habanalabs: improve IOCTLs behavior when disabled or reset

This patch makes some improvement in how IOCTLs behave when the device is
disabled or under reset.

The new code checks, at the start of every IOCTL, if the device is
disabled or in reset. If so, it prints an appropriate kernel message and
returns -EBUSY to user-space.

In addition, the code modifies the location of where the
hard_reset_pending flag is being set or cleared:

1. It is now cleared immediately after the reset *tear-down* flow is
   finished but before the re-initialization flow begins.

2. It is being set in the remove function of the device, to make the
   behavior the same with the hard-reset flow

There are two exceptions to the disable or in reset check:

1. The HL_INFO_DEVICE_STATUS opcode in the INFO IOCTL. This opcode allows
   the user to inquire about the status of the device, whether it is
   operational, in reset or malfunction (disabled). If the driver will
   block this IOCTL, the user won't be able to retrieve the status in
   case of malfunction or in reset.

2. The WAIT_FOR_CS IOCTL. This IOCTL allows the user to inquire about the
   status of a CS. We want to allow the user to continue to do so, even if
   we started a soft-reset process because it will allow the user to get
   the correct error code for each CS he submitted.
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

drivers/misc/habanalabs/command_buffer.c

@@ -214,6 +214,13 @@ int hl_cb_ioctl(struct hl_fpriv *hpriv, void *data)
 	u64 handle;
 	int rc;
 
+	if (hl_device_disabled_or_in_reset(hdev)) {
+		dev_warn_ratelimited(hdev->dev,
+			"Device is %s. Can't execute CB IOCTL\n",
+			atomic_read(&hdev->in_reset) ? "in_reset" : "disabled");
+		return -EBUSY;
+	}
+
 	switch (args->in.op) {
 	case HL_CB_OP_CREATE:
 		rc = hl_cb_create(hdev, &hpriv->cb_mgr, args->in.cb_size,

drivers/misc/habanalabs/device.c

@@ -641,6 +641,8 @@ int hl_device_reset(struct hl_device *hdev, bool hard_reset,
 	if ((hard_reset) && (!from_hard_reset_thread)) {
 		struct hl_device_reset_work *device_reset_work;
 
+		hdev->hard_reset_pending = true;
+
 		if (!hdev->pdev) {
 			dev_err(hdev->dev,
 				"Reset action is NOT supported in simulator\n");
@@ -648,8 +650,6 @@ int hl_device_reset(struct hl_device *hdev, bool hard_reset,
 			goto out_err;
 		}
 
-		hdev->hard_reset_pending = true;
-
 		device_reset_work = kzalloc(sizeof(*device_reset_work),
 						GFP_ATOMIC);
 		if (!device_reset_work) {
@@ -718,6 +718,7 @@ int hl_device_reset(struct hl_device *hdev, bool hard_reset,
 
 	if (hard_reset) {
 		hdev->device_cpu_disabled = false;
+		hdev->hard_reset_pending = false;
 
 		if (hdev->kernel_ctx) {
 			dev_crit(hdev->dev,
@@ -779,8 +780,6 @@ int hl_device_reset(struct hl_device *hdev, bool hard_reset,
 		}
 
 		hl_set_max_power(hdev, hdev->max_power);
-
-		hdev->hard_reset_pending = false;
 	} else {
 		rc = hdev->asic_funcs->soft_reset_late_init(hdev);
 		if (rc) {
@@ -1069,6 +1068,8 @@ void hl_device_fini(struct hl_device *hdev)
 	hdev->asic_funcs->hw_queues_lock(hdev);
 	hdev->asic_funcs->hw_queues_unlock(hdev);
 
+	hdev->hard_reset_pending = true;
+
 	device_kill_open_processes(hdev);
 
 	hl_hwmon_fini(hdev);

drivers/misc/habanalabs/habanalabs_ioctl.c

@@ -202,7 +202,8 @@ static int hl_info_ioctl(struct hl_fpriv *hpriv, void *data)
 
 	if (hl_device_disabled_or_in_reset(hdev)) {
 		dev_warn_ratelimited(hdev->dev,
-			"Device is disabled or in reset. Can't execute INFO IOCTL\n");
+			"Device is %s. Can't execute INFO IOCTL\n",
+			atomic_read(&hdev->in_reset) ? "in_reset" : "disabled");
 		return -EBUSY;
 	}
 

drivers/misc/habanalabs/memory.c

@@ -1159,7 +1159,8 @@ int hl_mem_ioctl(struct hl_fpriv *hpriv, void *data)
 
 	if (hl_device_disabled_or_in_reset(hdev)) {
 		dev_warn_ratelimited(hdev->dev,
-			"Device is disabled or in reset. Can't execute memory IOCTL\n");
+			"Device is %s. Can't execute MEMORY IOCTL\n",
+			atomic_read(&hdev->in_reset) ? "in_reset" : "disabled");
 		return -EBUSY;
 	}