Merge "mhi: core: Add support for new MHI hardware channel"

13 files changed, 233 insertions, 144 deletions

diff --git a/drivers/net/ethernet/msm/msm_rmnet_mhi.c b/drivers/net/ethernet/msm/msm_rmnet_mhi.c
index a55a26be4273..50d8e72a96c8 100644
--- a/drivers/net/ethernet/msm/msm_rmnet_mhi.c
+++ b/drivers/net/ethernet/msm/msm_rmnet_mhi.c
@@ -625,6 +625,9 @@ static int rmnet_mhi_xmit(struct sk_buff *skb, struct net_device *dev)
 				tx_ring_full_count[rmnet_mhi_ptr->dev_index]++;
 				netif_stop_queue(dev);
 				rmnet_log(MSG_VERBOSE, "Stopping Queue\n");
+				write_unlock_irqrestore(
+					    &rmnet_mhi_ptr->out_chan_full_lock,
+					    flags);
 				goto rmnet_mhi_xmit_error_cleanup;
 			} else {
 				retry = 1;
@@ -652,7 +655,6 @@ static int rmnet_mhi_xmit(struct sk_buff *skb, struct net_device *dev)
 
 rmnet_mhi_xmit_error_cleanup:
 	rmnet_log(MSG_VERBOSE, "Ring full\n");
-	write_unlock_irqrestore(&rmnet_mhi_ptr->out_chan_full_lock, flags);
 	return NETDEV_TX_BUSY;
 }
 
diff --git a/drivers/platform/msm/mhi/mhi.h b/drivers/platform/msm/mhi/mhi.h
index c6fa39d6e0e2..6919a97116ab 100644
--- a/drivers/platform/msm/mhi/mhi.h
+++ b/drivers/platform/msm/mhi/mhi.h
@@ -261,6 +261,12 @@ enum MHI_EVENT_CCS {
 	MHI_EVENT_CC_BAD_TRE = 0x11,
 };
 
+struct db_mode {
+	/* if set do not reset DB_Mode during M0 resume */
+	u32 preserve_db_state : 1;
+	u32 db_mode : 1;
+};
+
 struct mhi_ring {
 	void *base;
 	void *wp;
@@ -270,6 +276,9 @@ struct mhi_ring {
 	uintptr_t el_size;
 	u32 overwrite_en;
 	enum MHI_CHAN_DIR dir;
+	struct db_mode db_mode;
+	u32 msi_disable_cntr;
+	u32 msi_enable_cntr;
 };
 
 enum MHI_CMD_STATUS {
@@ -344,12 +353,6 @@ struct mhi_client_handle {
 	int event_ring_index;
 };
 
-enum MHI_EVENT_POLLING {
-	MHI_EVENT_POLLING_DISABLED = 0x0,
-	MHI_EVENT_POLLING_ENABLED = 0x1,
-	MHI_EVENT_POLLING_reserved = 0x80000000
-};
-
 enum MHI_TYPE_EVENT_RING {
 	MHI_ER_DATA_TYPE = 0x1,
 	MHI_ER_CTRL_TYPE = 0x2,
@@ -386,8 +389,6 @@ struct mhi_counters {
 	u32 m3_event_timeouts;
 	u32 m0_event_timeouts;
 	u32 m2_event_timeouts;
-	u32 msi_disable_cntr;
-	u32 msi_enable_cntr;
 	u32 nr_irq_migrations;
 	u32 *msi_counter;
 	u32 *ev_counter;
@@ -414,7 +415,6 @@ struct mhi_flags {
 	u32 ev_thread_stopped;
 	u32 st_thread_stopped;
 	u32 uldl_enabled;
-	u32 db_mode[MHI_MAX_CHANNELS];
 };
 
 struct mhi_wait_queues {
@@ -577,7 +577,8 @@ int mhi_init_chan_ctxt(struct mhi_chan_ctxt *cc_list,
 				   enum MHI_CHAN_DIR chan_type,
 				   u32 event_ring,
 				   struct mhi_ring *ring,
-				   enum MHI_CHAN_STATE chan_state);
+				   enum MHI_CHAN_STATE chan_state,
+				   bool preserve_db_state);
 int mhi_populate_event_cfg(struct mhi_device_ctxt *mhi_dev_ctxt);
 int mhi_get_event_ring_for_channel(struct mhi_device_ctxt *mhi_dev_ctxt,
 					      u32 chan);
diff --git a/drivers/platform/msm/mhi/mhi_hwio.h b/drivers/platform/msm/mhi/mhi_hwio.h
index 370ee0ebab7e..88a6a74566e6 100644
--- a/drivers/platform/msm/mhi/mhi_hwio.h
+++ b/drivers/platform/msm/mhi/mhi_hwio.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2014, 2016, 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
@@ -23,14 +23,14 @@
 
