Re: [PATCH v3 1/2] usb: dwc3: core: add support for disabling High-speed park mode

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Wed, Apr 19, 2023, Thinh Nguyen wrote:
> On Thu, Apr 13, 2023, Stanley Chang wrote:
> > Setting the PARKMODE_DISABLE_HS bit in the DWC3_USB3_GUCTL1.
> > When this bit is set to '1' all HS bus instances in park mode are disabled
> > 
> > For some USB wifi devices, if enable this feature it will reduce the
> > performance. Therefore, add an option for disabling HS park mode by
> > device-tree.
> > 
> > In Synopsys's dwc3 data book:
> > In a few high speed devices when an IN request is sent within 900ns of the
> > ACK of the previous packet, these devices send a NAK. When connected to
> > these devices, if required, the software can disable the park mode if you
> > see performance drop in your system. When park mode is disabled,
> > pipelining of multiple packet is disabled and instead one packet at a time
> > is requested by the scheduler. This allows up to 12 NAKs in a micro-frame
> > and improves performance of these slow devices.
> > 
> > Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
> > ---
> > v2 to v3 change:
> > 1. Add the comment message.
> > 2. cc the right maintainers.
> > ---
> >  drivers/usb/dwc3/core.c | 5 +++++
> >  drivers/usb/dwc3/core.h | 4 ++++
> >  2 files changed, 9 insertions(+)
> > 
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index 476b63618511..8fbc92a5f2cb 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -1233,6 +1233,9 @@ static int dwc3_core_init(struct dwc3 *dwc)
> >  		if (dwc->parkmode_disable_ss_quirk)
> >  			reg |= DWC3_GUCTL1_PARKMODE_DISABLE_SS;
> >  
> > +		if (dwc->parkmode_disable_hs_quirk)
> > +			reg |= DWC3_GUCTL1_PARKMODE_DISABLE_HS;
> > +
> >  		if (DWC3_VER_IS_WITHIN(DWC3, 290A, ANY) &&
> >  		    (dwc->maximum_speed == USB_SPEED_HIGH ||
> >  		     dwc->maximum_speed == USB_SPEED_FULL))
> > @@ -1555,6 +1558,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
> >  				"snps,resume-hs-terminations");
> >  	dwc->parkmode_disable_ss_quirk = device_property_read_bool(dev,
> >  				"snps,parkmode-disable-ss-quirk");
> > +	dwc->parkmode_disable_hs_quirk = device_property_read_bool(dev,
> > +				"snps,parkmode-disable-hs-quirk");
> >  	dwc->gfladj_refclk_lpm_sel = device_property_read_bool(dev,
> >  				"snps,gfladj-refclk-lpm-sel-quirk");
> >  
> > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> > index 4743e918dcaf..30907ffcb3ec 100644
> > --- a/drivers/usb/dwc3/core.h
> > +++ b/drivers/usb/dwc3/core.h
> > @@ -263,6 +263,7 @@
> >  #define DWC3_GUCTL1_DEV_FORCE_20_CLK_FOR_30_CLK	BIT(26)
> >  #define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW		BIT(24)
> >  #define DWC3_GUCTL1_PARKMODE_DISABLE_SS		BIT(17)
> > +#define DWC3_GUCTL1_PARKMODE_DISABLE_HS		BIT(16)
> >  #define DWC3_GUCTL1_RESUME_OPMODE_HS_HOST	BIT(10)
> >  
> >  /* Global Status Register */
> > @@ -1102,6 +1103,8 @@ struct dwc3_scratchpad_array {
> >   *			generation after resume from suspend.
> >   * @parkmode_disable_ss_quirk: set if we need to disable all SuperSpeed
> >   *			instances in park mode.
> > + * @parkmode_disable_hs_quirk: set if we need to disable all HishSpeed
> > + *			instances in park mode.
> >   * @tx_de_emphasis_quirk: set if we enable Tx de-emphasis quirk
> >   * @tx_de_emphasis: Tx de-emphasis value
> >   *	0	- -6dB de-emphasis
> > @@ -1318,6 +1321,7 @@ struct dwc3 {
> >  	unsigned		dis_tx_ipgap_linecheck_quirk:1;
> >  	unsigned		resume_hs_terminations:1;
> >  	unsigned		parkmode_disable_ss_quirk:1;
> > +	unsigned		parkmode_disable_hs_quirk:1;
> >  	unsigned		gfladj_refclk_lpm_sel:1;
> >  
> >  	unsigned		tx_de_emphasis_quirk:1;
> > -- 
> > 2.34.1
> > 
> 
> Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
> 

I forgot that you may need to resend v4 as per Greg's comment related to
threaded mails. If nothing else is changed, you can add my Ack on v4.

Thanks,
Thinh