diff --git a/drivers/misc/bcm-vk/Makefile b/drivers/misc/bcm-vk/Makefile
index a2ae79858409..79b4e365c9e6 100644
--- a/drivers/misc/bcm-vk/Makefile
+++ b/drivers/misc/bcm-vk/Makefile
@@ -6,5 +6,6 @@
 obj-$(CONFIG_BCM_VK) += bcm_vk.o
 bcm_vk-objs := \
 	bcm_vk_dev.o \
-	bcm_vk_msg.o
+	bcm_vk_msg.o \
+	bcm_vk_sg.o
 
diff --git a/drivers/misc/bcm-vk/bcm_vk.h b/drivers/misc/bcm-vk/bcm_vk.h
index 50f2a0cd6e13..d847a512d0ed 100644
--- a/drivers/misc/bcm-vk/bcm_vk.h
+++ b/drivers/misc/bcm-vk/bcm_vk.h
@@ -6,11 +6,13 @@
 #ifndef BCM_VK_H
 #define BCM_VK_H
 
+#include <linux/atomic.h>
 #include <linux/firmware.h>
 #include <linux/kref.h>
 #include <linux/miscdevice.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
+#include <linux/poll.h>
 #include <linux/sched/signal.h>
 #include <linux/uaccess.h>
 #include <uapi/linux/misc/bcm_vk.h>
@@ -93,14 +95,53 @@
 #define MAJOR_SOC_REV(_chip_id)		(((_chip_id) >> 20) & 0xf)
 
 #define BAR_CARD_TEMPERATURE		0x45c
+/* defines for all temperature sensor */
+#define BCM_VK_TEMP_FIELD_MASK		0xff
+#define BCM_VK_CPU_TEMP_SHIFT		0
+#define BCM_VK_DDR0_TEMP_SHIFT		8
+#define BCM_VK_DDR1_TEMP_SHIFT		16
 
 #define BAR_CARD_VOLTAGE		0x460
+/* defines for voltage rail conversion */
+#define BCM_VK_VOLT_RAIL_MASK		0xffff
+#define BCM_VK_3P3_VOLT_REG_SHIFT	16
 
 #define BAR_CARD_ERR_LOG		0x464
+/* Error log register bit definition - register for error alerts */
+#define ERR_LOG_UECC			BIT(0)
+#define ERR_LOG_SSIM_BUSY		BIT(1)
+#define ERR_LOG_AFBC_BUSY		BIT(2)
+#define ERR_LOG_HIGH_TEMP_ERR		BIT(3)
+#define ERR_LOG_WDOG_TIMEOUT		BIT(4)
+#define ERR_LOG_SYS_FAULT		BIT(5)
+#define ERR_LOG_RAMDUMP			BIT(6)
+#define ERR_LOG_COP_WDOG_TIMEOUT	BIT(7)
+/* warnings */
+#define ERR_LOG_MEM_ALLOC_FAIL		BIT(8)
+#define ERR_LOG_LOW_TEMP_WARN		BIT(9)
+#define ERR_LOG_ECC			BIT(10)
+#define ERR_LOG_IPC_DWN			BIT(11)
+
+/* Alert bit definitions detectd on host */
+#define ERR_LOG_HOST_INTF_V_FAIL	BIT(13)
+#define ERR_LOG_HOST_HB_FAIL		BIT(14)
+#define ERR_LOG_HOST_PCIE_DWN		BIT(15)
 
 #define BAR_CARD_ERR_MEM		0x468
+/* defines for mem err, all fields have same width */
+#define BCM_VK_MEM_ERR_FIELD_MASK	0xff
+#define BCM_VK_ECC_MEM_ERR_SHIFT	0
+#define BCM_VK_UECC_MEM_ERR_SHIFT	8
+/* threshold of event occurrence and logs start to come out */
+#define BCM_VK_ECC_THRESHOLD		10
+#define BCM_VK_UECC_THRESHOLD		1
 
 #define BAR_CARD_PWR_AND_THRE		0x46c
+/* defines for power and temp threshold, all fields have same width */
+#define BCM_VK_PWR_AND_THRE_FIELD_MASK	0xff
+#define BCM_VK_LOW_TEMP_THRE_SHIFT	0
+#define BCM_VK_HIGH_TEMP_THRE_SHIFT	8
+#define BCM_VK_PWR_STATE_SHIFT		16
 
 #define BAR_CARD_STATIC_INFO		0x470
 
@@ -143,6 +184,11 @@
 #define BAR_FIRMWARE_TAG_SIZE		50
 #define FIRMWARE_STATUS_PRE_INIT_DONE	0x1f
 
+/* VK MSG_ID defines */
+#define VK_MSG_ID_BITMAP_SIZE		4096
+#define VK_MSG_ID_BITMAP_MASK		(VK_MSG_ID_BITMAP_SIZE - 1)
+#define VK_MSG_ID_OVERFLOW		0xffff
+
 /*
  * BAR1
  */
@@ -197,6 +243,10 @@
 /* VK device supports a maximum of 3 bars */
 #define MAX_BAR	3
 
+/* default number of msg blk for inband SGL */
+#define BCM_VK_DEF_IB_SGL_BLK_LEN	 16
+#define BCM_VK_IB_SGL_BLK_MAX		 24
+
 enum pci_barno {
 	BAR_0 = 0,
 	BAR_1,
@@ -267,9 +317,27 @@ struct bcm_vk_proc_mon_info {
 	struct bcm_vk_proc_mon_entry_t entries[BCM_VK_PROC_MON_MAX];
 };
 
+struct bcm_vk_hb_ctrl {
+	struct timer_list timer;
+	u32 last_uptime;
+	u32 lost_cnt;
+};
+
+struct bcm_vk_alert {
+	u16 flags;
+	u16 notfs;
+};
+
+/* some alert counters that the driver will keep track */
+struct bcm_vk_alert_cnts {
+	u16 ecc;
+	u16 uecc;
+};
+
 struct bcm_vk {
 	struct pci_dev *pdev;
 	void __iomem *bar[MAX_BAR];
+	int num_irqs;
 
 	struct bcm_vk_card_info card_info;
 	struct bcm_vk_proc_mon_info proc_mon_info;
@@ -283,9 +351,17 @@ struct bcm_vk {
 	/* Reference-counting to handle file operations */
 	struct kref kref;
 
+	spinlock_t msg_id_lock; /* Spinlock for msg_id */
+	u16 msg_id;
+	DECLARE_BITMAP(bmap, VK_MSG_ID_BITMAP_SIZE);
 	spinlock_t ctx_lock; /* Spinlock for component context */
 	struct bcm_vk_ctx ctx[VK_CMPT_CTX_MAX];
 	struct bcm_vk_ht_entry pid_ht[VK_PID_HT_SZ];
+	pid_t reset_pid; /* process that issue reset */
+
+	atomic_t msgq_inited; /* indicate if info has been synced with vk */
+	struct bcm_vk_msg_chan to_v_msg_chan;
+	struct bcm_vk_msg_chan to_h_msg_chan;
 
 	struct workqueue_struct *wq_thread;
 	struct work_struct wq_work; /* work queue for deferred job */
@@ -294,6 +370,15 @@ struct bcm_vk {
 	dma_addr_t tdma_addr; /* test dma segment bus addr */
 
 	struct notifier_block panic_nb;
+	u32 ib_sgl_size; /* size allocated for inband sgl insertion */
+
+	/* heart beat mechanism control structure */
+	struct bcm_vk_hb_ctrl hb_ctrl;
+	/* house-keeping variable of error logs */
+	spinlock_t host_alert_lock; /* protection to access host_alert struct */
+	struct bcm_vk_alert host_alert;
+	struct bcm_vk_alert peer_alert; /* bits set by the card */
+	struct bcm_vk_alert_cnts alert_cnts;
 
 	/* offset of the peer log control in BAR2 */
 	u32 peerlog_off;
@@ -306,8 +391,26 @@ struct bcm_vk {
 enum bcm_vk_wq_offload_flags {
 	BCM_VK_WQ_DWNLD_PEND = 0,
 	BCM_VK_WQ_DWNLD_AUTO = 1,
+	BCM_VK_WQ_NOTF_PEND  = 2,
 };
 
+/* a macro to get an individual field with mask and shift */
+#define BCM_VK_EXTRACT_FIELD(_field, _reg, _mask, _shift) \
+		(_field = (((_reg) >> (_shift)) & (_mask)))
+
+struct bcm_vk_entry {
+	const u32 mask;
+	const u32 exp_val;
+	const char *str;
+};
+
+/* alerts that could be generated from peer */
+#define BCM_VK_PEER_ERR_NUM 12
+extern struct bcm_vk_entry const bcm_vk_peer_err[BCM_VK_PEER_ERR_NUM];
+/* alerts detected by the host */
+#define BCM_VK_HOST_ERR_NUM 3
+extern struct bcm_vk_entry const bcm_vk_host_err[BCM_VK_HOST_ERR_NUM];
+
 /*
  * check if PCIe interface is down on read.  Use it when it is
  * certain that _val should never be all ones.
@@ -354,8 +457,28 @@ static inline bool bcm_vk_msgq_marker_valid(struct bcm_vk *vk)
 }
 
 int bcm_vk_open(struct inode *inode, struct file *p_file);
+ssize_t bcm_vk_read(struct file *p_file, char __user *buf, size_t count,
+		    loff_t *f_pos);
+ssize_t bcm_vk_write(struct file *p_file, const char __user *buf,
+		     size_t count, loff_t *f_pos);
+__poll_t bcm_vk_poll(struct file *p_file, struct poll_table_struct *wait);
 int bcm_vk_release(struct inode *inode, struct file *p_file);
 void bcm_vk_release_data(struct kref *kref);
+irqreturn_t bcm_vk_msgq_irqhandler(int irq, void *dev_id);
+irqreturn_t bcm_vk_notf_irqhandler(int irq, void *dev_id);
+int bcm_vk_msg_init(struct bcm_vk *vk);
+void bcm_vk_msg_remove(struct bcm_vk *vk);
+int bcm_vk_sync_msgq(struct bcm_vk *vk, bool force_sync);
+void bcm_vk_blk_drv_access(struct bcm_vk *vk);
+s32 bcm_to_h_msg_dequeue(struct bcm_vk *vk);
+int bcm_vk_send_shutdown_msg(struct bcm_vk *vk, u32 shut_type,
+			     const pid_t pid, const u32 q_num);
+void bcm_to_v_q_doorbell(struct bcm_vk *vk, u32 q_num, u32 db_val);
 int bcm_vk_auto_load_all_images(struct bcm_vk *vk);
+void bcm_vk_hb_init(struct bcm_vk *vk);
+void bcm_vk_hb_deinit(struct bcm_vk *vk);
+void bcm_vk_handle_notf(struct bcm_vk *vk);
+bool bcm_vk_drv_access_ok(struct bcm_vk *vk);
+void bcm_vk_set_host_alert(struct bcm_vk *vk, u32 bit_mask);
 
