habanalabs: de-couple MMU and VM module initialization

This patch initializes the MMU S/W structures before the VM S/W
structures, instead of doing that as part of the VM S/W initialization.

This is done because we need to configure some MMU mappings for the kernel
context, before the VM is initialized. The VM initialization can't be
moved earlier because it depends on the size of the DRAM, which is
retrieved from the device CPU. Communication with the device CPU will
require the MMU mappings to be configured and hence the de-coupling.

Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

3 files changed, 22 insertions, 20 deletions

diff --git a/drivers/misc/habanalabs/device.c b/drivers/misc/habanalabs/device.c
index 4df8ef88ce2d..0c4894dd9c02 100644
--- a/drivers/misc/habanalabs/device.c
+++ b/drivers/misc/habanalabs/device.c
@@ -745,6 +745,7 @@ again:
 
 	if (hard_reset) {
 		hl_vm_fini(hdev);
+		hl_mmu_fini(hdev);
 		hl_eq_reset(hdev, &hdev->event_queue);
 	}
 
@@ -772,6 +773,13 @@ again:
 			goto out_err;
 		}
 
+		rc = hl_mmu_init(hdev);
+		if (rc) {
+			dev_err(hdev->dev,
+				"Failed to initialize MMU S/W after hard reset\n");
+			goto out_err;
+		}
+
 		/* Allocate the kernel context */
 		hdev->kernel_ctx = kzalloc(sizeof(*hdev->kernel_ctx),
 						GFP_KERNEL);
@@ -943,11 +951,18 @@ int hl_device_init(struct hl_device *hdev, struct class *hclass)
 		goto cq_fini;
 	}
 
+	/* MMU S/W must be initialized before kernel context is created */
+	rc = hl_mmu_init(hdev);
+	if (rc) {
+		dev_err(hdev->dev, "Failed to initialize MMU S/W structures\n");
+		goto eq_fini;
+	}
+
 	/* Allocate the kernel context */
 	hdev->kernel_ctx = kzalloc(sizeof(*hdev->kernel_ctx), GFP_KERNEL);
 	if (!hdev->kernel_ctx) {
 		rc = -ENOMEM;
-		goto eq_fini;
+		goto mmu_fini;
 	}
 
 	hdev->user_ctx = NULL;
@@ -995,8 +1010,6 @@ int hl_device_init(struct hl_device *hdev, struct class *hclass)
 		goto out_disabled;
 	}
 
-	/* After test_queues, KMD can start sending messages to device CPU */
-
 	rc = device_late_init(hdev);
 	if (rc) {
 		dev_err(hdev->dev, "Failed late initialization\n");
@@ -1042,6 +1055,8 @@ release_ctx:
 			"kernel ctx is still alive on initialization failure\n");
 free_ctx:
 	kfree(hdev->kernel_ctx);
+mmu_fini:
+	hl_mmu_fini(hdev);
 eq_fini:
 	hl_eq_fini(hdev, &hdev->event_queue);
 cq_fini:
@@ -1146,6 +1161,8 @@ void hl_device_fini(struct hl_device *hdev)
 
 	hl_vm_fini(hdev);
 
+	hl_mmu_fini(hdev);
+
 	hl_eq_fini(hdev, &hdev->event_queue);
 
 	for (i = 0 ; i < hdev->asic_prop.completion_queues_count ; i++)
diff --git a/drivers/misc/habanalabs/memory.c b/drivers/misc/habanalabs/memory.c
index 693877e37fd8..42d237cae1dc 100644
--- a/drivers/misc/habanalabs/memory.c
+++ b/drivers/misc/habanalabs/memory.c
@@ -1657,17 +1657,10 @@ int hl_vm_init(struct hl_device *hdev)
 	struct hl_vm *vm = &hdev->vm;
 	int rc;
 
-	rc = hl_mmu_init(hdev);
-	if (rc) {
-		dev_err(hdev->dev, "Failed to init MMU\n");
-		return rc;
-	}
-
 	vm->dram_pg_pool = gen_pool_create(__ffs(prop->dram_page_size), -1);
 	if (!vm->dram_pg_pool) {
 		dev_err(hdev->dev, "Failed to create dram page pool\n");
-		rc = -ENOMEM;
-		goto pool_create_err;
+		return -ENOMEM;
 	}
 
 	kref_init(&vm->dram_pg_pool_refcount);
@@ -1693,8 +1686,6 @@ int hl_vm_init(struct hl_device *hdev)
 
 pool_add_err:
 	gen_pool_destroy(vm->dram_pg_pool);
-pool_create_err:
-	hl_mmu_fini(hdev);
 
 	return rc;
 }
@@ -1724,7 +1715,5 @@ void hl_vm_fini(struct hl_device *hdev)
 		dev_warn(hdev->dev, "dram_pg_pool was not destroyed on %s\n",
 				__func__);
 
-	hl_mmu_fini(hdev);
-
 	vm->init_done = false;
 }
diff --git a/drivers/misc/habanalabs/mmu.c b/drivers/misc/habanalabs/mmu.c
index 10aee3141444..87968f32e718 100644
--- a/drivers/misc/habanalabs/mmu.c
+++ b/drivers/misc/habanalabs/mmu.c
@@ -385,12 +385,8 @@ static void dram_default_mapping_fini(struct hl_ctx *ctx)
  * @hdev: habanalabs device structure.
  *
  * This function does the following:
- * - Allocate max_asid zeroed hop0 pgts so no mapping is available.
- * - Enable MMU in H/W.
- * - Invalidate the MMU cache.
  * - Create a pool of pages for pgt_infos.
- *
- * This function depends on DMA QMAN to be working!
+ * - Create a shadow table for pgt
  *
  * Return: 0 for success, non-zero for failure.
  */