soc: qcom: Add snapshot of System Health Monitor

This snapshot is taken as of msm-3.18 commit e70ad0cd (Promotion of
kernel.lnx.3.18-151201.)

Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>

5 files changed, 1177 insertions, 0 deletions

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index dda229dd8e84..0ac12d7b96b0 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -211,6 +211,17 @@ config MSM_IPC_ROUTER_GLINK_XPRT
 	  this layer registers a transport with IPC Router and enable
 	  message exchange.
 
+config MSM_SYSTEM_HEALTH_MONITOR
+	bool "System Health Monitor"
+	depends on MSM_QMI_INTERFACE && MSM_SUBSYSTEM_RESTART
+	help
+	  System Health Monitor (SHM) passively monitors the health of the
+	  peripherals connected to the application processor. Software
+	  components in the application processor that experience
+	  communication failure can request the SHM to perform a system-wide
+	  health check. If any failures are detected during the health-check,
+	  then a subsystem restart will be triggered for the failed subsystem.
+
 config MSM_GLINK_PKT
 	bool "Enable device interface for GLINK packet channels"
 	depends on MSM_GLINK
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 7675dd5d64a3..62b84fa9b136 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -18,6 +18,8 @@ obj-$(CONFIG_MSM_IPC_ROUTER_SMD_XPRT)	+=	ipc_router_smd_xprt.o
 obj-$(CONFIG_MSM_IPC_ROUTER_HSIC_XPRT)	+=	ipc_router_hsic_xprt.o
 obj-$(CONFIG_MSM_IPC_ROUTER_MHI_XPRT)	+=	ipc_router_mhi_xprt.o
 obj-$(CONFIG_MSM_IPC_ROUTER_GLINK_XPRT)	+=	ipc_router_glink_xprt.o
+obj-$(CONFIG_MSM_SYSTEM_HEALTH_MONITOR)	+=	system_health_monitor_v01.o
+obj-$(CONFIG_MSM_SYSTEM_HEALTH_MONITOR)	+=	system_health_monitor.o
 obj-$(CONFIG_MSM_GLINK_PKT)	+=	msm_glink_pkt.o
 
 obj-$(CONFIG_MEM_SHARE_QMI_SERVICE)		+= memshare/
diff --git a/drivers/soc/qcom/system_health_monitor.c b/drivers/soc/qcom/system_health_monitor.c
new file mode 100644
index 000000000000..ebafde3faf54
--- /dev/null
+++ b/drivers/soc/qcom/system_health_monitor.c
@@ -0,0 +1,964 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/cdev.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/ioctl.h>
+#include <linux/ipc_logging.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/qmi_encdec.h>
+#include <linux/ratelimit.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/srcu.h>
+#include <linux/thread_info.h>
+#include <linux/uaccess.h>
+
+#include <soc/qcom/msm_qmi_interface.h>
+#include <soc/qcom/subsystem_notif.h>
+#include <soc/qcom/subsystem_restart.h>
+
+#include "system_health_monitor_v01.h"
+
+#define MODULE_NAME "system_health_monitor"
+
+#define SUBSYS_NAME_LEN 256
+#define SSRESTART_STRLEN 256
+
+enum {
+	SHM_INFO_FLAG = 0x1,
+	SHM_DEBUG_FLAG = 0x2,
+};
+static int shm_debug_mask = SHM_INFO_FLAG;
+module_param_named(debug_mask, shm_debug_mask,
+		   int, S_IRUGO | S_IWUSR | S_IWGRP);
+static int shm_default_timeout_ms = 2000;
+module_param_named(default_timeout_ms, shm_default_timeout_ms,
+		   int, S_IRUGO | S_IWUSR | S_IWGRP);
+
+#define DEFAULT_SHM_RATELIMIT_INTERVAL (HZ / 5)
+#define DEFAULT_SHM_RATELIMIT_BURST 2
+
+#define SHM_ILCTXT_NUM_PAGES 2
+static void *shm_ilctxt;
+#define SHM_INFO_LOG(x...) do { \
+	if ((shm_debug_mask & SHM_INFO_FLAG) && shm_ilctxt) \
+		ipc_log_string(shm_ilctxt, x); \
+} while (0)
+
+#define SHM_DEBUG(x...) do { \
+	if ((shm_debug_mask & SHM_DEBUG_FLAG) && shm_ilctxt) \
+		ipc_log_string(shm_ilctxt, x); \
+} while (0)
+
+#define SHM_ERR(x...) do { \
+	if (shm_ilctxt) \
+		ipc_log_string(shm_ilctxt, x); \
+	pr_err(x); \
+} while (0)
+
+struct class *system_health_monitor_classp;
+static dev_t system_health_monitor_dev;
+static struct cdev system_health_monitor_cdev;
+static struct device *system_health_monitor_devp;
+
+#define SYSTEM_HEALTH_MONITOR_IOCTL_MAGIC (0xC3)
+
+#define CHECK_SYSTEM_HEALTH_IOCTL \
+	_IOR(SYSTEM_HEALTH_MONITOR_IOCTL_MAGIC, 0, unsigned int)
+
+static struct workqueue_struct *shm_svc_workqueue;
+static void shm_svc_recv_msg(struct work_struct *work);
+static DECLARE_DELAYED_WORK(work_recv_msg, shm_svc_recv_msg);
+static struct qmi_handle *shm_svc_handle;
+
+struct disconnect_work {
+	struct work_struct work;
+	void *conn_h;
+};
+static void shm_svc_disconnect_worker(struct work_struct *work);
+
+struct req_work {
+	struct work_struct work;
+	void *conn_h;
+	void *req_h;
+	unsigned int msg_id;
+	void *req;
+};
+static void shm_svc_req_worker(struct work_struct *work);
+
+/**
+ * struct hma_info - Information about a Health Monitor Agent(HMA)
+ * @list:		List to chain up the hma to the hma_list.