 
 #define MHICFG (0x10)
-#define MHICFG_RESERVED_BITS31_24_MASK 0xff000000
-#define MHICFG_RESERVED_BITS31_24_SHIFT 0x18
-#define MHICFG_NER_MASK 0xff0000
-#define MHICFG_NER_SHIFT 0x10
-#define MHICFG_RESERVED_BITS15_8_MASK 0xff00
-#define MHICFG_RESERVED_BITS15_8_SHIFT 0x8
-#define MHICFG_NCH_MASK 0xff
-#define MHICFG_NCH_SHIFT 0x0
+#define MHICFG_NHWER_MASK (0xff000000)
+#define MHICFG_NHWER_SHIFT (24)
+#define MHICFG_NER_MASK (0xff0000)
+#define MHICFG_NER_SHIFT (16)
+#define MHICFG_NHWCH_MASK (0xff00)
+#define MHICFG_NHWCH_SHIFT (8)
+#define MHICFG_NCH_MASK (0xff)
+#define MHICFG_NCH_SHIFT (0)
 
 
 #define CHDBOFF (0x18)
diff --git a/drivers/platform/msm/mhi/mhi_init.c b/drivers/platform/msm/mhi/mhi_init.c
index 93c3de35473b..2982bd0831c7 100644
--- a/drivers/platform/msm/mhi/mhi_init.c
+++ b/drivers/platform/msm/mhi/mhi_init.c
@@ -585,21 +585,23 @@ error_during_props:
 /**
  * @brief Initialize the channel context and shadow context
  *
- * @cc_list:		Context to initialize
- * @trb_list_phy:	Physical base address for the TRE ring
- * @trb_list_virt:	Virtual base address for the TRE ring
- * @el_per_ring:	Number of TREs this ring will contain
- * @chan_type:		Type of channel IN/OUT
- * @event_ring:	 Event ring to be mapped to this channel context
- * @ring:		 Shadow context to be initialized alongside
- *
+ * @cc_list: Context to initialize
+ * @trb_list_phy: Physical base address for the TRE ring
+ * @trb_list_virt: Virtual base address for the TRE ring
+ * @el_per_ring: Number of TREs this ring will contain
+ * @chan_type: Type of channel IN/OUT
+ * @event_ring: Event ring to be mapped to this channel context
+ * @ring: Shadow context to be initialized alongside
+ * @chan_state: Channel state
+ * @preserve_db_state: Do not reset DB state during resume
  * @Return errno
  */
 int mhi_init_chan_ctxt(struct mhi_chan_ctxt *cc_list,
-		uintptr_t trb_list_phy, uintptr_t trb_list_virt,
-		u64 el_per_ring, enum MHI_CHAN_DIR chan_type,
-		u32 event_ring, struct mhi_ring *ring,
-		enum MHI_CHAN_STATE chan_state)
+		       uintptr_t trb_list_phy, uintptr_t trb_list_virt,
+		       u64 el_per_ring, enum MHI_CHAN_DIR chan_type,
+		       u32 event_ring, struct mhi_ring *ring,
+		       enum MHI_CHAN_STATE chan_state,
+		       bool preserve_db_state)
 {
 	cc_list->mhi_chan_state = chan_state;
 	cc_list->mhi_chan_type = chan_type;
@@ -617,6 +619,8 @@ int mhi_init_chan_ctxt(struct mhi_chan_ctxt *cc_list,
 	ring->el_size = sizeof(struct mhi_tx_pkt);
 	ring->overwrite_en = 0;
 	ring->dir = chan_type;
+	ring->db_mode.db_mode = 1;
+	ring->db_mode.preserve_db_state = (preserve_db_state) ? 1 : 0;
 	/* Flush writes to MMIO */
 	wmb();
 	return 0;
diff --git a/drivers/platform/msm/mhi/mhi_isr.c b/drivers/platform/msm/mhi/mhi_isr.c
index 5336b9ff0c11..04778a360289 100644
--- a/drivers/platform/msm/mhi/mhi_isr.c
+++ b/drivers/platform/msm/mhi/mhi_isr.c
@@ -277,20 +277,22 @@ struct mhi_result *mhi_poll(struct mhi_client_handle *client_handle)
 
