accel/habanalabs/gaudi2: move HMMU page tables to device memory

Currently the HMMU page tables reside in the host memory,
which will cause host access from the device for every page walk.
This can affect PCIe bandwidth in certain scenarios.

To prevent that problem, HMMU page tables will be moved to the device
memory so the miss transaction will read the hops from there instead of
going to the host.

Signed-off-by: Farah Kassabri <fkassabri@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/accel/habanalabs/common/hw_queue.c b/drivers/accel/habanalabs/common/hw_queue.c
index d0087c0ec48c..3d04a7507cce 100644
--- a/drivers/accel/habanalabs/common/hw_queue.c
+++ b/drivers/accel/habanalabs/common/hw_queue.c
@@ -84,6 +84,8 @@ void hl_hw_queue_submit_bd(struct hl_device *hdev, struct hl_hw_queue *q,
 		u32 ctl, u32 len, u64 ptr)
 {
 	struct hl_bd *bd;
+	u64 addr;
+	int i;
 
 	bd = q->kernel_address;
 	bd += hl_pi_2_offset(q->pi);
@@ -91,7 +93,16 @@ void hl_hw_queue_submit_bd(struct hl_device *hdev, struct hl_hw_queue *q,
 	bd->len = cpu_to_le32(len);
 	bd->ptr = cpu_to_le64(ptr);
 
+	if (q->dram_bd)
+		for (i = 0 ; i < 2 ; i++) {
+			addr = q->pq_dram_address +
+			((hl_pi_2_offset(q->pi) * sizeof(struct hl_bd))	+ (i * sizeof(u64)));
+			hdev->asic_funcs->access_dev_mem(hdev, PCI_REGION_DRAM,	addr,
+						(u64 *)(bd) + i, DEBUGFS_WRITE64);
+		}
+
 	q->pi = hl_queue_inc_ptr(q->pi);
+
 	hdev->asic_funcs->ring_doorbell(hdev, q->hw_queue_id, q->pi);
 }
 
@@ -1087,12 +1098,18 @@ int hl_hw_queues_create(struct hl_device *hdev)
 		q->supports_sync_stream =
 				asic->hw_queues_props[i].supports_sync_stream;
 		q->collective_mode = asic->hw_queues_props[i].collective_mode;
+		q->dram_bd = asic->hw_queues_props[i].dram_bd;
+
 		rc = queue_init(hdev, q, i);
 		if (rc) {
 			dev_err(hdev->dev,
 				"failed to initialize queue %d\n", i);
 			goto release_queues;
 		}
+
+		/* Set DRAM PQ address for the queue if it should be at DRAM */
+		if (q->dram_bd)
+			q->pq_dram_address = asic->hw_queues_props[i].q_dram_bd_address;
 	}
 
 	return 0;