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Subject[PATCH 2/2] usb: dwc3: drd: Fix lock-up on ID change during system suspend/resume
Date
Adding/removing host/gadget controller before .pm_complete()
causes a lock-up. Let's prevent any dual-role state change
between .pm_prepare() and .pm_complete() to fix this.

Signed-off-by: Roger Quadros <rogerq@ti.com>
---
drivers/usb/dwc3/core.c | 31 +++++++++++++++++++++++++++++++
drivers/usb/dwc3/core.h | 5 +++++
drivers/usb/dwc3/drd.c | 10 ++++++----
3 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 42379cc..85388dd 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1414,6 +1414,33 @@ static int dwc3_runtime_idle(struct device *dev)
#endif /* CONFIG_PM */

#ifdef CONFIG_PM_SLEEP
+static int dwc3_prepare(struct device *dev)
+{
+ struct dwc3 *dwc = dev_get_drvdata(dev);
+ unsigned long flags;
+
+ if (dwc->dr_mode == USB_DR_MODE_OTG) {
+ spin_lock_irqsave(&dwc->lock, flags);
+ dwc->dr_keep_role = true;
+ spin_unlock_irqrestore(&dwc->lock, flags);
+ }
+
+ return 0;
+}
+
+static void dwc3_complete(struct device *dev)
+{
+ struct dwc3 *dwc = dev_get_drvdata(dev);
+ unsigned long flags;
+
+ if (dwc->dr_mode == USB_DR_MODE_OTG) {
+ spin_lock_irqsave(&dwc->lock, flags);
+ dwc->dr_keep_role = false;
+ spin_unlock_irqrestore(&dwc->lock, flags);
+ dwc3_drd_update(dwc);
+ }
+}
+
static int dwc3_suspend(struct device *dev)
{
struct dwc3 *dwc = dev_get_drvdata(dev);
@@ -1451,6 +1478,10 @@ 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_PM_SLEEP
+ .prepare = dwc3_prepare,
+ .complete = dwc3_complete,
+#endif
};

#ifdef CONFIG_OF
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 4a4a4c9..f5eb474 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -786,6 +786,7 @@ struct dwc3_scratchpad_array {
* @dr_mode: requested mode of operation
* @current_dr_role: current role of operation when in dual-role mode
* @desired_dr_role: desired role of operation when in dual-role mode
+ * @dr_keep_role: keep the current dual-role irrespective of ID changes
* @edev: extcon handle
* @edev_nb: extcon notifier
* @hsphy_mode: UTMI phy mode, one of following:
@@ -901,6 +902,7 @@ struct dwc3 {
enum usb_dr_mode dr_mode;
u32 current_dr_role;
u32 desired_dr_role;
+ bool dr_keep_role;
struct extcon_dev *edev;
struct notifier_block edev_nb;
enum usb_phy_interface hsphy_mode;
@@ -1227,11 +1229,14 @@ static inline int dwc3_send_gadget_generic_command(struct dwc3 *dwc,
#if IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
int dwc3_drd_init(struct dwc3 *dwc);
void dwc3_drd_exit(struct dwc3 *dwc);
+void dwc3_drd_update(struct dwc3 *dwc);
#else
static inline int dwc3_drd_init(struct dwc3 *dwc)
{ return 0; }
static inline void dwc3_drd_exit(struct dwc3 *dwc)
{ }
+static inline void dwc3_drd_update(struct dwc3 *dwc);
+{ }
#endif

/* power management interface */
diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index cc8ab9a..177a8be 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -13,7 +13,7 @@
#include "core.h"
#include "gadget.h"

-static void dwc3_drd_update(struct dwc3 *dwc)
+void dwc3_drd_update(struct dwc3 *dwc)
{
int id;

@@ -31,9 +31,11 @@ static int dwc3_drd_notifier(struct notifier_block *nb,
{
struct dwc3 *dwc = container_of(nb, struct dwc3, edev_nb);

- dwc3_set_mode(dwc, event ?
- DWC3_GCTL_PRTCAP_HOST :
- DWC3_GCTL_PRTCAP_DEVICE);
+ if (!dwc->dr_keep_role) {
+ dwc3_set_mode(dwc, event ?
+ DWC3_GCTL_PRTCAP_HOST :
+ DWC3_GCTL_PRTCAP_DEVICE);
+ }

return NOTIFY_DONE;
}
--
cheers,
-roger
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

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