linux-kernel - [PATCH 2/4] habanalabs: release kernel context after hw

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Message-Id: <20200924070259.19833-2-oded.gabbay@gmail.com>
Date:   Thu, 24 Sep 2020 10:02:57 +0300
From:   Oded Gabbay <oded.gabbay@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     SW_Drivers@...ana.ai
Subject: [PATCH 2/4] habanalabs: release kernel context after hw_fini

Some engines use resources that belong to the kernel context (e.g. MMU
mappings). In case the halt-engines doesn't work properly due to H/W
restriction, we need to make sure the kernel context lives on until after
the hw_fini. The hw_fini resets the ASIC after that no engine is alive and
we can safely close the kernel context.

Signed-off-by: Oded Gabbay <oded.gabbay@...il.com>
---
 drivers/misc/habanalabs/common/device.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/habanalabs/common/device.c b/drivers/misc/habanalabs/common/device.c
index 196e35d71118..20572224099a 100644
--- a/drivers/misc/habanalabs/common/device.c
+++ b/drivers/misc/habanalabs/common/device.c
@@ -967,14 +967,13 @@ int hl_device_reset(struct hl_device *hdev, bool hard_reset,
 		flush_workqueue(hdev->eq_wq);
 	}
 
-	/* Release kernel context */
-	if ((hard_reset) && (hl_ctx_put(hdev->kernel_ctx) == 1))
-		hdev->kernel_ctx = NULL;
-
 	/* Reset the H/W. It will be in idle state after this returns */
 	hdev->asic_funcs->hw_fini(hdev, hard_reset);
 
 	if (hard_reset) {
+		/* Release kernel context */
+		if (hl_ctx_put(hdev->kernel_ctx) == 1)
+			hdev->kernel_ctx = NULL;
 		hl_vm_fini(hdev);
 		hl_mmu_fini(hdev);
 		hl_eq_reset(hdev, &hdev->event_queue);
@@ -1465,13 +1464,13 @@ void hl_device_fini(struct hl_device *hdev)
 
 	hl_cb_pool_fini(hdev);
 
+	/* Reset the H/W. It will be in idle state after this returns */
+	hdev->asic_funcs->hw_fini(hdev, true);
+
 	/* Release kernel context */
 	if ((hdev->kernel_ctx) && (hl_ctx_put(hdev->kernel_ctx) != 1))
 		dev_err(hdev->dev, "kernel ctx is still alive\n");
 
-	/* Reset the H/W. It will be in idle state after this returns */
-	hdev->asic_funcs->hw_fini(hdev, true);
-
 	hl_vm_fini(hdev);
 
 	hl_mmu_fini(hdev);
-- 
2.17.1