usb: cdns3: add runtime PM support

Introduce runtime PM and wakeup interrupt handler for cdns3,
the runtime PM is default off since other cdns3 may not
implement glue layer support for runtime PM.

One typical wakeup event use case is xHCI runtime suspend will clear
USBCMD.RS bit, after that the xHCI will not trigger any interrupts,
so its parent (cdns core device) needs to resume xHCI device when
any (wakeup) events occurs at host port.

When the controller is in low power mode, the lpm flag will be set.
The interrupt triggered later than lpm flag is set considers as
wakeup interrupt and handled at cdns_wakeup_irq. Once the wakeup
occurs, it first disables interrupt to avoid later interrupt
occurrence since the controller is in low power mode at that
time, and access registers may be invalid at that time. At wakeup
handler, it will call pm_request_resume to wakeup xHCI device, and
at runtime resume handler, it will enable interrupt again.

The API platform_suspend is introduced for glue layer to implement
platform specific PM sequence.

Reviewed-by: Pawel Laszczak <pawell@cadence.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/usb/cdns3/core.h b/drivers/usb/cdns3/core.h
index 1ad1f1fe61e9..1b1707796db2 100644
--- a/drivers/usb/cdns3/core.h
+++ b/drivers/usb/cdns3/core.h
@@ -38,6 +38,12 @@ struct cdns3_role_driver {
 };
 
 #define CDNS3_XHCI_RESOURCES_NUM	2
+
+struct cdns3_platform_data {
+	int (*platform_suspend)(struct device *dev,
+			bool suspend, bool wakeup);
+};
+
 /**
  * struct cdns3 - Representation of Cadence USB3 DRD controller.
  * @dev: pointer to Cadence device struct
@@ -50,6 +56,7 @@ struct cdns3_role_driver {
  * @otg_regs: pointer to base of otg registers
  * @otg_irq: irq number for otg controller
  * @dev_irq: irq number for device controller
+ * @wakeup_irq: irq number for wakeup event, it is optional
  * @roles: array of supported roles for this controller
  * @role: current role
  * @host_dev: the child host device pointer for cdns3 core
@@ -62,6 +69,10 @@ struct cdns3_role_driver {
  *           This field based on firmware setting, kernel configuration
  *           and hardware configuration.
  * @role_sw: pointer to role switch object.
+ * @in_lpm: indicate the controller is in low power mode
+ * @wakeup_pending: wakeup interrupt pending
+ * @pdata: platform data from glue layer
+ * @lock: spinlock structure
  */
 struct cdns3 {
 	struct device			*dev;
@@ -79,6 +90,7 @@ struct cdns3 {
 
 	int				otg_irq;
 	int				dev_irq;
+	int				wakeup_irq;
 	struct cdns3_role_driver	*roles[USB_ROLE_DEVICE + 1];
 	enum usb_role			role;
 	struct platform_device		*host_dev;
@@ -89,6 +101,10 @@ struct cdns3 {
 	struct mutex			mutex;
 	enum usb_dr_mode		dr_mode;
 	struct usb_role_switch		*role_sw;
+	bool				in_lpm;
+	bool				wakeup_pending;
+	struct cdns3_platform_data	*pdata;
+	spinlock_t			lock;
 };
 
 int cdns3_hw_role_switch(struct cdns3 *cdns);