Re: [PATCH v3 05/19] usb: dwc3: add lpm erratum support

[Bjorn Helgaas]

On Tue, Oct 28, 2014 at 5:54 AM, Huang Rui <ray.huang@xxxxxxx> wrote:
> When parameter DWC_USB3_LPM_ERRATA_ENABLE is enabled in Andvanced

"Advanced"

> Configuration of coreConsultant, it supports of xHCI BESL Errata Dated

I can't parse "is supports of" and I don't know enough to suggest an
alternate wording.

> 10/19/2011 is enabled in host mode. In device mode it adds the capability
> to send NYET response threshold based on the BESL value received in the LPM
> token, and the threhold is configurable for each soc platform.

"threshold"

> This patch adds an entry that soc platform is able to define the lpm
> capacity with their own device tree or bus glue layer.
>
> Signed-off-by: Huang Rui <ray.huang@xxxxxxx>
> ---
>  drivers/usb/dwc3/core.c          | 16 +++++++++++++++-
>  drivers/usb/dwc3/core.h          | 26 +++++++++++++++++---------
>  drivers/usb/dwc3/gadget.c        | 13 +++++++++++++
>  drivers/usb/dwc3/platform_data.h |  2 ++
>  4 files changed, 47 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index c320835..4f37a43 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -652,6 +652,7 @@ static int dwc3_probe(struct platform_device *pdev)
>         struct device_node      *node = dev->of_node;
>         struct resource         *res;
>         struct dwc3             *dwc;
> +       u8                      lpm_nyet_thres;
>
>         int                     ret;
>
> @@ -707,16 +708,27 @@ static int dwc3_probe(struct platform_device *pdev)
>          */
>         res->start -= DWC3_GLOBALS_REGS_START;
>
> +       /* default to highest possible threshold */
> +       lpm_nyet_thres = 0xff;
> +
>         if (node) {
>                 dwc->maximum_speed = of_usb_get_maximum_speed(node);
> +               dwc->has_lpm_erratum = of_property_read_bool(node,
> +                               "snps,has-lpm-erratum");
> +               of_property_read_u8(node, "snps,lpm-nyet-thres",
> +                               &lpm_nyet_thres);
>
> -               dwc->needs_fifo_resize = of_property_read_bool(node, "tx-fifo-resize");
> +               dwc->needs_fifo_resize = of_property_read_bool(node,
> +                               "tx-fifo-resize");
>                 dwc->dr_mode = of_usb_get_dr_mode(node);
>
>                 dwc->disable_scramble_quirk = of_property_read_bool(node,
>                                 "snps,disable_scramble_quirk");
>         } else if (pdata) {
>                 dwc->maximum_speed = pdata->maximum_speed;
> +               dwc->has_lpm_erratum = pdata->has_lpm_erratum;
> +               if (pdata->lpm_nyet_thres)
> +                       lpm_nyet_thres = pdata->lpm_nyet_thres;
>
>                 dwc->needs_fifo_resize = pdata->tx_fifo_resize;
>                 dwc->dr_mode = pdata->dr_mode;
> @@ -728,6 +740,8 @@ static int dwc3_probe(struct platform_device *pdev)
>         if (dwc->maximum_speed == USB_SPEED_UNKNOWN)
>                 dwc->maximum_speed = USB_SPEED_SUPER;
>
> +       dwc->lpm_nyet_thres = lpm_nyet_thres;
> +
>         ret = dwc3_core_get_phy(dwc);
>         if (ret)
>                 return ret;
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 56bada6..19d1ecb 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -246,16 +246,19 @@
>  #define DWC3_DCTL_TRGTULST_SS_INACT    (DWC3_DCTL_TRGTULST(6))
>
>  /* These apply for core versions 1.94a and later */
> -#define DWC3_DCTL_KEEP_CONNECT (1 << 19)
> -#define DWC3_DCTL_L1_HIBER_EN  (1 << 18)
> -#define DWC3_DCTL_CRS          (1 << 17)
> -#define DWC3_DCTL_CSS          (1 << 16)
> +#define DWC3_DCTL_LPM_ERRATA_MASK      DWC3_DCTL_LPM_ERRATA(0xf)
> +#define DWC3_DCTL_LPM_ERRATA(n)                ((n) << 20)
>
> -#define DWC3_DCTL_INITU2ENA    (1 << 12)
> -#define DWC3_DCTL_ACCEPTU2ENA  (1 << 11)
> -#define DWC3_DCTL_INITU1ENA    (1 << 10)
> -#define DWC3_DCTL_ACCEPTU1ENA  (1 << 9)
> -#define DWC3_DCTL_TSTCTRL_MASK (0xf << 1)
> +#define DWC3_DCTL_KEEP_CONNECT         (1 << 19)
> +#define DWC3_DCTL_L1_HIBER_EN          (1 << 18)
> +#define DWC3_DCTL_CRS                  (1 << 17)
> +#define DWC3_DCTL_CSS                  (1 << 16)
> +
> +#define DWC3_DCTL_INITU2ENA            (1 << 12)
> +#define DWC3_DCTL_ACCEPTU2ENA          (1 << 11)
> +#define DWC3_DCTL_INITU1ENA            (1 << 10)
> +#define DWC3_DCTL_ACCEPTU1ENA          (1 << 9)
> +#define DWC3_DCTL_TSTCTRL_MASK         (0xf << 1)
>
>  #define DWC3_DCTL_ULSTCHNGREQ_MASK     (0x0f << 5)
>  #define DWC3_DCTL_ULSTCHNGREQ(n) (((n) << 5) & DWC3_DCTL_ULSTCHNGREQ_MASK)
> @@ -664,6 +667,9 @@ struct dwc3_scratchpad_array {
>   * @ep0_bounced: true when we used bounce buffer
>   * @ep0_expect_in: true when we expect a DATA IN transfer
>   * @has_hibernation: true when dwc3 was configured with Hibernation
> + * @has_lpm_erratum: true when core was configured with LPM Erratum. Note that
> + *                     there's now way for software to detect this in runtime.

