diff mbox series

[v1,4/8] usb: dwc3: core: do not use 3.0 clock when operating in 2.0 mode

Message ID 20220225145432.422130-5-pgwipeout@gmail.com (mailing list archive)
State New, archived
Headers show
Series enable usb support on rk356x | expand

Commit Message

Peter Geis Feb. 25, 2022, 2:54 p.m. UTC
From: Bin Yang <yangbin@rock-chips.com>

In the 3.0 device core, if the core is programmed to operate in
2.0 only, then setting the GUCTL1.DEV_FORCE_20_CLK_FOR_30_CLK makes
the internal 2.0(utmi/ulpi) clock to be routed as the 3.0 (pipe)
clock. Enabling this feature allows the pipe3 clock to be not-running
when forcibly operating in 2.0 device mode.

Signed-off-by: Bin Yang <yangbin@rock-chips.com>
Signed-off-by: Peter Geis <pgwipeout@gmail.com>
---
 drivers/usb/dwc3/core.c | 4 ++++
 drivers/usb/dwc3/core.h | 1 +
 2 files changed, 5 insertions(+)

Comments

Jack Pham Feb. 25, 2022, 5:16 p.m. UTC | #1
+Thinh

Hi Peter,

On Fri, Feb 25, 2022 at 09:54:27AM -0500, Peter Geis wrote:
> From: Bin Yang <yangbin@rock-chips.com>
> 
> In the 3.0 device core, if the core is programmed to operate in
> 2.0 only, then setting the GUCTL1.DEV_FORCE_20_CLK_FOR_30_CLK makes
> the internal 2.0(utmi/ulpi) clock to be routed as the 3.0 (pipe)
> clock. Enabling this feature allows the pipe3 clock to be not-running
> when forcibly operating in 2.0 device mode.
> 
> Signed-off-by: Bin Yang <yangbin@rock-chips.com>
> Signed-off-by: Peter Geis <pgwipeout@gmail.com>
> ---
>  drivers/usb/dwc3/core.c | 4 ++++
>  drivers/usb/dwc3/core.h | 1 +
>  2 files changed, 5 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 18adddfba3da..032d40794fae 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -1167,6 +1167,10 @@ static int dwc3_core_init(struct dwc3 *dwc)
>  		if (dwc->parkmode_disable_ss_quirk)
>  			reg |= DWC3_GUCTL1_PARKMODE_DISABLE_SS;
>  
> +		if (dwc->maximum_speed == USB_SPEED_HIGH ||
> +		    dwc->maximum_speed == USB_SPEED_FULL)
> +			reg |= DWC3_GUCTL1_DEV_FORCE_20_CLK_FOR_30_CLK;
> +

I doubt this is applicable to all revisions of the DWC_usb3x IP cores?
For instance in the programming guide for DWC_usb31 1.90a bit 26 of
GUCTL1 is 'Reserved'.  While I do see it in the DWC_usb3 databook,
table 4-8 entry "Remove pipe_clk mux for 2.0 mode?" mentions this
feature was only added in v2.90a.

So this setting at least needs a revision check to make sure we're not
causing unexpected behavior.  Something like

	DWC3_VER_IS_WITHIN(DWC3, 290A, ANY)

Jack

>  		dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
>  	}
>  
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index eb9c1efced05..ea3ca04406bb 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -259,6 +259,7 @@
>  /* Global User Control 1 Register */
>  #define DWC3_GUCTL1_DEV_DECOUPLE_L1L2_EVT	BIT(31)
>  #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS	BIT(28)
> +#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)
>  
> -- 
> 2.25.1
>
Peter Geis Feb. 25, 2022, 5:55 p.m. UTC | #2
On Fri, Feb 25, 2022 at 12:16 PM Jack Pham <quic_jackp@quicinc.com> wrote:
>
> +Thinh
>
> Hi Peter,
>
> On Fri, Feb 25, 2022 at 09:54:27AM -0500, Peter Geis wrote:
> > From: Bin Yang <yangbin@rock-chips.com>
> >
> > In the 3.0 device core, if the core is programmed to operate in
> > 2.0 only, then setting the GUCTL1.DEV_FORCE_20_CLK_FOR_30_CLK makes
> > the internal 2.0(utmi/ulpi) clock to be routed as the 3.0 (pipe)
> > clock. Enabling this feature allows the pipe3 clock to be not-running
> > when forcibly operating in 2.0 device mode.
> >
> > Signed-off-by: Bin Yang <yangbin@rock-chips.com>
> > Signed-off-by: Peter Geis <pgwipeout@gmail.com>
> > ---
> >  drivers/usb/dwc3/core.c | 4 ++++
> >  drivers/usb/dwc3/core.h | 1 +
> >  2 files changed, 5 insertions(+)
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index 18adddfba3da..032d40794fae 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -1167,6 +1167,10 @@ static int dwc3_core_init(struct dwc3 *dwc)
> >               if (dwc->parkmode_disable_ss_quirk)
> >                       reg |= DWC3_GUCTL1_PARKMODE_DISABLE_SS;
> >
> > +             if (dwc->maximum_speed == USB_SPEED_HIGH ||
> > +                 dwc->maximum_speed == USB_SPEED_FULL)
> > +                     reg |= DWC3_GUCTL1_DEV_FORCE_20_CLK_FOR_30_CLK;
> > +
>
> I doubt this is applicable to all revisions of the DWC_usb3x IP cores?
> For instance in the programming guide for DWC_usb31 1.90a bit 26 of
> GUCTL1 is 'Reserved'.  While I do see it in the DWC_usb3 databook,
> table 4-8 entry "Remove pipe_clk mux for 2.0 mode?" mentions this
> feature was only added in v2.90a.

I was wondering about that, thanks for confirming for me.
Is it possible to get a copy of this programming guide or is it closed?

>
> So this setting at least needs a revision check to make sure we're not
> causing unexpected behavior.  Something like
>
>         DWC3_VER_IS_WITHIN(DWC3, 290A, ANY)

Will do, I appreciate it.

>
> Jack
>
> >               dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
> >       }
> >
> > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> > index eb9c1efced05..ea3ca04406bb 100644
> > --- a/drivers/usb/dwc3/core.h
> > +++ b/drivers/usb/dwc3/core.h
> > @@ -259,6 +259,7 @@
> >  /* Global User Control 1 Register */
> >  #define DWC3_GUCTL1_DEV_DECOUPLE_L1L2_EVT    BIT(31)
> >  #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS   BIT(28)
> > +#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)
> >
> > --
> > 2.25.1
> >
diff mbox series

Patch

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 18adddfba3da..032d40794fae 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1167,6 +1167,10 @@  static int dwc3_core_init(struct dwc3 *dwc)
 		if (dwc->parkmode_disable_ss_quirk)
 			reg |= DWC3_GUCTL1_PARKMODE_DISABLE_SS;
 
+		if (dwc->maximum_speed == USB_SPEED_HIGH ||
+		    dwc->maximum_speed == USB_SPEED_FULL)
+			reg |= DWC3_GUCTL1_DEV_FORCE_20_CLK_FOR_30_CLK;
+
 		dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
 	}
 
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index eb9c1efced05..ea3ca04406bb 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -259,6 +259,7 @@ 
 /* Global User Control 1 Register */
 #define DWC3_GUCTL1_DEV_DECOUPLE_L1L2_EVT	BIT(31)
 #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS	BIT(28)
+#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)