it go before
dwc3_set_prtcap() instead?
Jack
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