linux-kernel - Re: [PATCH v5 07/14] drivers: acpi: iort: add support for ARM SMMU platform devices creation

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Date:   Tue, 13 Sep 2016 16:48:15 +0800
From:   Hanjun Guo <hanjun.guo@...aro.org>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Cc:     nwatters@...eaurora.org, iommu@...ts.linux-foundation.org,
        Tomasz Nowicki <tn@...ihalf.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Will Deacon <will.deacon@....com>,
        Marc Zyngier <marc.zyngier@....com>,
        Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>, Jon Masters <jcm@...hat.com>,
        Eric Auger <eric.auger@...hat.com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Prem Mallappa <prem.mallappa@...adcom.com>,
        Dennis Chen <dennis.chen@....com>, linux-acpi@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v5 07/14] drivers: acpi: iort: add support for ARM SMMU
 platform devices creation

On 2016/9/13 16:24, Lorenzo Pieralisi wrote:
> On Tue, Sep 13, 2016 at 04:15:31PM +0800, Hanjun Guo wrote:
>
> [...]
>
>>>> +static acpi_status __init iort_match_iommu_callback(struct
>>>> acpi_iort_node *node,
>>>> +                            void *context)
>>>> +{
>>>> +    int ret;
>>>> +    struct fwnode_handle *fwnode;
>>>> +
>>>> +    fwnode = iort_get_fwnode(node);
>>>> +
>>>> +    if (!fwnode)
>>>> +        return AE_NOT_FOUND;
>>>> +
>>>> +    ret = iort_add_smmu_platform_device(fwnode, node);
>>>> +    if (ret) {
>>>> +        pr_err("Error in platform device creation\n");
>>>> +        return AE_ERROR;
>>>> +    }
>>>> +
>>>> +    return AE_OK;
>>>> +}
>>>> +
>>>> +static void __init iort_smmu_init(void)
>>>> +{
>>>> +    iort_scan_node(ACPI_IORT_NODE_SMMU, iort_match_iommu_callback,
>>>> NULL);
>>>> +    iort_scan_node(ACPI_IORT_NODE_SMMU_V3, iort_match_iommu_callback,
>>>> NULL);
>>>
>>> Since iort_scan_node() returns after the first successful match it finds,
>>> only the first SMMU_V3 in my IORT is being enumerated. I think you need
>>> to go back to the "iterator" like approach you had been using or make
>>> iort_match_iommu_callback() always return a non-AE_OK value so the scan
>>> continues and has a chance to visit all of the SMMU_V3 nodes.
>>
>> Please use the updated version of IORT patch (aka Tomasz's v11)
>> then things will work fine.
>
> Nate is right, I was too keen on using iort_scan_node(), it does
> not really work here (unless as he said I return a value !AE_OK in
> the callback, which is horrible), I reverted back to the iterator
> approach and I can push out a fixed up branch if useful before next
> posting.

Ah, sorry, I just noticed "the first SMMU_V3" which is pretty similar
with the second problem which is noticed by Nate...

Thanks
Hanjun