(sorry sent html with previous attempt)
On 10-11-2022 01:06, Thinh Nguyen wrote:
Hi Ferry,
On Wed, Nov 09, 2022, Ferry Toth wrote:
Since commit 0f010171
Dual Role support on Intel Merrifield platform broke due to rearranging
the call to dwc3_get_extcon().
It appears to be caused by ulpi_read_id() on the first test write failing
with -ETIMEDOUT. Currently ulpi_read_id() expects to discover the phy via
DT when the test write fails and returns 0 in that case even if DT does not
provide the phy. Due to the timeout being masked dwc3 probe continues by
calling dwc3_core_soft_reset() followed by dwc3_get_extcon() which happens
to return -EPROBE_DEFER. On deferred probe ulpi_read_id() finally succeeds.
This patch changes ulpi_read_id() to return -ETIMEDOUT when it occurs and
catches the error in dwc3_core_init(). It handles the error by calling
dwc3_core_soft_reset() after which it requests -EPROBE_DEFER. On deferred
probe ulpi_read_id() again succeeds.
Signed-off-by: Ferry Toth<ftoth@xxxxxxxxxxxxxx>
---
drivers/usb/common/ulpi.c | 5 +++--
drivers/usb/dwc3/core.c | 5 ++++-
2 files changed, 7 insertions(+), 3 deletions(-)
Can you split the dwc3 change and ulpi change to separate patches?
Thanks for your comments.
I will send v2
diff --git a/drivers/usb/common/ulpi.c b/drivers/usb/common/ulpi.c
index d7c8461976ce..d8f22bc2f9d0 100644
--- a/drivers/usb/common/ulpi.c
+++ b/drivers/usb/common/ulpi.c
@@ -206,8 +206,9 @@ static int ulpi_read_id(struct ulpi *ulpi)
/* Test the interface */
ret = ulpi_write(ulpi, ULPI_SCRATCH, 0xaa);
- if (ret < 0)
- goto err;
+ if (ret < 0) {
+ return ret;
+ }
ret = ulpi_read(ulpi, ULPI_SCRATCH);
if (ret < 0)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 648f1c570021..e293ef70039b 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1106,8 +1106,11 @@ static int dwc3_core_init(struct dwc3 *dwc)
if (!dwc->ulpi_ready) {
ret = dwc3_core_ulpi_init(dwc);
- if (ret)
+ if (ret) {
+ dwc3_core_soft_reset(dwc);
We shouldn't need to do soft reset here. The controller shouldn't be at
a bad/incorrect state at this point to warrant a soft-reset. There will
be a soft-reset when it goes through the initialization again.
It doesn't go through the initialization again unless we set
-EPROBE_DEFER. And when we make ulpi_read_id() return -EPROBE_DEFER it
will goto err0 here, so skips dwc3_core_soft_reset.
Do you mean you prefer something like:
if (ret) {
if (ret == -ETIMEDOUT) ret = -EPROBE_DEFER;
else goto err0;
}
+ ret = -EPROBE_DEFER;
We shouldn't automatically set every error status to correspond to
-EPROBE_DEFER. Check only the approapriate error codes (-ETIMEDOUT +
any other?).
Other could be -ENOMEM. I think no need to do any new handling for that.
goto err0;
+ }
dwc->ulpi_ready = true;
}
--
2.34.1
Thanks,
Thinh
