linux-kernel - Re: [PATCH 04/10] gpu: host1x: Lock classes during job submission

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Message-ID: <dc39398b-ea49-6e97-28ba-652f8b49db44@gmail.com>
Date:   Wed, 8 Nov 2017 00:23:45 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Mikko Perttunen <cyndis@...si.fi>,
        Mikko Perttunen <mperttunen@...dia.com>,
        thierry.reding@...il.com, jonathanh@...dia.com
Cc:     dri-devel@...ts.freedesktop.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/10] gpu: host1x: Lock classes during job submission

On 07.11.2017 15:28, Mikko Perttunen wrote:
> On 05.11.2017 18:46, Dmitry Osipenko wrote:
>> On 05.11.2017 14:01, Mikko Perttunen wrote:
>>> ...
>>>
>>> +static int mlock_id_for_class(unsigned int class)
>>> +{
>>> +#if HOST1X_HW >= 6
>>> +    switch (class)
>>> +    {
>>> +    case HOST1X_CLASS_HOST1X:
>>> +        return 0;
>>> +    case HOST1X_CLASS_VIC:
>>> +        return 17;
>>
>> What is the meaning of returned ID values that you have defined here? Why VIC
>> should have different ID on T186?
> 
> On T186, MLOCKs are not "generic" - the HW knows that each MLOCK corresponds to
> a specific class. Therefore we must map that correctly.
> 

Okay.

>>
>>> +    default:
>>> +        return -EINVAL;
>>> +    }
>>> +#else
>>> +    switch (class)
>>> +    {
>>> +    case HOST1X_CLASS_HOST1X:
>>> +        return 0;
>>> +    case HOST1X_CLASS_GR2D:
>>> +        return 1;
>>> +    case HOST1X_CLASS_GR2D_SB:
>>> +        return 2;
>>
>> Note that we are allowing to switch 2d classes in the same jobs context and
>> currently jobs class is somewhat hardcoded to GR2D.
>>
>> Even though that GR2D and GR2D_SB use different register banks, is it okay to
>> trigger execution of different classes simultaneously? Would syncpoint
>> differentiate classes on OP_DONE event?
> 
> Good point, we might need to use the same lock for these two.
> 
>>
>> I suppose that MLOCK (the module lock) implies the whole module locking,
>> wouldn't it make sense to just use the module ID's defined in the TRM?
> 
> Can you point out where these are defined?

See INDMODID / REGF_MODULEID fields of HOST1X_CHANNEL_INDOFF2_0 /
HOST1X_SYNC_REGF_ADDR_0 registers, bit numbers of HOST1X_SYNC_INTSTATUS_0 /
HOST1X_SYNC_INTC0MASK_0 / HOST1X_SYNC_MOD_TEARDOWN_0.