On 06/20/2013 03:11 PM, Felipe Balbi wrote:
> Hi,
>
> On Wed, Jun 19, 2013 at 05:05:51PM +0300, Roger Quadros wrote:
>> Runtime suspend the controller during bus suspend and resume it
>> during bus resume. This will ensure that the USB Host power domain
>> enters lower power state and does not prevent the SoC from
>> endering deeper sleep states.
>>
>> Remote wakeup will come up as an interrupt while the controller
>> is suspended, so tackle it carefully using a workqueue.
>>
>> Signed-off-by: Roger Quadros <rog...@ti.com>
>> ---
>> drivers/usb/host/ehci-omap.c | 82
>> ++++++++++++++++++++++++++++++++++++++++++
>> 1 files changed, 82 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/usb/host/ehci-omap.c b/drivers/usb/host/ehci-omap.c
>> index 16d7150..91f14f1 100644
>> --- a/drivers/usb/host/ehci-omap.c
>> +++ b/drivers/usb/host/ehci-omap.c
>> @@ -44,6 +44,8 @@
>> #include <linux/usb/hcd.h>
>> #include <linux/of.h>
>> #include <linux/dma-mapping.h>
>> +#include <linux/workqueue.h>
>> +#include <linux/spinlock.h>
>>
>> #include "ehci.h"
>>
>> @@ -69,6 +71,7 @@ static const char hcd_name[] = "ehci-omap";
>> struct omap_hcd {
>> struct usb_phy *phy[OMAP3_HS_USB_PORTS]; /* one PHY for each port */
>> int nports;
>> + struct work_struct work;
>> };
>>
>> static inline void ehci_write(void __iomem *base, u32 reg, u32 val)
>> @@ -81,6 +84,76 @@ static inline u32 ehci_read(void __iomem *base, u32 reg)
>> return __raw_readl(base + reg);
>> }
>>
>> +static void omap_ehci_work(struct work_struct *work)
>> +{
>> + struct omap_hcd *omap = container_of(work, struct omap_hcd, work);
>> + struct ehci_hcd *ehci = container_of((void *) omap,
>> + struct ehci_hcd, priv);
>> + struct usb_hcd *hcd = ehci_to_hcd(ehci);
>> + struct device *dev = hcd->self.controller;
>> +
>> + pm_runtime_get_sync(dev);
>> + enable_irq(hcd->irq);
>> + /*
>> + * enable_irq() should preempt us with a pending IRQ
>> + * so we can be sure that IRQ handler completes before
>> + * we call pm_runtime_put_sync()
>> + */
>> + pm_runtime_put_sync(dev);
>> +}
>> +
>> +static irqreturn_t omap_ehci_irq(struct usb_hcd *hcd)
>> +{
>> + struct omap_hcd *omap = (struct omap_hcd *)hcd_to_ehci(hcd)->priv;
>> + struct device *dev = hcd->self.controller;
>> + irqreturn_t ret;
>> +
>> + if (pm_runtime_suspended(dev)) {
>> + schedule_work(&omap->work);
>> + disable_irq_nosync(hcd->irq);
>> + ret = IRQ_HANDLED;
>
> looks like this could be done as:
>
> if (pm_runtime_suspended(dev)) {
> pm_runtime_get(dev);
> omap->flags |= OMAP_EHCI_IRQ_PENDING;
> disable_irq_nosync(hcd->irq);
> ret = IRQ_HANDLED;
> }
>
> then on your ->runtime_resume():
>
> runtime_resume(dev)
> {
> ...
>
> if (omap->flags & OMAP_EHCI_IRQ_PENDING) {
> process_pending_irqs(omap);
OK, thanks.
But I'm not sure if the generic ehci_irq handler is able to
run in a process context. Maybe if we replace spin_lock(&ehci->lock);
with spin_lock_irqsave() there, it will work.
Alan is this a doable option?
> omap->flags &= ~OMAP_EHCI_IRQ_PENDING;
> }
>
> return 0;
> }
>
> or something similar
>
cheers,
-roger
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