[PATCH v4 21/25] nvdimm/ocxl: Implement the heartbeat command

[Alastair D'Silva]

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 controller.

Signed-off-by: Alastair D'Silva <alastair at d-silva.org>
Reviewed-by: Andrew Donnellan <ajd at linux.ibm.com>
---
 drivers/nvdimm/ocxl/main.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/nvdimm/ocxl/main.c b/drivers/nvdimm/ocxl/main.c
index a4315472683c..2fbe3f2f77d9 100644
--- a/drivers/nvdimm/ocxl/main.c
+++ b/drivers/nvdimm/ocxl/main.c
@@ -272,6 +272,30 @@ static int setup_command_metadata(struct ocxlpmem *ocxlpmem)
 	return 0;
 }
 
+/**
+ * heartbeat() - Issue a heartbeat command to the controller
+ * @ocxlpmem: the device metadata
+ * Return: 0 if the controller responded correctly, negative on error
+ */
+static int heartbeat(struct ocxlpmem *ocxlpmem)
+{
+	int rc;
+
+	mutex_lock(&ocxlpmem->admin_command.lock);
+
+	rc = admin_command_execute(ocxlpmem, ADMIN_COMMAND_HEARTBEAT);
+	if (rc < 0)
+		goto out;
+	if (rc != STATUS_SUCCESS)
+		warn_status(ocxlpmem, "Unexpected status from heartbeat", rc);
+
+	(void)admin_response_handled(ocxlpmem);
+
+out:
+	mutex_unlock(&ocxlpmem->admin_command.lock);
+	return rc;
+}
+
 /**
  * allocate_minor() - Allocate a minor number to use for an OpenCAPI pmem device
  * @ocxlpmem: the device metadata
@@ -1460,6 +1484,12 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err;
 	}
 
+	rc = heartbeat(ocxlpmem);
+	if (rc) {
+		dev_err(&pdev->dev, "Heartbeat failed\n");
+		goto err;
+	}
+
 	elapsed = 0;
 	timeout = ocxlpmem->readiness_timeout +
 		  ocxlpmem->memory_available_timeout;
-- 
2.24.1