 void mhi_mask_irq(struct mhi_client_handle *client_handle)
 {
-	disable_irq_nosync(MSI_TO_IRQ(client_handle->mhi_dev_ctxt,
-					client_handle->msi_vec));
-	client_handle->mhi_dev_ctxt->counters.msi_disable_cntr++;
-	if (client_handle->mhi_dev_ctxt->counters.msi_disable_cntr >
-		   (client_handle->mhi_dev_ctxt->counters.msi_enable_cntr + 1))
-		mhi_log(MHI_MSG_INFO, "No nested IRQ disable Allowed\n");
+	struct mhi_device_ctxt *mhi_dev_ctxt =
+		client_handle->mhi_dev_ctxt;
+	struct mhi_ring *ev_ring = &mhi_dev_ctxt->
+		mhi_local_event_ctxt[client_handle->event_ring_index];
+
+	disable_irq_nosync(MSI_TO_IRQ(mhi_dev_ctxt, client_handle->msi_vec));
+	ev_ring->msi_disable_cntr++;
 }
 
 void mhi_unmask_irq(struct mhi_client_handle *client_handle)
 {
-	client_handle->mhi_dev_ctxt->counters.msi_enable_cntr++;
-	enable_irq(MSI_TO_IRQ(client_handle->mhi_dev_ctxt,
-			client_handle->msi_vec));
-	if (client_handle->mhi_dev_ctxt->counters.msi_enable_cntr >
-		   client_handle->mhi_dev_ctxt->counters.msi_disable_cntr)
-		mhi_log(MHI_MSG_INFO, "No nested IRQ enable Allowed\n");
+	struct mhi_device_ctxt *mhi_dev_ctxt =
+		client_handle->mhi_dev_ctxt;
+	struct mhi_ring *ev_ring = &mhi_dev_ctxt->
+		mhi_local_event_ctxt[client_handle->event_ring_index];
+
+	ev_ring->msi_enable_cntr++;
+	enable_irq(MSI_TO_IRQ(mhi_dev_ctxt, client_handle->msi_vec));
 }
diff --git a/drivers/platform/msm/mhi/mhi_macros.h b/drivers/platform/msm/mhi/mhi_macros.h
index bb47f53e244d..6f9ed293e6dd 100644
--- a/drivers/platform/msm/mhi/mhi_macros.h
+++ b/drivers/platform/msm/mhi/mhi_macros.h
@@ -96,7 +96,6 @@
 				((_mhi_dev_ctxt)->mmio_info.nr_event_rings - \
 				((_mhi_dev_ctxt)->mmio_info.nr_hw_event_rings)))
 
-
 /* MHI Transfer Ring Elements 7.4.1*/
 #define TX_TRB_LEN
 #define MHI_TX_TRB_LEN__SHIFT (0)
@@ -244,6 +243,10 @@
 #define MHI_CHAN_TYPE__MASK (3)
 #define MHI_CHAN_TYPE__SHIFT (6)
 
+#define PRESERVE_DB_STATE
+#define MHI_PRESERVE_DB_STATE__MASK (1)
+#define MHI_PRESERVE_DB_STATE__SHIFT (8)
+
 #define GET_CHAN_PROPS(_FIELD, _VAL) \
 	(((_VAL) >> MHI_##_FIELD ## __SHIFT) & MHI_##_FIELD ## __MASK)
 
diff --git a/drivers/platform/msm/mhi/mhi_main.c b/drivers/platform/msm/mhi/mhi_main.c
index c949745f5af7..6da133ce8e04 100644
--- a/drivers/platform/msm/mhi/mhi_main.c
+++ b/drivers/platform/msm/mhi/mhi_main.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2014-2016, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2014-2017, 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
@@ -212,7 +212,7 @@ int mhi_release_chan_ctxt(struct mhi_device_ctxt *mhi_dev_ctxt,
 			ring->len, ring->base,
 			 cc_list->mhi_trb_ring_base_addr);
 	mhi_init_chan_ctxt(cc_list, 0, 0, 0, 0, 0, ring,
-				MHI_CHAN_STATE_DISABLED);
+			   MHI_CHAN_STATE_DISABLED, false);
 	return 0;
 }
 
