On Mon, Mar 27, 2023 at 03:35:04PM +0100, John Keeping wrote:

On Fri, Mar 24, 2023 at 11:11:27AM +0000, 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.c b/drivers/iommu/rockchip-iommu.c
index f30db22ea5d7..437541004994 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c

[snip]

quoted

+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.

set_platform_dma_ops is never called on ARM64.

Not shown in the patch are the pm_runtime hooks.  Do they need to
change like this?

Most likely yes

Jason

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