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Message-ID: <057f7036-d8de-cb9f-1f2a-31e460d3e4af@linaro.org>
Date:   Wed, 7 Jun 2023 00:01:42 +0300
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Subject: Re: [Freedreno] [PATCH] drm/msm/dpu: re-introduce dpu core revision
 to the catalog
Content-Language: en-GB
To:     Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc:     freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        quic_khsieh@quicinc.com, quic_jesszhan@quicinc.com,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Sean Paul <sean@poorly.run>
References: <20230531005358.18090-1-quic_abhinavk@quicinc.com>
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 <451b114c-05e1-541c-1d3e-26bb81a307c4@linaro.org>
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 <804363cf-f6cf-71a6-be8f-5fc00eea3154@quicinc.com>
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 <0fa66ee1-b759-333a-c93b-90de830babbb@quicinc.com>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
In-Reply-To: <0fa66ee1-b759-333a-c93b-90de830babbb@quicinc.com>
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On 06/06/2023 22:28, Abhinav Kumar wrote:
> 
> 
> On 6/6/2023 12:09 PM, Dmitry Baryshkov wrote:
>> On 06/06/2023 20:51, Abhinav Kumar wrote:
>>>
>>>
>>> On 6/6/2023 4:14 AM, Dmitry Baryshkov wrote:
>>>> On Tue, 6 Jun 2023 at 05:35, Abhinav Kumar 
>>>> <quic_abhinavk@quicinc.com> wrote:
>>>>>
>>>>>
>>>>>
>>>>> On 6/5/2023 6:03 PM, Dmitry Baryshkov wrote:
>>>>>> On 06/06/2023 03:55, Abhinav Kumar wrote:
>>>>>>>
>>>>>>>
>>>>>>> On 6/3/2023 7:21 PM, Dmitry Baryshkov wrote:
>>>>>>>> On 31/05/2023 21:25, Abhinav Kumar wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On 5/31/2023 3:07 AM, Dmitry Baryshkov wrote:
>>>>>>>>>> On 31/05/2023 06:05, Abhinav Kumar wrote:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 5/30/2023 7:53 PM, Dmitry Baryshkov wrote:
>>>>>>>>>>>> On Wed, 31 May 2023 at 03:54, Abhinav Kumar
>>>>>>>>>>>> <quic_abhinavk@quicinc.com> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>> With [1] dpu core revision was dropped in favor of using the
>>>>>>>>>>>>> compatible string from the device tree to select the dpu 
>>>>>>>>>>>>> catalog
>>>>>>>>>>>>> being used in the device.
>>>>>>>>>>>>>
>>>>>>>>>>>>> This approach works well however also necessitates adding 
>>>>>>>>>>>>> catalog
>>>>>>>>>>>>> entries for small register level details as dpu 
>>>>>>>>>>>>> capabilities and/or
>>>>>>>>>>>>> features bloating the catalog unnecessarily. Examples 
>>>>>>>>>>>>> include but
>>>>>>>>>>>>> are not limited to data_compress, interrupt register set,
>>>>>>>>>>>>> widebus etc.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Introduce the dpu core revision back as an entry to the 
>>>>>>>>>>>>> catalog
>>>>>>>>>>>>> so that
>>>>>>>>>>>>> we can just use dpu revision checks and enable those bits 
>>>>>>>>>>>>> which
>>>>>>>>>>>>> should be enabled unconditionally and not controlled by a 
>>>>>>>>>>>>> catalog
>>>>>>>>>>>>> and also simplify the changes to do something like:
>>>>>>>>>>>>>
>>>>>>>>>>>>> if (dpu_core_revision > xxxxx && dpu_core_revision < xxxxx)
>>>>>>>>>>>>>           enable the bit;
>>>>>>>>>>>>>
>>>>>>>>>>>>> Also, add some of the useful macros back to be able to use 
>>>>>>>>>>>>> dpu core
>>>>>>>>>>>>> revision effectively.
