[PATCH v2 1/6] usb: dwc3: Add frame length adjustment quirk

[Ran Wang]

Hi Bin, Marek,

  Any comment for this serial? Thanks in advance.

Regards,
Ran

On Wednesday, October 21, 2020 6:02 PM, Ran Wang wrote:
> 
> Register Global frame length adjustment is used to do frame length adjustment
> for SOF/ITP counter which is running on the ref_clk. Allow updating it could help
> on avoiding potential USB 2.0 devices time-out over a longer run.
> 
> Refer to Linux commit db2be4e9e30c (“usb: dwc3: Add frame length
> adjustment quirk”)
> 
> Signed-off-by: Ran Wang <ran.wang_1 at nxp.com>
> ---
> Change in v2:
>  - None
> 
>  drivers/usb/dwc3/core.c | 34 ++++++++++++++++++++++++++++++++++
>  drivers/usb/dwc3/core.h |  7 +++++++
>  2 files changed, 41 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index
> 2e00353..b3d4751 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -310,6 +310,25 @@ static void dwc3_free_scratch_buffers(struct dwc3
> *dwc)
>  	kfree(dwc->scratchbuf);
>  }
> 
> +/*
> + * dwc3_frame_length_adjustment - Adjusts frame length if required
> + * @dwc3: Pointer to our controller context structure
> + * @val: Value of frame length
> + */
> +static void dwc3_frame_length_adjustment(struct dwc3 *dwc, u32 val) {
> +	u32 reg;
> +	u32 dft;
> +
> +	reg = dwc3_readl(dwc->regs, DWC3_GFLADJ);
> +	dft = reg & DWC3_GFLADJ_30MHZ_MASK;
> +	if (dft != val) {
> +		reg &= ~DWC3_GFLADJ_30MHZ_MASK;
> +		reg |= DWC3_GFLADJ_30MHZ_SDBND_SEL | val;
> +		dwc3_writel(dwc->regs, DWC3_GFLADJ, reg);
> +	}
> +}
> +
>  static void dwc3_core_num_eps(struct dwc3 *dwc)  {
>  	struct dwc3_hwparams	*parms = &dwc->hwparams;
> @@ -569,6 +588,9 @@ static int dwc3_core_init(struct dwc3 *dwc)
>  	if (ret)
>  		goto err1;
> 
> +	if (dwc->fladj_quirk && dwc->revision >= DWC3_REVISION_250A)
> +		dwc3_frame_length_adjustment(dwc, dwc->fladj);
> +
>  	return 0;
> 
>  err1:
> @@ -958,6 +980,18 @@ void dwc3_of_parse(struct dwc3 *dwc)
> 
>  	dwc->hird_threshold = hird_threshold
>  		| (dwc->is_utmi_l1_suspend << 4);
> +
> +	dwc->fladj_quirk = false;
> +	if (!dev_read_u32(dev,
> +			  "snps,quirk-frame-length-adjustment",
> +			  &dwc->fladj)) {
> +		if (dwc->fladj <=  DWC3_GFLADJ_30MHZ_MASK)
> +			dwc->fladj_quirk = true;
> +		else
> +			dev_err(dev,
> +				"snps,quirk-frame-length-adjustment invalid: 0x%x\n",
> +				dwc->fladj);
> +	}
>  }
> 
>  int dwc3_init(struct dwc3 *dwc)
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index
> 44533fd..4650216 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -115,6 +115,7 @@
>  #define DWC3_GEVNTCOUNT(n)	(0xc40c + (n * 0x10))
> 
>  #define DWC3_GHWPARAMS8		0xc600
> +#define DWC3_GFLADJ		0xc630
> 
>  /* Device Registers */
>  #define DWC3_DCFG		0xc700
> @@ -291,6 +292,10 @@
>  #define DWC3_DCTL_ULSTCHNG_COMPLIANCE
> 	(DWC3_DCTL_ULSTCHNGREQ(10))
>  #define DWC3_DCTL_ULSTCHNG_LOOPBACK
> 	(DWC3_DCTL_ULSTCHNGREQ(11))
> 
> +/* Global Frame Length Adjustment Register */
> +#define DWC3_GFLADJ_30MHZ_SDBND_SEL	BIT(7)
> +#define DWC3_GFLADJ_30MHZ_MASK		0x3f
> +
>  /* Device Event Enable Register */
>  #define DWC3_DEVTEN_VNDRDEVTSTRCVEDEN	(1 << 12)
>  #define DWC3_DEVTEN_EVNTOVERFLOWEN	(1 << 11)
> @@ -764,6 +769,7 @@ struct dwc3 {
>  	u32			num_event_buffers;
>  	u32			u1u2;
>  	u32			maximum_speed;
> +	u32			fladj;
>  	u32			revision;
> 
>  #define DWC3_REVISION_173A	0x5533173a
> @@ -845,6 +851,7 @@ struct dwc3 {
> 
>  	unsigned		tx_de_emphasis_quirk:1;
>  	unsigned		tx_de_emphasis:2;
> +	unsigned		fladj_quirk:1;
>  	int			index;
>  	struct list_head        list;
>  };
> --
> 2.7.4