[PATCH v4 07/25] iommu/mtk_iommu_v1: Implement an IDENTITY domain

[Jason Gunthorpe]

What mtk does during mtk_iommu_v1_set_platform_dma() is actually putting
the iommu into identity mode. Make this available as a proper IDENTITY
domain.

The mtk_iommu_v1_def_domain_type() from
commit 8bbe13f52cb7 ("iommu/mediatek-v1: Add def_domain_type") explains
this was needed to allow probe_finalize() to be called, but now the
IDENTITY domain will do the same job so change the returned
def_domain_type.

mkt_v1 is the only driver that returns IOMMU_DOMAIN_UNMANAGED from
def_domain_type().  This allows the next patch to enforce an IDENTITY
domain policy for this driver.

Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
---
 drivers/iommu/mtk_iommu_v1.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index 8a0a5e5d049f4a..cc3e7d53d33ad9 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -319,11 +319,27 @@ static int mtk_iommu_v1_attach_device(struct iommu_domain 
*domain, struct device
        return 0;
 }
 
-static void mtk_iommu_v1_set_platform_dma(struct device *dev)
+static int mtk_iommu_v1_identity_attach(struct iommu_domain *identity_domain,
+                                       struct device *dev)
 {
        struct mtk_iommu_v1_data *data = dev_iommu_priv_get(dev);
 
        mtk_iommu_v1_config(data, dev, false);
+       return 0;
+}
+
+static struct iommu_domain_ops mtk_iommu_v1_identity_ops = {
+       .attach_dev = mtk_iommu_v1_identity_attach,
+};
+
+static struct iommu_domain mtk_iommu_v1_identity_domain = {
+       .type = IOMMU_DOMAIN_IDENTITY,
+       .ops = &mtk_iommu_v1_identity_ops,
+};
+
+static void mtk_iommu_v1_set_platform_dma(struct device *dev)
+{
+       mtk_iommu_v1_identity_attach(&mtk_iommu_v1_identity_domain, dev);
 }
 
 static int mtk_iommu_v1_map(struct iommu_domain *domain, unsigned long iova,
@@ -443,7 +459,7 @@ static int mtk_iommu_v1_create_mapping(struct device *dev, 
struct of_phandle_arg
 
 static int mtk_iommu_v1_def_domain_type(struct device *dev)
 {
-       return IOMMU_DOMAIN_UNMANAGED;
+       return IOMMU_DOMAIN_IDENTITY;
 }
 
 static struct iommu_device *mtk_iommu_v1_probe_device(struct device *dev)
@@ -578,6 +594,7 @@ static int mtk_iommu_v1_hw_init(const struct 
mtk_iommu_v1_data *data)
 }
 
 static const struct iommu_ops mtk_iommu_v1_ops = {
+       .identity_domain = &mtk_iommu_v1_identity_domain,
        .domain_alloc   = mtk_iommu_v1_domain_alloc,
        .probe_device   = mtk_iommu_v1_probe_device,
        .probe_finalize = mtk_iommu_v1_probe_finalize,
-- 
2.40.1