+ * @subsys_name:	Name of the remote subsystem that hosts this HMA.
+ * @ssrestart_string:	String to restart the subsystem that hosts this HMA.
+ * @conn_h:		Opaque connection handle to the HMA.
+ * @timeout:		Timeout as registered by the HMA.
+ * @check_count:	Count of the health check attempts.
+ * @report_count:	Count of the health reports handled.
+ * @reset_srcu:		Sleepable RCU to protect the reset state.
+ * @is_in_reset:	Flag to identify if the remote subsystem is in reset.
+ * @restart_nb:		Notifier block to receive subsystem restart events.
+ * @restart_nb_h:	Handle to subsystem restart notifier block.
+ * @rs:			Rate-limit the health check.
+ */
+struct hma_info {
+	struct list_head list;
+	char subsys_name[SUBSYS_NAME_LEN];
+	char ssrestart_string[SSRESTART_STRLEN];
+	void *conn_h;
+	uint32_t timeout;
+	atomic_t check_count;
+	atomic_t report_count;
+	struct srcu_struct reset_srcu;
+	atomic_t is_in_reset;
+	struct notifier_block restart_nb;
+	void *restart_nb_h;
+	struct ratelimit_state rs;
+};
+
+struct restart_work {
+	struct delayed_work dwork;
+	struct hma_info *hmap;
+	void *conn_h;
+	int check_count;
+};
+static void shm_svc_restart_worker(struct work_struct *work);
+
+static DEFINE_MUTEX(hma_info_list_lock);
+static LIST_HEAD(hma_info_list);
+
+static struct msg_desc shm_svc_register_req_desc = {
+	.max_msg_len = HMON_REGISTER_REQ_MSG_V01_MAX_MSG_LEN,
+	.msg_id = QMI_HEALTH_MON_REG_REQ_V01,
+	.ei_array = hmon_register_req_msg_v01_ei,
+};
+
+static struct msg_desc shm_svc_register_resp_desc = {
+	.max_msg_len = HMON_REGISTER_RESP_MSG_V01_MAX_MSG_LEN,
+	.msg_id = QMI_HEALTH_MON_REG_RESP_V01,
+	.ei_array = hmon_register_resp_msg_v01_ei,
+};
+
+static struct msg_desc shm_svc_health_check_ind_desc = {
+	.max_msg_len = HMON_HEALTH_CHECK_IND_MSG_V01_MAX_MSG_LEN,
+	.msg_id = QMI_HEALTH_MON_HEALTH_CHECK_IND_V01,
+	.ei_array = hmon_health_check_ind_msg_v01_ei,
+};
+
+static struct msg_desc shm_svc_health_check_complete_req_desc = {
+	.max_msg_len = HMON_HEALTH_CHECK_COMPLETE_REQ_MSG_V01_MAX_MSG_LEN,
+	.msg_id = QMI_HEALTH_MON_HEALTH_CHECK_COMPLETE_REQ_V01,
+	.ei_array = hmon_health_check_complete_req_msg_v01_ei,
+};
+
+static struct msg_desc shm_svc_health_check_complete_resp_desc = {
+	.max_msg_len = HMON_HEALTH_CHECK_COMPLETE_RESP_MSG_V01_MAX_MSG_LEN,
+	.msg_id = QMI_HEALTH_MON_HEALTH_CHECK_COMPLETE_RESP_V01,
+	.ei_array = hmon_health_check_complete_resp_msg_v01_ei,
+};
+
+/**
+ * restart_notifier_cb() - Callback to handle SSR events
+ * @this:	Reference to the notifier block.
+ * @code:	Type of SSR event.
+ * @data:	Data that needs to be handled as part of SSR event.
+ *
+ * This function is used to identify if a subsystem which hosts an HMA
+ * is already in reset, so that a duplicate subsystem restart is not
+ * triggered.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int restart_notifier_cb(struct notifier_block *this,
+			       unsigned long code, void *data)
+{
+	struct hma_info *tmp_hma_info =
+		container_of(this, struct hma_info, restart_nb);
+
+	if (code == SUBSYS_BEFORE_SHUTDOWN) {
+		atomic_set(&tmp_hma_info->is_in_reset, 1);
+		synchronize_srcu(&tmp_hma_info->reset_srcu);
+		SHM_INFO_LOG("%s: %s going to shutdown\n",
+			 __func__, tmp_hma_info->ssrestart_string);
+	} else if (code == SUBSYS_AFTER_POWERUP) {
+		atomic_set(&tmp_hma_info->is_in_reset, 0);
+		SHM_INFO_LOG("%s: %s powered up\n",
+			 __func__, tmp_hma_info->ssrestart_string);
+	}
+	return 0;
+}
+
+/**
+ * shm_svc_restart_worker() - Worker to restart a subsystem
+ * @work:	Reference to the work item being handled.
+ *
+ * This function restarts the subsystem which hosts an HMA. This function
+ * checks the following before triggering a restart:
+ * 1) Health check report is not received.
+ * 2) The subsystem has not undergone a reset.
+ * 3) The subsystem is not undergoing a reset.
