Re: [PATCH v2] usb: dwc3: core: Add quirk for enabling AutoRetry feature in the controller

From: Felipe Balbi
Date: Thu Jul 26 2018 - 08:45:08 EST



Hi,

Anurag Kumar Vulisha <anurag.kumar.vulisha@xxxxxxxxxx> writes:
> By default when core sees any transaction error(CRC or overflow)
> it replies with terminating retry ACK (Retry=1 and Nump == 0).
> Enabling this Auto Retry feature in controller, on seeing any
> transaction errors makes the core to send a non-terminating ACK
> transaction packet (that is, ACK TP with Retry=1 and Nump != 0).
> Doing so will give controller a chance to recover from the error
> condition.
>
> Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xxxxxxxxxx>
> ---
> Changes in v2:
> 1. As suggested by Rob Herring & Felipe Balbi removed the
> quirk logic and setting the AutoRetry bits unconditionally
> for hostmode
> ---
> drivers/usb/dwc3/core.c | 14 ++++++++++++++
> drivers/usb/dwc3/core.h | 3 +++
> 2 files changed, 17 insertions(+)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 1038075..478c8a6 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -883,6 +883,20 @@ static int dwc3_core_init(struct dwc3 *dwc)
> dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
> }
>
> + if (dwc->dr_mode == USB_DR_MODE_HOST) {

almost there. You also wanna check for dr_mode == OTG. OTG
configurations can switch between device and host mode at will.

> + reg = dwc3_readl(dwc->regs, DWC3_GUCTL);
> +
> + /* Enable Auto retry Feature to make the controller operating in

match the multi-line comment style already in this file:

/*
* Enable Auto ....

--
balbi

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