RE: [PATCH] usb: dwc2: Read GNPTXFSIZ when in forced HOST mode.

[Paul Zimmerman]

> From: Doug Anderson [mailto:dianders@xxxxxxxxxxxx]
> Sent: Thursday, August 07, 2014 12:48 PM
> 
> The documentation for GNPTXFSIZ says that "For host mode, this field
> is always valid."  Since we're already switching to host mode for
> HPTXFSIZ, let's also read GNPTXFSIZ in host mode.
> 
> On an rk3288 SoC, without this change we see this at bootup:
>   dwc2 ff580000.usb: gnptxfsiz=00100400
>   dwc2 ff580000.usb: 128 invalid for host_nperio_tx_fifo_size. Check HW configuration.
> 
> After this change we see:
>   dwc2 ff580000.usb: gnptxfsiz=04000400
> 
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
> ---
>  drivers/usb/dwc2/core.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
> index 27d2c9b..c184ed43 100644
> --- a/drivers/usb/dwc2/core.c
> +++ b/drivers/usb/dwc2/core.c
> @@ -2674,23 +2674,23 @@ int dwc2_get_hwparams(struct dwc2_hsotg *hsotg)
>  	hwcfg2 = readl(hsotg->regs + GHWCFG2);
>  	hwcfg3 = readl(hsotg->regs + GHWCFG3);
>  	hwcfg4 = readl(hsotg->regs + GHWCFG4);
> -	gnptxfsiz = readl(hsotg->regs + GNPTXFSIZ);
>  	grxfsiz = readl(hsotg->regs + GRXFSIZ);
> 
>  	dev_dbg(hsotg->dev, "hwcfg1=%08x\n", hwcfg1);
>  	dev_dbg(hsotg->dev, "hwcfg2=%08x\n", hwcfg2);
>  	dev_dbg(hsotg->dev, "hwcfg3=%08x\n", hwcfg3);
>  	dev_dbg(hsotg->dev, "hwcfg4=%08x\n", hwcfg4);
> -	dev_dbg(hsotg->dev, "gnptxfsiz=%08x\n", gnptxfsiz);
>  	dev_dbg(hsotg->dev, "grxfsiz=%08x\n", grxfsiz);
> 
> -	/* Force host mode to get HPTXFSIZ exact power on value */
> +	/* Force host mode to get HPTXFSIZ / GNPTXFSIZ exact power on value */
>  	gusbcfg = readl(hsotg->regs + GUSBCFG);
>  	gusbcfg |= GUSBCFG_FORCEHOSTMODE;
>  	writel(gusbcfg, hsotg->regs + GUSBCFG);
>  	usleep_range(100000, 150000);
> 
> +	gnptxfsiz = readl(hsotg->regs + GNPTXFSIZ);
>  	hptxfsiz = readl(hsotg->regs + HPTXFSIZ);
> +	dev_dbg(hsotg->dev, "gnptxfsiz=%08x\n", gnptxfsiz);
>  	dev_dbg(hsotg->dev, "hptxfsiz=%08x\n", hptxfsiz);
>  	gusbcfg = readl(hsotg->regs + GUSBCFG);
>  	gusbcfg &= ~GUSBCFG_FORCEHOSTMODE;

Nice! I wonder if this is a bug in the original driver, and they
actually meant to read this register instead of HPTXFSIZ? Well, it
doesn't really matter I guess.

Acked-by: Paul Zimmerman <paulz@xxxxxxxxxxxx>

You may want to resend this to Greg after -rc1 is out and he reopens
his usb-next tree.

-- 
Paul

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