+ */
+static void shm_svc_restart_worker(struct work_struct *work)
+{
+	int rc;
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct restart_work *rwp =
+		container_of(dwork, struct restart_work, dwork);
+	struct hma_info *tmp_hma_info = rwp->hmap;
+	int rcu_id;
+
+	if (rwp->check_count <= atomic_read(&tmp_hma_info->report_count)) {
+		SHM_INFO_LOG("%s: No Action on Health Check Attempt %d to %s\n",
+			 __func__, rwp->check_count,
+			 tmp_hma_info->subsys_name);
+		kfree(rwp);
+		return;
+	}
+
+	if (!tmp_hma_info->conn_h || rwp->conn_h != tmp_hma_info->conn_h) {
+		SHM_INFO_LOG(
+			"%s: Connection to %s is reset. No further action\n",
+			 __func__, tmp_hma_info->subsys_name);
+		kfree(rwp);
+		return;
+	}
+
+	rcu_id = srcu_read_lock(&tmp_hma_info->reset_srcu);
+	if (atomic_read(&tmp_hma_info->is_in_reset)) {
+		SHM_INFO_LOG(
+			"%s: %s is going thru restart. No further action\n",
+			 __func__, tmp_hma_info->subsys_name);
+		srcu_read_unlock(&tmp_hma_info->reset_srcu, rcu_id);
+		kfree(rwp);
+		return;
+	}
+
+	SHM_ERR("%s: HMA in %s failed to respond in time. Restarting %s...\n",
+		__func__, tmp_hma_info->subsys_name,
+		tmp_hma_info->ssrestart_string);
+	rc = subsystem_restart(tmp_hma_info->ssrestart_string);
+	if (rc < 0)
+		SHM_ERR("%s: Error %d restarting %s\n",
+			__func__, rc, tmp_hma_info->ssrestart_string);
+	srcu_read_unlock(&tmp_hma_info->reset_srcu, rcu_id);
+	kfree(rwp);
+}
+
+/**
+ * shm_send_health_check_ind() - Initiate a subsystem health check
+ * @tmp_hma_info:	Info about an HMA which resides in a subsystem.
+ *
+ * This function initiates a health check of a subsytem, which hosts the
+ * HMA, by sending a health check QMI indication message.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int shm_send_health_check_ind(struct hma_info *tmp_hma_info)
+{
+	int rc;
+	struct restart_work *rwp;
+
+	if (!tmp_hma_info->conn_h)
+		return 0;
+
+	/* Rate limit the health check as configured by the subsystem */
+	if (!__ratelimit(&tmp_hma_info->rs))
+		return 0;
+
+	rwp = kzalloc(sizeof(*rwp), GFP_KERNEL);
+	if (!rwp) {
+		SHM_ERR("%s: Error allocating restart work\n", __func__);
+		return -ENOMEM;
+	}
+
+	INIT_DELAYED_WORK(&rwp->dwork, shm_svc_restart_worker);
+	rwp->hmap = tmp_hma_info;
+	rwp->conn_h = tmp_hma_info->conn_h;
+
+	rc = qmi_send_ind(shm_svc_handle, tmp_hma_info->conn_h,
+			  &shm_svc_health_check_ind_desc, NULL, 0);
+	if (rc < 0) {
+		SHM_ERR("%s: Send Error %d to %s\n",
+			__func__, rc, tmp_hma_info->subsys_name);
+		kfree(rwp);
+		return rc;
+	}
+
+	rwp->check_count = atomic_inc_return(&tmp_hma_info->check_count);
+	queue_delayed_work(shm_svc_workqueue, &rwp->dwork,
+			   msecs_to_jiffies(tmp_hma_info->timeout));
+	return 0;
+}
+
+/**
+ * kern_check_system_health() - Check the system health
+ *
+ * This function is used by the kernel drivers to initiate the
+ * system health check. This function in turn triggers SHM to send
+ * QMI message to all the HMAs connected to it.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+int kern_check_system_health(void)
+{
+	int rc;
+	int final_rc = 0;
+	struct hma_info *tmp_hma_info;
+
+	mutex_lock(&hma_info_list_lock);
+	list_for_each_entry(tmp_hma_info, &hma_info_list, list) {
+		rc = shm_send_health_check_ind(tmp_hma_info);
+		if (rc < 0) {
+			SHM_ERR("%s by %s failed for %s - rc %d\n", __func__,
+				current->comm, tmp_hma_info->subsys_name, rc);
+			final_rc = rc;
+		}
+	}
+	mutex_unlock(&hma_info_list_lock);
+	return final_rc;
+}
+EXPORT_SYMBOL(kern_check_system_health);
+
+/**
+ * shm_svc_connect_cb() - Callback to handle connect event from an HMA
+ * @handle:	QMI Service handle in which a connect event is received.
+ * @conn_h:	Opaque reference to the connection handle.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int shm_svc_connect_cb(struct qmi_handle *handle, void *conn_h)
+{
+	SHM_DEBUG("%s: conn_h %p\n", __func__, conn_h);
+	return 0;
+}
+
+/**
+ * shm_svc_disconnect_worker() - Worker to handle disconnect event from an HMA
+ * @work:	Reference to the work item.
+ *
+ * This function handles the disconnect event from an HMA in a deferred manner.
+ */
+static void shm_svc_disconnect_worker(struct work_struct *work)
+{
+	struct hma_info *tmp_hma_info;
+	struct disconnect_work *dwp =
+		container_of(work, struct disconnect_work, work);
+
+	mutex_lock(&hma_info_list_lock);
+	list_for_each_entry(tmp_hma_info, &hma_info_list, list) {
+		if (dwp->conn_h == tmp_hma_info->conn_h) {
+			SHM_INFO_LOG("%s: conn_h %p to HMA in %s exited\n",
+				 __func__, dwp->conn_h,
+				 tmp_hma_info->subsys_name);
+			tmp_hma_info->conn_h = NULL;
+			atomic_set(&tmp_hma_info->report_count,
+				   atomic_read(&tmp_hma_info->check_count));
+			break;
+		}
+	}
+	mutex_unlock(&hma_info_list_lock);
+	kfree(dwp);
+}
+
+/**
+ * shm_svc_disconnect_cb() - Callback to handle disconnect event from an HMA
+ * @handle:	QMI Service handle in which a disconnect event is received.
