Hi Felipe,

On 30/05/16 14:35, Felipe Balbi wrote:
> this patch implements the most basic pm_runtime
> support for dwc3. Whenever USB cable is dettached,
> then we will allow core to runtime_suspend.
> 
> Runtime suspending will involve completely tearing
> down event buffers and require a full soft-reset of
> the IP.
> 
> Note that a further optimization could be
> implemented once we decide to support hibernation,
> which is to allow runtime_suspend with cable
> connected when bus is in U3. That's subject to a
> separate patch, however.
> 
> Tested-by: Baolin Wang <baolin.w...@linaro.org>
> Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com>

We've discussed this offline but for the record, this patch
breaks DWC3 on OMAP platforms. At least on dra7-evm I could see
both USB host and gadget breaking.

I will try to implement the runtime resume hooks for dwc3-omap
and let you know if we can make it work.

cheers,
-roger

> ---
>  drivers/usb/dwc3/core.c   | 146 
> +++++++++++++++++++++++++++++++++++++++++-----
>  drivers/usb/dwc3/core.h   |   9 +++
>  drivers/usb/dwc3/gadget.c |  32 +++++++++-
>  3 files changed, 171 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 80e9affd3d77..167d44375640 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -48,7 +48,7 @@
>  
>  #include "debug.h"
>  
> -/* 
> -------------------------------------------------------------------------- */
> +#define DWC3_DEFAULT_AUTOSUSPEND_DELAY       5000 /* ms */
>  
>  void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
>  {
> @@ -996,9 +996,11 @@ static int dwc3_probe(struct platform_device *pdev)
>               dma_set_coherent_mask(dev, dev->parent->coherent_dma_mask);
>       }
>  
> +     pm_runtime_set_active(dev);
> +     pm_runtime_use_autosuspend(dev);
> +     pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY);
>       pm_runtime_enable(dev);
>       pm_runtime_get_sync(dev);
> -     pm_runtime_forbid(dev);
>  
>       ret = dwc3_alloc_event_buffers(dwc, DWC3_EVENT_BUFFERS_SIZE);
>       if (ret) {
> @@ -1057,7 +1059,7 @@ static int dwc3_probe(struct platform_device *pdev)
>               goto err3;
>  
>       dwc3_debugfs_init(dwc);
> -     pm_runtime_allow(dev);
> +     pm_runtime_put(dev);
>  
>       return 0;
>  
> @@ -1087,6 +1089,7 @@ static int dwc3_remove(struct platform_device *pdev)
>       struct dwc3     *dwc = platform_get_drvdata(pdev);
>       struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  
> +     pm_runtime_get_sync(&pdev->dev);
>       /*
>        * restore res->start back to its original value so that, in case the
>        * probe is deferred, we don't end up getting error in request the
> @@ -1100,24 +1103,26 @@ static int dwc3_remove(struct platform_device *pdev)
>       dwc3_core_exit(dwc);
>       dwc3_ulpi_exit(dwc);
>  
> -     dwc3_free_event_buffers(dwc);
> -     dwc3_free_scratch_buffers(dwc);
> -
>       pm_runtime_put_sync(&pdev->dev);
>       pm_runtime_disable(&pdev->dev);
>  
> +     dwc3_free_event_buffers(dwc);
> +     dwc3_free_scratch_buffers(dwc);
> +
>       return 0;
>  }
>  
> -#ifdef CONFIG_PM_SLEEP
> -static int dwc3_suspend(struct device *dev)
> +#ifdef CONFIG_PM
> +static int dwc3_suspend_common(struct dwc3 *dwc)
>  {
> -     struct dwc3     *dwc = dev_get_drvdata(dev);
> +     unsigned long   flags;
>  
>       switch (dwc->dr_mode) {
>       case USB_DR_MODE_PERIPHERAL:
>       case USB_DR_MODE_OTG:
> +             spin_lock_irqsave(&dwc->lock, flags);
>               dwc3_gadget_suspend(dwc);
> +             spin_unlock_irqrestore(&dwc->lock, flags);
>               break;
>       case USB_DR_MODE_HOST:
>       default:
> @@ -1127,18 +1132,14 @@ static int dwc3_suspend(struct device *dev)
>  
>       dwc3_core_exit(dwc);
>  
> -     pinctrl_pm_select_sleep_state(dev);
> -
>       return 0;
>  }
>  
> -static int dwc3_resume(struct device *dev)
> +static int dwc3_resume_common(struct dwc3 *dwc)
>  {
> -     struct dwc3     *dwc = dev_get_drvdata(dev);
> +     unsigned long   flags;
>       int             ret;
>  
> -     pinctrl_pm_select_default_state(dev);
> -
>       ret = dwc3_core_init(dwc);
>       if (ret)
>               return ret;
> @@ -1146,7 +1147,9 @@ static int dwc3_resume(struct device *dev)
>       switch (dwc->dr_mode) {
>       case USB_DR_MODE_PERIPHERAL:
>       case USB_DR_MODE_OTG:
