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Subject: Re: [PATCH V3 1/2] ACPI / scan: Support multiple dma windows with
 different offsets
To:     Robin Murphy <robin.murphy@arm.com>, lpieralisi@kernel.org,
        chenhuacai@loongson.cn
Cc:     guohanjun@huawei.com, sudeep.holla@arm.com, rafael@kernel.org,
        lenb@kernel.org, robert.moore@intel.com,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        loongarch@lists.linux.dev
References: <20220830030139.29899-1-lvjianmin@loongson.cn>
 <20220830030139.29899-2-lvjianmin@loongson.cn>
 <435e1283-9ff6-f089-6436-3c31a178fd60@arm.com>
From:   Jianmin Lv <lvjianmin@loongson.cn>
Message-ID: <66baf6f8-0f18-e0a6-4ed4-e2f783497d2d@loongson.cn>
Date:   Tue, 6 Sep 2022 20:40:48 +0800
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On 2022/9/5 下午8:20, Robin Murphy wrote:
> On 2022-08-30 04:01, Jianmin Lv wrote:
>> For DT, of_dma_get_range returns bus_dma_region typed dma regions,
>> which makes multiple dma windows with different offset available
>> for translation between dma address and cpu address.
>>
>> But for ACPI, acpi_dma_get_range doesn't return similar dma regions,
>> causing no path for setting dev->dma_range_map conveniently. So the
>> patch changes acpi_dma_get_range and returns bus_dma_region typed
>> dma regions according to of_dma_get_range.
>>
>> After changing acpi_dma_get_range, acpi_arch_dma_setup is changed for
>> ARM64, where original dma_addr and size are removed as these
>> arguments are now redundant, and pass 0 and U64_MAX for dma_base
>> and size of arch_setup_dma_ops, so this is a simplification consistent
>> with what other ACPI architectures also pass to iommu_setup_dma_ops().
> 
> Other than a micro-nit that acpi_dma_get_range() could probably use 
> resource_size(),
> 

Ok, thanks, I'll use resource_size() in acpi_dma_get_range().

> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> 
> It took me longer than I care to admit to figure out where the implicit 
> declaration of struct bus_dma_region in the scope of acpi.h and 
> acpi_bus.h comes from, but in the end I guess it's sufficiently 
> well-defined by the C spec to be reliable.
> 
> Thanks for getting this done!
> 

It's a pleasure!


> Robin.
> 

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