[PATCH AUTOSEL 6.1 23/41] accel/habanalabs: add pci health check during heartbeat

[Sasha Levin <sashal@kernel.org>]

From: Ofir Bitton <obitton@habana.ai>

[ Upstream commit d8b9cea584661b30305cf341bf9f675dc0a25471 ]

Currently upon a heartbeat failure, we don't know if the failure
is due to firmware hang or due to a bad PCI link. Hence, we
are reading a PCI config space register with a known value (vendor ID)
so we will know which of the two possibilities caused the heartbeat
failure.

Signed-off-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/misc/habanalabs/common/device.c         | 15 ++++++++++++++-
 drivers/misc/habanalabs/common/habanalabs.h     |  2 ++
 drivers/misc/habanalabs/common/habanalabs_drv.c |  2 --
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/misc/habanalabs/common/device.c b/drivers/misc/habanalabs/common/device.c
index e0dca445abf14..9ee1b6abd8a05 100644
--- a/drivers/misc/habanalabs/common/device.c
+++ b/drivers/misc/habanalabs/common/device.c
@@ -870,6 +870,18 @@ static void device_early_fini(struct hl_device *hdev)
 		hdev->asic_funcs->early_fini(hdev);
 }
 
+static bool is_pci_link_healthy(struct hl_device *hdev)
+{
+	u16 vendor_id;
+
+	if (!hdev->pdev)
+		return false;
+
+	pci_read_config_word(hdev->pdev, PCI_VENDOR_ID, &vendor_id);
+
+	return (vendor_id == PCI_VENDOR_ID_HABANALABS);
+}
+
 static void hl_device_heartbeat(struct work_struct *work)
 {
 	struct hl_device *hdev = container_of(work, struct hl_device,
@@ -882,7 +894,8 @@ static void hl_device_heartbeat(struct work_struct *work)
 		goto reschedule;
 
 	if (hl_device_operational(hdev, NULL))
-		dev_err(hdev->dev, "Device heartbeat failed!\n");
+		dev_err(hdev->dev, "Device heartbeat failed! PCI link is %s\n",
+			is_pci_link_healthy(hdev) ? "healthy" : "broken");
 
 	hl_device_reset(hdev, HL_DRV_RESET_HARD | HL_DRV_RESET_HEARTBEAT);
 
diff --git a/drivers/misc/habanalabs/common/habanalabs.h b/drivers/misc/habanalabs/common/habanalabs.h
index 58c95b13be69a..257b94cec6248 100644
--- a/drivers/misc/habanalabs/common/habanalabs.h
+++ b/drivers/misc/habanalabs/common/habanalabs.h
@@ -34,6 +34,8 @@
 struct hl_device;
 struct hl_fpriv;
 
+#define PCI_VENDOR_ID_HABANALABS	0x1da3
+
 /* Use upper bits of mmap offset to store habana driver specific information.
  * bits[63:59] - Encode mmap type
  * bits[45:0]  - mmap offset value
diff --git a/drivers/misc/habanalabs/common/habanalabs_drv.c b/drivers/misc/habanalabs/common/habanalabs_drv.c
index 112632afe7d53..ae3cab3f4aa55 100644
--- a/drivers/misc/habanalabs/common/habanalabs_drv.c
+++ b/drivers/misc/habanalabs/common/habanalabs_drv.c
@@ -54,8 +54,6 @@ module_param(boot_error_status_mask, ulong, 0444);
 MODULE_PARM_DESC(boot_error_status_mask,
 	"Mask of the error status during device CPU boot (If bitX is cleared then error X is masked. Default all 1's)");
 
-#define PCI_VENDOR_ID_HABANALABS	0x1da3
-
 #define PCI_IDS_GOYA			0x0001
 #define PCI_IDS_GAUDI			0x1000
 #define PCI_IDS_GAUDI_SEC		0x1010
-- 
2.39.2