Re: [PATCH v8 6/9] usb: dwc3: qcom: Add multiport controller support for qcom wrapper

Bjorn Andersson
2023-05-26T02:52:10Z

On Mon, May 15, 2023 at 03:27:30PM -0700, Bjorn Andersson wrote:
> On Sun, May 14, 2023 at 11:19:14AM +0530, Krishna Kurapati wrote:
> > QCOM SoC SA8295P's tertiary quad port controller supports 2 HS+SS
> > ports and 2 HS only ports. Add support for configuring PWR_EVENT_IRQ's
> > for all the ports during suspend/resume.
> >
> > Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
> > ---
> > drivers/usb/dwc3/dwc3-qcom.c | 28 ++++++++++++++++++++++------
> > 1 file changed, 22 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> > index 959fc925ca7c..7a9bce66295d 100644
> > --- a/drivers/usb/dwc3/dwc3-qcom.c
> > +++ b/drivers/usb/dwc3/dwc3-qcom.c
> > @@ -37,7 +37,10 @@
> > #define PIPE3_PHYSTATUS_SW BIT(3)
> > #define PIPE_UTMI_CLK_DIS BIT(8)
> >
> > -#define PWR_EVNT_IRQ_STAT_REG 0x58
> > +#define PWR_EVNT_IRQ1_STAT_REG 0x58
> > +#define PWR_EVNT_IRQ2_STAT_REG 0x1dc
> > +#define PWR_EVNT_IRQ3_STAT_REG 0x228
> > +#define PWR_EVNT_IRQ4_STAT_REG 0x238
> > #define PWR_EVNT_LPM_IN_L2_MASK BIT(4)
> > #define PWR_EVNT_LPM_OUT_L2_MASK BIT(5)
> >
> > @@ -93,6 +96,13 @@ struct dwc3_qcom {
> > struct icc_path *icc_path_apps;
> > };
> >
> > +static u32 pwr_evnt_irq_stat_reg_offset[4] = {
> > + PWR_EVNT_IRQ1_STAT_REG,
> > + PWR_EVNT_IRQ2_STAT_REG,
> > + PWR_EVNT_IRQ3_STAT_REG,
> > + PWR_EVNT_IRQ4_STAT_REG,
>
> Seems to be excessive indentation of these...
>
> Can you also please confirm that these should be counted starting at 1 -
> given that you otherwise talk about port0..N-1?
>
> > +};
> > +
> > static inline void dwc3_qcom_setbits(void __iomem *base, u32 offset, u32 val)
> > {
> > u32 reg;
> > @@ -413,13 +423,16 @@ static int dwc3_qcom_suspend(struct dwc3_qcom *qcom, bool wakeup)
> > {
> > u32 val;
> > int i, ret;
> > + struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3);
> >
> > if (qcom->is_suspended)
> > return 0;
> >
> > - val = readl(qcom->qscratch_base + PWR_EVNT_IRQ_STAT_REG);
> > - if (!(val & PWR_EVNT_LPM_IN_L2_MASK))
> > - dev_err(qcom->dev, "HS-PHY not in L2\n");
> > + for (i = 0; i < dwc->num_usb2_ports; i++) {
>
> In the event that the dwc3 core fails to acquire or enable e.g. clocks
> its drvdata will be NULL. If you then hit a runtime pm transition in the
> dwc3-qcom glue you will dereference NULL here. (You can force this issue
> by e.g. returning -EINVAL from dwc3_clk_enable()).
>

I looked at this once more, and realized that I missed the fact that
dwc3_qcom_is_host() will happily dereference the drvdata() just a few
lines further down...

So this is already broken.

> So if you're peaking into qcom->dwc3 you need to handle the fact that
> dwc might be NULL, here and in resume below.
>

We need to fix the dwc3 glue design, so that the glue and the core can
cooperate - and we have a few other use cases where this is needed (e.g.
usb_role_switch propagation to the glue code).

Regards,
Bjorn

> Regards,
> Bjorn