 #endif
diff --git a/drivers/misc/bcm-vk/bcm_vk_dev.c b/drivers/misc/bcm-vk/bcm_vk_dev.c
index a63208513c64..5d82f02c0f27 100644
--- a/drivers/misc/bcm-vk/bcm_vk_dev.c
+++ b/drivers/misc/bcm-vk/bcm_vk_dev.c
@@ -8,6 +8,7 @@
 #include <linux/firmware.h>
 #include <linux/fs.h>
 #include <linux/idr.h>
+#include <linux/interrupt.h>
 #include <linux/kref.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -102,6 +103,54 @@ static uint nr_scratch_pages = VK_BAR1_SCRATCH_DEF_NR_PAGES;
 module_param(nr_scratch_pages, uint, 0444);
 MODULE_PARM_DESC(nr_scratch_pages,
 		 "Number of pre allocated DMAable coherent pages.\n");
+static uint nr_ib_sgl_blk = BCM_VK_DEF_IB_SGL_BLK_LEN;
+module_param(nr_ib_sgl_blk, uint, 0444);
+MODULE_PARM_DESC(nr_ib_sgl_blk,
+		 "Number of in-band msg blks for short SGL.\n");
+
+/*
+ * alerts that could be generated from peer
+ */
+const struct bcm_vk_entry bcm_vk_peer_err[BCM_VK_PEER_ERR_NUM] = {
+	{ERR_LOG_UECC, ERR_LOG_UECC, "uecc"},
+	{ERR_LOG_SSIM_BUSY, ERR_LOG_SSIM_BUSY, "ssim_busy"},
+	{ERR_LOG_AFBC_BUSY, ERR_LOG_AFBC_BUSY, "afbc_busy"},
+	{ERR_LOG_HIGH_TEMP_ERR, ERR_LOG_HIGH_TEMP_ERR, "high_temp"},
+	{ERR_LOG_WDOG_TIMEOUT, ERR_LOG_WDOG_TIMEOUT, "wdog_timeout"},
+	{ERR_LOG_SYS_FAULT, ERR_LOG_SYS_FAULT, "sys_fault"},
+	{ERR_LOG_RAMDUMP, ERR_LOG_RAMDUMP, "ramdump"},
+	{ERR_LOG_COP_WDOG_TIMEOUT, ERR_LOG_COP_WDOG_TIMEOUT,
+	 "cop_wdog_timeout"},
+	{ERR_LOG_MEM_ALLOC_FAIL, ERR_LOG_MEM_ALLOC_FAIL, "malloc_fail warn"},
+	{ERR_LOG_LOW_TEMP_WARN, ERR_LOG_LOW_TEMP_WARN, "low_temp warn"},
+	{ERR_LOG_ECC, ERR_LOG_ECC, "ecc"},
+	{ERR_LOG_IPC_DWN, ERR_LOG_IPC_DWN, "ipc_down"},
+};
+
+/* alerts detected by the host */
+const struct bcm_vk_entry bcm_vk_host_err[BCM_VK_HOST_ERR_NUM] = {
+	{ERR_LOG_HOST_PCIE_DWN, ERR_LOG_HOST_PCIE_DWN, "PCIe_down"},
+	{ERR_LOG_HOST_HB_FAIL, ERR_LOG_HOST_HB_FAIL, "hb_fail"},
+	{ERR_LOG_HOST_INTF_V_FAIL, ERR_LOG_HOST_INTF_V_FAIL, "intf_ver_fail"},
+};
+
+irqreturn_t bcm_vk_notf_irqhandler(int irq, void *dev_id)
+{
+	struct bcm_vk *vk = dev_id;
+
+	if (!bcm_vk_drv_access_ok(vk)) {
+		dev_err(&vk->pdev->dev,
+			"Interrupt %d received when msgq not inited\n", irq);
+		goto skip_schedule_work;
+	}
+
+	/* if notification is not pending, set bit and schedule work */
+	if (test_and_set_bit(BCM_VK_WQ_NOTF_PEND, vk->wq_offload) == 0)
+		queue_work(vk->wq_thread, &vk->wq_work);
+
+skip_schedule_work:
+	return IRQ_HANDLED;
+}
 
 static int bcm_vk_intf_ver_chk(struct bcm_vk *vk)
 {
@@ -126,6 +175,7 @@ static int bcm_vk_intf_ver_chk(struct bcm_vk *vk)
 		dev_err(dev,
 			"Intf major.minor=%d.%d rejected - drv %d.%d\n",
 			major, minor, SEMANTIC_MAJOR, SEMANTIC_MINOR);
+		bcm_vk_set_host_alert(vk, ERR_LOG_HOST_INTF_V_FAIL);
 		ret = -EPFNOSUPPORT;
 	} else {
 		dev_dbg(dev,
@@ -135,6 +185,154 @@ static int bcm_vk_intf_ver_chk(struct bcm_vk *vk)
 	return ret;
 }
 
+static void bcm_vk_log_notf(struct bcm_vk *vk,
+			    struct bcm_vk_alert *alert,
+			    struct bcm_vk_entry const *entry_tab,
+			    const u32 table_size)
+{
+	u32 i;
+	u32 masked_val, latched_val;
+	struct bcm_vk_entry const *entry;
+	u32 reg;
+	u16 ecc_mem_err, uecc_mem_err;
+	struct device *dev = &vk->pdev->dev;
+
+	for (i = 0; i < table_size; i++) {
+		entry = &entry_tab[i];
+		masked_val = entry->mask & alert->notfs;
+		latched_val = entry->mask & alert->flags;
+
+		if (masked_val == ERR_LOG_UECC) {
+			/*
+			 * if there is difference between stored cnt and it
+			 * is greater than threshold, log it.
+			 */
+			reg = vkread32(vk, BAR_0, BAR_CARD_ERR_MEM);
+			BCM_VK_EXTRACT_FIELD(uecc_mem_err, reg,
+					     BCM_VK_MEM_ERR_FIELD_MASK,
+					     BCM_VK_UECC_MEM_ERR_SHIFT);
+			if ((uecc_mem_err != vk->alert_cnts.uecc) &&
+			    (uecc_mem_err >= BCM_VK_UECC_THRESHOLD))
+				dev_info(dev,
+					 "ALERT! %s.%d uecc RAISED - ErrCnt %d\n",
+					 DRV_MODULE_NAME, vk->devid,
+					 uecc_mem_err);
+			vk->alert_cnts.uecc = uecc_mem_err;
+		} else if (masked_val == ERR_LOG_ECC) {
+			reg = vkread32(vk, BAR_0, BAR_CARD_ERR_MEM);
+			BCM_VK_EXTRACT_FIELD(ecc_mem_err, reg,
+					     BCM_VK_MEM_ERR_FIELD_MASK,
+					     BCM_VK_ECC_MEM_ERR_SHIFT);
+			if ((ecc_mem_err != vk->alert_cnts.ecc) &&
+			    (ecc_mem_err >= BCM_VK_ECC_THRESHOLD))
+				dev_info(dev, "ALERT! %s.%d ecc RAISED - ErrCnt %d\n",
+					 DRV_MODULE_NAME, vk->devid,
+					 ecc_mem_err);
+			vk->alert_cnts.ecc = ecc_mem_err;
+		} else if (masked_val != latched_val) {
+			/* print a log as info */
+			dev_info(dev, "ALERT! %s.%d %s %s\n",
+				 DRV_MODULE_NAME, vk->devid, entry->str,
+				 masked_val ? "RAISED" : "CLEARED");
+		}
+	}
+}
+
+static void bcm_vk_dump_peer_log(struct bcm_vk *vk)
+{
+	struct bcm_vk_peer_log log;
+	struct bcm_vk_peer_log *log_info = &vk->peerlog_info;
+	char loc_buf[BCM_VK_PEER_LOG_LINE_MAX];
+	int cnt;
+	struct device *dev = &vk->pdev->dev;
+	unsigned int data_offset;
+
+	memcpy_fromio(&log, vk->bar[BAR_2] + vk->peerlog_off, sizeof(log));
+
+	dev_dbg(dev, "Peer PANIC: Size 0x%x(0x%x), [Rd Wr] = [%d %d]\n",
+		log.buf_size, log.mask, log.rd_idx, log.wr_idx);
+
+	if (!log_info->buf_size) {
+		dev_err(dev, "Peer log dump disabled - skipped!\n");
+		return;
+	}
+
+	/* perform range checking for rd/wr idx */
+	if ((log.rd_idx > log_info->mask) ||
+	    (log.wr_idx > log_info->mask) ||
+	    (log.buf_size != log_info->buf_size) ||
+	    (log.mask != log_info->mask)) {
+		dev_err(dev,
+			"Corrupted Ptrs: Size 0x%x(0x%x) Mask 0x%x(0x%x) [Rd Wr] = [%d %d], skip log dump.\n",
+			log_info->buf_size, log.buf_size,
+			log_info->mask, log.mask,
+			log.rd_idx, log.wr_idx);
+		return;
+	}
+
+	cnt = 0;
+	data_offset = vk->peerlog_off + sizeof(struct bcm_vk_peer_log);
+	loc_buf[BCM_VK_PEER_LOG_LINE_MAX - 1] = '\0';
+	while (log.rd_idx != log.wr_idx) {
+		loc_buf[cnt] = vkread8(vk, BAR_2, data_offset + log.rd_idx);
+
+		if ((loc_buf[cnt] == '\0') ||
+		    (cnt == (BCM_VK_PEER_LOG_LINE_MAX - 1))) {
+			dev_err(dev, "%s", loc_buf);
+			cnt = 0;
+		} else {
+			cnt++;
+		}
+		log.rd_idx = (log.rd_idx + 1) & log.mask;
+	}
+	/* update rd idx at the end */
+	vkwrite32(vk, log.rd_idx, BAR_2,
+		  vk->peerlog_off + offsetof(struct bcm_vk_peer_log, rd_idx));
+}
+
+void bcm_vk_handle_notf(struct bcm_vk *vk)
+{
+	u32 reg;
+	struct bcm_vk_alert alert;
+	bool intf_down;
+	unsigned long flags;
+
+	/* handle peer alerts and then locally detected ones */
+	reg = vkread32(vk, BAR_0, BAR_CARD_ERR_LOG);
+	intf_down = BCM_VK_INTF_IS_DOWN(reg);
+	if (!intf_down) {
+		vk->peer_alert.notfs = reg;
+		bcm_vk_log_notf(vk, &vk->peer_alert, bcm_vk_peer_err,
+				ARRAY_SIZE(bcm_vk_peer_err));
+		vk->peer_alert.flags = vk->peer_alert.notfs;
+	} else {
+		/* turn off access */
+		bcm_vk_blk_drv_access(vk);
+	}
+
+	/* check and make copy of alert with lock and then free lock */
+	spin_lock_irqsave(&vk->host_alert_lock, flags);
+	if (intf_down)
+		vk->host_alert.notfs |= ERR_LOG_HOST_PCIE_DWN;
+
+	alert = vk->host_alert;
+	vk->host_alert.flags = vk->host_alert.notfs;
+	spin_unlock_irqrestore(&vk->host_alert_lock, flags);
+
+	/* call display with copy */
+	bcm_vk_log_notf(vk, &alert, bcm_vk_host_err,
+			ARRAY_SIZE(bcm_vk_host_err));
+
+	/*
+	 * If it is a sys fault or heartbeat timeout, we would like extract
+	 * log msg from the card so that we would know what is the last fault
+	 */
+	if (!intf_down &&
+	    ((vk->host_alert.flags & ERR_LOG_HOST_HB_FAIL) ||
+	     (vk->peer_alert.flags & ERR_LOG_SYS_FAULT)))
+		bcm_vk_dump_peer_log(vk);
+}
+
 static inline int bcm_vk_wait(struct bcm_vk *vk, enum pci_barno bar,
 			      u64 offset, u32 mask, u32 value,
 			      unsigned long timeout_ms)
@@ -301,6 +499,31 @@ static int bcm_vk_sync_card_info(struct bcm_vk *vk)
 	return 0;
 }
 
+void bcm_vk_blk_drv_access(struct bcm_vk *vk)
+{
+	int i;
+
+	/*
+	 * kill all the apps
+	 */
+	spin_lock(&vk->ctx_lock);
+
+	/* set msgq_inited to 0 so that all rd/wr will be blocked */
+	atomic_set(&vk->msgq_inited, 0);
+
+	for (i = 0; i < VK_PID_HT_SZ; i++) {
+		struct bcm_vk_ctx *ctx;
+
+		list_for_each_entry(ctx, &vk->pid_ht[i].head, node) {
+			dev_dbg(&vk->pdev->dev,
+				"Send kill signal to pid %d\n",
+				ctx->pid);
+			kill_pid(find_vpid(ctx->pid), SIGKILL, 1);
+		}
+	}
+	spin_unlock(&vk->ctx_lock);
+}
+
 static void bcm_vk_buf_notify(struct bcm_vk *vk, void *bufp,
 			      dma_addr_t host_buf_addr, u32 buf_size)
 {
@@ -518,6 +741,17 @@ static int bcm_vk_load_image_by_type(struct bcm_vk *vk, u32 load_type,
 				goto err_firmware_out;
 			}
 
+			/*
+			 * Next, initialize Message Q if we are loading boot2.
+			 * Do a force sync
+			 */
+			ret = bcm_vk_sync_msgq(vk, true);
+			if (ret) {
+				dev_err(dev, "Boot2 Error reading comm msg Q info\n");
+				ret = -EIO;
+				goto err_firmware_out;
+			}
+
 			/* sync & channel other info */
 			ret = bcm_vk_sync_card_info(vk);
 			if (ret) {
@@ -668,12 +902,20 @@ static int bcm_vk_trigger_autoload(struct bcm_vk *vk)
 }
 
