Re: [PATCH v4 6/9] usb: dwc3: save/restore OTG registers during suspend/resume

Felipe Balbi
2015-09-02T14:44:39Z

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On Wed, Sep 02, 2015 at 05:24:21PM +0300, Roger Quadros wrote:
> Without this we loose OTG controller register context and malfunction
> after a system suspend-resume.
>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
> drivers/usb/dwc3/core.c | 17 +++++++++++++++++
> drivers/usb/dwc3/core.h | 6 +++++-
> 2 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 632ee53..684010c 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -56,6 +56,7 @@ void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
> reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> reg &= ~(DWC3_GCTL_PRTCAPDIR(DWC3_GCTL_PRTCAP_OTG));
> reg |= DWC3_GCTL_PRTCAPDIR(mode);
> + dwc->current_mode = mode;
> dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> }
>
> @@ -1443,6 +1444,14 @@ static int dwc3_suspend(struct device *dev)
>
> spin_lock_irqsave(&dwc->lock, flags);
>
> + /* Save OTG state only if we're really using it */
> + if (dwc->current_mode == DWC3_GCTL_PRTCAP_OTG) {
> + dwc->ocfg = dwc3_readl(dwc->regs, DWC3_OCFG);
> + dwc->octl = dwc3_readl(dwc->regs, DWC3_OCTL);
> + dwc->oevt = dwc3_readl(dwc->regs, DWC3_OEVT);

oevt is what you use to clear pending IRQs, which means that ...

> + dwc->oevten = dwc3_readl(dwc->regs, DWC3_OEVTEN);
> + }
> +
> switch (dwc->dr_mode) {
> case USB_DR_MODE_PERIPHERAL:
> case USB_DR_MODE_OTG:
> @@ -1486,6 +1495,14 @@ static int dwc3_resume(struct device *dev)
> dwc3_event_buffers_setup(dwc);
> dwc3_writel(dwc->regs, DWC3_GCTL, dwc->gctl);
>
> + /* Restore OTG state only if we're really using it */
> + if (dwc->current_mode == DWC3_GCTL_PRTCAP_OTG) {
> + dwc3_writel(dwc->regs, DWC3_OCFG, dwc->ocfg);
> + dwc3_writel(dwc->regs, DWC3_OCTL, dwc->octl);
> + dwc3_writel(dwc->regs, DWC3_OEVT, dwc->oevt);

... you could be clearing pending IRQs right here.

> + dwc3_writel(dwc->regs, DWC3_OEVTEN, dwc->oevten);
> + }
> +
> switch (dwc->dr_mode) {
> case USB_DR_MODE_PERIPHERAL:
> case USB_DR_MODE_OTG:
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 129ef37..1115ce0 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -737,6 +737,7 @@ struct dwc3_scratchpad_array {
> * @regs: base address for our registers
> * @regs_size: address space size
> * @oevten: otg interrupt enable mask copy
> + * @current_mode: current mode of operation written to PRTCAPDIR
> * @nr_scratch: number of scratch buffers
> * @num_event_buffers: calculated number of event buffers
> * @u1u2: only used on revisions <1.83a for workaround
> @@ -858,9 +859,12 @@ struct dwc3 {
> /* used for suspend/resume */
> u32 dcfg;
> u32 gctl;
> -
> + u32 ocfg;
> + u32 octl;
> + u32 oevt;
> u32 oevten;
>
> + u32 current_mode;
> u32 nr_scratch;
> u32 num_event_buffers;
> u32 u1u2;
> --
> 2.1.4
>

--
balbi

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