[RFC 5/8] drm/xe/dma_buf: Add support for IOV interconnect

[Vivek Kasireddy <vivek.kasireddy@intel.com>]

Provide an op for supports_interconnects() to indicate to the
dma-buf core and to the exporter that Xe supports interconnects.
Note that Xe would support IOV interconnect only if the buffer
is located in LMEM region.

Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 drivers/gpu/drm/xe/xe_dma_buf.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_dma_buf.c b/drivers/gpu/drm/xe/xe_dma_buf.c
index a7d67725c3ee..2d63dd86a249 100644
--- a/drivers/gpu/drm/xe/xe_dma_buf.c
+++ b/drivers/gpu/drm/xe/xe_dma_buf.c
@@ -13,6 +13,7 @@
 #include <drm/drm_prime.h>
 #include <drm/ttm/ttm_tt.h>
 
+#include "regs/xe_bars.h"
 #include "tests/xe_test.h"
 #include "xe_bo.h"
 #include "xe_device.h"
@@ -274,9 +275,25 @@ static void xe_dma_buf_move_notify(struct dma_buf_attachment *attach)
 	XE_WARN_ON(xe_bo_evict(bo, exec));
 }
 
+static bool
+xe_dma_buf_supports_interconnects(struct dma_buf_attachment *attach,
+				  const struct dma_buf_interconnect_match *exp,
+				  unsigned int exp_ics)
+{
+	struct pci_dev *pdev = to_pci_dev(attach->dev);
+	unsigned int bar = LMEM_BAR;
+	const struct dma_buf_interconnect_match supports_ics[] = {
+		CREATE_IOV_INTERCONNECT(pdev, bar),
+	};
+
+	return dma_buf_match_interconnects(attach, exp, exp_ics, supports_ics,
+					   ARRAY_SIZE(supports_ics));
+}
+
 static const struct dma_buf_attach_ops xe_dma_buf_attach_ops = {
 	.allow_peer2peer = true,
-	.move_notify = xe_dma_buf_move_notify
+	.move_notify = xe_dma_buf_move_notify,
+	.supports_interconnects = xe_dma_buf_supports_interconnects,
 };
 
 #if IS_ENABLED(CONFIG_DRM_XE_KUNIT_TEST)
-- 
2.50.1