 /*
- * deferred work queue for auto download.
+ * deferred work queue for draining and auto download.
  */
 static void bcm_vk_wq_handler(struct work_struct *work)
 {
 	struct bcm_vk *vk = container_of(work, struct bcm_vk, wq_work);
+	struct device *dev = &vk->pdev->dev;
+	s32 ret;
 
+	/* check wq offload bit map to perform various operations */
+	if (test_bit(BCM_VK_WQ_NOTF_PEND, vk->wq_offload)) {
+		/* clear bit right the way for notification */
+		clear_bit(BCM_VK_WQ_NOTF_PEND, vk->wq_offload);
+		bcm_vk_handle_notf(vk);
+	}
 	if (test_bit(BCM_VK_WQ_DWNLD_AUTO, vk->wq_offload)) {
 		bcm_vk_auto_load_all_images(vk);
 
@@ -684,6 +926,14 @@ static void bcm_vk_wq_handler(struct work_struct *work)
 		clear_bit(BCM_VK_WQ_DWNLD_AUTO, vk->wq_offload);
 		clear_bit(BCM_VK_WQ_DWNLD_PEND, vk->wq_offload);
 	}
+
+	/* next, try to drain */
+	ret = bcm_to_h_msg_dequeue(vk);
+
+	if (ret == 0)
+		dev_dbg(dev, "Spurious trigger for workqueue\n");
+	else if (ret < 0)
+		bcm_vk_blk_drv_access(vk);
 }
 
 static long bcm_vk_load_image(struct bcm_vk *vk,
@@ -837,6 +1087,9 @@ static long bcm_vk_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 static const struct file_operations bcm_vk_fops = {
 	.owner = THIS_MODULE,
 	.open = bcm_vk_open,
+	.read = bcm_vk_read,
+	.write = bcm_vk_write,
+	.poll = bcm_vk_poll,
 	.release = bcm_vk_release,
 	.unlocked_ioctl = bcm_vk_ioctl,
 };
@@ -869,6 +1122,12 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		return -ENOMEM;
 
 	kref_init(&vk->kref);
+	if (nr_ib_sgl_blk > BCM_VK_IB_SGL_BLK_MAX) {
+		dev_warn(dev, "Inband SGL blk %d limited to max %d\n",
+			 nr_ib_sgl_blk, BCM_VK_IB_SGL_BLK_MAX);
+		nr_ib_sgl_blk = BCM_VK_IB_SGL_BLK_MAX;
+	}
+	vk->ib_sgl_size = nr_ib_sgl_blk * VK_MSGQ_BLK_SIZE;
 	mutex_init(&vk->mutex);
 
 	err = pci_enable_device(pdev);
@@ -932,11 +1191,34 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		}
 	}
 
+	for (vk->num_irqs = 0;
+	     vk->num_irqs < VK_MSIX_MSGQ_MAX;
+	     vk->num_irqs++) {
+		err = devm_request_irq(dev, pci_irq_vector(pdev, vk->num_irqs),
+				       bcm_vk_msgq_irqhandler,
+				       IRQF_SHARED, DRV_MODULE_NAME, vk);
+		if (err) {
+			dev_err(dev, "failed to request msgq IRQ %d for MSIX %d\n",
+				pdev->irq + vk->num_irqs, vk->num_irqs + 1);
+			goto err_irq;
+		}
+	}
+	/* one irq for notification from VK */
+	err = devm_request_irq(dev, pci_irq_vector(pdev, vk->num_irqs),
+			       bcm_vk_notf_irqhandler,
+			       IRQF_SHARED, DRV_MODULE_NAME, vk);
+	if (err) {
+		dev_err(dev, "failed to request notf IRQ %d for MSIX %d\n",
+			pdev->irq + vk->num_irqs, vk->num_irqs + 1);
+		goto err_irq;
+	}
+	vk->num_irqs++;
+
 	id = ida_simple_get(&bcm_vk_ida, 0, 0, GFP_KERNEL);
 	if (id < 0) {
 		err = id;
 		dev_err(dev, "unable to get id\n");
-		goto err_iounmap;
+		goto err_irq;
 	}
 
 	vk->devid = id;
@@ -966,6 +1248,12 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err_misc_deregister;
 	}
 
+	err = bcm_vk_msg_init(vk);
+	if (err) {
+		dev_err(dev, "failed to init msg queue info\n");
+		goto err_destroy_workqueue;
+	}
+
 	/* sync other info */
 	bcm_vk_sync_card_info(vk);
 
@@ -994,6 +1282,9 @@ static int bcm_vk_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		}
 	}
 
+	/* enable hb */
+	bcm_vk_hb_init(vk);
+
 	dev_dbg(dev, "BCM-VK:%u created\n", id);
 
 	return 0;
@@ -1015,6 +1306,13 @@ err_kfree_name:
 err_ida_remove:
 	ida_simple_remove(&bcm_vk_ida, id);
 
+err_irq:
+	for (i = 0; i < vk->num_irqs; i++)
+		devm_free_irq(dev, pci_irq_vector(pdev, i), vk);
+
+	pci_disable_msix(pdev);
+	pci_disable_msi(pdev);
+
 err_iounmap:
 	for (i = 0; i < MAX_BAR; i++) {
 		if (vk->bar[i])
@@ -1053,6 +1351,8 @@ static void bcm_vk_remove(struct pci_dev *pdev)
 	struct bcm_vk *vk = pci_get_drvdata(pdev);
 	struct miscdevice *misc_device = &vk->miscdev;
 
+	bcm_vk_hb_deinit(vk);
+
 	/*
 	 * Trigger a reset to card and wait enough time for UCODE to rerun,
 	 * which re-initialize the card into its default state.
@@ -1076,6 +1376,11 @@ static void bcm_vk_remove(struct pci_dev *pdev)
 		kfree(misc_device->name);
 		ida_simple_remove(&bcm_vk_ida, vk->devid);
 	}
+	for (i = 0; i < vk->num_irqs; i++)
+		devm_free_irq(&pdev->dev, pci_irq_vector(pdev, i), vk);
+
+	pci_disable_msix(pdev);
+	pci_disable_msi(pdev);
 
 	cancel_work_sync(&vk->wq_work);
 	destroy_workqueue(vk->wq_thread);
diff --git a/drivers/misc/bcm-vk/bcm_vk_msg.c b/drivers/misc/bcm-vk/bcm_vk_msg.c
index 2d9a6b4e5f61..b05e20a72a8b 100644
--- a/drivers/misc/bcm-vk/bcm_vk_msg.c
+++ b/drivers/misc/bcm-vk/bcm_vk_msg.c
@@ -3,8 +3,200 @@
  * Copyright 2018-2020 Broadcom.
  */
 
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/hash.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/sizes.h>
+#include <linux/spinlock.h>
+#include <linux/timer.h>
+
 #include "bcm_vk.h"
 #include "bcm_vk_msg.h"
+#include "bcm_vk_sg.h"
+
+/* functions to manipulate the transport id in msg block */
+#define BCM_VK_MSG_Q_SHIFT	 4
+#define BCM_VK_MSG_Q_MASK	 0xF
+#define BCM_VK_MSG_ID_MASK	 0xFFF
+
+#define BCM_VK_DMA_DRAIN_MAX_MS	  2000
+
+/* number x q_size will be the max number of msg processed per loop */
+#define BCM_VK_MSG_PROC_MAX_LOOP 2
+
+/* module parameter */
+static bool hb_mon = true;
+module_param(hb_mon, bool, 0444);
+MODULE_PARM_DESC(hb_mon, "Monitoring heartbeat continuously.\n");
+static int batch_log = 1;
+module_param(batch_log, int, 0444);
+MODULE_PARM_DESC(batch_log, "Max num of logs per batch operation.\n");
+
+static bool hb_mon_is_on(void)
+{
+	return hb_mon;
+}
+
+static u32 get_q_num(const struct vk_msg_blk *msg)
+{
+	u32 q_num = msg->trans_id & BCM_VK_MSG_Q_MASK;
+
+	if (q_num >= VK_MSGQ_PER_CHAN_MAX)
+		q_num = VK_MSGQ_NUM_DEFAULT;
+	return q_num;
+}
+
+static void set_q_num(struct vk_msg_blk *msg, u32 q_num)
+{
+	msg->trans_id = (msg->trans_id & ~BCM_VK_MSG_Q_MASK) |
+		(q_num >= VK_MSGQ_PER_CHAN_MAX) ? VK_MSGQ_NUM_DEFAULT : q_num;
+}
+
+static u32 get_msg_id(const struct vk_msg_blk *msg)
+{
+	return ((msg->trans_id >> BCM_VK_MSG_Q_SHIFT) & BCM_VK_MSG_ID_MASK);
+}
+
+static void set_msg_id(struct vk_msg_blk *msg, u32 val)
+{
+	msg->trans_id = (val << BCM_VK_MSG_Q_SHIFT) | get_q_num(msg);
+}
+
+static u32 msgq_inc(const struct bcm_vk_sync_qinfo *qinfo, u32 idx, u32 inc)
+{
+	return ((idx + inc) & qinfo->q_mask);
+}
+
+static
+struct vk_msg_blk __iomem *msgq_blk_addr(const struct bcm_vk_sync_qinfo *qinfo,
+					 u32 idx)
+{
+	return qinfo->q_start + (VK_MSGQ_BLK_SIZE * idx);
+}
+
+static u32 msgq_occupied(const struct bcm_vk_msgq __iomem *msgq,
+			 const struct bcm_vk_sync_qinfo *qinfo)
+{
+	u32 wr_idx, rd_idx;
+
+	wr_idx = readl_relaxed(&msgq->wr_idx);
+	rd_idx = readl_relaxed(&msgq->rd_idx);
+
+	return ((wr_idx - rd_idx) & qinfo->q_mask);
+}
+
+static
+u32 msgq_avail_space(const struct bcm_vk_msgq __iomem *msgq,
+		     const struct bcm_vk_sync_qinfo *qinfo)
+{
+	return (qinfo->q_size - msgq_occupied(msgq, qinfo) - 1);
+}
+
+/* number of retries when enqueue message fails before returning EAGAIN */
+#define BCM_VK_H2VK_ENQ_RETRY 10
+#define BCM_VK_H2VK_ENQ_RETRY_DELAY_MS 50
+
+bool bcm_vk_drv_access_ok(struct bcm_vk *vk)
+{
+	return (!!atomic_read(&vk->msgq_inited));
+}
+
+void bcm_vk_set_host_alert(struct bcm_vk *vk, u32 bit_mask)
+{
+	struct bcm_vk_alert *alert = &vk->host_alert;
+	unsigned long flags;
+
+	/* use irqsave version as this maybe called inside timer interrupt */
+	spin_lock_irqsave(&vk->host_alert_lock, flags);
+	alert->notfs |= bit_mask;
+	spin_unlock_irqrestore(&vk->host_alert_lock, flags);
+
+	if (test_and_set_bit(BCM_VK_WQ_NOTF_PEND, vk->wq_offload) == 0)
+		queue_work(vk->wq_thread, &vk->wq_work);
+}
+
+/*
+ * Heartbeat related defines
+ * The heartbeat from host is a last resort.  If stuck condition happens
+ * on the card, firmware is supposed to detect it.  Therefore, the heartbeat
+ * values used will be more relaxed on the driver, which need to be bigger
+ * than the watchdog timeout on the card.  The watchdog timeout on the card
+ * is 20s, with a jitter of 2s => 22s.  We use a value of 27s here.
+ */
+#define BCM_VK_HB_TIMER_S 3
+#define BCM_VK_HB_TIMER_VALUE (BCM_VK_HB_TIMER_S * HZ)
+#define BCM_VK_HB_LOST_MAX (27 / BCM_VK_HB_TIMER_S)
+
+static void bcm_vk_hb_poll(struct timer_list *t)
+{
+	u32 uptime_s;
+	struct bcm_vk_hb_ctrl *hb = container_of(t, struct bcm_vk_hb_ctrl,
+						 timer);
+	struct bcm_vk *vk = container_of(hb, struct bcm_vk, hb_ctrl);
+
+	if (bcm_vk_drv_access_ok(vk) && hb_mon_is_on()) {
+		/* read uptime from register and compare */
+		uptime_s = vkread32(vk, BAR_0, BAR_OS_UPTIME);
+
+		if (uptime_s == hb->last_uptime)
+			hb->lost_cnt++;
+		else /* reset to avoid accumulation */
+			hb->lost_cnt = 0;
+
+		dev_dbg(&vk->pdev->dev, "Last uptime %d current %d, lost %d\n",
+			hb->last_uptime, uptime_s, hb->lost_cnt);
+
+		/*
+		 * if the interface goes down without any activity, a value
+		 * of 0xFFFFFFFF will be continuously read, and the detection
+		 * will be happened eventually.
+		 */
+		hb->last_uptime = uptime_s;
+	} else {
+		/* reset heart beat lost cnt */
+		hb->lost_cnt = 0;
+	}
+
+	/* next, check if heartbeat exceeds limit */
+	if (hb->lost_cnt > BCM_VK_HB_LOST_MAX) {
+		dev_err(&vk->pdev->dev, "Heartbeat Misses %d times, %d s!\n",
+			BCM_VK_HB_LOST_MAX,
+			BCM_VK_HB_LOST_MAX * BCM_VK_HB_TIMER_S);
+
+		bcm_vk_blk_drv_access(vk);
+		bcm_vk_set_host_alert(vk, ERR_LOG_HOST_HB_FAIL);
+	}
+	/* re-arm timer */
+	mod_timer(&hb->timer, jiffies + BCM_VK_HB_TIMER_VALUE);
+}
+
+void bcm_vk_hb_init(struct bcm_vk *vk)
+{
+	struct bcm_vk_hb_ctrl *hb = &vk->hb_ctrl;
+
+	timer_setup(&hb->timer, bcm_vk_hb_poll, 0);
+	mod_timer(&hb->timer, jiffies + BCM_VK_HB_TIMER_VALUE);
+}
+
+void bcm_vk_hb_deinit(struct bcm_vk *vk)
+{
+	struct bcm_vk_hb_ctrl *hb = &vk->hb_ctrl;
+
+	del_timer(&hb->timer);
+}
+
+static void bcm_vk_msgid_bitmap_clear(struct bcm_vk *vk,
+				      unsigned int start,
+				      unsigned int nbits)
+{
+	spin_lock(&vk->msg_id_lock);
+	bitmap_clear(vk->bmap, start, nbits);
+	spin_unlock(&vk->msg_id_lock);
+}
 