+ * @conn_h:	Opaque reference to the connection handle.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int shm_svc_disconnect_cb(struct qmi_handle *handle, void *conn_h)
+{
+	struct disconnect_work *dwp;
+
+	dwp = kzalloc(sizeof(*dwp), GFP_ATOMIC);
+	if (!dwp) {
+		SHM_ERR("%s: Error allocating work item\n", __func__);
+		return -ENOMEM;
+	}
+
+	INIT_WORK(&dwp->work, shm_svc_disconnect_worker);
+	dwp->conn_h = conn_h;
+	queue_work(shm_svc_workqueue, &dwp->work);
+	return 0;
+}
+
+/**
+ * shm_svc_req_desc_cb() - Callback to identify the request descriptor
+ * @msg_id:	Message ID of the QMI request.
+ * @req_desc:	Request Descriptor of the QMI request.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int shm_svc_req_desc_cb(unsigned int msg_id,
+			       struct msg_desc **req_desc)
+{
+	int rc;
+	SHM_DEBUG("%s: called for msg_id %d\n", __func__, msg_id);
+	switch (msg_id) {
+	case QMI_HEALTH_MON_REG_REQ_V01:
+		*req_desc = &shm_svc_register_req_desc;
+		rc = sizeof(struct hmon_register_req_msg_v01);
+		break;
+
+	case QMI_HEALTH_MON_HEALTH_CHECK_COMPLETE_REQ_V01:
+		*req_desc = &shm_svc_health_check_complete_req_desc;
+		rc = sizeof(struct hmon_health_check_complete_req_msg_v01);
+		break;
+
+	default:
+		SHM_ERR("%s: Invalid msg_id %d\n", __func__, msg_id);
+		rc = -ENOTSUPP;
+	}
+	return rc;
+}
+
+/**
+ * handle_health_mon_reg_req() - Handle the HMA register QMI request
+ * @conn_h:	Opaque reference to the connection handle to an HMA.
+ * @req_h:	Opaque reference to the request handle.
+ * @buf:	Pointer to the QMI request structure.
+ *
+ * This function handles the register request from an HMA. The request
+ * contains the subsystem name which hosts the HMA and health check
+ * timeout for the HMA.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int handle_health_mon_reg_req(void *conn_h, void *req_h, void *buf)
+{
+	int rc;
+	struct hma_info *tmp_hma_info;
+	struct hmon_register_req_msg_v01 *req =
+		(struct hmon_register_req_msg_v01 *)buf;
+	struct hmon_register_resp_msg_v01 resp;
+	bool hma_info_found = false;
+
+	if (!req->name_valid) {
+		SHM_ERR("%s: host name invalid\n", __func__);
+		goto send_reg_resp;
+	}
+
+	mutex_lock(&hma_info_list_lock);
+	list_for_each_entry(tmp_hma_info, &hma_info_list, list) {
+		if (!strcmp(tmp_hma_info->subsys_name, req->name) &&
+		    !tmp_hma_info->conn_h) {
+			tmp_hma_info->conn_h = conn_h;
+			if (req->timeout_valid)
+				tmp_hma_info->timeout = req->timeout;
+			else
+				tmp_hma_info->timeout = shm_default_timeout_ms;
+			ratelimit_state_init(&tmp_hma_info->rs,
+					     DEFAULT_SHM_RATELIMIT_INTERVAL,
+					     DEFAULT_SHM_RATELIMIT_BURST);
+			SHM_INFO_LOG("%s: from %s timeout_ms %d\n",
+				 __func__, req->name, tmp_hma_info->timeout);
+			hma_info_found = true;
+		} else if (!strcmp(tmp_hma_info->subsys_name, req->name)) {
+			SHM_ERR("%s: Duplicate HMA from %s - cur %p, new %p\n",
+				__func__, req->name, tmp_hma_info->conn_h,
+				conn_h);
+		}
+	}
+	mutex_unlock(&hma_info_list_lock);
+
+send_reg_resp:
+	if (hma_info_found) {
+		memset(&resp, 0, sizeof(resp));
+	} else {
+		resp.resp.result = QMI_RESULT_FAILURE_V01;
+		resp.resp.error = QMI_ERR_INVALID_ID_V01;
+	}
+	rc = qmi_send_resp(shm_svc_handle, conn_h, req_h,
+			   &shm_svc_register_resp_desc, &resp, sizeof(resp));
+	if (rc < 0)
+		SHM_ERR("%s: send_resp failed to %s - rc %d\n",
+			__func__, req->name, rc);
+	return rc;
+}
+
+/**
+ * handle_health_mon_health_check_complete_req() - Handle the HMA health report
+ * @conn_h:	Opaque reference to the connection handle to an HMA.
+ * @req_h:	Opaque reference to the request handle.
+ * @buf:	Pointer to the QMI request structure.
