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

From: Doug Anderson
Date: Thu Aug 07 2014 - 20:11:45 EST


Paul,

On Thu, Aug 7, 2014 at 1:18 PM, Paul Zimmerman
<Paul.Zimmerman@xxxxxxxxxxxx> wrote:
>> 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.

Thanks!

...do you think this is a fix that needs to go in for 3.17? Is it
affecting anyone there?

-Doug
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