@@ -259,7 +259,9 @@ static int populate_tre_ring(struct mhi_client_handle *client_handle)
 				client_handle->chan_info.flags),
 			   client_handle->chan_info.ev_ring,
 			   &mhi_dev_ctxt->mhi_local_chan_ctxt[chan],
-			   MHI_CHAN_STATE_ENABLED);
+			   MHI_CHAN_STATE_ENABLED,
+			   GET_CHAN_PROPS(PRESERVE_DB_STATE,
+				client_handle->chan_info.flags));
 	mhi_log(MHI_MSG_INFO, "Exited\n");
 	return 0;
 }
@@ -520,9 +522,9 @@ static inline int mhi_queue_tre(struct mhi_device_ctxt
 		}
 	} else {
 		mhi_log(MHI_MSG_VERBOSE,
-			"Wakeup, pending data state %d chan state %d\n",
-						 mhi_dev_ctxt->mhi_state,
-						 chan_ctxt->mhi_chan_state);
+			"Wakeup, pending data state %s chan state %d\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+			chan_ctxt->mhi_chan_state);
 			ret_val = 0;
 	}
 	return ret_val;
@@ -654,6 +656,7 @@ static int mhi_queue_dma_xfer(
 	MHI_ASSERT(VALID_BUF(buf, buf_len, mhi_dev_ctxt),
 			"Client buffer is of invalid length\n");
 	chan = client_handle->chan_info.chan_nr;
+
 	mhi_log(MHI_MSG_INFO, "Getting Reference %d", chan);
 	pm_runtime_get(&mhi_dev_ctxt->dev_info->pcie_device->dev);
 
@@ -698,6 +701,7 @@ static int mhi_queue_dma_xfer(
 
 error:
 	pm_runtime_mark_last_busy(&mhi_dev_ctxt->dev_info->pcie_device->dev);
+
 	mhi_log(MHI_MSG_INFO, "Putting Reference %d", chan);
 	pm_runtime_put_noidle(&mhi_dev_ctxt->dev_info->pcie_device->dev);
 	return ret_val;
@@ -766,10 +770,9 @@ int mhi_send_cmd(struct mhi_device_ctxt *mhi_dev_ctxt,
 	}
 
 	mhi_log(MHI_MSG_INFO,
-		"Entered, MHI state %d dev_exec_env %d chan %d cmd %d\n",
-			mhi_dev_ctxt->mhi_state,
-			mhi_dev_ctxt->dev_exec_env,
-			chan, cmd);
+		"Entered, MHI state %s dev_exec_env %d chan %d cmd %d\n",
+		TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+		mhi_dev_ctxt->dev_exec_env, chan, cmd);
 	mhi_log(MHI_MSG_INFO, "Getting Reference %d", chan);
 	pm_runtime_get(&mhi_dev_ctxt->dev_info->pcie_device->dev);
 	/*
@@ -870,7 +873,6 @@ static void parse_inbound_bb(struct mhi_device_ctxt *mhi_dev_ctxt,
 
 	result->buf_addr = bb->client_buf;
 	result->bytes_xferd = bb->filled_size;
-	result->transaction_status = 0;
 
 	/* At this point the bounce buffer is no longer necessary
 	 * Whatever was received from the device was copied back to the
@@ -1166,13 +1168,17 @@ int parse_xfer_event(struct mhi_device_ctxt *ctxt,
 	{
 		struct mhi_ring *chan_ctxt = NULL;
 		u64 db_value = 0;
+		unsigned long flags;
 
 		mhi_dev_ctxt->flags.uldl_enabled = 1;
 		chan = MHI_EV_READ_CHID(EV_CHID, event);
-		mhi_dev_ctxt->flags.db_mode[chan] = 1;
 		chan_ctxt =
 			&mhi_dev_ctxt->mhi_local_chan_ctxt[chan];
+
 		mhi_log(MHI_MSG_INFO, "DB_MODE/OOB Detected chan %d.\n", chan);
+		spin_lock_irqsave(&mhi_dev_ctxt->db_write_lock[chan],
+				  flags);
+		chan_ctxt->db_mode.db_mode = 1;
 		if (chan_ctxt->wp != chan_ctxt->rp) {
 			db_value = mhi_v2p_addr(mhi_dev_ctxt,
 						MHI_RING_TYPE_XFER_RING, chan,
@@ -1182,8 +1188,10 @@ int parse_xfer_event(struct mhi_device_ctxt *ctxt,
 				     db_value);
 		}
 		client_handle = mhi_dev_ctxt->client_handle_list[chan];
-			if (NULL != client_handle)
-				result->transaction_status = -ENOTCONN;
+		if (client_handle)
+			result->transaction_status = -ENOTCONN;
+		spin_unlock_irqrestore(&mhi_dev_ctxt->db_write_lock[chan],
+				       flags);
 		break;
 	}
 	case MHI_EVENT_CC_BAD_TRE:
@@ -1393,8 +1401,10 @@ static int start_chan_cmd(struct mhi_device_ctxt *mhi_dev_ctxt,
 	u32 chan;
 