> +             spin_lock_irqsave(&dwc->lock, flags);
>               dwc3_gadget_resume(dwc);
> +             spin_unlock_irqrestore(&dwc->lock, flags);
>               /* FALLTHROUGH */
>       case USB_DR_MODE_HOST:
>       default:
> @@ -1154,6 +1157,117 @@ static int dwc3_resume(struct device *dev)
>               break;
>       }
>  
> +     return 0;
> +}
> +
> +static int dwc3_runtime_checks(struct dwc3 *dwc)
> +{
> +     switch (dwc->dr_mode) {
> +     case USB_DR_MODE_PERIPHERAL:
> +     case USB_DR_MODE_OTG:
> +             if (dwc->connected)
> +                     return -EBUSY;
> +             break;
> +     case USB_DR_MODE_HOST:
> +     default:
> +             /* do nothing */
> +             break;
> +     }
> +
> +     return 0;
> +}
> +
> +static int dwc3_runtime_suspend(struct device *dev)
> +{
> +     struct dwc3     *dwc = dev_get_drvdata(dev);
> +     int             ret;
> +
> +     if (dwc3_runtime_checks(dwc))
> +             return -EBUSY;
> +
> +     ret = dwc3_suspend_common(dwc);
> +     if (ret)
> +             return ret;
> +
> +     device_init_wakeup(dev, true);
> +
> +     return 0;
> +}
> +
> +static int dwc3_runtime_resume(struct device *dev)
> +{
> +     struct dwc3     *dwc = dev_get_drvdata(dev);
> +     int             ret;
> +
> +     device_init_wakeup(dev, false);
> +
> +     ret = dwc3_resume_common(dwc);
> +     if (ret)
> +             return ret;
> +
> +     switch (dwc->dr_mode) {
> +     case USB_DR_MODE_PERIPHERAL:
> +     case USB_DR_MODE_OTG:
> +             dwc3_gadget_process_pending_events(dwc);
> +             break;
> +     case USB_DR_MODE_HOST:
> +     default:
> +             /* do nothing */
> +             break;
> +     }
> +
> +     return 0;
> +}
> +
> +static int dwc3_runtime_idle(struct device *dev)
> +{
> +     struct dwc3     *dwc = dev_get_drvdata(dev);
> +
> +     switch (dwc->dr_mode) {
> +     case USB_DR_MODE_PERIPHERAL:
> +     case USB_DR_MODE_OTG:
> +             if (dwc3_runtime_checks(dwc))
> +                     return -EBUSY;
> +             break;
> +     case USB_DR_MODE_HOST:
> +     default:
> +             /* do nothing */
> +             break;
> +     }
> +
> +     pm_runtime_mark_last_busy(dev);
> +     pm_runtime_autosuspend(dev);
> +
> +     return 0;
> +}
> +#endif /* CONFIG_PM */
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int dwc3_suspend(struct device *dev)
> +{
> +     struct dwc3     *dwc = dev_get_drvdata(dev);
> +     int             ret;
> +
> +     ret = dwc3_suspend_common(dwc);
> +     if (ret)
> +             return ret;
> +
> +     pinctrl_pm_select_sleep_state(dev);
> +
> +     return 0;
> +}
> +
> +static int dwc3_resume(struct device *dev)
> +{
> +     struct dwc3     *dwc = dev_get_drvdata(dev);
> +     int             ret;
> +
> +     pinctrl_pm_select_default_state(dev);
> +
> +     ret = dwc3_resume_common(dwc);
> +     if (ret)
> +             return ret;
> +
>       pm_runtime_disable(dev);
>       pm_runtime_set_active(dev);
>       pm_runtime_enable(dev);
> @@ -1164,6 +1278,8 @@ static int dwc3_resume(struct device *dev)
>  
>  static const struct dev_pm_ops dwc3_dev_pm_ops = {
>       SET_SYSTEM_SLEEP_PM_OPS(dwc3_suspend, dwc3_resume)
> +     SET_RUNTIME_PM_OPS(dwc3_runtime_suspend, dwc3_runtime_resume,
> +                     dwc3_runtime_idle)
>  };
>  
>  #ifdef CONFIG_OF
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 5f67c4bc1d37..a71e2604bb86 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -762,6 +762,7 @@ struct dwc3_scratchpad_array {
>   * @lpm_nyet_threshold: LPM NYET response threshold
>   * @hird_threshold: HIRD threshold
>   * @hsphy_interface: "utmi" or "ulpi"
> + * @connected: true when we're connected to a host, false otherwise
>   * @delayed_status: true when gadget driver asks for delayed status
>   * @ep0_bounced: true when we used bounce buffer
>   * @ep0_expect_in: true when we expect a DATA IN transfer
> @@ -772,6 +773,7 @@ struct dwc3_scratchpad_array {
>   *   0       - utmi_sleep_n
>   *   1       - utmi_l1_suspend_n
>   * @is_fpga: true when we are using the FPGA board
> + * @pending_events: true when we have pending IRQs to be handled
>   * @pullups_connected: true when Run/Stop bit is set
>   * @setup_packet_pending: true when there's a Setup Packet in FIFO. 
> Workaround
>   * @start_config_issued: true when StartConfig command has been issued
