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

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Date:   Mon, 11 Dec 2023 12:19:37 +0100
From:   neil.armstrong@...aro.org
To:     Konrad Dybcio <konrad.dybcio@...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 10:54, Konrad Dybcio wrote:
> 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_...)

Ok right I just use the same namings as in rmtfs_mem, fastrpc & ath10k/qmi,
but indeed the qcom_scm_assign_mem() 3rd param name is srcvm but doc says "vmid for current set of owners",
so yeah it could be named owners.

I'll send a v5 with the rename.

Neil


> 
> Konrad