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?
> 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.
> + 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?).
> goto err0;
> + }
> dwc->ulpi_ready = true;
> }
>
> --
> 2.34.1
>
Thanks,
Thinh
