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Message-ID: <20230517233218.rjfmvptrexgkpam3@synopsys.com>
Date: Wed, 17 May 2023 23:32:22 +0000
From: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
To: Krishna Kurapati PSSNV <quic_kriskura@...cinc.com>
CC: Thinh Nguyen <Thinh.Nguyen@...opsys.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"quic_ppratap@...cinc.com" <quic_ppratap@...cinc.com>,
"quic_wcheng@...cinc.com" <quic_wcheng@...cinc.com>,
"quic_jackp@...cinc.com" <quic_jackp@...cinc.com>,
"quic_ugoswami@...cinc.com" <quic_ugoswami@...cinc.com>
Subject: Re: [PATCH v2] usb: dwc3: core: set force_gen1 bit in USB31 devices
if max speed is SS
On Wed, May 17, 2023, Krishna Kurapati PSSNV wrote:
>
>
> On 5/17/2023 6:00 AM, Thinh Nguyen wrote:
> > On Wed, May 17, 2023, Thinh Nguyen wrote:
> > > On Sun, May 14, 2023, Krishna Kurapati wrote:
> > > > Currently for dwc3_usb31 controller, if maximum_speed is limited to
> > > > super-speed in DT, then device mode is limited to SS, but host mode
> > > > still works in SSP.
> > > >
> > > > The documentation for max-speed property is as follows:
> > > >
> > > > "Tells USB controllers we want to work up to a certain speed.
> > > > Incase this isn't passed via DT, USB controllers should default to
> > > > their maximum HW capability."
> > > >
> > > > It doesn't specify that the property is only for device mode.
> > > > There are cases where we need to limit the host's maximum speed to
> > > > SuperSpeed only. Use this property for host mode to contrain host's
> > > > speed to SuperSpeed.
> > > >
> > > > Signed-off-by: Krishna Kurapati <quic_kriskura@...cinc.com>
> > > > ---
> > > > Link to v1: https://urldefense.com/v3/__https://lore.kernel.org/all/20230512170107.18821-1-quic_kriskura@quicinc.com/__;!!A4F2R9G_pg!dCg_3WK2oNXNb6d0a_VuyjkeeZJTU1aY4dik6g35XB7mtG7EJeR1uPMfxFja49OfXp7Yhsg1yqjnylCYYEg7YCAhqfAZ0Q$
> > > >
> > > > Discussion regarding the same at:
> > > > https://urldefense.com/v3/__https://lore.kernel.org/all/e465c69c-3a9d-cbdb-d44e-96b99cfa1a92@quicinc.com/__;!!A4F2R9G_pg!dCg_3WK2oNXNb6d0a_VuyjkeeZJTU1aY4dik6g35XB7mtG7EJeR1uPMfxFja49OfXp7Yhsg1yqjnylCYYEg7YCDRLUrJWg$
> > > >
> > > > drivers/usb/dwc3/core.c | 8 ++++++++
> > > > drivers/usb/dwc3/core.h | 5 +++++
> > > > 2 files changed, 13 insertions(+)
> > > >
> > > > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > > > index 278cd1c33841..33bc72595e74 100644
> > > > --- a/drivers/usb/dwc3/core.c
> > > > +++ b/drivers/usb/dwc3/core.c
> > > > @@ -1262,6 +1262,14 @@ static int dwc3_core_init(struct dwc3 *dwc)
> > > > }
> > > > }
> > > > + if ((hw_mode != DWC3_GHWPARAMS0_MODE_GADGET) &&
> > > > + (DWC3_IP_IS(DWC31)) &&
> > > > + (dwc->maximum_speed == USB_SPEED_SUPER)) {
> > > > + reg = dwc3_readl(dwc->regs, DWC3_LLUCTL);
> > > > + reg |= DWC3_LLUCTL_FORCE_GEN1;
> > > > + dwc3_writel(dwc->regs, DWC3_LLUCTL, reg);
> > > > + }
> > > > +
> > >
> > > Perhaps this should be done for every usb3 port rather than just the
> > > port_0. This patch can go after your multi-port series is added to
> > > Greg's branch where you can check for number of usb3 ports.