>>>>>>>>>>>>>
>>>>>>>>>>>>> [1]:
>>>>>>>>>>>>> https://patchwork.freedesktop.org/patch/530891/?series=113910&rev=4
>>>>>>>>>>>>>
>>>>>>>>>>>>> Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
>>>>>>>>>>>>> ---
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_3_0_msm8998.h   |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_4_0_sdm845.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_5_0_sm8150.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_5_1_sc8180x.h   |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_6_0_sm8250.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_6_2_sc7180.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_6_3_sm6115.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_6_5_qcm2290.h   |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_7_0_sm8350.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_7_2_sc7280.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_8_0_sc8280xp.h  |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_8_1_sm8450.h    |  1 +
>>>>>>>>>>>>>    .../msm/disp/dpu1/catalog/dpu_9_0_sm8550.h    |  1 +
>>>>>>>>>>>>>    .../gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h    | 31
>>>>>>>>>>>>> ++++++++++++++++++-
>>>>>>>>>>>>>    14 files changed, 43 insertions(+), 1 deletion(-)
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> [skipped catalog changes]
>>>>>>>>>>>>
>>>>>>>>>>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>>>>>>>>>>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>>>>>>>>>>>>> index 677048cc3b7d..cc4aa75a1219 100644
>>>>>>>>>>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>>>>>>>>>>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
>>>>>>>>>>>>> @@ -19,6 +19,33 @@
>>>>>>>>>>>>>     */
>>>>>>>>>>>>>    #define MAX_BLOCKS    12
>>>>>>>>>>>>>
>>>>>>>>>>>>> +#define DPU_HW_VER(MAJOR, MINOR, STEP)\
>>>>>>>>>>>>> +                 ((((unsigned int)MAJOR & 0xF) << 28) |\
>>>>>>>>>>>>> +                 ((MINOR & 0xFFF) << 16) |\
>>>>>>>>>>>>> +                 (STEP & 0xFFFF))
>>>>>>>>>>>>> +
>>>>>>>>>>>>> +#define DPU_HW_MAJOR(rev)((rev) >> 28)
>>>>>>>>>>>>> +#define DPU_HW_MINOR(rev)(((rev) >> 16) & 0xFFF)
>>>>>>>>>>>>> +#define DPU_HW_STEP(rev)((rev) & 0xFFFF)
>>>>>>>>>>>>> +#define DPU_HW_MAJOR_MINOR(rev)((rev) >> 16)
>>>>>>>>>>>>> +
>>>>>>>>>>>>> +#define IS_DPU_MAJOR_MINOR_SAME(rev1, rev2)   \
>>>>>>>>>>>>> +(DPU_HW_MAJOR_MINOR((rev1)) == DPU_HW_MAJOR_MINOR((rev2)))
>>>>>>>>>>>>> +
>>>>>>>>>>>>> +#define DPU_HW_VER_300 DPU_HW_VER(3, 0, 0) /* 8998 v1.0 */
>>>>>>>>>>>>> +#define DPU_HW_VER_400 DPU_HW_VER(4, 0, 0) /* sdm845 v1.0 */
>>>>>>>>>>>>> +#define DPU_HW_VER_500 DPU_HW_VER(5, 0, 0) /* sm8150 v1.0 */
>>>>>>>>>>>>> +#define DPU_HW_VER_510 DPU_HW_VER(5, 1, 1) /* sc8180 */
>>>>>>>>>>>>> +#define DPU_HW_VER_600 DPU_HW_VER(6, 0, 0) /* sm8250 */
>>>>>>>>>>>>> +#define DPU_HW_VER_620 DPU_HW_VER(6, 2, 0) /* sc7180 v1.0 */
>>>>>>>>>>>>> +#define DPU_HW_VER_630 DPU_HW_VER(6, 3, 0) /* 
>>>>>>>>>>>>> sm6115|sm4250 */
>>>>>>>>>>>>> +#define DPU_HW_VER_650 DPU_HW_VER(6, 5, 0) /* 
>>>>>>>>>>>>> qcm2290|sm4125 */
>>>>>>>>>>>>> +#define DPU_HW_VER_700 DPU_HW_VER(7, 0, 0) /* sm8350 */
>>>>>>>>>>>>> +#define DPU_HW_VER_720 DPU_HW_VER(7, 2, 0) /* sc7280 */
>>>>>>>>>>>>> +#define DPU_HW_VER_800 DPU_HW_VER(8, 0, 0) /* sc8280xp */
>>>>>>>>>>>>> +#define DPU_HW_VER_810 DPU_HW_VER(8, 1, 0) /* sm8450 */
>>>>>>>>>>>>> +#define DPU_HW_VER_900 DPU_HW_VER(9, 0, 0) /* sm8550 */
>>>>>>>>>>>>
>>>>>>>>>>>> Instead of having defines for all SoCs (which can quickly 
>>>>>>>>>>>> become
>>>>>>>>>>>> unmanageable) and can cause merge conflicts, I'd suggest 
>>>>>>>>>>>> inlining
>>>>>>>>>>>> all
>>>>>>>>>>>> the defines into respective catalog files.
