Re: [PATCH v2] iommu/rockchip: Add missing set_platform_dma_ops callback
From: Steven Price <steven.price@arm.com>
Date: 2023-03-24 13:24:57
Also in:
linux-iommu, linux-rockchip, lkml
On 24/03/2023 13:16, Baolu Lu wrote:
On 2023/3/24 19:11, Steven Price wrote:quoted
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.cb/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/ (local) Steve
Best regards, baolu
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