[PATCH v2 22/27] nvdimm/ocxl: Implement the heartbeat command

[Alastair D'Silva]

From: Alastair D'Silva <alastair at d-silva.org>

The heartbeat admin command is a simple admin command that exercises
the communication mechanisms within the controller.

This patch issues a heartbeat command to the card during init to ensure
we can communicate with the card's crontroller.

Signed-off-by: Alastair D'Silva <alastair at d-silva.org>
---
 drivers/nvdimm/ocxl/scm.c | 43 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/nvdimm/ocxl/scm.c b/drivers/nvdimm/ocxl/scm.c
index 8a30c887b5ed..e8b34262f397 100644
--- a/drivers/nvdimm/ocxl/scm.c
+++ b/drivers/nvdimm/ocxl/scm.c
@@ -353,6 +353,44 @@ static bool scm_is_usable(const struct scm_data *scm_data)
 	return true;
 }
 
+/**
+ * scm_heartbeat() - Issue a heartbeat command to the controller
+ * @scm_data: a pointer to the SCM device data
+ * Return: 0 if the controller responded correctly, negative on error
+ */
+static int scm_heartbeat(struct scm_data *scm_data)
+{
+	int rc;
+
+	mutex_lock(&scm_data->admin_command.lock);
+
+	rc = scm_admin_command_request(scm_data, ADMIN_COMMAND_HEARTBEAT);
+	if (rc)
+		goto out;
+
+	rc = scm_admin_command_execute(scm_data);
+	if (rc)
+		goto out;
+
+	rc = scm_admin_command_complete_timeout(scm_data, ADMIN_COMMAND_HEARTBEAT);
+	if (rc < 0) {
+		dev_err(&scm_data->dev, "Heartbeat timeout\n");
+		goto out;
+	}
+
+	rc = scm_admin_response(scm_data);
+	if (rc < 0)
+		goto out;
+	if (rc != STATUS_SUCCESS)
+		scm_warn_status(scm_data, "Unexpected status from heartbeat", rc);
+
+	rc = scm_admin_response_handled(scm_data);
+
+out:
+	mutex_unlock(&scm_data->admin_command.lock);
+	return rc;
+}
+
 /**
  * allocate_scm_minor() - Allocate a minor number to use for an SCM device
  * @scm_data: The SCM device to associate the minor with
@@ -1508,6 +1546,11 @@ static int scm_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err;
 	}
 
+	if (scm_heartbeat(scm_data)) {
+		dev_err(&pdev->dev, "SCM Heartbeat failed\n");
+		goto err;
+	}
+
 	elapsed = 0;
 	timeout = scm_data->readiness_timeout + scm_data->memory_available_timeout;
 	while (!scm_is_usable(scm_data)) {
-- 
2.23.0