> > >
> >
> > Can you also add dwc_usb32 settings? It should look something like this:
> >
> >
> > diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> > index 0beaab932e7d..4bd2564aa163 100644
> > --- a/drivers/usb/dwc3/core.c
> > +++ b/drivers/usb/dwc3/core.c
> > @@ -1262,6 +1262,40 @@ static int dwc3_core_init(struct dwc3 *dwc)
> > }
> > }
> > + if (hw_mode != DWC3_GHWPARAMS0_MODE_GADGET) {
> > + int i;
> > +
> > + if (DWC3_IP_IS(DWC31) &&
> > + dwc->maximum_speed == USB_SPEED_SUPER) {
> > + for (i = 0; i < dwc->num_usb3_ports; i++) {
> > + reg = dwc3_readl(dwc->regs, DWC3_LLUCTL(i));
> > + reg |= DWC3_LLUCTL_FORCE_GEN1;
> > + dwc3_writel(dwc->regs, DWC3_LLUCTL(i), reg);
> > + }
> > + }
> > +
> > + if (DWC3_IP_IS(DWC32) &&
> > + dwc->max_ssp_rate != USB_SSP_GEN_2x2) {
> > + int lsr_speed = -EINVAL;
> > +
> > + if (dwc->maximum_speed == USB_SPEED_SUPER)
> > + lsr_speed = DWC3_LCSR_GEN_1x1;
> > + else if (dwc->max_ssp_rate == USB_SSP_GEN_2x1)
> > + lsr_speed = DWC3_LCSR_GEN_2x1;
> > + else if (dwc->max_ssp_rate == USB_SSP_GEN_1x2)
> > + lsr_speed = DWC3_LCSR_GEN_1x2;
> > +
> > + if (lsr_speed != -EINVAL) {
> > + for (i = 0; i < dwc->num_usb3_ports; i++) {
> > + reg = dwc3_readl(dwc->regs, DWC3_LCSR_USB32CTL(i));
> > + reg &= ~DWC3_LCSR_USB32CTL_SPEED_MASK;
> > + reg |= lsr_speed;
> > + dwc3_writel(dwc->regs, DWC3_LCSR_USB32CTL(i), reg);
> > + }
> > + }
> > + }
> > + }
> > +
> > return 0;
> > err_power_off_phy:
> > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> > index d56457c02996..415e0215fe00 100644
> > --- a/drivers/usb/dwc3/core.h
> > +++ b/drivers/usb/dwc3/core.h
> > @@ -170,6 +170,9 @@
> > #define DWC3_OEVTEN 0xcc0C
> > #define DWC3_OSTS 0xcc10
> > +#define DWC3_LLUCTL(n) (0xd024 + ((n) * 0x80))
> > +#define DWC3_LCSR_USB32CTL(n) (0xd07c + ((n) * 0x80))
> > +
> > /* Bit fields */
> > /* Global SoC Bus Configuration INCRx Register 0 */
> > @@ -653,6 +656,16 @@
> > #define DWC3_OSTS_VBUSVLD BIT(1)
> > #define DWC3_OSTS_CONIDSTS BIT(0)
> > +/* LLUCTL Register */
> > +#define DWC3_LLUCTL_FORCE_GEN1 BIT(10)
> > +
> > +/* LCSR_USB32CTL Register */
> > +#define DWC3_LCSR_USB32CTL_SPEED_MASK 0x3
> > +#define DWC3_LCSR_GEN_1x1 0
> > +#define DWC3_LCSR_GEN_1x2 1
> > +#define DWC3_LCSR_GEN_2x1 2
> > +#define DWC3_LCSR_GEN_2x2 3
> > +
> > /* Structures */
> > struct dwc3_trb;
> >
> > --
> >
> > Thanks,
> > Thinh
>
>
> Hi Thinh,
>
> Sure, will split it up into two patches and send as a series. But might
> need your help in testing SSP patch as I don't have any device supporting
> ssp.
>
Sure. I can do that.
btw, it doesn't have to be SSP dwc_usb3x device. SSP devices are pretty
common nowadays.
Thanks,
Thinh
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