+ *
+ * This function handles health reports from an HMA. The health report is sent
+ * in response to a health check QMI indication sent by SHM.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int handle_health_mon_health_check_complete_req(void *conn_h,
+						void *req_h, void *buf)
+{
+	int rc;
+	struct hma_info *tmp_hma_info;
+	struct hmon_health_check_complete_req_msg_v01 *req =
+		(struct hmon_health_check_complete_req_msg_v01 *)buf;
+	struct hmon_health_check_complete_resp_msg_v01 resp;
+	bool hma_info_found = false;
+
+	if (!req->result_valid) {
+		SHM_ERR("%s: Invalid result\n", __func__);
+		goto send_resp;
+	}
+
+	mutex_lock(&hma_info_list_lock);
+	list_for_each_entry(tmp_hma_info, &hma_info_list, list) {
+		if (tmp_hma_info->conn_h != conn_h)
+			continue;
+		hma_info_found = true;
+		if (req->result == HEALTH_MONITOR_CHECK_SUCCESS_V01) {
+			atomic_inc(&tmp_hma_info->report_count);
+			SHM_INFO_LOG("%s: %s Health Check Success\n",
+				 __func__, tmp_hma_info->subsys_name);
+		} else {
+			SHM_INFO_LOG("%s: %s Health Check Failure\n",
+				 __func__, tmp_hma_info->subsys_name);
+		}
+	}
+	mutex_unlock(&hma_info_list_lock);
+
+send_resp:
+	if (hma_info_found) {
+		memset(&resp, 0, sizeof(resp));
+	} else {
+		resp.resp.result = QMI_RESULT_FAILURE_V01;
+		resp.resp.error = QMI_ERR_INVALID_ID_V01;
+	}
+	rc = qmi_send_resp(shm_svc_handle, conn_h, req_h,
+			   &shm_svc_health_check_complete_resp_desc,
+			   &resp, sizeof(resp));
+	if (rc < 0)
+		SHM_ERR("%s: send_resp failed - rc %d\n",
+			__func__, rc);
+	return rc;
+}
+
+/**
+ * shm_svc_req_worker() - Worker to handle QMI requests
+ * @work:	Reference to the work item.
+ *
+ * This function handles QMI requests from HMAs in a deferred manner.
+ */
+static void shm_svc_req_worker(struct work_struct *work)
+{
+	struct req_work *rwp =
+		container_of(work, struct req_work, work);
+
+	switch (rwp->msg_id) {
+	case QMI_HEALTH_MON_REG_REQ_V01:
+		handle_health_mon_reg_req(rwp->conn_h, rwp->req_h, rwp->req);
+		break;
+
+	case QMI_HEALTH_MON_HEALTH_CHECK_COMPLETE_REQ_V01:
+		handle_health_mon_health_check_complete_req(rwp->conn_h,
+						rwp->req_h, rwp->req);
+		break;
+	default:
+		SHM_ERR("%s: Invalid msg_id %d\n", __func__, rwp->msg_id);
+	}
+	kfree(rwp->req);
+	kfree(rwp);
+}
+
+/**
+ * shm_svc_req_cb() - Callback to notify about QMI requests from HMA
+ * @handle;	QMI Service handle in which the request is received.
+ * @conn_h:	Opaque reference to the connection handle to an HMA.
+ * @req_h:	Opaque reference to the request handle.
+ * @msg_id:	Message ID of the request.
+ * @req:	Pointer to the request structure.
+ *
+ * This function is called by kernel QMI Service Interface to notify the
+ * incoming QMI request on the SHM service handle.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int shm_svc_req_cb(struct qmi_handle *handle, void *conn_h,
+			  void *req_h, unsigned int msg_id, void *req)
+{
+	struct req_work *rwp;
+	void *req_buf;
+	uint32_t req_sz = 0;
+
+	rwp = kzalloc(sizeof(*rwp), GFP_KERNEL);
+	if (!rwp) {
+		SHM_ERR("%s: Error allocating work item\n", __func__);
+		return -ENOMEM;
+	}
+
+	switch (msg_id) {
+	case QMI_HEALTH_MON_REG_REQ_V01:
+		req_sz = sizeof(struct hmon_register_req_msg_v01);
+		break;
+
+	case QMI_HEALTH_MON_HEALTH_CHECK_COMPLETE_REQ_V01:
+		req_sz = sizeof(struct hmon_health_check_complete_req_msg_v01);
+		break;
+
+	default:
+		SHM_ERR("%s: Invalid msg_id %d\n", __func__, msg_id);
+		kfree(rwp);
+		return -ENOTSUPP;
+	}
+
+	req_buf = kzalloc(req_sz, GFP_KERNEL);
+	if (!req_buf) {
+		SHM_ERR("%s: Error allocating request buffer\n", __func__);
+		kfree(rwp);
+		return -ENOMEM;
+	}
+	memcpy(req_buf, req, req_sz);
+
+	INIT_WORK(&rwp->work, shm_svc_req_worker);
+	rwp->conn_h = conn_h;
+	rwp->req_h = req_h;
+	rwp->msg_id = msg_id;
+	rwp->req = req_buf;
+	queue_work(shm_svc_workqueue, &rwp->work);
+	return 0;
+}
+
+/**
+ * shm_svc_recv_msg() - Worker to receive a QMI message
+ * @work:	Reference to the work item.
+ *
+ * This function handles any incoming QMI messages to the SHM QMI service.
+ */
+static void shm_svc_recv_msg(struct work_struct *work)
+{
+	int rc;
+
+	do {
+		SHM_DEBUG("%s: Notified about a receive event\n", __func__);
+	} while ((rc = qmi_recv_msg(shm_svc_handle)) == 0);
+
+	if (rc != -ENOMSG)
+		SHM_ERR("%s: Error %d receiving message\n", __func__, rc);
+}
+
+/**
+ * shm_svc_notify() - Callback function to receive SHM QMI service events
+ * @handle:	QMI handle in which the event is received.
+ * @event:	Type of the QMI event.
+ * @priv:	Opaque reference to the private data as registered by the
+ *		service.
