From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>,
Thierry Reding <thierry.reding@gmail.com>
Cc: <jonathanh@nvidia.com>, <frankc@nvidia.com>, <hverkuil@xs4all.nl>,
<sakari.ailus@iki.fi>, <robh+dt@kernel.org>,
<helen.koike@collabora.com>, <gregkh@linuxfoundation.org>,
<linux-media@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v8 08/10] gpu: host1x: mipi: Keep MIPI clock enabled till calibration is done
Date: Thu, 6 Aug 2020 11:51:59 -0700 [thread overview]
Message-ID: <3a4be8e9-32a5-e7d8-8727-8d860368bc8e@nvidia.com> (raw)
In-Reply-To: <50aa439e-a572-ce77-9d06-e060304b9bd4@nvidia.com>
On 8/6/20 11:44 AM, Sowjanya Komatineni wrote:
>
> On 8/6/20 11:18 AM, Dmitry Osipenko wrote:
>> 06.08.2020 21:07, Sowjanya Komatineni пишет:
>>> On 8/6/20 11:01 AM, Dmitry Osipenko wrote:
>>>> 06.08.2020 20:52, Sowjanya Komatineni пишет:
>>>> ...
>>>>> Right mutex_unlock should happen at end of finish_calibration.
>>>>>
>>>>> With keeping mutex locked in start, we dont have to check for
>>>>> active to
>>>>> be 0 to issue start as mutex will keep it locked and other pads
>>>>> calibration can only go thru when current one is done.
>>>>>
>>>>> So instead of below sequence, its simpler to do this way?
>>>>>
>>>>> start_calibration()
>>>>>
>>>>> - mutex_lock
>>>>>
>>>>> - wait for 72uS after start
>>>>>
>>>>> finish_calibration()
>>>>>
>>>>> - keep check for ACTIVE = 0 and DONE = 1
>>>> I think only the DONE bits which correspond to the mipi_device->pads
>>>> bitmask should be awaited.
>>> As next START can't be triggered when auto cal is ACTIVE, we should
>>> keep
>>> this in finish.
>>>
>>> As we do mutex_unlock only at end of finish, other pads calibrations
>>> dont go thru till the one in process is finished.
>>>
>>> So in this case ACTIVE applies to current selected pads that are under
>>> calibration.
>> Should be better to check only the relevant bits in order to catch bugs,
>> otherwise you may get a DONE status from the irrelevant pads.
> tegra_mipi_device is separate for DSI and CSI channels. mutex lock
> used during calibrate is device specific lock.
> So, it will not prevent other devices to hold till on going
> calibration is done unless we add wait for active bit before
> triggering start.
>
> Currently we wait for active bit at end during calibration done check
> after start trigger. But when other devices go thru calibration in
> parallel as lock is device specific and not common lock for all
> devices it will trigger start but MIPI calibration logic ignore if
> previous calibration is still in progress.
>
> Need to serialize calibration start requests from different devices
> based on ACTIVE bit.
Sorry confused. MIPI driver is using common lock from tegra_mipi for all
tegra_mipi_device
So should be ok as only one device start_calibration can happen at a time.
But its still good to check ACTIVE is cleared and to report as error if
not as ACTIVE will be cleared once set of pads enabled for this calibration.
Eg: CSI port can be 4 lane and all 4 pads gets enabled at same time and
with this ACTIVE should still be verified to be 0 to make sure all pads
calibration is done
>
>>>> Perhaps the start_calibration() also needs to be changed to not touch
>>>> the MIPI_CAL_CONFIG bits of the unrelated pads?
>>> Driver already takes care of programming corresponding pads config
>>> only.
>> It writes 0 to the config of the unrelated pads, which probably isn't
>> nice if some pads use periodic auto-calibration.
>>
>> https://elixir.bootlin.com/linux/v5.8/source/drivers/gpu/host1x/mipi.c#L350
>>
>>
>> Although looks like auto-calibration isn't supported by the current
>> driver.
>
> Yes we don't use auto-calibration.
>
> Only common bit here is MIPI_CAL_CTRL start. All others are pad
> specific currently.
>
next prev parent reply other threads:[~2020-08-06 18:52 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-03 15:42 [PATCH v8 00/10] Support for Tegra video capture from external sensor Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 01/10] media: tegra-video: Fix channel format alignment Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 02/10] media: tegra-video: Enable TPG based on kernel config Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 03/10] media: tegra-video: Update format lookup to offset based Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 04/10] dt-bindings: tegra: Update VI and CSI bindings with port info Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 05/10] media: tegra-video: Separate CSI stream enable and disable implementations Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 06/10] media: tegra-video: Add support for external sensor capture Sowjanya Komatineni
2020-08-04 5:57 ` Dmitry Osipenko
2020-08-03 15:42 ` [PATCH v8 07/10] media: tegra-video: Add support for selection ioctl ops Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 08/10] gpu: host1x: mipi: Keep MIPI clock enabled till calibration is done Sowjanya Komatineni
2020-08-05 13:46 ` Thierry Reding
2020-08-05 14:05 ` Dmitry Osipenko
2020-08-05 14:19 ` Dmitry Osipenko
2020-08-05 16:33 ` Sowjanya Komatineni
2020-08-05 16:47 ` Dmitry Osipenko
2020-08-05 16:50 ` Sowjanya Komatineni
2020-08-05 16:57 ` Dmitry Osipenko
2020-08-05 17:04 ` Sowjanya Komatineni
2020-08-05 17:23 ` Dmitry Osipenko
2020-08-05 17:32 ` Sowjanya Komatineni
2020-08-05 17:29 ` Sowjanya Komatineni
2020-08-05 17:34 ` Dmitry Osipenko
2020-08-05 17:46 ` Sowjanya Komatineni
2020-08-05 18:06 ` Sowjanya Komatineni
2020-08-06 0:47 ` Sowjanya Komatineni
2020-08-06 13:32 ` Dmitry Osipenko
2020-08-06 15:59 ` Sowjanya Komatineni
2020-08-06 16:10 ` Dmitry Osipenko
2020-08-06 16:41 ` Sowjanya Komatineni
2020-08-06 16:45 ` Dmitry Osipenko
2020-08-06 16:51 ` Sowjanya Komatineni
2020-08-06 17:15 ` Dmitry Osipenko
2020-08-06 17:12 ` Sowjanya Komatineni
2020-08-06 17:27 ` Dmitry Osipenko
2020-08-06 17:44 ` Sowjanya Komatineni
2020-08-06 17:52 ` Sowjanya Komatineni
2020-08-06 18:01 ` Dmitry Osipenko
2020-08-06 18:07 ` Sowjanya Komatineni
2020-08-06 18:18 ` Dmitry Osipenko
2020-08-06 18:44 ` Sowjanya Komatineni
2020-08-06 18:51 ` Sowjanya Komatineni [this message]
2020-08-06 16:13 ` Dmitry Osipenko
2020-08-06 16:37 ` Dmitry Osipenko
2020-08-06 16:42 ` Sowjanya Komatineni
2020-08-06 16:43 ` Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 09/10] media: tegra-video: Add CSI MIPI pads calibration Sowjanya Komatineni
2020-08-03 15:42 ` [PATCH v8 10/10] media: tegra-video: Compute settle times based on the clock rate Sowjanya Komatineni
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