 /*
  * allocate a ctx per file struct
@@ -39,12 +231,47 @@ static struct bcm_vk_ctx *bcm_vk_get_ctx(struct bcm_vk *vk, const pid_t pid)
 	/* increase kref */
 	kref_get(&vk->kref);
 
+	/* clear counter */
+	atomic_set(&ctx->pend_cnt, 0);
+	atomic_set(&ctx->dma_cnt, 0);
+	init_waitqueue_head(&ctx->rd_wq);
+
 all_in_use_exit:
 	spin_unlock(&vk->ctx_lock);
 
 	return ctx;
 }
 
+static u16 bcm_vk_get_msg_id(struct bcm_vk *vk)
+{
+	u16 rc = VK_MSG_ID_OVERFLOW;
+	u16 test_bit_count = 0;
+
+	spin_lock(&vk->msg_id_lock);
+	while (test_bit_count < (VK_MSG_ID_BITMAP_SIZE - 1)) {
+		/*
+		 * first time come in this loop, msg_id will be 0
+		 * and the first one tested will be 1.  We skip
+		 * VK_SIMPLEX_MSG_ID (0) for one way host2vk
+		 * communication
+		 */
+		vk->msg_id++;
+		if (vk->msg_id == VK_MSG_ID_BITMAP_SIZE)
+			vk->msg_id = 1;
+
+		if (test_bit(vk->msg_id, vk->bmap)) {
+			test_bit_count++;
+			continue;
+		}
+		rc = vk->msg_id;
+		bitmap_set(vk->bmap, vk->msg_id, 1);
+		break;
+	}
+	spin_unlock(&vk->msg_id_lock);
+
+	return rc;
+}
+
 static int bcm_vk_free_ctx(struct bcm_vk *vk, struct bcm_vk_ctx *ctx)
 {
 	u32 idx;
@@ -82,6 +309,636 @@ static int bcm_vk_free_ctx(struct bcm_vk *vk, struct bcm_vk_ctx *ctx)
 	return count;
 }
 
