Thread (8 messages) flat view 8 messages, 4 authors, 2023-03-30

Re: [PATCH v2] iommu/rockchip: Add missing set_platform_dma_ops callback

From: John Keeping <hidden>
Date: 2023-03-27 14:35:45
Also in: linux-iommu, linux-rockchip, lkml

On Fri, Mar 24, 2023 at 11:11:27AM +0000, Steven Price wrote:
quoted hunk ↗ jump to hunk
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
[snip]
+static struct iommu_domain rk_identity_domain = {
+	.type = IOMMU_DOMAIN_IDENTITY,
+	.ops = &rk_identity_ops,
+};
+
+#ifdef CONFIG_ARM
Is this #ifdef needed?  I can't see anything ARM-specific about this
function or .set_platform_dma_ops.
+static void rk_iommu_set_platform_dma(struct device *dev)
+{
+	WARN_ON(rk_iommu_identity_attach(&rk_identity_domain, dev));
 }
+#endif
Not shown in the patch are the pm_runtime hooks.  Do they need to
change like this?

 static int __maybe_unused rk_iommu_suspend(struct device *dev)
 {
 	struct rk_iommu *iommu = dev_get_drvdata(dev);
 
-	if (!iommu->domain)
+	if (iommu->domain == &rk_identity_domain)
 		return 0;
 
 	rk_iommu_disable(iommu);
 	return 0;
 }
 
 static int __maybe_unused rk_iommu_resume(struct device *dev)
 {
 	struct rk_iommu *iommu = dev_get_drvdata(dev);
 
-	if (!iommu->domain)
+	if (iommu->domain == &rk_identity_domain)
 		return 0;
 
 	return rk_iommu_enable(iommu);
 }

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