habanalabs: add device reset support

This patch adds support for doing various on-the-fly reset of Goya.

The driver supports two types of resets:
1. soft-reset
2. hard-reset

Soft-reset is done when the device detects a timeout of a command
submission that was given to the device. The soft-reset process only resets
the engines that are relevant for the submission of compute jobs, i.e. the
DMA channels, the TPCs and the MME. The purpose is to bring the device as
fast as possible to a working state.

Hard-reset is done in several cases:
1. After soft-reset is done but the device is not responding
2. When fatal errors occur inside the device, e.g. ECC error
3. When the driver is removed

Hard-reset performs a reset of the entire chip except for the PCI
controller and the PLLs. It is a much longer process then soft-reset but it
helps to recover the device without the need to reboot the Host.

After hard-reset, the driver will restore the max power attribute and in
case of manual power management, the frequencies that were set.

This patch also adds two entries to the sysfs, which allows the root user
to initiate a soft or hard reset.

Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/misc/habanalabs/command_buffer.c b/drivers/misc/habanalabs/command_buffer.c
index e659ca3035e4..1e90025204c0 100644
--- a/drivers/misc/habanalabs/command_buffer.c
+++ b/drivers/misc/habanalabs/command_buffer.c
@@ -91,9 +91,14 @@ int hl_cb_create(struct hl_device *hdev, struct hl_cb_mgr *mgr,
 	bool alloc_new_cb = true;
 	int rc;
 
-	if (hdev->disabled) {
+	/*
+	 * Can't use generic function to check this because of special case
+	 * where we create a CB as part of the reset process
+	 */
+	if ((hdev->disabled) || ((atomic_read(&hdev->in_reset)) &&
+					(ctx_id != HL_KERNEL_ASID_ID))) {
 		dev_warn_ratelimited(hdev->dev,
-			"Device is disabled. Can't create new CBs\n");
+			"Device is disabled or in reset. Can't create new CBs\n");
 		rc = -EBUSY;
 		goto out_err;
 	}