+static void bcm_vk_free_wkent(struct device *dev, struct bcm_vk_wkent *entry)
+{
+	int proc_cnt;
+
+	bcm_vk_sg_free(dev, entry->dma, VK_DMA_MAX_ADDRS, &proc_cnt);
+	if (proc_cnt)
+		atomic_dec(&entry->ctx->dma_cnt);
+
+	kfree(entry->to_h_msg);
+	kfree(entry);
+}
+
+static void bcm_vk_drain_all_pend(struct device *dev,
+				  struct bcm_vk_msg_chan *chan,
+				  struct bcm_vk_ctx *ctx)
+{
+	u32 num;
+	struct bcm_vk_wkent *entry, *tmp;
+	struct bcm_vk *vk;
+	struct list_head del_q;
+
+	if (ctx)
+		vk = container_of(ctx->miscdev, struct bcm_vk, miscdev);
+
+	INIT_LIST_HEAD(&del_q);
+	spin_lock(&chan->pendq_lock);
+	for (num = 0; num < chan->q_nr; num++) {
+		list_for_each_entry_safe(entry, tmp, &chan->pendq[num], node) {
+			if ((!ctx) || (entry->ctx->idx == ctx->idx)) {
+				list_del(&entry->node);
+				list_add_tail(&entry->node, &del_q);
+			}
+		}
+	}
+	spin_unlock(&chan->pendq_lock);
+
+	/* batch clean up */
+	num = 0;
+	list_for_each_entry_safe(entry, tmp, &del_q, node) {
+		list_del(&entry->node);
+		num++;
+		if (ctx) {
+			struct vk_msg_blk *msg;
+			int bit_set;
+			bool responded;
+			u32 msg_id;
+
+			/* if it is specific ctx, log for any stuck */
+			msg = entry->to_v_msg;
+			msg_id = get_msg_id(msg);
+			bit_set = test_bit(msg_id, vk->bmap);
+			responded = entry->to_h_msg ? true : false;
+			if (num <= batch_log)
+				dev_info(dev,
+					 "Drained: fid %u size %u msg 0x%x(seq-%x) ctx 0x%x[fd-%d] args:[0x%x 0x%x] resp %s, bmap %d\n",
+					 msg->function_id, msg->size,
+					 msg_id, entry->seq_num,
+					 msg->context_id, entry->ctx->idx,
+					 msg->cmd, msg->arg,
+					 responded ? "T" : "F", bit_set);
+			if (responded)
+				atomic_dec(&ctx->pend_cnt);
+			else if (bit_set)
+				bcm_vk_msgid_bitmap_clear(vk, msg_id, 1);
+		}
+		bcm_vk_free_wkent(dev, entry);
+	}
+	if (num && ctx)
+		dev_info(dev, "Total drained items %d [fd-%d]\n",
+			 num, ctx->idx);
+}
+
+/*
+ * Function to sync up the messages queue info that is provided by BAR1
+ */
+int bcm_vk_sync_msgq(struct bcm_vk *vk, bool force_sync)
+{
+	struct bcm_vk_msgq __iomem *msgq;
+	struct device *dev = &vk->pdev->dev;
+	u32 msgq_off;
+	u32 num_q;
+	struct bcm_vk_msg_chan *chan_list[] = {&vk->to_v_msg_chan,
+					       &vk->to_h_msg_chan};
+	struct bcm_vk_msg_chan *chan;
+	int i, j;
+	int ret = 0;
+
+	/*
+	 * If the driver is loaded at startup where vk OS is not up yet,
+	 * the msgq-info may not be available until a later time.  In
+	 * this case, we skip and the sync function is supposed to be
+	 * called again.
+	 */
+	if (!bcm_vk_msgq_marker_valid(vk)) {
+		dev_info(dev, "BAR1 msgq marker not initialized.\n");
+		return -EAGAIN;
+	}
+
+	msgq_off = vkread32(vk, BAR_1, VK_BAR1_MSGQ_CTRL_OFF);
+
+	/* each side is always half the total  */
+	num_q = vkread32(vk, BAR_1, VK_BAR1_MSGQ_NR) / 2;
+	if (!num_q || (num_q > VK_MSGQ_PER_CHAN_MAX)) {
+		dev_err(dev,
+			"Advertised msgq %d error - max %d allowed\n",
+			num_q, VK_MSGQ_PER_CHAN_MAX);
+		return -EINVAL;
+	}
+
+	vk->to_v_msg_chan.q_nr = num_q;
+	vk->to_h_msg_chan.q_nr = num_q;
+
+	/* first msgq location */
+	msgq = vk->bar[BAR_1] + msgq_off;
+
+	/*
+	 * if this function is called when it is already inited,
+	 * something is wrong
+	 */
+	if (bcm_vk_drv_access_ok(vk) && !force_sync) {
+		dev_err(dev, "Msgq info already in sync\n");
+		return -EPERM;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(chan_list); i++) {
+		chan = chan_list[i];
+		memset(chan->sync_qinfo, 0, sizeof(chan->sync_qinfo));
+
+		for (j = 0; j < num_q; j++) {
+			struct bcm_vk_sync_qinfo *qinfo;
+			u32 msgq_start;
+			u32 msgq_size;
+			u32 msgq_nxt;
+			u32 msgq_db_offset, q_db_offset;
+
+			chan->msgq[j] = msgq;
+			msgq_start = readl_relaxed(&msgq->start);
+			msgq_size = readl_relaxed(&msgq->size);
+			msgq_nxt = readl_relaxed(&msgq->nxt);
+			msgq_db_offset = readl_relaxed(&msgq->db_offset);
+			q_db_offset = (msgq_db_offset & ((1 << DB_SHIFT) - 1));
+			if (q_db_offset  == (~msgq_db_offset >> DB_SHIFT))
+				msgq_db_offset = q_db_offset;
+			else
+				/* fall back to default */
+				msgq_db_offset = VK_BAR0_Q_DB_BASE(j);
+
+			dev_info(dev,
+				 "MsgQ[%d] type %d num %d, @ 0x%x, db_offset 0x%x rd_idx %d wr_idx %d, size %d, nxt 0x%x\n",
+				 j,
+				 readw_relaxed(&msgq->type),
+				 readw_relaxed(&msgq->num),
+				 msgq_start,
+				 msgq_db_offset,
+				 readl_relaxed(&msgq->rd_idx),
+				 readl_relaxed(&msgq->wr_idx),
+				 msgq_size,
+				 msgq_nxt);
+
+			qinfo = &chan->sync_qinfo[j];
+			/* formulate and record static info */
+			qinfo->q_start = vk->bar[BAR_1] + msgq_start;
+			qinfo->q_size = msgq_size;
+			/* set low threshold as 50% or 1/2 */
+			qinfo->q_low = qinfo->q_size >> 1;
+			qinfo->q_mask = qinfo->q_size - 1;
+			qinfo->q_db_offset = msgq_db_offset;
+
+			msgq++;
+		}
+	}
+	atomic_set(&vk->msgq_inited, 1);
+
+	return ret;
+}
+
+static int bcm_vk_msg_chan_init(struct bcm_vk_msg_chan *chan)
+{
+	u32 i;
+
+	mutex_init(&chan->msgq_mutex);
+	spin_lock_init(&chan->pendq_lock);
+	for (i = 0; i < VK_MSGQ_MAX_NR; i++)
+		INIT_LIST_HEAD(&chan->pendq[i]);
+
+	return 0;
+}
+
+static void bcm_vk_append_pendq(struct bcm_vk_msg_chan *chan, u16 q_num,
+				struct bcm_vk_wkent *entry)
+{
+	struct bcm_vk_ctx *ctx;
+
+	spin_lock(&chan->pendq_lock);
+	list_add_tail(&entry->node, &chan->pendq[q_num]);
+	if (entry->to_h_msg) {
+		ctx = entry->ctx;
+		atomic_inc(&ctx->pend_cnt);
+		wake_up_interruptible(&ctx->rd_wq);
+	}
+	spin_unlock(&chan->pendq_lock);
+}
+
+static u32 bcm_vk_append_ib_sgl(struct bcm_vk *vk,
+				struct bcm_vk_wkent *entry,
+				struct _vk_data *data,
+				unsigned int num_planes)
+{
+	unsigned int i;
+	unsigned int item_cnt = 0;
+	struct device *dev = &vk->pdev->dev;
+	struct bcm_vk_msg_chan *chan = &vk->to_v_msg_chan;
+	struct vk_msg_blk *msg = &entry->to_v_msg[0];
+	struct bcm_vk_msgq __iomem *msgq;
+	struct bcm_vk_sync_qinfo *qinfo;
+	u32 ib_sgl_size = 0;
+	u8 *buf = (u8 *)&entry->to_v_msg[entry->to_v_blks];
+	u32 avail;
+	u32 q_num;
+
+	/* check if high watermark is hit, and if so, skip */
+	q_num = get_q_num(msg);
+	msgq = chan->msgq[q_num];
+	qinfo = &chan->sync_qinfo[q_num];
+	avail = msgq_avail_space(msgq, qinfo);
+	if (avail < qinfo->q_low) {
+		dev_dbg(dev, "Skip inserting inband SGL, [0x%x/0x%x]\n",
+			avail, qinfo->q_size);
+		return 0;
+	}
+
+	for (i = 0; i < num_planes; i++) {
+		if (data[i].address &&
+		    (ib_sgl_size + data[i].size) <= vk->ib_sgl_size) {
+			item_cnt++;
+			memcpy(buf, entry->dma[i].sglist, data[i].size);
+			ib_sgl_size += data[i].size;
+			buf += data[i].size;
+		}
+	}
+
+	dev_dbg(dev, "Num %u sgl items appended, size 0x%x, room 0x%x\n",
+		item_cnt, ib_sgl_size, vk->ib_sgl_size);
+
+	/* round up size */
+	ib_sgl_size = (ib_sgl_size + VK_MSGQ_BLK_SIZE - 1)
+		       >> VK_MSGQ_BLK_SZ_SHIFT;
+
+	return ib_sgl_size;
+}
+
+void bcm_to_v_q_doorbell(struct bcm_vk *vk, u32 q_num, u32 db_val)
+{
+	struct bcm_vk_msg_chan *chan = &vk->to_v_msg_chan;
+	struct bcm_vk_sync_qinfo *qinfo = &chan->sync_qinfo[q_num];
+
+	vkwrite32(vk, db_val, BAR_0, qinfo->q_db_offset);
+}
+
+static int bcm_to_v_msg_enqueue(struct bcm_vk *vk, struct bcm_vk_wkent *entry)
+{
+	static u32 seq_num;
+	struct bcm_vk_msg_chan *chan = &vk->to_v_msg_chan;
+	struct device *dev = &vk->pdev->dev;
+	struct vk_msg_blk *src = &entry->to_v_msg[0];
+
+	struct vk_msg_blk __iomem *dst;
+	struct bcm_vk_msgq __iomem *msgq;
+	struct bcm_vk_sync_qinfo *qinfo;
+	u32 q_num = get_q_num(src);
+	u32 wr_idx; /* local copy */
+	u32 i;
+	u32 avail;
+	u32 retry;
+
+	if (entry->to_v_blks != src->size + 1) {
+		dev_err(dev, "number of blks %d not matching %d MsgId[0x%x]: func %d ctx 0x%x\n",
+			entry->to_v_blks,
+			src->size + 1,
+			get_msg_id(src),
+			src->function_id,
+			src->context_id);
+		return -EMSGSIZE;
+	}
+
+	msgq = chan->msgq[q_num];
+	qinfo = &chan->sync_qinfo[q_num];
+
+	mutex_lock(&chan->msgq_mutex);
+
+	avail = msgq_avail_space(msgq, qinfo);
+
+	/* if not enough space, return EAGAIN and let app handles it */
+	retry = 0;
+	while ((avail < entry->to_v_blks) &&
+	       (retry++ < BCM_VK_H2VK_ENQ_RETRY)) {
+		mutex_unlock(&chan->msgq_mutex);
+
+		msleep(BCM_VK_H2VK_ENQ_RETRY_DELAY_MS);
+		mutex_lock(&chan->msgq_mutex);
+		avail = msgq_avail_space(msgq, qinfo);
+	}
+	if (retry > BCM_VK_H2VK_ENQ_RETRY) {
+		mutex_unlock(&chan->msgq_mutex);
+		return -EAGAIN;
+	}
+
+	/* at this point, mutex is taken and there is enough space */
+	entry->seq_num = seq_num++; /* update debug seq number */
+	wr_idx = readl_relaxed(&msgq->wr_idx);
+
+	if (wr_idx >= qinfo->q_size) {
+		dev_crit(dev, "Invalid wr_idx 0x%x => max 0x%x!",
+			 wr_idx, qinfo->q_size);
+		bcm_vk_blk_drv_access(vk);
+		bcm_vk_set_host_alert(vk, ERR_LOG_HOST_PCIE_DWN);
+		goto idx_err;
+	}
+
+	dst = msgq_blk_addr(qinfo, wr_idx);
+	for (i = 0; i < entry->to_v_blks; i++) {
+		memcpy_toio(dst, src, sizeof(*dst));
+
+		src++;
+		wr_idx = msgq_inc(qinfo, wr_idx, 1);
+		dst = msgq_blk_addr(qinfo, wr_idx);
+	}
+
+	/* flush the write pointer */
+	writel(wr_idx, &msgq->wr_idx);
+
+	/* log new info for debugging */
+	dev_dbg(dev,
+		"MsgQ[%d] [Rd Wr] = [%d %d] blks inserted %d - Q = [u-%d a-%d]/%d\n",
+		readl_relaxed(&msgq->num),
+		readl_relaxed(&msgq->rd_idx),
+		wr_idx,
+		entry->to_v_blks,
+		msgq_occupied(msgq, qinfo),
+		msgq_avail_space(msgq, qinfo),
+		readl_relaxed(&msgq->size));
+	/*
+	 * press door bell based on queue number. 1 is added to the wr_idx
+	 * to avoid the value of 0 appearing on the VK side to distinguish
+	 * from initial value.
+	 */
+	bcm_to_v_q_doorbell(vk, q_num, wr_idx + 1);
+idx_err:
+	mutex_unlock(&chan->msgq_mutex);
+	return 0;
+}
+
+int bcm_vk_send_shutdown_msg(struct bcm_vk *vk, u32 shut_type,
+			     const pid_t pid, const u32 q_num)
+{
+	int rc = 0;
+	struct bcm_vk_wkent *entry;
+	struct device *dev = &vk->pdev->dev;
+
+	/*
+	 * check if the marker is still good.  Sometimes, the PCIe interface may
+	 * have gone done, and if so and we ship down thing based on broken
+	 * values, kernel may panic.
+	 */
+	if (!bcm_vk_msgq_marker_valid(vk)) {
+		dev_info(dev, "PCIe comm chan - invalid marker (0x%x)!\n",
+			 vkread32(vk, BAR_1, VK_BAR1_MSGQ_DEF_RDY));
+		return -EINVAL;
+	}
+
+	entry = kzalloc(sizeof(*entry) +
+			sizeof(struct vk_msg_blk), GFP_KERNEL);
+	if (!entry)
+		return -ENOMEM;
+
+	/* fill up necessary data */
+	entry->to_v_msg[0].function_id = VK_FID_SHUTDOWN;
+	set_q_num(&entry->to_v_msg[0], q_num);
+	set_msg_id(&entry->to_v_msg[0], VK_SIMPLEX_MSG_ID);
+	entry->to_v_blks = 1; /* always 1 block */
+
+	entry->to_v_msg[0].cmd = shut_type;
+	entry->to_v_msg[0].arg = pid;
+
+	rc = bcm_to_v_msg_enqueue(vk, entry);
+	if (rc)
+		dev_err(dev,
+			"Sending shutdown message to q %d for pid %d fails.\n",
+			get_q_num(&entry->to_v_msg[0]), pid);
+
+	kfree(entry);
+
+	return rc;
+}
+
+static int bcm_vk_handle_last_sess(struct bcm_vk *vk, const pid_t pid,
+				   const u32 q_num)
+{
+	int rc = 0;
+	struct device *dev = &vk->pdev->dev;
+
+	/*
+	 * don't send down or do anything if message queue is not initialized
+	 */
+	if (!bcm_vk_drv_access_ok(vk))
+		return -EPERM;
+
+	dev_dbg(dev, "No more sessions, shut down pid %d\n", pid);
+
+	rc = bcm_vk_send_shutdown_msg(vk, VK_SHUTDOWN_PID, pid, q_num);
+
+	return rc;
+}
+
+static struct bcm_vk_wkent *bcm_vk_dequeue_pending(struct bcm_vk *vk,
+						   struct bcm_vk_msg_chan *chan,
+						   u16 q_num,
+						   u16 msg_id)
+{
+	bool found = false;
+	struct bcm_vk_wkent *entry;
+
+	spin_lock(&chan->pendq_lock);
+	list_for_each_entry(entry, &chan->pendq[q_num], node) {
+		if (get_msg_id(&entry->to_v_msg[0]) == msg_id) {
+			list_del(&entry->node);
+			found = true;
+			bcm_vk_msgid_bitmap_clear(vk, msg_id, 1);
+			break;
+		}
+	}
+	spin_unlock(&chan->pendq_lock);
+	return ((found) ? entry : NULL);
+}
+
+s32 bcm_to_h_msg_dequeue(struct bcm_vk *vk)
+{
+	struct device *dev = &vk->pdev->dev;
+	struct bcm_vk_msg_chan *chan = &vk->to_h_msg_chan;
+	struct vk_msg_blk *data;
+	struct vk_msg_blk __iomem *src;
+	struct vk_msg_blk *dst;
+	struct bcm_vk_msgq __iomem *msgq;
+	struct bcm_vk_sync_qinfo *qinfo;
+	struct bcm_vk_wkent *entry;
+	u32 rd_idx, wr_idx;
+	u32 q_num, msg_id, j;
+	u32 num_blks;
+	s32 total = 0;
+	int cnt = 0;
+	int msg_processed = 0;
+	int max_msg_to_process;
+	bool exit_loop;
+
+	/*
+	 * drain all the messages from the queues, and find its pending
+	 * entry in the to_v queue, based on msg_id & q_num, and move the
+	 * entry to the to_h pending queue, waiting for user space
+	 * program to extract
+	 */
+	mutex_lock(&chan->msgq_mutex);
+
+	for (q_num = 0; q_num < chan->q_nr; q_num++) {
+		msgq = chan->msgq[q_num];
+		qinfo = &chan->sync_qinfo[q_num];
+		max_msg_to_process = BCM_VK_MSG_PROC_MAX_LOOP * qinfo->q_size;
+
+		rd_idx = readl_relaxed(&msgq->rd_idx);
+		wr_idx = readl_relaxed(&msgq->wr_idx);
+		msg_processed = 0;
+		exit_loop = false;
+		while ((rd_idx != wr_idx) && !exit_loop) {
+			u8 src_size;
+
+			/*
+			 * Make a local copy and get pointer to src blk
+			 * The rd_idx is masked before getting the pointer to
+			 * avoid out of bound access in case the interface goes
+			 * down.  It will end up pointing to the last block in
+			 * the buffer, but subsequent src->size check would be
+			 * able to catch this.
+			 */
+			src = msgq_blk_addr(qinfo, rd_idx & qinfo->q_mask);
+			src_size = readb(&src->size);
+
+			if ((rd_idx >= qinfo->q_size) ||
+			    (src_size > (qinfo->q_size - 1))) {
+				dev_crit(dev,
+					 "Invalid rd_idx 0x%x or size 0x%x => max 0x%x!",
+					 rd_idx, src_size, qinfo->q_size);
+				bcm_vk_blk_drv_access(vk);
+				bcm_vk_set_host_alert(vk,
+						      ERR_LOG_HOST_PCIE_DWN);
+				goto idx_err;
+			}
+
+			num_blks = src_size + 1;
+			data = kzalloc(num_blks * VK_MSGQ_BLK_SIZE, GFP_KERNEL);
+			if (data) {
+				/* copy messages and linearize it */
+				dst = data;
+				for (j = 0; j < num_blks; j++) {
+					memcpy_fromio(dst, src, sizeof(*dst));
+
+					dst++;
+					rd_idx = msgq_inc(qinfo, rd_idx, 1);
+					src = msgq_blk_addr(qinfo, rd_idx);
+				}
+				total++;
+			} else {
+				/*
+				 * if we could not allocate memory in kernel,
+				 * that is fatal.
+				 */
+				dev_crit(dev, "Kernel mem allocation failure.\n");
+				return -ENOMEM;
+			}
+
+			/* flush rd pointer after a message is dequeued */
+			writel(rd_idx, &msgq->rd_idx);
+
+			/* log new info for debugging */
+			dev_dbg(dev,
+				"MsgQ[%d] [Rd Wr] = [%d %d] blks extracted %d - Q = [u-%d a-%d]/%d\n",
+				readl_relaxed(&msgq->num),
+				rd_idx,
+				wr_idx,
+				num_blks,
+				msgq_occupied(msgq, qinfo),
+				msgq_avail_space(msgq, qinfo),
+				readl_relaxed(&msgq->size));
+
+			/*
+			 * No need to search if it is an autonomous one-way
+			 * message from driver, as these messages do not bear
+			 * a to_v pending item. Currently, only the shutdown
+			 * message falls into this category.
+			 */
+			if (data->function_id == VK_FID_SHUTDOWN) {
+				kfree(data);
+				continue;
+			}
+
+			msg_id = get_msg_id(data);
+			/* lookup original message in to_v direction */
+			entry = bcm_vk_dequeue_pending(vk,
+						       &vk->to_v_msg_chan,
+						       q_num,
+						       msg_id);
+
+			/*
+			 * if there is message to does not have prior send,
+			 * this is the location to add here
+			 */
+			if (entry) {
+				entry->to_h_blks = num_blks;
+				entry->to_h_msg = data;
+				bcm_vk_append_pendq(&vk->to_h_msg_chan,
+						    q_num, entry);
+
+			} else {
+				if (cnt++ < batch_log)
+					dev_info(dev,
+						 "Could not find MsgId[0x%x] for resp func %d bmap %d\n",
+						 msg_id, data->function_id,
+						 test_bit(msg_id, vk->bmap));
+				kfree(data);
+			}
+			/* Fetch wr_idx to handle more back-to-back events */
+			wr_idx = readl(&msgq->wr_idx);
+
+			/*
+			 * cap the max so that even we try to handle more back-to-back events,
+			 * so that it won't hold CPU too long or in case rd/wr idexes are
+			 * corrupted which triggers infinite looping.
+			 */
+			if (++msg_processed >= max_msg_to_process) {
+				dev_warn(dev, "Q[%d] Per loop processing exceeds %d\n",
+					 q_num, max_msg_to_process);
+				exit_loop = true;
+			}
+		}
+	}
+idx_err:
+	mutex_unlock(&chan->msgq_mutex);
+	dev_dbg(dev, "total %d drained from queues\n", total);
+
+	return total;
+}
+
+/*
+ * init routine for all required data structures
+ */
+static int bcm_vk_data_init(struct bcm_vk *vk)
+{
+	int i;
+
+	spin_lock_init(&vk->ctx_lock);
+	for (i = 0; i < ARRAY_SIZE(vk->ctx); i++) {
+		vk->ctx[i].in_use = false;
+		vk->ctx[i].idx = i;	/* self identity */
+		vk->ctx[i].miscdev = NULL;
+	}
+	spin_lock_init(&vk->msg_id_lock);
+	spin_lock_init(&vk->host_alert_lock);
+	vk->msg_id = 0;
+
+	/* initialize hash table */
+	for (i = 0; i < VK_PID_HT_SZ; i++)
+		INIT_LIST_HEAD(&vk->pid_ht[i].head);
+
+	return 0;
+}
+
+irqreturn_t bcm_vk_msgq_irqhandler(int irq, void *dev_id)
+{
+	struct bcm_vk *vk = dev_id;
+
+	if (!bcm_vk_drv_access_ok(vk)) {
+		dev_err(&vk->pdev->dev,
+			"Interrupt %d received when msgq not inited\n", irq);
+		goto skip_schedule_work;
+	}
+
+	queue_work(vk->wq_thread, &vk->wq_work);
+
+skip_schedule_work:
+	return IRQ_HANDLED;
+}
+
 int bcm_vk_open(struct inode *inode, struct file *p_file)
 {
 	struct bcm_vk_ctx *ctx;
@@ -112,16 +969,346 @@ int bcm_vk_open(struct inode *inode, struct file *p_file)
 	return rc;
 }
 
