[PATCH v3] usb: dwc3: gadget: Improve dwc3_gadget_suspend() and dwc3_gadget_resume()

Roger Quadros
2023-05-03T11:01:26Z

Prevent -ETIMEDOUT error on .suspend().
e.g. If gadget driver is loaded and we are connected to a USB host,
all transfers must be stopped before stopping the controller else
we will not get a clean stop i.e. dwc3_gadget_run_stop() will take
several seconds to complete and will return -ETIMEDOUT.

Handle error cases properly in dwc3_gadget_suspend().
Simplify dwc3_gadget_resume() by using the introduced helper function.

Fixes: 9f8a67b65a49 ("usb: dwc3: gadget: fix gadget suspend/resume")
Cc: stable@vger.kernel.org
Suggested-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Roger Quadros <rogerq@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---

Changelog:

v3:
- dropped patch 1. Now no longer check for softconnect during .suspend
- in suspend error path check for softconnect and enable softconnect accordingly
- added Acked-by tag by Thinh Nguyen

v2:
- rebase on greg/usb-next
- split into 2 patches. Add Fixes tag and cc stable.
- do not check for !softconnect in error condition in dwc3_gadget_suspend()

drivers/usb/dwc3/gadget.c | 67 ++++++++++++++++++++-------------------
1 file changed, 34 insertions(+), 33 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index c0ca4d12f95d..2996bcb4d53d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2699,6 +2699,21 @@ static int dwc3_gadget_soft_disconnect(struct dwc3 *dwc)
return ret;
}

+static int dwc3_gadget_soft_connect(struct dwc3 *dwc)
+{
+ /*
+ * In the Synopsys DWC_usb31 1.90a programming guide section
+ * 4.1.9, it specifies that for a reconnect after a
+ * device-initiated disconnect requires a core soft reset
+ * (DCTL.CSftRst) before enabling the run/stop bit.
+ */
+ dwc3_core_soft_reset(dwc);
+
+ dwc3_event_buffers_setup(dwc);
+ __dwc3_gadget_start(dwc);
+ return dwc3_gadget_run_stop(dwc, true);
+}
+
static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)
{
struct dwc3 *dwc = gadget_to_dwc(g);
@@ -2737,21 +2752,10 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on)

synchronize_irq(dwc->irq_gadget);

- if (!is_on) {
+ if (!is_on)
ret = dwc3_gadget_soft_disconnect(dwc);
- } else {
- /*
- * In the Synopsys DWC_usb31 1.90a programming guide section
- * 4.1.9, it specifies that for a reconnect after a
- * device-initiated disconnect requires a core soft reset
- * (DCTL.CSftRst) before enabling the run/stop bit.
- */
- dwc3_core_soft_reset(dwc);
-
- dwc3_event_buffers_setup(dwc);
- __dwc3_gadget_start(dwc);
- ret = dwc3_gadget_run_stop(dwc, true);
- }
+ else
+ ret = dwc3_gadget_soft_connect(dwc);

pm_runtime_put(dwc->dev);

@@ -4655,42 +4659,39 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
int dwc3_gadget_suspend(struct dwc3 *dwc)
{
unsigned long flags;
+ int ret;

if (!dwc->gadget_driver)
return 0;

- dwc3_gadget_run_stop(dwc, false);
+ ret = dwc3_gadget_soft_disconnect(dwc);
+ if (ret)
+ goto err;

spin_lock_irqsave(&dwc->lock, flags);
dwc3_disconnect_gadget(dwc);
- __dwc3_gadget_stop(dwc);
spin_unlock_irqrestore(&dwc->lock, flags);

return 0;
+
+err:
+ /*
+ * Attempt to reset the controller's state. Likely no
+ * communication can be established until the host
+ * performs a port reset.
+ */
+ if (dwc->softconnect)
+ dwc3_gadget_soft_connect(dwc);
+
+ return ret;
}

int dwc3_gadget_resume(struct dwc3 *dwc)
{
- int ret;
-
if (!dwc->gadget_driver || !dwc->softconnect)
return 0;

- ret = __dwc3_gadget_start(dwc);
- if (ret < 0)
- goto err0;
-
- ret = dwc3_gadget_run_stop(dwc, true);
- if (ret < 0)
- goto err1;
-
- return 0;
-
-err1:
- __dwc3_gadget_stop(dwc);
-
-err0:
- return ret;
+ return dwc3_gadget_soft_connect(dwc);
}

void dwc3_gadget_process_pending_events(struct dwc3 *dwc)
--
2.34.1