gpu: host1x: Add IOMMU support

Add support for the Host1x unit to be located behind
an IOMMU. This is required when gather buffers may be
allocated non-contiguously in physical memory, as can
be the case when TegraDRM is also using the IOMMU.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 58 insertions, 16 deletions

diff --git a/drivers/gpu/host1x/cdma.c b/drivers/gpu/host1x/cdma.c
index c5d82a8a2ec9..28541b280739 100644
--- a/drivers/gpu/host1x/cdma.c
+++ b/drivers/gpu/host1x/cdma.c
@@ -51,9 +51,15 @@ static void host1x_pushbuffer_destroy(struct push_buffer *pb)
 	struct host1x_cdma *cdma = pb_to_cdma(pb);
 	struct host1x *host1x = cdma_to_host1x(cdma);
 
-	if (pb->phys != 0)
-		dma_free_wc(host1x->dev, pb->size_bytes + 4, pb->mapped,
-			    pb->phys);
+	if (!pb->phys)
+		return;
+
+	if (host1x->domain) {
+		iommu_unmap(host1x->domain, pb->dma, pb->alloc_size);
+		free_iova(&host1x->iova, iova_pfn(&host1x->iova, pb->dma));
+	}
+
+	dma_free_wc(host1x->dev, pb->alloc_size, pb->mapped, pb->phys);
 
 	pb->mapped = NULL;
 	pb->phys = 0;
@@ -66,28 +72,64 @@ static int host1x_pushbuffer_init(struct push_buffer *pb)
 {
 	struct host1x_cdma *cdma = pb_to_cdma(pb);
 	struct host1x *host1x = cdma_to_host1x(cdma);
+	struct iova *alloc;
+	u32 size;
+	int err;
 
 	pb->mapped = NULL;
 	pb->phys = 0;
-	pb->size_bytes = HOST1X_PUSHBUFFER_SLOTS * 8;
+	pb->size = HOST1X_PUSHBUFFER_SLOTS * 8;
+
+	size = pb->size + 4;
 
 	/* initialize buffer pointers */
-	pb->fence = pb->size_bytes - 8;
+	pb->fence = pb->size - 8;
 	pb->pos = 0;
 
-	/* allocate and map pushbuffer memory */
-	pb->mapped = dma_alloc_wc(host1x->dev, pb->size_bytes + 4, &pb->phys,
-				  GFP_KERNEL);
-	if (!pb->mapped)
-		goto fail;
+	if (host1x->domain) {
+		unsigned long shift;
+
+		size = iova_align(&host1x->iova, size);
+
+		pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
+					  GFP_KERNEL);
+		if (!pb->mapped)
+			return -ENOMEM;
+
+		shift = iova_shift(&host1x->iova);
+		alloc = alloc_iova(&host1x->iova, size >> shift,
+				   host1x->iova_end >> shift, true);
+		if (!alloc) {
+			err = -ENOMEM;
+			goto iommu_free_mem;
+		}
+
+		pb->dma = iova_dma_addr(&host1x->iova, alloc);
+		err = iommu_map(host1x->domain, pb->dma, pb->phys, size,
+				IOMMU_READ);
+		if (err)
+			goto iommu_free_iova;
+	} else {
+		pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
+					  GFP_KERNEL);
+		if (!pb->mapped)
+			return -ENOMEM;
+
+		pb->dma = pb->phys;
+	}
+
+	pb->alloc_size = size;
 
 	host1x_hw_pushbuffer_init(host1x, pb);
 
 	return 0;
 
-fail:
-	host1x_pushbuffer_destroy(pb);
-	return -ENOMEM;
+iommu_free_iova:
+	__free_iova(&host1x->iova, alloc);
+iommu_free_mem:
+	dma_free_wc(host1x->dev, pb->alloc_size, pb->mapped, pb->phys);
+
+	return err;
 }
 
 /*
@@ -101,7 +143,7 @@ static void host1x_pushbuffer_push(struct push_buffer *pb, u32 op1, u32 op2)
 	WARN_ON(pb->pos == pb->fence);
 	*(p++) = op1;
 	*(p++) = op2;
-	pb->pos = (pb->pos + 8) & (pb->size_bytes - 1);
+	pb->pos = (pb->pos + 8) & (pb->size - 1);
 }
 
 /*
@@ -111,7 +153,7 @@ static void host1x_pushbuffer_push(struct push_buffer *pb, u32 op1, u32 op2)
 static void host1x_pushbuffer_pop(struct push_buffer *pb, unsigned int slots)
 {
 	/* Advance the next write position */
-	pb->fence = (pb->fence + slots * 8) & (pb->size_bytes - 1);
+	pb->fence = (pb->fence + slots * 8) & (pb->size - 1);
 }
 
 /*
@@ -119,7 +161,7 @@ static void host1x_pushbuffer_pop(struct push_buffer *pb, unsigned int slots)
  */
 static u32 host1x_pushbuffer_space(struct push_buffer *pb)
 {
-	return ((pb->fence - pb->pos) & (pb->size_bytes - 1)) / 8;
+	return ((pb->fence - pb->pos) & (pb->size - 1)) / 8;
 }
 
 /*