 	MHI_TRB_GET_INFO(CMD_TRB_CHID, cmd_pkt, chan);
-	if (!VALID_CHAN_NR(chan))
+	if (!VALID_CHAN_NR(chan)) {
 		mhi_log(MHI_MSG_ERROR, "Bad chan: 0x%x\n", chan);
+		return -EINVAL;
+	}
 	mhi_dev_ctxt->mhi_chan_pend_cmd_ack[chan] =
 					MHI_CMD_NOT_PENDING;
 	mhi_log(MHI_MSG_INFO, "Processed START CMD chan %d\n", chan);
@@ -1652,6 +1662,8 @@ void mhi_process_db(struct mhi_device_ctxt *mhi_dev_ctxt,
 		  void __iomem *io_addr,
 		  uintptr_t chan, u32 val)
 {
+	struct mhi_ring *chan_ctxt = &mhi_dev_ctxt->mhi_local_chan_ctxt[chan];
+
 	mhi_log(MHI_MSG_VERBOSE,
 			"db.set addr: %p io_offset 0x%lx val:0x%x\n",
 			io_addr, chan, val);
@@ -1662,14 +1674,14 @@ void mhi_process_db(struct mhi_device_ctxt *mhi_dev_ctxt,
 	if (io_addr == mhi_dev_ctxt->mmio_info.chan_db_addr) {
 		if (!(IS_HARDWARE_CHANNEL(chan) &&
 		    mhi_dev_ctxt->flags.uldl_enabled &&
-		    !mhi_dev_ctxt->flags.db_mode[chan])) {
+		    !chan_ctxt->db_mode.db_mode)) {
 			mhi_write_db(mhi_dev_ctxt, io_addr, chan, val);
-			mhi_dev_ctxt->flags.db_mode[chan] = 0;
+			chan_ctxt->db_mode.db_mode = 0;
 		} else {
 			mhi_log(MHI_MSG_INFO,
-			 "Not ringing xfer db, chan %ld, ul_dl %d db_mode %d\n",
-			  chan, mhi_dev_ctxt->flags.uldl_enabled,
-				mhi_dev_ctxt->flags.db_mode[chan]);
+				"Not ringing xfer db, chan %ld, ul_dl %d db_mode %d\n",
+				chan, mhi_dev_ctxt->flags.uldl_enabled,
+				chan_ctxt->db_mode.db_mode);
 		}
 	/* Event Doorbell and Polling mode Disabled */
 	} else if (io_addr == mhi_dev_ctxt->mmio_info.event_db_addr) {
@@ -1677,11 +1689,9 @@ void mhi_process_db(struct mhi_device_ctxt *mhi_dev_ctxt,
 		if (IS_SW_EV_RING(mhi_dev_ctxt, chan) ||
 		    !mhi_dev_ctxt->flags.uldl_enabled) {
 			mhi_write_db(mhi_dev_ctxt, io_addr, chan, val);
-			mhi_dev_ctxt->flags.db_mode[chan] = 0;
 		}
 	} else {
 		mhi_write_db(mhi_dev_ctxt, io_addr, chan, val);
-		mhi_dev_ctxt->flags.db_mode[chan] = 0;
 	}
 }
 
diff --git a/drivers/platform/msm/mhi/mhi_mmio_ops.c b/drivers/platform/msm/mhi/mhi_mmio_ops.c
index ddf18e466cd3..6f56587a172b 100644
--- a/drivers/platform/msm/mhi/mhi_mmio_ops.c
+++ b/drivers/platform/msm/mhi/mhi_mmio_ops.c
@@ -144,6 +144,11 @@ int mhi_init_mmio(struct mhi_device_ctxt *mhi_dev_ctxt)
 				MHICFG,
 				MHICFG_NER_MASK, MHICFG_NER_SHIFT,
 				mhi_dev_ctxt->mmio_info.nr_event_rings);
+	mhi_reg_write_field(mhi_dev_ctxt, mhi_dev_ctxt->mmio_info.mmio_addr,
+			    MHICFG,
+			    MHICFG_NHWER_MASK,
+			    MHICFG_NHWER_SHIFT,
+			    mhi_dev_ctxt->mmio_info.nr_hw_event_rings);
 
 	pcie_dword_val = mhi_dev_ctxt->dev_space.ring_ctxt.dma_cc_list;
 	pcie_word_val = HIGH_WORD(pcie_dword_val);
diff --git a/drivers/platform/msm/mhi/mhi_pm.c b/drivers/platform/msm/mhi/mhi_pm.c
index a928c05b805a..d62d4189d3f3 100644
--- a/drivers/platform/msm/mhi/mhi_pm.c
+++ b/drivers/platform/msm/mhi/mhi_pm.c
@@ -46,8 +46,8 @@ int mhi_pci_suspend(struct device *dev)
 
 	if (NULL == mhi_dev_ctxt)
 		return -EINVAL;
-	mhi_log(MHI_MSG_INFO, "Entered, MHI state %d\n",
-			mhi_dev_ctxt->mhi_state);
+	mhi_log(MHI_MSG_INFO, "Entered, MHI state %s\n",
+		TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state));
 	atomic_set(&mhi_dev_ctxt->flags.pending_resume, 1);
 