+ssize_t bcm_vk_read(struct file *p_file,
+		    char __user *buf,
+		    size_t count,
+		    loff_t *f_pos)
+{
+	ssize_t rc = -ENOMSG;
+	struct bcm_vk_ctx *ctx = p_file->private_data;
+	struct bcm_vk *vk = container_of(ctx->miscdev, struct bcm_vk,
+					 miscdev);
+	struct device *dev = &vk->pdev->dev;
+	struct bcm_vk_msg_chan *chan = &vk->to_h_msg_chan;
+	struct bcm_vk_wkent *entry = NULL;
+	u32 q_num;
+	u32 rsp_length;
+	bool found = false;
+
+	if (!bcm_vk_drv_access_ok(vk))
+		return -EPERM;
+
+	dev_dbg(dev, "Buf count %zu\n", count);
+	found = false;
+
+	/*
+	 * search through the pendq on the to_h chan, and return only those
+	 * that belongs to the same context.  Search is always from the high to
+	 * the low priority queues
+	 */
+	spin_lock(&chan->pendq_lock);
+	for (q_num = 0; q_num < chan->q_nr; q_num++) {
+		list_for_each_entry(entry, &chan->pendq[q_num], node) {
+			if (entry->ctx->idx == ctx->idx) {
+				if (count >=
+				    (entry->to_h_blks * VK_MSGQ_BLK_SIZE)) {
+					list_del(&entry->node);
+					atomic_dec(&ctx->pend_cnt);
+					found = true;
+				} else {
+					/* buffer not big enough */
+					rc = -EMSGSIZE;
+				}
+				goto read_loop_exit;
+			}
+		}
+	}
+read_loop_exit:
+	spin_unlock(&chan->pendq_lock);
+
+	if (found) {
+		/* retrieve the passed down msg_id */
+		set_msg_id(&entry->to_h_msg[0], entry->usr_msg_id);
+		rsp_length = entry->to_h_blks * VK_MSGQ_BLK_SIZE;
+		if (copy_to_user(buf, entry->to_h_msg, rsp_length) == 0)
+			rc = rsp_length;
+
+		bcm_vk_free_wkent(dev, entry);
+	} else if (rc == -EMSGSIZE) {
+		struct vk_msg_blk tmp_msg = entry->to_h_msg[0];
+
+		/*
+		 * in this case, return just the first block, so
+		 * that app knows what size it is looking for.
+		 */
+		set_msg_id(&tmp_msg, entry->usr_msg_id);
+		tmp_msg.size = entry->to_h_blks - 1;
+		if (copy_to_user(buf, &tmp_msg, VK_MSGQ_BLK_SIZE) != 0) {
+			dev_err(dev, "Error return 1st block in -EMSGSIZE\n");
+			rc = -EFAULT;
+		}
+	}
+	return rc;
+}
+
+ssize_t bcm_vk_write(struct file *p_file,
+		     const char __user *buf,
+		     size_t count,
+		     loff_t *f_pos)
+{
+	ssize_t rc;
+	struct bcm_vk_ctx *ctx = p_file->private_data;
+	struct bcm_vk *vk = container_of(ctx->miscdev, struct bcm_vk,
+					 miscdev);
+	struct bcm_vk_msgq __iomem *msgq;
+	struct device *dev = &vk->pdev->dev;
+	struct bcm_vk_wkent *entry;
+	u32 sgl_extra_blks;
+	u32 q_num;
+	u32 msg_size;
+	u32 msgq_size;
+
+	if (!bcm_vk_drv_access_ok(vk))
+		return -EPERM;
+
+	dev_dbg(dev, "Msg count %zu\n", count);
+
+	/* first, do sanity check where count should be multiple of basic blk */
+	if (count & (VK_MSGQ_BLK_SIZE - 1)) {
+		dev_err(dev, "Failure with size %zu not multiple of %zu\n",
+			count, VK_MSGQ_BLK_SIZE);
+		rc = -EINVAL;
+		goto write_err;
+	}
+
+	/* allocate the work entry + buffer for size count and inband sgl */
+	entry = kzalloc(sizeof(*entry) + count + vk->ib_sgl_size,
+			GFP_KERNEL);
+	if (!entry) {
+		rc = -ENOMEM;
+		goto write_err;
+	}
+
+	/* now copy msg from user space, and then formulate the work entry */
+	if (copy_from_user(&entry->to_v_msg[0], buf, count)) {
+		rc = -EFAULT;
+		goto write_free_ent;
+	}
+
+	entry->to_v_blks = count >> VK_MSGQ_BLK_SZ_SHIFT;
+	entry->ctx = ctx;
+
+	/* do a check on the blk size which could not exceed queue space */
+	q_num = get_q_num(&entry->to_v_msg[0]);
+	msgq = vk->to_v_msg_chan.msgq[q_num];
+	msgq_size = readl_relaxed(&msgq->size);
+	if (entry->to_v_blks + (vk->ib_sgl_size >> VK_MSGQ_BLK_SZ_SHIFT)
+	    > (msgq_size - 1)) {
+		dev_err(dev, "Blk size %d exceed max queue size allowed %d\n",
+			entry->to_v_blks, msgq_size - 1);
+		rc = -EINVAL;
+		goto write_free_ent;
+	}
+
+	/* Use internal message id */
+	entry->usr_msg_id = get_msg_id(&entry->to_v_msg[0]);
+	rc = bcm_vk_get_msg_id(vk);
+	if (rc == VK_MSG_ID_OVERFLOW) {
+		dev_err(dev, "msg_id overflow\n");
+		rc = -EOVERFLOW;
+		goto write_free_ent;
+	}
+	set_msg_id(&entry->to_v_msg[0], rc);
+	ctx->q_num = q_num;
+
+	dev_dbg(dev,
+		"[Q-%d]Message ctx id %d, usr_msg_id 0x%x sent msg_id 0x%x\n",
+		ctx->q_num, ctx->idx, entry->usr_msg_id,
+		get_msg_id(&entry->to_v_msg[0]));
+
+	if (entry->to_v_msg[0].function_id == VK_FID_TRANS_BUF) {
+		/* Convert any pointers to sg list */
+		unsigned int num_planes;
+		int dir;
+		struct _vk_data *data;
+
+		num_planes = entry->to_v_msg[0].cmd & VK_CMD_PLANES_MASK;
+		if ((entry->to_v_msg[0].cmd & VK_CMD_MASK) == VK_CMD_DOWNLOAD)
+			dir = DMA_FROM_DEVICE;
+		else
+			dir = DMA_TO_DEVICE;
+
+		/* Calculate vk_data location */
+		/* Go to end of the message */
+		msg_size = entry->to_v_msg[0].size;
+		if (msg_size > entry->to_v_blks) {
+			rc = -EMSGSIZE;
+			goto write_free_msgid;
+		}
+
+		data = (struct _vk_data *)&entry->to_v_msg[msg_size + 1];
+
+		/* Now back up to the start of the pointers */
+		data -= num_planes;
+
+		/* Convert user addresses to DMA SG List */
+		rc = bcm_vk_sg_alloc(dev, entry->dma, dir, data, num_planes);
+		if (rc)
+			goto write_free_msgid;
+
+		atomic_inc(&ctx->dma_cnt);
+		/* try to embed inband sgl */
+		sgl_extra_blks = bcm_vk_append_ib_sgl(vk, entry, data,
+						      num_planes);
+		entry->to_v_blks += sgl_extra_blks;
+		entry->to_v_msg[0].size += sgl_extra_blks;
+	} else if (entry->to_v_msg[0].function_id == VK_FID_INIT &&
+		   entry->to_v_msg[0].context_id == VK_NEW_CTX) {
+		/*
+		 * Init happens in 2 stages, only the first stage contains the
+		 * pid that needs translating.
+		 */
+		pid_t org_pid, pid;
+
+		/*
+		 * translate the pid into the unique host space as user
+		 * may run sessions inside containers or process
+		 * namespaces.
+		 */
+#define VK_MSG_PID_MASK 0xffffff00
+#define VK_MSG_PID_SH   8
+		org_pid = (entry->to_v_msg[0].arg & VK_MSG_PID_MASK)
+			   >> VK_MSG_PID_SH;
+
+		pid = task_tgid_nr(current);
+		entry->to_v_msg[0].arg =
+			(entry->to_v_msg[0].arg & ~VK_MSG_PID_MASK) |
+			(pid << VK_MSG_PID_SH);
+		if (org_pid != pid)
+			dev_dbg(dev, "In PID 0x%x(%d), converted PID 0x%x(%d)\n",
+				org_pid, org_pid, pid, pid);
+	}
+
+	/*
+	 * store work entry to pending queue until a response is received.
+	 * This needs to be done before enqueuing the message
+	 */
+	bcm_vk_append_pendq(&vk->to_v_msg_chan, q_num, entry);
+
+	rc = bcm_to_v_msg_enqueue(vk, entry);
+	if (rc) {
+		dev_err(dev, "Fail to enqueue msg to to_v queue\n");
+
+		/* remove message from pending list */
+		entry = bcm_vk_dequeue_pending
+			       (vk,
+				&vk->to_v_msg_chan,
+				q_num,
+				get_msg_id(&entry->to_v_msg[0]));
+		goto write_free_ent;
+	}
+
+	return count;
+
+write_free_msgid:
+	bcm_vk_msgid_bitmap_clear(vk, get_msg_id(&entry->to_v_msg[0]), 1);
+write_free_ent:
+	kfree(entry);
+write_err:
+	return rc;
+}
+
+__poll_t bcm_vk_poll(struct file *p_file, struct poll_table_struct *wait)
+{
+	__poll_t ret = 0;
+	int cnt;
+	struct bcm_vk_ctx *ctx = p_file->private_data;
+	struct bcm_vk *vk = container_of(ctx->miscdev, struct bcm_vk, miscdev);
+	struct device *dev = &vk->pdev->dev;
+
+	poll_wait(p_file, &ctx->rd_wq, wait);
+
+	cnt = atomic_read(&ctx->pend_cnt);
+	if (cnt) {
+		ret = (__force __poll_t)(POLLIN | POLLRDNORM);
+		if (cnt < 0) {
+			dev_err(dev, "Error cnt %d, setting back to 0", cnt);
+			atomic_set(&ctx->pend_cnt, 0);
+		}
+	}
+
+	return ret;
+}
+
 int bcm_vk_release(struct inode *inode, struct file *p_file)
 {
 	int ret;
 	struct bcm_vk_ctx *ctx = p_file->private_data;
 	struct bcm_vk *vk = container_of(ctx->miscdev, struct bcm_vk, miscdev);
+	struct device *dev = &vk->pdev->dev;
+	pid_t pid = ctx->pid;
+	int dma_cnt;
+	unsigned long timeout, start_time;
+
+	/*
+	 * if there are outstanding DMA transactions, need to delay long enough
+	 * to ensure that the card side would have stopped touching the host buffer
+	 * and its SGL list.  A race condition could happen if the host app is killed
+	 * abruptly, eg kill -9, while some DMA transfer orders are still inflight.
+	 * Nothing could be done except for a delay as host side is running in a
+	 * completely async fashion.
+	 */
+	start_time = jiffies;
+	timeout = start_time + msecs_to_jiffies(BCM_VK_DMA_DRAIN_MAX_MS);
+	do {
+		if (time_after(jiffies, timeout)) {
+			dev_warn(dev, "%d dma still pending for [fd-%d] pid %d\n",
+				 dma_cnt, ctx->idx, pid);
+			break;
+		}
+		dma_cnt = atomic_read(&ctx->dma_cnt);
+		cpu_relax();
+		cond_resched();
+	} while (dma_cnt);
+	dev_dbg(dev, "Draining for [fd-%d] pid %d - delay %d ms\n",
+		ctx->idx, pid, jiffies_to_msecs(jiffies - start_time));
+
+	bcm_vk_drain_all_pend(&vk->pdev->dev, &vk->to_v_msg_chan, ctx);
+	bcm_vk_drain_all_pend(&vk->pdev->dev, &vk->to_h_msg_chan, ctx);
 
