1 files changed, 86 insertions, 0 deletions
diff --git a/drivers/misc/ibmasm/r_heartbeat.c b/drivers/misc/ibmasm/r_heartbeat.c
new file mode 100644
index 0000000000..21c9b6a6f2
--- /dev/null
+++ b/drivers/misc/ibmasm/r_heartbeat.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/*
+ *
+ * Copyright (C) IBM Corporation, 2004
+ *
+ * Author: Max Asböck <amax@us.ibm.com>
+ */
+
+#include <linux/sched/signal.h>
+#include "ibmasm.h"
+#include "dot_command.h"
+
+/*
+ * Reverse Heartbeat, i.e. heartbeats sent from the driver to the
+ * service processor.
+ * These heartbeats are initiated by user level programs.
+ */
+
+/* the reverse heartbeat dot command */
+#pragma pack(1)
+static struct {
+	struct dot_command_header	header;
+	unsigned char			command[3];
+} rhb_dot_cmd = {
+	.header = {
+		.type =		sp_read,
+		.command_size = 3,
+		.data_size =	0,
+		.status =	0
+	},
+	.command = { 4, 3, 6 }
+};
+#pragma pack()
+
+void ibmasm_init_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
+{
+	init_waitqueue_head(&rhb->wait);
+	rhb->stopped = 0;
+}
+
+/*
+ * start_reverse_heartbeat
+ * Loop forever, sending a reverse heartbeat dot command to the service
+ * processor, then sleeping. The loop comes to an end if the service
+ * processor fails to respond 3 times or we were interrupted.
+ */
+int ibmasm_start_reverse_heartbeat(struct service_processor *sp, struct reverse_heartbeat *rhb)
+{
+	struct command *cmd;
+	int times_failed = 0;
+	int result = 1;
+
+	cmd = ibmasm_new_command(sp, sizeof rhb_dot_cmd);
+	if (!cmd)
+		return -ENOMEM;
+
+	while (times_failed < 3) {
+		memcpy(cmd->buffer, (void *)&rhb_dot_cmd, sizeof rhb_dot_cmd);
+		cmd->status = IBMASM_CMD_PENDING;
+		ibmasm_exec_command(sp, cmd);
+		ibmasm_wait_for_response(cmd, IBMASM_CMD_TIMEOUT_NORMAL);
+
+		if (cmd->status != IBMASM_CMD_COMPLETE)
+			times_failed++;
+
+		wait_event_interruptible_timeout(rhb->wait,
+			rhb->stopped,
+			REVERSE_HEARTBEAT_TIMEOUT * HZ);
+
+		if (signal_pending(current) || rhb->stopped) {
+			result = -EINTR;
+			break;
+		}
+	}
+	command_put(cmd);
+	rhb->stopped = 0;
+
+	return result;
+}
+
+void ibmasm_stop_reverse_heartbeat(struct reverse_heartbeat *rhb)
+{
+	rhb->stopped = 1;
+	wake_up_interruptible(&rhb->wait);
+}