 	r = mhi_initiate_m3(mhi_dev_ctxt);
@@ -115,7 +115,8 @@ int mhi_pci_resume(struct device *dev)
 		break;
 	default:
 		mhi_log(MHI_MSG_INFO,
-			"Wait complete state: %d\n", mhi_dev_ctxt->mhi_state);
+			"Wait complete state: %s\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state));
 		r = 0;
 	}
 exit:
@@ -181,8 +182,8 @@ ssize_t sysfs_init_m0(struct device *dev, struct device_attribute *attr,
 	}
 	mhi_initiate_m0(mhi_dev_ctxt);
 	mhi_log(MHI_MSG_CRITICAL,
-			"Current mhi_state = 0x%x\n",
-			mhi_dev_ctxt->mhi_state);
+		"Current mhi_state = %s\n",
+		TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state));
 
 	return count;
 }
diff --git a/drivers/platform/msm/mhi/mhi_ring_ops.c b/drivers/platform/msm/mhi/mhi_ring_ops.c
index e5a6dd51f51a..07d0098a1b61 100644
--- a/drivers/platform/msm/mhi/mhi_ring_ops.c
+++ b/drivers/platform/msm/mhi/mhi_ring_ops.c
@@ -48,6 +48,9 @@ static int add_element(struct mhi_ring *ring, void **rp,
 		*assigned_addr = (char *)ring->wp;
 	*wp = (void *)(((d_wp + 1) % ring_size) * ring->el_size +
 						(uintptr_t)ring->base);
+
+	/* force update visible to other cores */
+	smp_wmb();
 	return 0;
 }
 
@@ -101,6 +104,9 @@ int delete_element(struct mhi_ring *ring, void **rp,
 
 	*rp = (void *)(((d_rp + 1) % ring_size) * ring->el_size +
 						(uintptr_t)ring->base);
+
+	/* force update visible to other cores */
+	smp_wmb();
 	return 0;
 }
 
@@ -108,6 +114,7 @@ int mhi_get_free_desc(struct mhi_client_handle *client_handle)
 {
 	u32 chan;
 	struct mhi_device_ctxt *ctxt;
+	int bb_ring, ch_ring;
 
 	if (!client_handle || MHI_HANDLE_MAGIC != client_handle->magic ||
 	    !client_handle->mhi_dev_ctxt)
@@ -115,7 +122,10 @@ int mhi_get_free_desc(struct mhi_client_handle *client_handle)
 	ctxt = client_handle->mhi_dev_ctxt;
 	chan = client_handle->chan_info.chan_nr;
 
-	return get_nr_avail_ring_elements(&ctxt->mhi_local_chan_ctxt[chan]);
+	bb_ring = get_nr_avail_ring_elements(&ctxt->chan_bb_list[chan]);
+	ch_ring = get_nr_avail_ring_elements(&ctxt->mhi_local_chan_ctxt[chan]);
+
+	return min(bb_ring, ch_ring);
 }
 EXPORT_SYMBOL(mhi_get_free_desc);
 
diff --git a/drivers/platform/msm/mhi/mhi_states.c b/drivers/platform/msm/mhi/mhi_states.c
index ca4520a3c57d..f0404da98cf7 100644
--- a/drivers/platform/msm/mhi/mhi_states.c
+++ b/drivers/platform/msm/mhi/mhi_states.c
@@ -17,6 +17,29 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 
+static const char *state_transition_str(enum STATE_TRANSITION state)
+{
+	static const char * const mhi_states_transition_str[] = {
+		"RESET",
+		"READY",
+		"M0",
+		"M1",
+		"M2",
+		"M3",
+		"BHI",
+		"SBL",
+		"AMSS",
+		"LINK_DOWN",
+		"WAKE"
+	};
+
+	if (state == STATE_TRANSITION_SYS_ERR)
+		return "SYS_ERR";
+
+	return (state <= STATE_TRANSITION_WAKE) ?
+		mhi_states_transition_str[state] : "Invalid";
+}
+
 static inline void mhi_set_m_state(struct mhi_device_ctxt *mhi_dev_ctxt,
 					enum MHI_STATE new_state)
 {
@@ -57,7 +80,8 @@ static void conditional_chan_db_write(
 	spin_unlock_irqrestore(&mhi_dev_ctxt->db_write_lock[chan], flags);
 }
 
