Messages in this thread | | | Date | Fri, 24 Mar 2023 21:31:10 +0800 | Subject | Re: [PATCH v2] iommu/rockchip: Add missing set_platform_dma_ops callback | From | Baolu Lu <> |
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On 2023/3/24 21:24, Steven Price wrote: > On 24/03/2023 13:16, Baolu Lu wrote: >> On 2023/3/24 19:11, Steven Price wrote: >>> 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 have 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> >>> --- >>> Changes since v1[1]: >>> >>> * Reworked the code to avoid a NULL domain, instead a singleton >>> rk_identity_domain is used instead. The 'detach' language is no >>> longer used. >>> >>> [1] >>> https://lore.kernel.org/r/20230315164152.333251-1-steven.price%40arm.com >>> >>> drivers/iommu/rockchip-iommu.c | 50 ++++++++++++++++++++++++++-------- >>> 1 file changed, 39 insertions(+), 11 deletions(-) >>> >>> diff --git a/drivers/iommu/rockchip-iommu.c >>> b/drivers/iommu/rockchip-iommu.c >>> index f30db22ea5d7..437541004994 100644 >>> --- a/drivers/iommu/rockchip-iommu.c >>> +++ b/drivers/iommu/rockchip-iommu.c >>> @@ -124,6 +124,7 @@ struct rk_iommudata { >>> static struct device *dma_dev; >>> static const struct rk_iommu_ops *rk_ops; >>> +static struct iommu_domain rk_identity_domain; >>> static inline void rk_table_flush(struct rk_iommu_domain *dom, >>> dma_addr_t dma, >>> unsigned int count) >>> @@ -980,26 +981,27 @@ static int rk_iommu_enable(struct rk_iommu *iommu) >>> return ret; >>> } >>> -static void rk_iommu_detach_device(struct iommu_domain *domain, >>> - struct device *dev) >>> +static int rk_iommu_identity_attach(struct iommu_domain >>> *identity_domain, >>> + struct device *dev) >>> { >>> struct rk_iommu *iommu; >>> - struct rk_iommu_domain *rk_domain = to_rk_domain(domain); >>> + struct rk_iommu_domain *rk_domain; >>> unsigned long flags; >>> int ret; >>> /* Allow 'virtual devices' (eg drm) to detach from domain */ >>> iommu = rk_iommu_from_dev(dev); >>> if (!iommu) >>> - return; >>> + return -ENODEV; >>> + >>> + rk_domain = to_rk_domain(iommu->domain); >>> dev_dbg(dev, "Detaching from iommu domain\n"); >>> - /* iommu already detached */ >>> - if (iommu->domain != domain) >>> - return; >>> + if (iommu->domain == identity_domain) >>> + return 0; >>> - iommu->domain = NULL; >>> + iommu->domain = identity_domain; >> Where did identity_domain come from? Is it rk_identity_domain? > It's a parameter of the function. In the case of the call in > rk_iommu_attach_device() then, yes, it's rk_identity_domain. But this > function is also the "attach_dev" callback of "rk_identity_ops". > > I'll admit this is cargo-culted from Jason's example: > > https://lore.kernel.org/linux-iommu/ZBnef7g7GCxogPNz@ziepe.ca/
Oh! I overlooked that. Thank you for the explanation.
Best regards, baolu
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