 	ret = bcm_vk_free_ctx(vk, ctx);
+	if (ret == 0)
+		ret = bcm_vk_handle_last_sess(vk, pid, ctx->q_num);
+	else
+		ret = 0;
 
 	kref_put(&vk->kref, bcm_vk_release_data);
 
 	return ret;
 }
 
+int bcm_vk_msg_init(struct bcm_vk *vk)
+{
+	struct device *dev = &vk->pdev->dev;
+	int ret;
+
+	if (bcm_vk_data_init(vk)) {
+		dev_err(dev, "Error initializing internal data structures\n");
+		return -EINVAL;
+	}
+
+	if (bcm_vk_msg_chan_init(&vk->to_v_msg_chan) ||
+	    bcm_vk_msg_chan_init(&vk->to_h_msg_chan)) {
+		dev_err(dev, "Error initializing communication channel\n");
+		return -EIO;
+	}
+
+	/* read msgq info if ready */
+	ret = bcm_vk_sync_msgq(vk, false);
+	if (ret && (ret != -EAGAIN)) {
+		dev_err(dev, "Error reading comm msg Q info\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+void bcm_vk_msg_remove(struct bcm_vk *vk)
+{
+	bcm_vk_blk_drv_access(vk);
+
+	/* drain all pending items */
+	bcm_vk_drain_all_pend(&vk->pdev->dev, &vk->to_v_msg_chan, NULL);
+	bcm_vk_drain_all_pend(&vk->pdev->dev, &vk->to_h_msg_chan, NULL);
+}
+
diff --git a/drivers/misc/bcm-vk/bcm_vk_msg.h b/drivers/misc/bcm-vk/bcm_vk_msg.h
index 32516abcaf89..4eaad84825d6 100644
--- a/drivers/misc/bcm-vk/bcm_vk_msg.h
+++ b/drivers/misc/bcm-vk/bcm_vk_msg.h
@@ -6,6 +6,78 @@
 #ifndef BCM_VK_MSG_H
 #define BCM_VK_MSG_H
 
+#include <uapi/linux/misc/bcm_vk.h>
+#include "bcm_vk_sg.h"
+
+/* Single message queue control structure */
+struct bcm_vk_msgq {
+	u16 type;	/* queue type */
+	u16 num;	/* queue number */
+	u32 start;	/* offset in BAR1 where the queue memory starts */
+
+	u32 rd_idx; /* read idx */
+	u32 wr_idx; /* write idx */
+
+	u32 size;	/*
+			 * size, which is in number of 16byte blocks,
+			 * to align with the message data structure.
+			 */
+	u32 nxt;	/*
+			 * nxt offset to the next msg queue struct.
+			 * This is to provide flexibity for alignment purposes.
+			 */
+
+/* Least significant 16 bits in below field hold doorbell register offset */
+#define DB_SHIFT 16
+
+	u32 db_offset; /* queue doorbell register offset in BAR0 */
+
+	u32 rsvd;
+};
+
+/*
+ * Structure to record static info from the msgq sync.  We keep local copy
+ * for some of these variables for both performance + checking purpose.
+ */
+struct bcm_vk_sync_qinfo {
+	void __iomem *q_start;
+	u32 q_size;
+	u32 q_mask;
+	u32 q_low;
+	u32 q_db_offset;
+};
+
+#define VK_MSGQ_MAX_NR 4 /* Maximum number of message queues */
+
+/*
+ * message block - basic unit in the message where a message's size is always
+ *		   N x sizeof(basic_block)
+ */
+struct vk_msg_blk {
+	u8 function_id;
+#define VK_FID_TRANS_BUF	5
+#define VK_FID_SHUTDOWN		8
+#define VK_FID_INIT		9
+	u8 size; /* size of the message in number of vk_msg_blk's */
+	u16 trans_id; /* transport id, queue & msg_id */
+	u32 context_id;
+#define VK_NEW_CTX		0
+	u32 cmd;
+#define VK_CMD_PLANES_MASK	0x000f /* number of planes to up/download */
+#define VK_CMD_UPLOAD		0x0400 /* memory transfer to vk */
+#define VK_CMD_DOWNLOAD		0x0500 /* memory transfer from vk */
+#define VK_CMD_MASK		0x0f00 /* command mask */
+	u32 arg;
+};
+
+/* vk_msg_blk is 16 bytes fixed */
+#define VK_MSGQ_BLK_SIZE   (sizeof(struct vk_msg_blk))
+/* shift for fast division of basic msg blk size */
+#define VK_MSGQ_BLK_SZ_SHIFT 4
+
+/* use msg_id 0 for any simplex host2vk communication */
+#define VK_SIMPLEX_MSG_ID 0
+
 /* context per session opening of sysfs */
 struct bcm_vk_ctx {
 	struct list_head node; /* use for linkage in Hash Table */
@@ -13,7 +85,11 @@ struct bcm_vk_ctx {
 	bool in_use;
 	pid_t pid;
 	u32 hash_idx;
+	u32 q_num; /* queue number used by the stream */
 	struct miscdevice *miscdev;
+	atomic_t pend_cnt; /* number of items pending to be read from host */
+	atomic_t dma_cnt; /* any dma transaction outstanding */
+	wait_queue_head_t rd_wq;
 };
 
 /* pid hash table entry */
@@ -21,6 +97,55 @@ struct bcm_vk_ht_entry {
 	struct list_head head;
 };
 
+#define VK_DMA_MAX_ADDRS 4 /* Max 4 DMA Addresses */
+/* structure for house keeping a single work entry */
+struct bcm_vk_wkent {
+	struct list_head node; /* for linking purpose */
+	struct bcm_vk_ctx *ctx;
+
+	/* Store up to 4 dma pointers */
+	struct bcm_vk_dma dma[VK_DMA_MAX_ADDRS];
+
+	u32 to_h_blks; /* response */
+	struct vk_msg_blk *to_h_msg;
+
+	/*
+	 * put the to_v_msg at the end so that we could simply append to_v msg
+	 * to the end of the allocated block
+	 */
+	u32 usr_msg_id;
+	u32 to_v_blks;
+	u32 seq_num;
+	struct vk_msg_blk to_v_msg[0];
+};
+
+/* queue stats counters */
+struct bcm_vk_qs_cnts {
+	u32 cnt; /* general counter, used to limit output */
+	u32 acc_sum;
+	u32 max_occ; /* max during a sampling period */
+	u32 max_abs; /* the abs max since reset */
+};
+
+/* control channel structure for either to_v or to_h communication */
+struct bcm_vk_msg_chan {
+	u32 q_nr;
+	/* Mutex to access msgq */
+	struct mutex msgq_mutex;
+	/* pointing to BAR locations */
+	struct bcm_vk_msgq __iomem *msgq[VK_MSGQ_MAX_NR];
+	/* Spinlock to access pending queue */
+	spinlock_t pendq_lock;
+	/* for temporary storing pending items, one for each queue */
+	struct list_head pendq[VK_MSGQ_MAX_NR];
+	/* static queue info from the sync */
+	struct bcm_vk_sync_qinfo sync_qinfo[VK_MSGQ_MAX_NR];
+};
+
+/* totol number of message q allowed by the driver */
+#define VK_MSGQ_PER_CHAN_MAX	3
+#define VK_MSGQ_NUM_DEFAULT	(VK_MSGQ_PER_CHAN_MAX - 1)
+
 /* total number of supported ctx, 32 ctx each for 5 components */
 #define VK_CMPT_CTX_MAX		(32 * 5)
 
@@ -28,4 +153,11 @@ struct bcm_vk_ht_entry {
 #define VK_PID_HT_SHIFT_BIT	7 /* 128 */
 #define VK_PID_HT_SZ		BIT(VK_PID_HT_SHIFT_BIT)
 
