Subject: [PATCH v1 3/6] drm/msm/adreno: ADd support for IOMMU auxiliary domains

From: Jordan Crouse <[email-masked]>
Date: Tue, 28 Jan 2020 15:16:07 -0700

Add support for creating a auxiliary domain from the IOMMU device to
implement per-instance pagetables. Also add a helper function to
return the pagetable base address (ttbr) and asid to the caller so
that the GPU target code can set up the pagetable switch.

Signed-off-by: Jordan Crouse <[email-masked]>
---

 drivers/gpu/drm/msm/msm_iommu.c | 72 +++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/msm_mmu.h   |  3 ++
 2 files changed, 75 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_iommu.c b/drivers/gpu/drm/msm/msm_iommu.c
index e773ef8..df0d70a 100644
--- a/drivers/gpu/drm/msm/msm_iommu.c
+++ b/drivers/gpu/drm/msm/msm_iommu.c
@@ -7,9 +7,17 @@
 #include "msm_drv.h"
 #include "msm_mmu.h"
 
+/*
+ * It is up to us to assign ASIDS for our instances. Start at 32 to give a
+ * cushion to account for ASIDS assigned to real context banks
+ */
+static int msm_iommu_asid = 32;
+
 struct msm_iommu {
 	struct msm_mmu base;
 	struct iommu_domain *domain;
+	u64 ttbr;
+	int asid;
 };
 #define to_msm_iommu(x) container_of(x, struct msm_iommu, base)
 
@@ -58,6 +66,20 @@ static void msm_iommu_destroy(struct msm_mmu *mmu)
 	kfree(iommu);
 }
 
+static void msm_iommu_aux_detach(struct msm_mmu *mmu)
+{
+	struct msm_iommu *iommu = to_msm_iommu(mmu);
+
+	iommu_aux_detach_device(iommu->domain, mmu->dev);
+}
+
+static const struct msm_mmu_funcs aux_funcs = {
+		.detach = msm_iommu_aux_detach,
+		.map = msm_iommu_map,
+		.unmap = msm_iommu_unmap,
+		.destroy = msm_iommu_destroy,
+};
+
 static const struct msm_mmu_funcs funcs = {
 		.detach = msm_iommu_detach,
 		.map = msm_iommu_map,
@@ -65,6 +87,56 @@ static const struct msm_mmu_funcs funcs = {
 		.destroy = msm_iommu_destroy,
 };
 
+bool msm_iommu_get_ptinfo(struct msm_mmu *mmu, u64 *ttbr, u32 *asid)
+{
+	struct msm_iommu *iommu = to_msm_iommu(mmu);
+
+	if (!iommu->ttbr)
+		return false;
+
+	if (ttbr)
+		*ttbr = iommu->ttbr;
+	if (asid)
+		*asid = iommu->asid;
+
+	return true;
+}
+
+struct msm_mmu *msm_iommu_new_instance(struct device *dev,
+		struct iommu_domain *domain)
+{
+	struct msm_iommu *iommu;
+	u64 ptbase;
+	int ret;
+
+	ret = iommu_aux_attach_device(domain, dev);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = iommu_domain_get_attr(domain, DOMAIN_ATTR_PTBASE, &ptbase);
+	if (ret) {
+		iommu_aux_detach_device(domain, dev);
+		return ERR_PTR(ret);
+	}
+
+	iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
+	if (!iommu) {
+		iommu_aux_detach_device(domain, dev);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	iommu->domain = domain;
+	iommu->ttbr = ptbase;
+	iommu->asid = msm_iommu_asid++;
+
+	if (msm_iommu_asid > 0xff)
+		msm_iommu_asid = 32;
+
+	msm_mmu_init(&iommu->base, dev, &aux_funcs);
+
+	return &iommu->base;
+}
+
 struct msm_mmu *msm_iommu_new(struct device *dev, struct iommu_domain *domain)
 {
 	struct msm_iommu *iommu;
diff --git a/drivers/gpu/drm/msm/msm_mmu.h b/drivers/gpu/drm/msm/msm_mmu.h
index bae9e8e..65a5cb2 100644
--- a/drivers/gpu/drm/msm/msm_mmu.h
+++ b/drivers/gpu/drm/msm/msm_mmu.h
@@ -32,6 +32,9 @@ static inline void msm_mmu_init(struct msm_mmu *mmu, struct device *dev,
 }
 
 struct msm_mmu *msm_iommu_new(struct device *dev, struct iommu_domain *domain);
+struct msm_mmu *msm_iommu_new_instance(struct device *dev,
+		struct iommu_domain *domain);
+bool msm_iommu_get_ptinfo(struct msm_mmu *mmu, u64 *ttbr, u32 *asid);
 struct msm_mmu *msm_gpummu_new(struct device *dev, struct msm_gpu *gpu);
 
 static inline void msm_mmu_set_fault_handler(struct msm_mmu *mmu, void *arg,
-- 
2.7.4

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