Re: [PATCH v3] usb: dwc2: reset dwc2 core before dwc2_get_hwparams()

From: John Youn
Date: Thu Aug 20 2015 - 21:05:12 EST


On 8/19/2015 5:22 AM, Yunzhi Li wrote:
> We initiate dwc2 usb controller in BIOS, dwc2_core_reset() should
> be called before dwc2_get_hwparams() to reset core registers to
> default value. Without this the FIFO setting might be incorrect
> because calculating FIFO size need power-on value of
> GRXFSIZ/GNPTXFSIZ/HPTXFSIZ registers.
>
> This patch could avoid warnning massage like in rk3288 platform:
> [ 2.074764] dwc2 ff580000.usb: 256 invalid for
> host_perio_tx_fifo_size. Check HW configuration.
>
> Signed-off-by: Yunzhi Li <lyz@xxxxxxxxxxxxxx>
>
> ---
>
> drivers/usb/dwc2/core.c | 2 +-
> drivers/usb/dwc2/core.h | 1 +
> drivers/usb/dwc2/platform.c | 21 ++++++++++++++++++++-
> 3 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc2/core.c b/drivers/usb/dwc2/core.c
> index c3cc1a7..86d1d65 100644
> --- a/drivers/usb/dwc2/core.c
> +++ b/drivers/usb/dwc2/core.c
> @@ -474,7 +474,7 @@ static void dwc2_init_fs_ls_pclk_sel(struct dwc2_hsotg *hsotg)
> * Do core a soft reset of the core. Be careful with this because it
> * resets all the internal state machines of the core.
> */
> -static int dwc2_core_reset(struct dwc2_hsotg *hsotg)
> +int dwc2_core_reset(struct dwc2_hsotg *hsotg)
> {
> u32 greset;
> int count = 0;
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 0ed87620..5d95aec 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -846,6 +846,7 @@ enum dwc2_halt_status {
> * The following functions support initialization of the core driver component
> * and the DWC_otg controller
> */
> +extern int dwc2_core_reset(struct dwc2_hsotg *hsotg);
> extern void dwc2_core_host_init(struct dwc2_hsotg *hsotg);
> extern int dwc2_enter_hibernation(struct dwc2_hsotg *hsotg);
> extern int dwc2_exit_hibernation(struct dwc2_hsotg *hsotg, bool restore);
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index 9093530..55d378a 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -166,7 +166,8 @@ static int dwc2_driver_probe(struct platform_device *dev)
> struct phy *phy;
> struct usb_phy *uphy;
> int retval;
> - int irq;
> + int irq, count = 0;
> + u32 greset;
>
> match = of_match_device(dwc2_of_match_table, &dev->dev);
> if (match && match->data) {
> @@ -243,6 +244,24 @@ static int dwc2_driver_probe(struct platform_device *dev)
> spin_lock_init(&hsotg->lock);
> mutex_init(&hsotg->init_mutex);
>
> + /*
> + * Reset before dwc2_get_hwparams() then it could get power-on real
> + * reset value form registers.
> + */
> + count = 0;
> + greset |= GRSTCTL_CSFTRST;
> + writel(greset, hsotg->regs + GRSTCTL);
> + do {
> + usleep_range(20000, 40000);
> + greset = readl(hsotg->regs + GRSTCTL);
> + if (++count > 50) {
> + dev_warn(hsotg->dev,
> + "%s() HANG! Soft Reset GRSTCTL=%0x\n",
> + __func__, greset);
> + return -EBUSY;
> + }
> + } while (greset & GRSTCTL_CSFTRST);
> +


Could you move this out to a separate function so
that we don't have duplicate code?

Thanks,
John








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