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From:   Heiko =?ISO-8859-1?Q?St=FCbner?= <heiko@sntech.de>
To:     Joerg Roedel <joro@8bytes.org>, Jason Gunthorpe <jgg@ziepe.ca>,
        Steven Price <steven.price@arm.com>
Cc:     Steven Price <steven.price@arm.com>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>, iommu@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-rockchip@lists.infradead.org,
        John Keeping <john@metanate.com>
Subject: Re: [PATCH v4] iommu/rockchip: Add missing set_platform_dma_ops callback
Date:   Fri, 31 Mar 2023 23:49:03 +0200
Message-ID: <2077066.bB369e8A3T@diego>
In-Reply-To: <20230331095154.2671129-1-steven.price@arm.com>
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Am Freitag, 31. März 2023, 11:51:54 CEST schrieb Steven Price:
> Similar to exynos, we need a set_platform_dma_ops() callback for proper
> operation on ARM 32 bit after recent changes in the IOMMU framework
> (detach ops removal). But also the use of a NULL domain is confusing.
> 
> Rework the code to add support for IOMMU_DOMAIN_IDENTITY and a singleton
> rk_identity_domain which is assigned to domain when using an identity
> mapping rather than "detaching". This makes the code easier to reason about.
> 
> Signed-off-by: Steven Price <steven.price@arm.com>

My knowledge of IOMMU magic is not that deep. Nevertheless I do believe
to mostly understand the change and the splats on my rk3288-pinky are gone
now with this patch:

Acked-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>