On 12/24/19 9:23 AM, Ley Foon Tan wrote:
In Cyclone 5 SoC platform, the first USB probing is failed but second probing is success. DWC2 driver read gsnpsid register right after de-assert reset, but controller is not ready yet and it returns gsnpsid 0. Polling reset status after de-assert reset to solve the issue.
Retry with this fix more than 10 times without issue.
=> usb reset resetting USB... Bus usb@ffb40000: usb probe SNPSID invalid (not DWC2 OTG device): 00000000 Port not available. => usb reset resetting USB... Bus usb@ffb40000: usb probe scanning bus usb@ffb40000 for devices... 2 USB Device(s) found scanning usb for storage devices... 1 Storage Device(s) found
Signed-off-by: Ley Foon Tan ley.foon.tan@intel.com
v2:
- Change from constant delay to poll for reset status.
drivers/usb/host/dwc2.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c index b9c56f763b..1bc41990ee 100644 --- a/drivers/usb/host/dwc2.c +++ b/drivers/usb/host/dwc2.c @@ -1132,6 +1132,7 @@ int _submit_int_msg(struct dwc2_priv *priv, struct usb_device *dev, static int dwc2_reset(struct udevice *dev) { int ret;
int i = 1000; struct dwc2_priv *priv = dev_get_priv(dev);
ret = reset_get_bulk(dev, &priv->resets);
@@ -1153,7 +1154,14 @@ static int dwc2_reset(struct udevice *dev) return ret; }
- return 0;
- /* Poll until reset is completed. */
- do {
ret = reset_status(&priv->resets.resets[0]);if (!ret)return 0;- } while (i--);
- return -ETIMEDOUT;
[...]
Can't we implement some sort of "reset_wait_clear()" API instead of open-coding this in the driver ?
Or rather, shouldn't the socfpga_reset_deassert wait until the reset was actually de-asserted ? This might be even better, I think it should.