linux-kernel - Re: [PATCH v4 2/3] remoteproc: qcom: pas: make region assign more generic

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Message-ID: <b4b0ed80-eed5-4045-8ceb-5b507c77e4e2@linaro.org>
Date:   Mon, 11 Dec 2023 10:54:32 +0100
From:   Konrad Dybcio <konrad.dybcio@...aro.org>
To:     neil.armstrong@...aro.org, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Manivannan Sadhasivam <mani@...nel.org>
Cc:     linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Mukesh Ojha <quic_mojha@...cinc.com>
Subject: Re: [PATCH v4 2/3] remoteproc: qcom: pas: make region assign more
 generic

On 11.12.2023 10:37, Neil Armstrong wrote:
> On 09/12/2023 19:06, Konrad Dybcio wrote:
>> On 8.12.2023 16:04, Neil Armstrong wrote:
>>> The current memory region assign only supports a single
>>> memory region.
>>>
>>> But new platforms introduces more regions to make the
>>> memory requirements more flexible for various use cases.
>>> Those new platforms also shares the memory region between the
>>> DSP and HLOS.
>>>
>>> To handle this, make the region assign more generic in order
>>> to support more than a single memory region and also permit
>>> setting the regions permissions as shared.
>>>
>>> Reviewed-by: Mukesh Ojha <quic_mojha@...cinc.com>
>>> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
>>> ---
>> [...]
>>
>>> +    for (offset = 0; offset < adsp->region_assign_count; ++offset) {
>>> +        struct reserved_mem *rmem = NULL;
>>> +
>>> +        node = of_parse_phandle(adsp->dev->of_node, "memory-region",
>>> +                    adsp->region_assign_idx + offset);
>>> +        if (node)
>>> +            rmem = of_reserved_mem_lookup(node);
>>> +        of_node_put(node);
>> Shouldn't this only be called when parse_phandle succeeds? (separate
>> patch with a fix + cc stable if so?)
> 
> It's not a bug, it was added like that because of_node_put() already
> checks for a NULL pointer:
> https://elixir.bootlin.com/linux/v6.7-rc5/source/drivers/of/dynamic.c#L45
Ack

> 
>>
>>> +        if (!rmem) {
>>> +            dev_err(adsp->dev, "unable to resolve shareable memory-region index %d\n",
>>> +                offset);
>>> +            return -EINVAL;
>>> +        }
>>>   -    perm.vmid = QCOM_SCM_VMID_MSS_MSA;
>>> -    perm.perm = QCOM_SCM_PERM_RW;
>>> +        if (adsp->region_assign_shared)  {
>>> +            perm[0].vmid = QCOM_SCM_VMID_HLOS;
>>> +            perm[0].perm = QCOM_SCM_PERM_RW;
>>> +            perm[1].vmid = adsp->region_assign_vmid;
>>> +            perm[1].perm = QCOM_SCM_PERM_RW;
>>> +            perm_size = 2;
>>> +        } else {
>>> +            perm[0].vmid = adsp->region_assign_vmid;
>>> +            perm[0].perm = QCOM_SCM_PERM_RW;
>>> +            perm_size = 1;
>>> +        }
>>>   -    adsp->region_assign_phys = rmem->base;
>>> -    adsp->region_assign_size = rmem->size;
>>> -    adsp->region_assign_perms = BIT(QCOM_SCM_VMID_HLOS);
>>> +        adsp->region_assign_phys[offset] = rmem->base;
>>> +        adsp->region_assign_size[offset] = rmem->size;
>>> +        adsp->region_assign_perms[offset] = BIT(QCOM_SCM_VMID_HLOS);
>>>   -    ret = qcom_scm_assign_mem(adsp->region_assign_phys,
>>> -                  adsp->region_assign_size,
>>> -                  &adsp->region_assign_perms,
>> I think this should be renamed to region_assign_owner(s)
> 
> Why ? this bitfield is names "perms" everywhere qcom_scm_assign_mem is used
And IMO that's not correct - there's the qcom_scm_vmperm.perm field which
is oneOf r/w/x/rw/rwx and this one is filled with ORed BIT()-ed elements
allowed in qcom_scm_vmperm.vmid (QCOM_SCM_VMID_...)

Konrad