1 files changed, 88 insertions, 0 deletions
diff --git a/drivers/misc/ibmasm/heartbeat.c b/drivers/misc/ibmasm/heartbeat.c
new file mode 100644
index 0000000000..59c9a0d956
--- /dev/null
+++ b/drivers/misc/ibmasm/heartbeat.c
@@ -0,0 +1,88 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/*
+ * IBM ASM Service Processor Device Driver
+ *
+ * Copyright (C) IBM Corporation, 2004
+ *
+ * Author: Max Asböck <amax@us.ibm.com>
+ */
+
+#include <linux/notifier.h>
+#include <linux/panic_notifier.h>
+#include "ibmasm.h"
+#include "dot_command.h"
+#include "lowlevel.h"
+
+static int suspend_heartbeats = 0;
+
+/*
+ * Once the driver indicates to the service processor that it is running
+ * - see send_os_state() - the service processor sends periodic heartbeats
+ * to the driver. The driver must respond to the heartbeats or else the OS
+ * will be rebooted.
+ * In the case of a panic the interrupt handler continues to work and thus
+ * continues to respond to heartbeats, making the service processor believe
+ * the OS is still running and thus preventing a reboot.
+ * To prevent this from happening a callback is added the panic_notifier_list.
+ * Before responding to a heartbeat the driver checks if a panic has happened,
+ * if yes it suspends heartbeat, causing the service processor to reboot as
+ * expected.
+ */
+static int panic_happened(struct notifier_block *n, unsigned long val, void *v)
+{
+	suspend_heartbeats = 1;
+	return 0;
+}
+
+static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };
+
+void ibmasm_register_panic_notifier(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
+}
+
+void ibmasm_unregister_panic_notifier(void)
+{
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+			&panic_notifier);
+}
+
+
+int ibmasm_heartbeat_init(struct service_processor *sp)
+{
+	sp->heartbeat = ibmasm_new_command(sp, HEARTBEAT_BUFFER_SIZE);
+	if (sp->heartbeat == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void ibmasm_heartbeat_exit(struct service_processor *sp)
+{
+	char tsbuf[32];
+
+	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
+	ibmasm_wait_for_response(sp->heartbeat, IBMASM_CMD_TIMEOUT_NORMAL);
+	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
+	suspend_heartbeats = 1;
+	command_put(sp->heartbeat);
+}
+
+void ibmasm_receive_heartbeat(struct service_processor *sp,  void *message, size_t size)
+{
+	struct command *cmd = sp->heartbeat;
+	struct dot_command_header *header = (struct dot_command_header *)cmd->buffer;
+	char tsbuf[32];
+
+	dbg("%s:%d at %s\n", __func__, __LINE__, get_timestamp(tsbuf));
+	if (suspend_heartbeats)
+		return;
+
+	/* return the received dot command to sender */
+	cmd->status = IBMASM_CMD_PENDING;
+	size = min(size, cmd->buffer_size);
+	memcpy_fromio(cmd->buffer, message, size);
+	header->type = sp_write;
+	ibmasm_exec_command(sp, cmd);
+}