> @@ -906,6 +908,7 @@ struct dwc3 {
>  
>       const char              *hsphy_interface;
>  
> +     unsigned                connected:1;
>       unsigned                delayed_status:1;
>       unsigned                ep0_bounced:1;
>       unsigned                ep0_expect_in:1;
> @@ -913,6 +916,7 @@ struct dwc3 {
>       unsigned                has_lpm_erratum:1;
>       unsigned                is_utmi_l1_suspend:1;
>       unsigned                is_fpga:1;
> +     unsigned                pending_events:1;
>       unsigned                pullups_connected:1;
>       unsigned                setup_packet_pending:1;
>       unsigned                three_stage_setup:1;
> @@ -1138,6 +1142,7 @@ static inline int 
> dwc3_send_gadget_generic_command(struct dwc3 *dwc,
>  #if !IS_ENABLED(CONFIG_USB_DWC3_HOST)
>  int dwc3_gadget_suspend(struct dwc3 *dwc);
>  int dwc3_gadget_resume(struct dwc3 *dwc);
> +void dwc3_gadget_process_pending_events(struct dwc3 *dwc);
>  #else
>  static inline int dwc3_gadget_suspend(struct dwc3 *dwc)
>  {
> @@ -1148,6 +1153,10 @@ static inline int dwc3_gadget_resume(struct dwc3 *dwc)
>  {
>       return 0;
>  }
> +
> +static inline void dwc3_gadget_process_pending_events(struct dwc3 *dwc)
> +{
> +}
>  #endif /* !IS_ENABLED(CONFIG_USB_DWC3_HOST) */
>  
>  #if IS_ENABLED(CONFIG_USB_DWC3_ULPI)
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index d9df5916efdb..a39e64bc0627 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -199,6 +199,9 @@ void dwc3_gadget_giveback(struct dwc3_ep *dep, struct 
> dwc3_request *req,
>       spin_unlock(&dwc->lock);
>       usb_gadget_giveback_request(&dep->endpoint, &req->request);
>       spin_lock(&dwc->lock);
> +
> +     if (dep->number > 1)
> +             pm_runtime_put(dwc->dev);
>  }
>  
>  int dwc3_send_gadget_generic_command(struct dwc3 *dwc, unsigned cmd, u32 
> param)
> @@ -1059,6 +1062,8 @@ static int __dwc3_gadget_ep_queue(struct dwc3_ep *dep, 
> struct dwc3_request *req)
>               return -EINVAL;
>       }
>  
> +     pm_runtime_get(dwc->dev);
> +
>       req->request.actual     = 0;
>       req->request.status     = -EINPROGRESS;
>       req->direction          = dep->direction;
> @@ -1487,6 +1492,9 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int 
> is_on, int suspend)
>       u32                     reg;
>       u32                     timeout = 500;
>  
> +     if (pm_runtime_suspended(dwc->dev))
> +             return 0;
> +
>       reg = dwc3_readl(dwc->regs, DWC3_DCTL);
>       if (is_on) {
>               if (dwc->revision <= DWC3_REVISION_187A) {
> @@ -1744,7 +1752,9 @@ static int dwc3_gadget_start(struct usb_gadget *g,
>  
>       dwc->gadget_driver      = driver;
>  
> -     __dwc3_gadget_start(dwc);
> +     if (pm_runtime_active(dwc->dev))
> +             __dwc3_gadget_start(dwc);
> +
>       spin_unlock_irqrestore(&dwc->lock, flags);
>  
>       return 0;
> @@ -2336,12 +2346,16 @@ static void dwc3_gadget_disconnect_interrupt(struct 
> dwc3 *dwc)
>       dwc->gadget.speed = USB_SPEED_UNKNOWN;
>       dwc->setup_packet_pending = false;
>       usb_gadget_set_state(&dwc->gadget, USB_STATE_NOTATTACHED);
> +
> +     dwc->connected = false;
>  }
>  
>  static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
>  {
>       u32                     reg;
>  
> +     dwc->connected = true;
> +
>       /*
>        * WORKAROUND: DWC3 revisions <1.88a have an issue which
>        * would cause a missing Disconnect Event if there's a
> @@ -2803,6 +2817,13 @@ static irqreturn_t dwc3_check_event_buf(struct 
> dwc3_event_buffer *evt)
>       u32 count;
>       u32 reg;
>  
> +     if (pm_runtime_suspended(dwc->dev)) {
> +             pm_runtime_get(dwc->dev);
> +             disable_irq_nosync(dwc->irq_gadget);
> +             dwc->pending_events = true;
> +             return IRQ_HANDLED;
> +     }
> +
>       count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0));
>       count &= DWC3_GEVNTCOUNT_MASK;
>       if (!count)
> @@ -3009,3 +3030,12 @@ err1:
>  err0:
>       return ret;
>  }
> +
> +void dwc3_gadget_process_pending_events(struct dwc3 *dwc)
> +{
> +     if (dwc->pending_events) {
> +             dwc3_interrupt(dwc->irq_gadget, dwc->ev_buf);
> +             dwc->pending_events = false;
> +             enable_irq(dwc->irq_gadget);
> +     }
> +}
> 
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