-static void ring_all_chan_dbs(struct mhi_device_ctxt *mhi_dev_ctxt)
+static void ring_all_chan_dbs(struct mhi_device_ctxt *mhi_dev_ctxt,
+			      bool reset_db_mode)
 {
 	u32 i = 0;
 	struct mhi_ring *local_ctxt = NULL;
@@ -66,11 +90,13 @@ static void ring_all_chan_dbs(struct mhi_device_ctxt *mhi_dev_ctxt)
 	for (i = 0; i < MHI_MAX_CHANNELS; ++i)
 		if (VALID_CHAN_NR(i)) {
 			local_ctxt = &mhi_dev_ctxt->mhi_local_chan_ctxt[i];
-			if (IS_HARDWARE_CHANNEL(i))
-				mhi_dev_ctxt->flags.db_mode[i] = 1;
-			if ((local_ctxt->wp != local_ctxt->rp) ||
-			   ((local_ctxt->wp != local_ctxt->rp) &&
-			    (local_ctxt->dir == MHI_IN)))
+
+			/* Reset the DB Mode state to DB Mode */
+			if (local_ctxt->db_mode.preserve_db_state == 0
+			    && reset_db_mode)
+				local_ctxt->db_mode.db_mode = 1;
+
+			if (local_ctxt->wp != local_ctxt->rp)
 				conditional_chan_db_write(mhi_dev_ctxt, i);
 		}
 }
@@ -150,8 +176,9 @@ static int process_m0_transition(
 			"Transitioning from M1.\n");
 	} else {
 		mhi_log(MHI_MSG_INFO,
-			"MHI State %d link state %d. Quitting\n",
-			mhi_dev_ctxt->mhi_state, mhi_dev_ctxt->flags.link_up);
+			"MHI State %s link state %d. Quitting\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+			mhi_dev_ctxt->flags.link_up);
 	}
 
 	read_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
@@ -162,7 +189,7 @@ static int process_m0_transition(
 
 	if (mhi_dev_ctxt->flags.mhi_initialized) {
 		ring_all_ev_dbs(mhi_dev_ctxt);
-		ring_all_chan_dbs(mhi_dev_ctxt);
+		ring_all_chan_dbs(mhi_dev_ctxt, true);
 		ring_all_cmd_dbs(mhi_dev_ctxt);
 	}
 	atomic_dec(&mhi_dev_ctxt->flags.data_pending);
@@ -196,8 +223,8 @@ static int process_m1_transition(
 	int r = 0;
 
 	mhi_log(MHI_MSG_INFO,
-			"Processing M1 state transition from state %d\n",
-			mhi_dev_ctxt->mhi_state);
+		"Processing M1 state transition from state %s\n",
+		TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state));
 
 	write_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
 	if (!mhi_dev_ctxt->flags.pending_M3) {
@@ -444,8 +471,8 @@ static int process_reset_transition(
 					STATE_TRANSITION_RESET);
 		if (0 != r)
 			mhi_log(MHI_MSG_CRITICAL,
-				"Failed to initiate 0x%x state trans\n",
-				STATE_TRANSITION_RESET);
+				"Failed to initiate %s state trans\n",
+				state_transition_str(STATE_TRANSITION_RESET));
 		break;
 	default:
 		mhi_log(MHI_MSG_CRITICAL,
@@ -475,8 +502,8 @@ static int process_reset_transition(
 				STATE_TRANSITION_READY);
 	if (0 != r)
 		mhi_log(MHI_MSG_CRITICAL,
-		"Failed to initiate 0x%x state trans\n",
-		STATE_TRANSITION_READY);
+			"Failed to initiate %s state trans\n",
+			state_transition_str(STATE_TRANSITION_READY));
 	return r;
 }
 
@@ -594,7 +621,7 @@ static int process_amss_transition(
 				"Failed to set local chan state ret %d\n", r);
 			return r;
 		}
-		ring_all_chan_dbs(mhi_dev_ctxt);
+		ring_all_chan_dbs(mhi_dev_ctxt, true);
 		mhi_log(MHI_MSG_INFO,
 			"Notifying clients that MHI is enabled\n");
 		enable_clients(mhi_dev_ctxt, mhi_dev_ctxt->dev_exec_env);
@@ -608,7 +635,7 @@ static int process_amss_transition(
 					i, r);
 				return r;
 		}
-		ring_all_chan_dbs(mhi_dev_ctxt);
+		ring_all_chan_dbs(mhi_dev_ctxt, true);
 	}
 	ring_all_ev_dbs(mhi_dev_ctxt);
 	atomic_dec(&mhi_dev_ctxt->flags.data_pending);
@@ -636,8 +663,8 @@ int mhi_trigger_reset(struct mhi_device_ctxt *mhi_dev_ctxt)
 					    STATE_TRANSITION_RESET);
 	if (0 != r)
 		mhi_log(MHI_MSG_CRITICAL,
-			"Failed to initiate 0x%x state trans ret %d\n",
-			STATE_TRANSITION_RESET, r);
+			"Failed to initiate %s state trans ret %d\n",
+			state_transition_str(STATE_TRANSITION_RESET), r);
 	mhi_log(MHI_MSG_INFO, "Exiting\n");
 	return r;
 }
@@ -648,8 +675,8 @@ static int process_stt_work_item(
 {
 	int r = 0;
 
