On Tue 04 Jun 01:13 PDT 2019, Bean Huo (beanhuo) wrote:
> >@@ -6159,6 +6179,9 @@ static int ufshcd_reset_and_restore(struct ufs_hba
> >*hba)
> > int retries = MAX_HOST_RESET_RETRIES;
> >
> > do {
> >+ /* Reset the attached device */
> >+ ufshcd_device_reset(hba);
> >+
>
> what's problem you met, and you should reset UFS device here? could you give more info?
>
> It is true that we don't reset UFS device in case of device fatal error. According to UFS host spec,
> Host should be device reset except that in addition to resetting UIC. But as so far,
> We didn't experience any problems result from this missing reset.
>
> We have three UFS device reset ways. Comparing to this hardware reset,
> I prefer to use DME_ENDPOINTRESET.req software reset.
>
Hi Bean,
Thanks for your questions. With some memories we see issues establishing
the link during bootup, so that's the purpose of issuing this reset.
Unfortunately the downstream Qualcomm patch [1] (which I should have
remembered to attribute), does not mention why the reset during host
controller reset is needed - but I'm fairly certain that this scenario
would be similar to the handover from bootloader to kernel that we do
see an issue with.
[1] https://source.codeaurora.org/quic/la/kernel/msm-4.4/commit/?h=msm-4.4&id=0c82737188e2d63a08196e078e411032dbbc3b89
Regards,
Bjorn
