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

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Message-Id: <20191203034655.51561-23-alastair@au1.ibm.com>
Date:   Tue,  3 Dec 2019 14:46:50 +1100
From:   "Alastair D'Silva" <alastair@....ibm.com>
To:     alastair@...ilva.org
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Frederic Barrat <fbarrat@...ux.ibm.com>,
        Andrew Donnellan <ajd@...ux.ibm.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Keith Busch <keith.busch@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Rob Herring <robh@...nel.org>,
        Anton Blanchard <anton@...abs.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>,
        Cédric Le Goater <clg@...d.org>,
        Anju T Sudhakar <anju@...ux.vnet.ibm.com>,
        Hari Bathini <hbathini@...ux.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kurz <groug@...d.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Alexey Kardashevskiy <aik@...abs.ru>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-nvdimm@...ts.01.org, linux-mm@...ck.org
Subject: [PATCH v2 22/27] nvdimm/ocxl: Implement the heartbeat command

From: Alastair D'Silva <alastair@...ilva.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@...ilva.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