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Sure, that can be done.
>>>>>>>>>>>
>>>>>>>>>>>> Also, I'm not sure that the "step" should be a part of the
>>>>>>>>>>>> catalog. I
>>>>>>>>>>>> know that this follows the hardware revision. However, please
>>>>>>>>>>>> correct
>>>>>>>>>>>> me if I'm wrong, different step levels are used for 
>>>>>>>>>>>> revisions of the
>>>>>>>>>>>> same SoC. The original code that was reading the hw revision 
>>>>>>>>>>>> from
>>>>>>>>>>>> the
>>>>>>>>>>>> hardware register, listed both 5.0.0 and 5.0.1 for sm8150.
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> This is one of the things i noticed while making this change.
>>>>>>>>>>>
>>>>>>>>>>> Before the catalog rework, we used to handle even steps as we 
>>>>>>>>>>> used
>>>>>>>>>>> to read that from the register and match it with the mdss_cfg
>>>>>>>>>>> handler. But after the rework, we dont handle steps anymore. 
>>>>>>>>>>> Yes,
>>>>>>>>>>> you are right that different step levels are used for the
>>>>>>>>>>> revisions of the same SOC and so with that, i dont expect or
>>>>>>>>>>> atleast am not aware of DPU differences between steps but I 
>>>>>>>>>>> am not
>>>>>>>>>>> able to rule it out.
>>>>>>>>>>>
>>>>>>>>>>> So are you suggesting we drop step altogether and DPU_HW_VER()
>>>>>>>>>>> macro shall only handle major and minor versions? With the 
>>>>>>>>>>> current
>>>>>>>>>>> chipsets I see, it should not make a difference . Its just 
>>>>>>>>>>> that I
>>>>>>>>>>> am not sure if that will never happen.
>>>>>>>>>>
>>>>>>>>>> Yes. The goal of this rework would be to drop generic features 
>>>>>>>>>> and
>>>>>>>>>> to replace those checks with DPU-revision lookups. Correct?
>>>>>>>>>
>>>>>>>>> Yes thats right.
>>>>>>>>>
>>>>>>>>>> I think that from this perspective having to handle toe step
>>>>>>>>>> revision is a sign of an overkill. Having to handle the step
>>>>>>>>>> revision is a sign of paltform feature (or mis-feature) rather 
>>>>>>>>>> than
>>>>>>>>>> a generic DPU bit.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Not entirely. Lets not forget that at the moment even dpu_perf_cfg
>>>>>>>>> is part of the catalog. Even if in terms of major HW blocks steps
>>>>>>>>> shouldnt change, there is absolutely no guarantee that perf data
>>>>>>>>> cannot.
>>>>>>>>>
>>>>>>>>> This is what is the sticking point for me which is holding me back
>>>>>>>>> against dropping step. Thoughts?
>>>>>>>>
>>>>>>>> We usually do not support ES versions of the chips, only the final
>>>>>>>> version. So supporting the perf data for earlier revisions is also
>>>>>>>> not required.