+ */
+static void shm_svc_notify(struct qmi_handle *handle,
+			   enum qmi_event_type event, void *priv)
+{
+	switch (event) {
+	case QMI_RECV_MSG:
+		queue_delayed_work(shm_svc_workqueue, &work_recv_msg, 0);
+		break;
+	default:
+		break;
+	}
+}
+
+static struct qmi_svc_ops_options shm_svc_ops_options = {
+	.version = 1,
+	.service_id = HMON_SERVICE_ID_V01,
+	.service_vers = HMON_SERVICE_VERS_V01,
+	.service_ins = 0,
+	.connect_cb = shm_svc_connect_cb,
+	.disconnect_cb = shm_svc_disconnect_cb,
+	.req_desc_cb = shm_svc_req_desc_cb,
+	.req_cb = shm_svc_req_cb,
+};
+
+static int system_health_monitor_open(struct inode *inode, struct file *file)
+{
+	SHM_DEBUG("%s by %s\n", __func__, current->comm);
+	return 0;
+}
+
+static int system_health_monitor_release(struct inode *inode,
+					  struct file *file)
+{
+	SHM_DEBUG("%s by %s\n", __func__, current->comm);
+	return 0;
+}
+
+static ssize_t system_health_monitor_write(struct file *file,
+	const char __user *buf, size_t count, loff_t *ppos)
+{
+	SHM_ERR("%s by %s\n", __func__, current->comm);
+	return -ENOTSUPP;
+}
+
+static ssize_t system_health_monitor_read(struct file *file, char __user *buf,
+			    size_t count, loff_t *ppos)
+{
+	SHM_ERR("%s by %s\n", __func__, current->comm);
+	return -ENOTSUPP;
+}
+
+static long system_health_monitor_ioctl(struct file *file, unsigned int cmd,
+			  unsigned long arg)
+{
+	int rc;
+
+	switch (cmd) {
+	case CHECK_SYSTEM_HEALTH_IOCTL:
+		SHM_INFO_LOG("%s by %s\n", __func__, current->comm);
+		rc = kern_check_system_health();
+		break;
+	default:
+		SHM_ERR("%s: Invalid cmd %d by %s\n",
+			__func__, cmd, current->comm);
+		rc = -EINVAL;
+	}
+	return rc;
+}
+
+static const struct file_operations system_health_monitor_fops = {
+	.owner = THIS_MODULE,
+	.open = system_health_monitor_open,
+	.release = system_health_monitor_release,
+	.read = system_health_monitor_read,
+	.write = system_health_monitor_write,
+	.unlocked_ioctl = system_health_monitor_ioctl,
+	.compat_ioctl = system_health_monitor_ioctl,
+};
+
+/**
+ * start_system_health_monitor_service() - Start the SHM QMI service
+ *
+ * This function registers the SHM QMI service, if it is not already
+ * registered.
+ */
+static int start_system_health_monitor_service(void)
+{
+	int rc;
+
+	shm_svc_workqueue = create_singlethread_workqueue("shm_svc");
+	if (!shm_svc_workqueue) {
+		SHM_ERR("%s: Error creating workqueue\n", __func__);
+		return -EFAULT;
+	}
+
+	shm_svc_handle = qmi_handle_create(shm_svc_notify, NULL);
+	if (!shm_svc_handle) {
+		SHM_ERR("%s: Creating shm_svc_handle failed\n", __func__);
+		rc = -ENOMEM;
+		goto start_svc_error1;
+	}
+
+	rc = qmi_svc_register(shm_svc_handle, &shm_svc_ops_options);
+	if (rc < 0) {
+		SHM_ERR("%s: Registering shm svc failed - %d\n", __func__, rc);
+		goto start_svc_error2;
+	}
+	return 0;
+start_svc_error2:
+	qmi_handle_destroy(shm_svc_handle);
+start_svc_error1:
+	destroy_workqueue(shm_svc_workqueue);
+	return rc;
+}
+
+/**
+ * parse_devicetree() - Parse the device tree for HMA information
+ * @node:	Pointer to the device tree node.
+ * @hma:	HMA information which needs to be extracted.
+ *
+ * This function parses the device tree, extracts the HMA information.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int parse_devicetree(struct device_node *node,
+			    struct hma_info *hma)
+{
+	char *key;
+	const char *subsys_name;
+	const char *ssrestart_string;
+
+	key = "qcom,subsys-name";
+	subsys_name = of_get_property(node, key, NULL);
+	if (!subsys_name)
+		goto error;
+	strlcpy(hma->subsys_name, subsys_name, SUBSYS_NAME_LEN);
+
+	key = "qcom,ssrestart-string";
+	ssrestart_string = of_get_property(node, key, NULL);
+	if (!ssrestart_string)
+		goto error;
+	strlcpy(hma->ssrestart_string, ssrestart_string, SSRESTART_STRLEN);
+	return 0;
+error:
+	SHM_ERR("%s: missing key: %s\n", __func__, key);
+	return -ENODEV;
+}
+
+/**
+ * system_health_monitor_probe() - Probe function to construct HMA info
+ * @pdev:	Platform device pointing to a device tree node.
