Changes in v2:
- Modified logic for executing the runtime PM resume. Using a sychronous get
call to avoid race conditions.
During the following scenario, the DWC3 runtime suspend routine is blocked as
the connected flag is still true:
1. Enumerate device w/ host.
2. Gadget is unbinded
- echo "" > /sys/kernel/config/usb_gadget/g1/UDC
3. Disconnect the USB cable (VBUS low)
4. No dwc3_gadget_disconnect_interrupt() seen (since controller is
halted from step#1)
5. Runtime PM autosuspend fails due to "dwc->connected" being true
(cleared in dwc3_gadget_disconnect_interrupt())
6. Gadget binded
- echo udc_name > /sys/kernel/config/usb_gadget/g1/UDC
7. No runtime suspend until cable is plugged in and out
Technically, for device initiated disconnects, there is no active session/link
with the host, so the DWC3 controller should be allowed to go into a low power
state. Also, we need to now consider when re-binding the UDC,
dwc3_gadget_set_speed() is executed before dwc3_gadget_pullup(), so if the DWC3
controller is suspended/disabled, while accessing the DCFG, that could result in
bus timeouts, etc... Change the dwc3_gadget_set_speed() to save the speed
being requested, and program it during dwc3_gadget_run_stop(), which is executed
during PM runtime resume. If not, previous setting will be overridden as we
execute a DWC3 controller reset during PM runtime resume.
Wesley Cheng (2):
usb: dwc3: gadget: Allow runtime suspend if UDC unbinded
usb: dwc3: gadget: Preserve UDC max speed setting
drivers/usb/dwc3/core.h | 1 +
drivers/usb/dwc3/gadget.c | 121 ++++++++++++++++++++++----------------
2 files changed, 71 insertions(+), 51 deletions(-)
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
The USB gadget/UDC driver can restrict the DWC3 controller speed using
dwc3_gadget_set_speed(). Store this setting into a variable, in order for
this setting to persist across controller resets due to runtime PM.
Signed-off-by: Wesley Cheng <[email protected]>
---
drivers/usb/dwc3/core.h | 1 +
drivers/usb/dwc3/gadget.c | 108 ++++++++++++++++++++------------------
2 files changed, 58 insertions(+), 51 deletions(-)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 2f04b3e42bf1..390d3deef0ba 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1119,6 +1119,7 @@ struct dwc3 {
u32 nr_scratch;
u32 u1u2;
u32 maximum_speed;
+ u32 gadget_max_speed;
u32 ip;
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index babf977cadc0..c145da1d8ba5 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1941,6 +1941,61 @@ static void dwc3_stop_active_transfers(struct dwc3 *dwc)
}
}
+static void __dwc3_gadget_set_speed(struct dwc3 *dwc)
+{
+ u32 reg;
+
+ reg = dwc3_readl(dwc->regs, DWC3_DCFG);
+ reg &= ~(DWC3_DCFG_SPEED_MASK);
+
+ /*
+ * WORKAROUND: DWC3 revision < 2.20a have an issue
+ * which would cause metastability state on Run/Stop
+ * bit if we try to force the IP to USB2-only mode.
+ *
+ * Because of that, we cannot configure the IP to any
+ * speed other than the SuperSpeed
+ *
+ * Refers to:
+ *
+ * STAR#9000525659: Clock Domain Crossing on DCTL in
+ * USB 2.0 Mode
+ */
+ if (DWC3_VER_IS_PRIOR(DWC3, 220A) &&
+ !dwc->dis_metastability_quirk) {
+ reg |= DWC3_DCFG_SUPERSPEED;
+ } else {
+ switch (dwc->gadget_max_speed) {
+ case USB_SPEED_LOW:
+ reg |= DWC3_DCFG_LOWSPEED;
+ break;
+ case USB_SPEED_FULL:
+ reg |= DWC3_DCFG_FULLSPEED;
+ break;
+ case USB_SPEED_HIGH:
+ reg |= DWC3_DCFG_HIGHSPEED;
+ break;
+ case USB_SPEED_SUPER:
+ reg |= DWC3_DCFG_SUPERSPEED;
+ break;
+ case USB_SPEED_SUPER_PLUS:
+ if (DWC3_IP_IS(DWC3))
+ reg |= DWC3_DCFG_SUPERSPEED;
+ else
+ reg |= DWC3_DCFG_SUPERSPEED_PLUS;
+ break;
+ default:
+ dev_err(dwc->dev, "invalid speed (%d)\n", dwc->gadget_max_speed);
+
+ if (DWC3_IP_IS(DWC3))
+ reg |= DWC3_DCFG_SUPERSPEED;
+ else
+ reg |= DWC3_DCFG_SUPERSPEED_PLUS;
+ }
+ }
+ dwc3_writel(dwc->regs, DWC3_DCFG, reg);
+}
+
static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
{
u32 reg;
@@ -1963,6 +2018,7 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
if (dwc->has_hibernation)
reg |= DWC3_DCTL_KEEP_CONNECT;
+ __dwc3_gadget_set_speed(dwc);
dwc->pullups_connected = true;
} else {
reg &= ~DWC3_DCTL_RUN_STOP;
@@ -2325,59 +2381,9 @@ static void dwc3_gadget_set_speed(struct usb_gadget *g,
{
struct dwc3 *dwc = gadget_to_dwc(g);
unsigned long flags;
- u32 reg;
spin_lock_irqsave(&dwc->lock, flags);
- reg = dwc3_readl(dwc->regs, DWC3_DCFG);
- reg &= ~(DWC3_DCFG_SPEED_MASK);
-
- /*
- * WORKAROUND: DWC3 revision < 2.20a have an issue
- * which would cause metastability state on Run/Stop
- * bit if we try to force the IP to USB2-only mode.
- *
- * Because of that, we cannot configure the IP to any
- * speed other than the SuperSpeed
- *
- * Refers to:
- *
- * STAR#9000525659: Clock Domain Crossing on DCTL in
- * USB 2.0 Mode
- */
- if (DWC3_VER_IS_PRIOR(DWC3, 220A) &&
- !dwc->dis_metastability_quirk) {
- reg |= DWC3_DCFG_SUPERSPEED;
- } else {
- switch (speed) {
- case USB_SPEED_LOW:
- reg |= DWC3_DCFG_LOWSPEED;
- break;
- case USB_SPEED_FULL:
- reg |= DWC3_DCFG_FULLSPEED;
- break;
- case USB_SPEED_HIGH:
- reg |= DWC3_DCFG_HIGHSPEED;
- break;
- case USB_SPEED_SUPER:
- reg |= DWC3_DCFG_SUPERSPEED;
- break;
- case USB_SPEED_SUPER_PLUS:
- if (DWC3_IP_IS(DWC3))
- reg |= DWC3_DCFG_SUPERSPEED;
- else
- reg |= DWC3_DCFG_SUPERSPEED_PLUS;
- break;
- default:
- dev_err(dwc->dev, "invalid speed (%d)\n", speed);
-
- if (DWC3_IP_IS(DWC3))
- reg |= DWC3_DCFG_SUPERSPEED;
- else
- reg |= DWC3_DCFG_SUPERSPEED_PLUS;
- }
- }
- dwc3_writel(dwc->regs, DWC3_DCFG, reg);
-
+ dwc->gadget_max_speed = speed;
spin_unlock_irqrestore(&dwc->lock, flags);
}
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project