>>>>>>>>
>>>>>>>
>>>>>>> ack, we will drop step in that case. and good to know about the ES
>>>>>>> versions.
>>>>>>>
>>>>>>>>>
>>>>>>>>>> In fact I suppose that even handling a minor revision would be an
>>>>>>>>>> overkill. Why don't we start with .dpu_major instead of 
>>>>>>>>>> .core_rev?
>>>>>>>>>> We can add .dpu_minor if/when required.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> No, unfortunately we cannot drop minor version for sure. I am 
>>>>>>>>> seeing
>>>>>>>>> examples in downstream code where some of the features are 
>>>>>>>>> available
>>>>>>>>> after a minor verion as well.
>>>>>>>>
>>>>>>>> Can you please give an example?
>>>>>>>>
>>>>>>>
>>>>>>> Yes, watchdog timer, intf reset counter are available only after DPU
>>>>>>> HW version 8.1 (not major version 8).
>>>>>>
>>>>>> Hmm, IIRC, wd timer was available for ages. Was it moved together 
>>>>>> with
>>>>>> the introduction of MDSS_PERIPH_0_REMOVED?
>>>>>>
>>>>>
>>>>> I am not sure of the timeline but its certainly tied to 8.1.
>>>>>
>>>>>> But anyway, I see your point. Let's have major and minor. I'd 
>>>>>> probably
>>>>>> still ask for the separate major and minor fields, if you don't mind.
>>>>>>
>>>>>
>>>>> hmmm so something like this?
>>>>>
>>>>> +#define DPU_HW_VER_300 DPU_HW_VER(3, 0) /* 8998 v1.0 */
>>>>>
>>>>> const struct dpu_mdss_cfg dpu_msm8998_cfg = {
>>>>> .......
>>>>> .dpu_major_rev = DPU_HW_MAJOR(DPU_HW_VER_300),
>>>>> .dpu_minor_rev = DPU_HW_MINOR(DPU_HW_VER_300)
>>>>
>>>> Just:
>>>>
>>>> const struct dpu_mdss_cfg dpu_msm8998_cfg = {
>>>>      .dpu_major_rev = 3,
>>>>      .dpu_minor_rev = 0,
>>>>      /* .... */
>>>> };
>>>>
>>>> We do not need a single enumeration of all the versions. It can easily
>>>> become a source of merge conflicts.
>>>>
>>>
>>> The issue with this approch is then the DPU_HW_VER_xxx macros become 
>>> redundant but we should keep them. Because in the code, its much more 
>>> readable to have
>>>
>>> if (core_rev > DPU_HW_MAJOR(DPU_HW_VER_xxx))
>>>      then enable feature;
>>>
>>> But now we will have to do
>>>
>>> if (dpu_major_rev > xxx && dpu_minor_ver > yyy)
>>>      then enable feature;
>>>
>>> /// probably folks will question this xxx and yyy as to what it means.
>>
>> The first approach is less readable. It will require anybody to check, 
>> what is the major/minor of the mentioned XXX platform. In the second 
>> case we know exactly what we are looking for. E.g. we have new INTF 
>> interrupt addresses since 7.0. We have MDP_TOP_PERIPH0_REMOVED since 
>> 8.0 (or 8.1?) We have PP_TE until 5.0 (not included) and INTF_TE since 
>> 5.0.
>>
>> Having DPU_HW_VER_foo, I'd have to look up each time, what is the HW 
>> revision of sm8350, sc8280xp, sm8150, etc.
>>
> 
> Agreed, it will avoid one extra lookup but are you comfortable with a 
> hard-coded number in the code? So for example.
> 
> if (dpu_major_rev > 0x3 && dpu_minor_ver > 0x5)
>      enable feature;
> 
> Is this acceptable more than having to lookup?

Yes, definitely.

Note that this is not a correct condition for what you have meant.

> 
> Thats my only concern.

-- 
With best wishes
Dmitry