+/* The following are offsets of DDR info provided by the vk card */
+#define VK_BAR0_SEG_SIZE	(4 * SZ_1K) /* segment size for BAR0 */
+
+/* shutdown types supported */
+#define VK_SHUTDOWN_PID		1
+#define VK_SHUTDOWN_GRACEFUL	2
+
 #endif
diff --git a/drivers/misc/bcm-vk/bcm_vk_sg.c b/drivers/misc/bcm-vk/bcm_vk_sg.c
new file mode 100644
index 000000000000..2e9daaf3e492
--- /dev/null
+++ b/drivers/misc/bcm-vk/bcm_vk_sg.c
@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018-2020 Broadcom.
+ */
+#include <linux/dma-mapping.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/pgtable.h>
+#include <linux/vmalloc.h>
+
+#include <asm/page.h>
+#include <asm/unaligned.h>
+
+#include <uapi/linux/misc/bcm_vk.h>
+
+#include "bcm_vk.h"
+#include "bcm_vk_msg.h"
+#include "bcm_vk_sg.h"
+
+/*
+ * Valkyrie has a hardware limitation of 16M transfer size.
+ * So limit the SGL chunks to 16M.
+ */
+#define BCM_VK_MAX_SGL_CHUNK SZ_16M
+
+static int bcm_vk_dma_alloc(struct device *dev,
+			    struct bcm_vk_dma *dma,
+			    int dir,
+			    struct _vk_data *vkdata);
+static int bcm_vk_dma_free(struct device *dev, struct bcm_vk_dma *dma);
+
+/* Uncomment to dump SGLIST */
+/* #define BCM_VK_DUMP_SGLIST */
+
+static int bcm_vk_dma_alloc(struct device *dev,
+			    struct bcm_vk_dma *dma,
+			    int direction,
+			    struct _vk_data *vkdata)
+{
+	dma_addr_t addr, sg_addr;
+	int err;
+	int i;
+	int offset;
+	u32 size;
+	u32 remaining_size;
+	u32 transfer_size;
+	u64 data;
+	unsigned long first, last;
+	struct _vk_data *sgdata;
+
+	/* Get 64-bit user address */
+	data = get_unaligned(&vkdata->address);
+
+	/* offset into first page */
+	offset = offset_in_page(data);
+
+	/* Calculate number of pages */
+	first = (data & PAGE_MASK) >> PAGE_SHIFT;
+	last  = ((data + vkdata->size - 1) & PAGE_MASK) >> PAGE_SHIFT;
+	dma->nr_pages = last - first + 1;
+
+	/* Allocate DMA pages */
+	dma->pages = kmalloc_array(dma->nr_pages,
+				   sizeof(struct page *),
+				   GFP_KERNEL);
+	if (!dma->pages)
+		return -ENOMEM;
+
+	dev_dbg(dev, "Alloc DMA Pages [0x%llx+0x%x => %d pages]\n",
+		data, vkdata->size, dma->nr_pages);
+
+	dma->direction = direction;
+
+	/* Get user pages into memory */
+	err = get_user_pages_fast(data & PAGE_MASK,
+				  dma->nr_pages,
+				  direction == DMA_FROM_DEVICE,
+				  dma->pages);
+	if (err != dma->nr_pages) {
+		dma->nr_pages = (err >= 0) ? err : 0;
+		dev_err(dev, "get_user_pages_fast, err=%d [%d]\n",
+			err, dma->nr_pages);
+		return err < 0 ? err : -EINVAL;
+	}
+
+	/* Max size of sg list is 1 per mapped page + fields at start */
+	dma->sglen = (dma->nr_pages * sizeof(*sgdata)) +
+		     (sizeof(u32) * SGLIST_VKDATA_START);
+
+	/* Allocate sglist */
+	dma->sglist = dma_alloc_coherent(dev,
+					 dma->sglen,
+					 &dma->handle,
+					 GFP_KERNEL);
+	if (!dma->sglist)
+		return -ENOMEM;
+
+	dma->sglist[SGLIST_NUM_SG] = 0;
+	dma->sglist[SGLIST_TOTALSIZE] = vkdata->size;
+	remaining_size = vkdata->size;
+	sgdata = (struct _vk_data *)&dma->sglist[SGLIST_VKDATA_START];
+
+	/* Map all pages into DMA */
+	size = min_t(size_t, PAGE_SIZE - offset, remaining_size);
+	remaining_size -= size;
+	sg_addr = dma_map_page(dev,
+			       dma->pages[0],
+			       offset,
+			       size,
+			       dma->direction);
+	transfer_size = size;
+	if (unlikely(dma_mapping_error(dev, sg_addr))) {
+		__free_page(dma->pages[0]);
+		return -EIO;
+	}
+
+	for (i = 1; i < dma->nr_pages; i++) {
+		size = min_t(size_t, PAGE_SIZE, remaining_size);
+		remaining_size -= size;
+		addr = dma_map_page(dev,
+				    dma->pages[i],
+				    0,
+				    size,
+				    dma->direction);
+		if (unlikely(dma_mapping_error(dev, addr))) {
+			__free_page(dma->pages[i]);
+			return -EIO;
+		}
+
+		/*
+		 * Compress SG list entry when pages are contiguous
+		 * and transfer size less or equal to BCM_VK_MAX_SGL_CHUNK
+		 */
+		if ((addr == (sg_addr + transfer_size)) &&
+		    ((transfer_size + size) <= BCM_VK_MAX_SGL_CHUNK)) {
+			/* pages are contiguous, add to same sg entry */
+			transfer_size += size;
+		} else {
+			/* pages are not contiguous, write sg entry */
+			sgdata->size = transfer_size;
+			put_unaligned(sg_addr, (u64 *)&sgdata->address);
+			dma->sglist[SGLIST_NUM_SG]++;
+
+			/* start new sg entry */
+			sgdata++;
+			sg_addr = addr;
+			transfer_size = size;
+		}
+	}
+	/* Write last sg list entry */
+	sgdata->size = transfer_size;
+	put_unaligned(sg_addr, (u64 *)&sgdata->address);
+	dma->sglist[SGLIST_NUM_SG]++;
+
+	/* Update pointers and size field to point to sglist */
+	put_unaligned((u64)dma->handle, &vkdata->address);
+	vkdata->size = (dma->sglist[SGLIST_NUM_SG] * sizeof(*sgdata)) +
+		       (sizeof(u32) * SGLIST_VKDATA_START);
+
+#ifdef BCM_VK_DUMP_SGLIST
+	dev_dbg(dev,
+		"sgl 0x%llx handle 0x%llx, sglen: 0x%x sgsize: 0x%x\n",
+		(u64)dma->sglist,
+		dma->handle,
+		dma->sglen,
+		vkdata->size);
+	for (i = 0; i < vkdata->size / sizeof(u32); i++)
+		dev_dbg(dev, "i:0x%x 0x%x\n", i, dma->sglist[i]);
+#endif
+
+	return 0;
+}
+
+int bcm_vk_sg_alloc(struct device *dev,
+		    struct bcm_vk_dma *dma,
+		    int dir,
+		    struct _vk_data *vkdata,
+		    int num)
+{
+	int i;
+	int rc = -EINVAL;
+
+	/* Convert user addresses to DMA SG List */
+	for (i = 0; i < num; i++) {
+		if (vkdata[i].size && vkdata[i].address) {
+			/*
+			 * If both size and address are non-zero
+			 * then DMA alloc.
+			 */
+			rc = bcm_vk_dma_alloc(dev,
+					      &dma[i],
+					      dir,
+					      &vkdata[i]);
+		} else if (vkdata[i].size ||
+			   vkdata[i].address) {
+			/*
+			 * If one of size and address are zero
+			 * there is a problem.
+			 */
+			dev_err(dev,
+				"Invalid vkdata %x 0x%x 0x%llx\n",
+				i, vkdata[i].size, vkdata[i].address);
+			rc = -EINVAL;
+		} else {
+			/*
+			 * If size and address are both zero
+			 * don't convert, but return success.
+			 */
+			rc = 0;
+		}
+
+		if (rc)
+			goto fail_alloc;
+	}
+	return rc;
+
+fail_alloc:
+	while (i > 0) {
+		i--;
+		if (dma[i].sglist)
+			bcm_vk_dma_free(dev, &dma[i]);
+	}
+	return rc;
+}
+
+static int bcm_vk_dma_free(struct device *dev, struct bcm_vk_dma *dma)
+{
+	dma_addr_t addr;
+	int i;
+	int num_sg;
+	u32 size;
+	struct _vk_data *vkdata;
+
+	dev_dbg(dev, "free sglist=%p sglen=0x%x\n", dma->sglist, dma->sglen);
+
+	/* Unmap all pages in the sglist */
+	num_sg = dma->sglist[SGLIST_NUM_SG];
+	vkdata = (struct _vk_data *)&dma->sglist[SGLIST_VKDATA_START];
+	for (i = 0; i < num_sg; i++) {
+		size = vkdata[i].size;
+		addr = get_unaligned(&vkdata[i].address);
+
+		dma_unmap_page(dev, addr, size, dma->direction);
+	}
+
+	/* Free allocated sglist */
+	dma_free_coherent(dev, dma->sglen, dma->sglist, dma->handle);
+
+	/* Release lock on all pages */
+	for (i = 0; i < dma->nr_pages; i++)
+		put_page(dma->pages[i]);
+
+	/* Free allocated dma pages */
+	kfree(dma->pages);
+	dma->sglist = NULL;
+
+	return 0;
+}
+
+int bcm_vk_sg_free(struct device *dev, struct bcm_vk_dma *dma, int num,
+		   int *proc_cnt)
+{
+	int i;
+
+	*proc_cnt = 0;
+	/* Unmap and free all pages and sglists */
+	for (i = 0; i < num; i++) {
+		if (dma[i].sglist) {
+			bcm_vk_dma_free(dev, &dma[i]);
+			*proc_cnt += 1;
+		}
+	}
+
+	return 0;
+}
diff --git a/drivers/misc/bcm-vk/bcm_vk_sg.h b/drivers/misc/bcm-vk/bcm_vk_sg.h
new file mode 100644
index 000000000000..81b3d0976ddb
--- /dev/null
+++ b/drivers/misc/bcm-vk/bcm_vk_sg.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2018-2020 Broadcom.
+ */
+
+#ifndef BCM_VK_SG_H
+#define BCM_VK_SG_H
+
+#include <linux/dma-mapping.h>
+
+struct bcm_vk_dma {
+	/* for userland buffer */
+	struct page **pages;
+	int nr_pages;
+
+	/* common */
+	dma_addr_t handle;
+	/*
+	 * sglist is of the following LE format
+	 * [U32] num_sg  = number of sg addresses (N)
+	 * [U32] totalsize = totalsize of data being transferred in sglist
+	 * [U32] size[0] = size of data in address0
+	 * [U32] addr_l[0] = lower 32-bits of address0
+	 * [U32] addr_h[0] = higher 32-bits of address0
+	 * ..
+	 * [U32] size[N-1] = size of data in addressN-1
+	 * [U32] addr_l[N-1] = lower 32-bits of addressN-1
+	 * [U32] addr_h[N-1] = higher 32-bits of addressN-1
+	 */
+	u32 *sglist;
+#define SGLIST_NUM_SG		0
+#define SGLIST_TOTALSIZE	1
+#define SGLIST_VKDATA_START	2
+
+	int sglen; /* Length (bytes) of sglist */
+	int direction;
+};
+
+struct _vk_data {
+	u32 size;    /* data size in bytes */
+	u64 address; /* Pointer to data     */
+} __packed;
+
+/*
+ * Scatter-gather DMA buffer API.
+ *
+ * These functions provide a simple way to create a page list and a
+ * scatter-gather list from userspace address and map the memory
+ * for DMA operation.
+ */
+int bcm_vk_sg_alloc(struct device *dev,
+		    struct bcm_vk_dma *dma,
+		    int dir,
+		    struct _vk_data *vkdata,
+		    int num);
+
+int bcm_vk_sg_free(struct device *dev, struct bcm_vk_dma *dma, int num,
+		   int *proc_cnt);
+
+#endif
+