"no way" (not "now way").  Also, "at runtime" is more idiomatic than
"in runtime."

> + * @lpm_nyet_thres: LPM NYET response threshold
>   * @is_selfpowered: true when we are selfpowered
>   * @is_fpga: true when we are using the FPGA board
>   * @needs_fifo_resize: not all users might want fifo resizing, flag it
> @@ -769,6 +775,8 @@ struct dwc3 {
>         unsigned                ep0_bounced:1;
>         unsigned                ep0_expect_in:1;
>         unsigned                has_hibernation:1;
> +       unsigned                has_lpm_erratum:1;
> +       unsigned                lpm_nyet_thres:4;
>         unsigned                is_selfpowered:1;
>         unsigned                is_fpga:1;
>         unsigned                needs_fifo_resize:1;
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 7a64c2f..b918a65 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -2297,6 +2297,19 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
>                  */
>                 reg |= DWC3_DCTL_HIRD_THRES(12);
>
> +               /*
> +                * When dwc3 revisions >= 2.40a, LPM Erratum is enabled and
> +                * DCFG.LPMCap is set, core responses with an ACK and the
> +                * BESL value in the LPM token is less than or equal to lPM
> +                * NYET threshold.
> +                */
> +               WARN(dwc->revision < DWC3_REVISION_240A
> +                               && dwc->has_lpm_erratum,
> +                               "LPM Erratum not available on dwc3 revisisions < 2.40a\n");
> +
> +               if (dwc->has_lpm_erratum)
> +                       reg |= DWC3_DCTL_LPM_ERRATA(dwc->lpm_nyet_thres);
> +
>                 dwc3_writel(dwc->regs, DWC3_DCTL, reg);
>         } else {
>                 reg = dwc3_readl(dwc->regs, DWC3_DCTL);
> diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
> index 9209d02..2e546ac 100644
> --- a/drivers/usb/dwc3/platform_data.h
> +++ b/drivers/usb/dwc3/platform_data.h
> @@ -26,4 +26,6 @@ struct dwc3_platform_data {
>         bool tx_fifo_resize;
>
>         unsigned disable_scramble_quirk:1;
> +       unsigned has_lpm_erratum:1;
> +       unsigned lpm_nyet_thres:4;
>  };
> --
> 1.9.1
>
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