[PATCH v2 13/23] accel/habanalabs: Use the SGT_P2P mapping type

[Alistair Popple]

From: Jason Gunthorpe <jgg at nvidia.com>

habana has special code to check pci_p2pdma_distance() and rejects any
importer that cannot do P2P DMA to its MMIO.

Convert this directly to a SGT_P2P match which does the same check
inside the matching logic.

Someday this should be converted to use dma_buf_phys_vec_to_sgt() which
does the P2P checking correctly, for both direct and IOMMU based cases,
instead of this hack.

Remove the now empty attach function.

Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
Signed-off-by: Alistair Popple <apopple at nvidia.com>
---
 drivers/accel/habanalabs/common/memory.c | 54 ++++++++++++++------------------
 1 file changed, 24 insertions(+), 30 deletions(-)

diff --git a/drivers/accel/habanalabs/common/memory.c b/drivers/accel/habanalabs/common/memory.c
index 361cff577381..6745af1328c1 100644
--- a/drivers/accel/habanalabs/common/memory.c
+++ b/drivers/accel/habanalabs/common/memory.c
@@ -9,10 +9,10 @@
 #include "habanalabs.h"
 #include "../include/hw_ip/mmu/mmu_general.h"
 
+#include <linux/dma-buf-mapping.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
-#include <linux/pci-p2pdma.h>
 
 MODULE_IMPORT_NS("DMA_BUF");
 
@@ -1704,23 +1704,6 @@ static struct sg_table *alloc_sgt_from_device_pages(struct hl_device *hdev, u64
 	return ERR_PTR(rc);
 }
 
-static int hl_dmabuf_attach(struct dma_buf *dmabuf,
-				struct dma_buf_attachment *attachment)
-{
-	struct hl_dmabuf_priv *hl_dmabuf;
-	struct hl_device *hdev;
-	int rc;
-
-	hl_dmabuf = dmabuf->priv;
-	hdev = hl_dmabuf->ctx->hdev;
-
-	rc = pci_p2pdma_distance(hdev->pdev, attachment->dev, true);
-
-	if (rc < 0)
-		attachment->peer2peer = false;
-	return 0;
-}
-
 static struct sg_table *hl_map_dmabuf(struct dma_buf_attachment *attachment,
 					enum dma_data_direction dir)
 {
@@ -1734,11 +1717,6 @@ static struct sg_table *hl_map_dmabuf(struct dma_buf_attachment *attachment,
 	hl_dmabuf = dma_buf->priv;
 	hdev = hl_dmabuf->ctx->hdev;
 
-	if (!attachment->peer2peer) {
-		dev_dbg(hdev->dev, "Failed to map dmabuf because p2p is disabled\n");
-		return ERR_PTR(-EPERM);
-	}
-
 	exported_size = hl_dmabuf->dmabuf->size;
 	offset = hl_dmabuf->offset;
 	phys_pg_pack = hl_dmabuf->phys_pg_pack;
@@ -1753,8 +1731,10 @@ static struct sg_table *hl_map_dmabuf(struct dma_buf_attachment *attachment,
 		page_size = hl_dmabuf->dmabuf->size;
 	}
 
-	sgt = alloc_sgt_from_device_pages(hdev, pages, npages, page_size, exported_size, offset,
-						attachment->dev, dir);
+	sgt = alloc_sgt_from_device_pages(hdev, pages, npages, page_size,
+					  exported_size, offset,
+					  dma_buf_sgt_dma_device(attachment),
+					  dir);
 	if (IS_ERR(sgt))
 		dev_err(hdev->dev, "failed (%ld) to initialize sgt for dmabuf\n", PTR_ERR(sgt));
 
@@ -1776,9 +1756,9 @@ static void hl_unmap_dmabuf(struct dma_buf_attachment *attachment,
 	 * a sync of the memory to the CPU's cache, as it never resided inside that cache.
 	 */
 	for_each_sgtable_dma_sg(sgt, sg, i)
-		dma_unmap_resource(attachment->dev, sg_dma_address(sg),
-					sg_dma_len(sg), dir,
-					DMA_ATTR_SKIP_CPU_SYNC);
+		dma_unmap_resource(dma_buf_sgt_dma_device(attachment),
+				   sg_dma_address(sg), sg_dma_len(sg), dir,
+				   DMA_ATTR_SKIP_CPU_SYNC);
 
 	/* Need to restore orig_nents because sg_free_table use that field */
 	sgt->orig_nents = sgt->nents;
@@ -1848,11 +1828,25 @@ static void hl_release_dmabuf(struct dma_buf *dmabuf)
 	kfree(hl_dmabuf);
 }
 
-static const struct dma_buf_ops habanalabs_dmabuf_ops = {
-	.attach = hl_dmabuf_attach,
+static const struct dma_buf_mapping_sgt_exp_ops hl_dma_buf_sgt_ops = {
 	.map_dma_buf = hl_map_dmabuf,
 	.unmap_dma_buf = hl_unmap_dmabuf,
+};
+
+static int hl_match_mapping(struct dma_buf_match_args *args)
+{
+	struct hl_dmabuf_priv *hl_dmabuf = args->dmabuf->priv;
+	struct dma_buf_mapping_match sgt_match[] = {
+		DMA_BUF_EMAPPING_SGT_P2P(&hl_dma_buf_sgt_ops,
+					 hl_dmabuf->ctx->hdev->pdev),
+	};
+
+	return dma_buf_match_mapping(args, sgt_match, ARRAY_SIZE(sgt_match));
+}
+
+static const struct dma_buf_ops habanalabs_dmabuf_ops = {
 	.release = hl_release_dmabuf,
+	.match_mapping = hl_match_mapping,
 };
 
 static int export_dmabuf(struct hl_ctx *ctx,

-- 
2.54.0