[RFC PATCH 4/6] USB: ehci-omap: Suspend the controller during bus suspend
Felipe Balbi
balbi at ti.com
Thu Jun 20 08:11:51 EDT 2013
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 <rogerq at 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);
omap->flags &= ~OMAP_EHCI_IRQ_PENDING;
}
return 0;
}
or something similar
--
balbi
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