From: cang@codeaurora.org
To: Mark Salyzyn <salyzyn@android.com>
Cc: asutoshd@codeaurora.org, nguyenb@codeaurora.org,
rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
kernel-team@android.com, saravanak@google.com,
salyzyn@google.com, Alim Akhtar <alim.akhtar@samsung.com>,
Avri Altman <avri.altman@wdc.com>,
Pedro Sousa <pedrom.sousa@synopsys.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Stanley Chu <stanley.chu@mediatek.com>,
Bean Huo <beanhuo@micron.com>,
Tomas Winkler <tomas.winkler@intel.com>,
Subhash Jadavani <subhashj@codeaurora.org>,
Arnd Bergmann <arnd@arndb.de>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 1/2] scsi: ufs: Introduce a vops for resetting host controller
Date: Fri, 01 Nov 2019 09:18:06 +0800 [thread overview]
Message-ID: <8b7e86d09cde1ea45c1ad979d88dc022@codeaurora.org> (raw)
In-Reply-To: <61b83149-e89b-bb4c-d747-a4c596c8eede@android.com>
On 2019-10-31 22:44, Mark Salyzyn wrote:
> On 10/22/19 9:13 PM, Can Guo wrote:
>> Some UFS host controllers need their specific implementations of
>> resetting
>> to get them into a good state. Provide a new vops to allow the
>> platform
>> driver to implement this own reset operation.
>>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> ---
>> drivers/scsi/ufs/ufshcd.c | 16 ++++++++++++++++
>> drivers/scsi/ufs/ufshcd.h | 10 ++++++++++
>> 2 files changed, 26 insertions(+)
>>
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index c28c144..161e3c4 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -3859,6 +3859,14 @@ static int ufshcd_link_recovery(struct ufs_hba
>> *hba)
>> ufshcd_set_eh_in_progress(hba);
>> spin_unlock_irqrestore(hba->host->host_lock, flags);
>> + ret = ufshcd_vops_full_reset(hba);
>> + if (ret)
>> + dev_warn(hba->dev, "%s: full reset returned %d\n",
>> + __func__, ret);
>> +
>> + /* Reset the attached device */
>> + ufshcd_vops_device_reset(hba);
>> +
>> ret = ufshcd_host_reset_and_restore(hba);
>> spin_lock_irqsave(hba->host->host_lock, flags);
>
> In all your cases, especially after this adjustment,
> ufshcd_vops_full_reset is called blindly (+error checking message)
> before ufshcd_vops_device_reset. What about dropping the .full_reset
> (should really have been called .hw_reset or .host_reset) addition to
> the vops, just adding ufshcd_vops_device_reset call here before
> ufshcd_host_reset_and_restore, and in the driver folding the
> ufshcd_vops_full_reset code into the .device_reset handler?
>
> Would that be workable? It would be simpler if so.
>
> I can see a desire for the heads up
> (ufshcd_vops_full_reset+)ufshcd_vops_device_reset calls before
> ufshcd_host_reset_and_restore because that function will spin 10
> seconds waiting for a response from a standardized register, that
> itself could be hardware locked up requiring product specific reset
> procedures. But if that is the case, then what about all the other
> calls to ufshcd_host_reset_and_restore in this file that are not
> provided the heads up? My guess is that the host device only
> demonstrated issues in the ufshcd_link_recovery handling path? Are you
> sure this is the only path that tickles the controller into a hardware
> lockup state?
>
> Sincerely -- Mark Salyzyn
Hi Mark Salyzyn,
Folding the "full_reset" vops inito "device_reset" vops is one choice
for now. Shall do that.
Your guess is correct. the head up is needed in ufshcd_link_recovery()
path because
link is already in bad state when we are here, expeically after hibern8
exit fails.
So we need a full reset to PHY and host controller here before
host_reset_and_restore.
But other calls to host_reset_and_restore are under good conditions.
Regards,
Can Guo.
next prev parent reply other threads:[~2019-11-01 1:18 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1571804009-29787-1-git-send-email-cang@codeaurora.org>
2019-10-23 4:13 ` [PATCH v1 1/2] scsi: ufs: Introduce a vops for resetting host controller Can Guo
2019-10-23 10:39 ` [EXT] " Bean Huo (beanhuo)
2019-10-29 2:11 ` cang
2019-10-31 14:44 ` Mark Salyzyn
2019-11-01 1:18 ` cang [this message]
2019-11-04 14:28 ` Avri Altman
2019-11-04 14:34 ` [EXT] " Bean Huo (beanhuo)
2019-11-04 23:46 ` cang
2019-11-04 23:44 ` cang
2019-10-23 4:13 ` [PATCH v1 2/2] scsi: ufs-qcom: Add reset control support for " Can Guo
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