+ *
+ * This function extracts the HMA information from the device tree, constructs
+ * it and adds it to the global list.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int system_health_monitor_probe(struct platform_device *pdev)
+{
+	int rc;
+	struct hma_info *hma, *tmp_hma;
+	struct device_node *node;
+
+	mutex_lock(&hma_info_list_lock);
+	for_each_child_of_node(pdev->dev.of_node, node) {
+		hma = kzalloc(sizeof(*hma), GFP_KERNEL);
+		if (!hma) {
+			SHM_ERR("%s: Error allocation hma_info\n", __func__);
+			rc = -ENOMEM;
+			goto probe_err;
+		}
+
+		rc = parse_devicetree(node, hma);
+		if (rc) {
+			SHM_ERR("%s Failed to parse Device Tree\n", __func__);
+			kfree(hma);
+			goto probe_err;
+		}
+
+		init_srcu_struct(&hma->reset_srcu);
+		hma->restart_nb.notifier_call = restart_notifier_cb;
+		hma->restart_nb_h = subsys_notif_register_notifier(
+				hma->ssrestart_string, &hma->restart_nb);
+		if (IS_ERR_OR_NULL(hma->restart_nb_h)) {
+			cleanup_srcu_struct(&hma->reset_srcu);
+			kfree(hma);
+			rc = -EFAULT;
+			SHM_ERR("%s: Error registering restart notif for %s\n",
+				__func__, hma->ssrestart_string);
+			goto probe_err;
+		}
+
+		list_add_tail(&hma->list, &hma_info_list);
+		SHM_INFO_LOG("%s: Added HMA info for %s\n",
+			 __func__, hma->subsys_name);
+	}
+
+	rc = start_system_health_monitor_service();
+	if (rc) {
+		SHM_ERR("%s Failed to start service %d\n", __func__, rc);
+		goto probe_err;
+	}
+	mutex_unlock(&hma_info_list_lock);
+	return 0;
+probe_err:
+	list_for_each_entry_safe(hma, tmp_hma, &hma_info_list, list) {
+		list_del(&hma->list);
+		subsys_notif_unregister_notifier(hma->restart_nb_h,
+						 &hma->restart_nb);
+		cleanup_srcu_struct(&hma->reset_srcu);
+		kfree(hma);
+	}
+	mutex_unlock(&hma_info_list_lock);
+	return rc;
+}
+
+static struct of_device_id system_health_monitor_match_table[] = {
+	{ .compatible = "qcom,system-health-monitor" },
+	{},
+};
+
+static struct platform_driver system_health_monitor_driver = {
+	.probe = system_health_monitor_probe,
+	.driver = {
+		.name = MODULE_NAME,
+		.owner = THIS_MODULE,
+		.of_match_table = system_health_monitor_match_table,
+	},
+};
+
+/**
+ * system_health_monitor_init() - Initialize the system health monitor module
+ *
+ * This functions registers a platform driver to probe for and extract the HMA
+ * information. This function registers the character device interface to the
+ * user-space.
+ *
+ * Return: 0 on success, standard Linux error codes on failure.
+ */
+static int __init system_health_monitor_init(void)
+{
+	int rc;
+
+	shm_ilctxt = ipc_log_context_create(SHM_ILCTXT_NUM_PAGES, "shm", 0);
+	if (!shm_ilctxt) {
+		SHM_ERR("%s: Unable to create SHM logging context\n", __func__);
+		shm_debug_mask = 0;
+	}
+
+	rc = platform_driver_register(&system_health_monitor_driver);
+	if (rc) {
+		SHM_ERR("%s: system_health_monitor_driver register failed %d\n",
+			__func__, rc);
+		return rc;
+	}
+
+	rc = alloc_chrdev_region(&system_health_monitor_dev,
+				 0, 1, "system_health_monitor");
+	if (rc < 0) {
+		SHM_ERR("%s: alloc_chrdev_region() failed %d\n", __func__, rc);
+		return rc;
+	}
+
+	system_health_monitor_classp = class_create(THIS_MODULE,
+						"system_health_monitor");
+	if (IS_ERR_OR_NULL(system_health_monitor_classp)) {
+		SHM_ERR("%s: class_create() failed\n", __func__);
+		rc = -ENOMEM;
+		goto init_error1;
+	}
+
+	cdev_init(&system_health_monitor_cdev, &system_health_monitor_fops);
+	system_health_monitor_cdev.owner = THIS_MODULE;
+	rc = cdev_add(&system_health_monitor_cdev,
+		      system_health_monitor_dev , 1);
+	if (rc < 0) {
+		SHM_ERR("%s: cdev_add() failed - rc %d\n",
+			__func__, rc);
+		goto init_error2;
+	}
+
+	system_health_monitor_devp = device_create(system_health_monitor_classp,
+					NULL, system_health_monitor_dev, NULL,
+					"system_health_monitor");
+	if (IS_ERR_OR_NULL(system_health_monitor_devp)) {
+		SHM_ERR("%s: device_create() failed - rc %d\n",
+			__func__, rc);
+		rc = PTR_ERR(system_health_monitor_devp);
+		goto init_error3;
+	}
+	SHM_INFO_LOG("%s: Complete\n", __func__);
+	return 0;
+init_error3:
+	cdev_del(&system_health_monitor_cdev);
+init_error2:
+	class_destroy(system_health_monitor_classp);
+init_error1:
+	unregister_chrdev_region(MAJOR(system_health_monitor_dev), 1);
+	return rc;
+}
+
+module_init(system_health_monitor_init);
+MODULE_DESCRIPTION("System Health Monitor");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/soc/qcom/system_health_monitor_v01.c b/drivers/soc/qcom/system_health_monitor_v01.c
new file mode 100644
index 000000000000..fe6d7c368312
--- /dev/null
+++ b/drivers/soc/qcom/system_health_monitor_v01.c
@@ -0,0 +1,134 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/qmi_encdec.h>
+
+#include <soc/qcom/msm_qmi_interface.h>
+
+#include "system_health_monitor_v01.h"
+
+struct elem_info hmon_register_req_msg_v01_ei[] = {
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(uint8_t),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct hmon_register_req_msg_v01,
+					   name_valid),
+	},
+	{
+		.data_type      = QMI_STRING,
+		.elem_len       = 255,
+		.elem_size      = sizeof(char),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(struct hmon_register_req_msg_v01,
+					   name),
+	},
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(uint8_t),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x11,
+		.offset         = offsetof(struct hmon_register_req_msg_v01,
+					   timeout_valid),
+	},
+	{
+		.data_type      = QMI_UNSIGNED_4_BYTE,
+		.elem_len       = 1,
+		.elem_size      = sizeof(uint32_t),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x11,
+		.offset         = offsetof(struct hmon_register_req_msg_v01,
+					   timeout),
+	},
+	{
+		.data_type      = QMI_EOTI,
+		.is_array       = NO_ARRAY,
+		.is_array       = QMI_COMMON_TLV_TYPE,
+	},
+};
+
+struct elem_info hmon_register_resp_msg_v01_ei[] = {
+	{
+		.data_type      = QMI_STRUCT,
+		.elem_len       = 1,
+		.elem_size      = sizeof(struct qmi_response_type_v01),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(struct hmon_register_resp_msg_v01,
+					   resp),
+		.ei_array      = get_qmi_response_type_v01_ei(),
+	},
+	{
+		.data_type      = QMI_EOTI,
+		.is_array       = NO_ARRAY,
+		.is_array       = QMI_COMMON_TLV_TYPE,
+	},
+};
+
+struct elem_info hmon_health_check_ind_msg_v01_ei[] = {
+	{
+		.data_type      = QMI_EOTI,
+		.is_array       = NO_ARRAY,
+		.is_array       = QMI_COMMON_TLV_TYPE,
+	},
+};
+
+struct elem_info hmon_health_check_complete_req_msg_v01_ei[] = {
+	{
+		.data_type      = QMI_OPT_FLAG,
+		.elem_len       = 1,
+		.elem_size      = sizeof(uint8_t),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(
+				struct hmon_health_check_complete_req_msg_v01,
+				result_valid),
+	},
+	{
+		.data_type      = QMI_SIGNED_4_BYTE_ENUM,
+		.elem_len       = 1,
+		.elem_size      = sizeof(enum hmon_check_result_v01),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x10,
+		.offset         = offsetof(
+				struct hmon_health_check_complete_req_msg_v01,
+				result),
+	},
+	{
+		.data_type      = QMI_EOTI,
+		.is_array       = NO_ARRAY,
+		.is_array       = QMI_COMMON_TLV_TYPE,
+	},
+};
+
+struct elem_info hmon_health_check_complete_resp_msg_v01_ei[] = {
+	{
+		.data_type      = QMI_STRUCT,
+		.elem_len       = 1,
+		.elem_size      = sizeof(struct qmi_response_type_v01),
+		.is_array       = NO_ARRAY,
+		.tlv_type       = 0x02,
+		.offset         = offsetof(
+				struct hmon_health_check_complete_resp_msg_v01,
+				resp),
+		.ei_array      = get_qmi_response_type_v01_ei(),
+	},
+	{
+		.data_type      = QMI_EOTI,
+		.is_array       = NO_ARRAY,
+		.is_array       = QMI_COMMON_TLV_TYPE,
+	},
+};
diff --git a/drivers/soc/qcom/system_health_monitor_v01.h b/drivers/soc/qcom/system_health_monitor_v01.h
new file mode 100644
index 000000000000..ca0e42a8032b
--- /dev/null
+++ b/drivers/soc/qcom/system_health_monitor_v01.h
@@ -0,0 +1,66 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#ifndef SYSTEM_HEALTH_MONITOR_V01_H
+#define SYSTEM_HEALTH_MONITOR_V01_H
+
+#define HMON_SERVICE_ID_V01 0x3C
+#define HMON_SERVICE_VERS_V01 0x01
+
+#define QMI_HEALTH_MON_HEALTH_CHECK_COMPLETE_REQ_V01 0x0022
+#define QMI_HEALTH_MON_HEALTH_CHECK_COMPLETE_RESP_V01 0x0022
+#define QMI_HEALTH_MON_HEALTH_CHECK_IND_V01 0x0021
+#define QMI_HEALTH_MON_REG_RESP_V01 0x0020
+#define QMI_HEALTH_MON_REG_REQ_V01 0x0020
+
+struct hmon_register_req_msg_v01 {
+	uint8_t name_valid;
+	char name[256];
+	uint8_t timeout_valid;
+	uint32_t timeout;
+};
+#define HMON_REGISTER_REQ_MSG_V01_MAX_MSG_LEN 265
+extern struct elem_info hmon_register_req_msg_v01_ei[];
+
+struct hmon_register_resp_msg_v01 {
+	struct qmi_response_type_v01 resp;
+};
+#define HMON_REGISTER_RESP_MSG_V01_MAX_MSG_LEN 7
+extern struct elem_info hmon_register_resp_msg_v01_ei[];
+
+struct hmon_health_check_ind_msg_v01 {
+	char placeholder;
+};
+#define HMON_HEALTH_CHECK_IND_MSG_V01_MAX_MSG_LEN 0
+extern struct elem_info hmon_health_check_ind_msg_v01_ei[];
+
+enum hmon_check_result_v01 {
+	HMON_CHECK_RESULT_MIN_VAL_V01 = INT_MIN,
+	HEALTH_MONITOR_CHECK_SUCCESS_V01 = 0,
+	HEALTH_MONITOR_CHECK_FAILURE_V01 = 1,
+	HMON_CHECK_RESULT_MAX_VAL_V01 = INT_MAX,
+};
+
+struct hmon_health_check_complete_req_msg_v01 {
+	uint8_t result_valid;
+	enum hmon_check_result_v01 result;
+};
+#define HMON_HEALTH_CHECK_COMPLETE_REQ_MSG_V01_MAX_MSG_LEN 7
+extern struct elem_info hmon_health_check_complete_req_msg_v01_ei[];
+
+struct hmon_health_check_complete_resp_msg_v01 {
+	struct qmi_response_type_v01 resp;
+};
+#define HMON_HEALTH_CHECK_COMPLETE_RESP_MSG_V01_MAX_MSG_LEN 7
+extern struct elem_info hmon_health_check_complete_resp_msg_v01_ei[];
+
+#endif /* SYSTEM_HEALTH_MONITOR_V01_H */