-	mhi_log(MHI_MSG_INFO, "Transitioning to %d\n",
-				(int)cur_work_item);
+	mhi_log(MHI_MSG_INFO, "Transitioning to %s\n",
+		state_transition_str(cur_work_item));
 	trace_mhi_state(cur_work_item);
 	switch (cur_work_item) {
 	case STATE_TRANSITION_BHI:
@@ -689,7 +716,8 @@ static int process_stt_work_item(
 		break;
 	default:
 		mhi_log(MHI_MSG_ERROR,
-				"Unrecongized state: %d\n", cur_work_item);
+			"Unrecongized state: %s\n",
+			state_transition_str(cur_work_item));
 		break;
 	}
 	return r;
@@ -762,8 +790,8 @@ int mhi_init_state_transition(struct mhi_device_ctxt *mhi_dev_ctxt,
 
 	BUG_ON(nr_avail_work_items <= 0);
 	mhi_log(MHI_MSG_VERBOSE,
-		"Processing state transition %x\n",
-		new_state);
+		"Processing state transition %s\n",
+		state_transition_str(new_state));
 	*(enum STATE_TRANSITION *)stt_ring->wp = new_state;
 	r = ctxt_add_element(stt_ring, (void **)&cur_work_item);
 	BUG_ON(r);
@@ -778,13 +806,14 @@ int mhi_initiate_m0(struct mhi_device_ctxt *mhi_dev_ctxt)
 	unsigned long flags;
 
 	mhi_log(MHI_MSG_INFO,
-		"Entered MHI state %d, Pending M0 %d Pending M3 %d\n",
-		mhi_dev_ctxt->mhi_state, mhi_dev_ctxt->flags.pending_M0,
-					mhi_dev_ctxt->flags.pending_M3);
+		"Entered MHI state %s, Pending M0 %d Pending M3 %d\n",
+		TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+		mhi_dev_ctxt->flags.pending_M0,
+		mhi_dev_ctxt->flags.pending_M3);
 	mutex_lock(&mhi_dev_ctxt->pm_lock);
 	mhi_log(MHI_MSG_INFO,
-		"Waiting for M0 M1 or M3. Currently %d...\n",
-					mhi_dev_ctxt->mhi_state);
+		"Waiting for M0 M1 or M3. Currently %s...\n",
+		 TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state));
 
 	r = wait_event_interruptible_timeout(*mhi_dev_ctxt->mhi_ev_wq.m3_event,
 			mhi_dev_ctxt->mhi_state == MHI_STATE_M3 ||
@@ -794,9 +823,9 @@ int mhi_initiate_m0(struct mhi_device_ctxt *mhi_dev_ctxt)
 	switch (r) {
 	case 0:
 		mhi_log(MHI_MSG_CRITICAL,
-			"Timeout: State %d after %d ms\n",
-				mhi_dev_ctxt->mhi_state,
-				MHI_MAX_SUSPEND_TIMEOUT);
+			"Timeout: State %s after %d ms\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+			MHI_MAX_SUSPEND_TIMEOUT);
 		mhi_dev_ctxt->counters.m0_event_timeouts++;
 		r = -ETIME;
 		goto exit;
@@ -806,7 +835,8 @@ int mhi_initiate_m0(struct mhi_device_ctxt *mhi_dev_ctxt)
 		goto exit;
 	default:
 		mhi_log(MHI_MSG_INFO,
-			"Wait complete state: %d\n", mhi_dev_ctxt->mhi_state);
+			"Wait complete state: %s\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state));
 		r = 0;
 		break;
 	}
@@ -814,8 +844,8 @@ int mhi_initiate_m0(struct mhi_device_ctxt *mhi_dev_ctxt)
 	    mhi_dev_ctxt->mhi_state == MHI_STATE_M1) {
 		mhi_assert_device_wake(mhi_dev_ctxt);
 		mhi_log(MHI_MSG_INFO,
-				"MHI state %d, done\n",
-					mhi_dev_ctxt->mhi_state);
+			"MHI state %s, done\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state));
 		goto exit;
 	} else {
 		if (0 != mhi_turn_on_pcie_link(mhi_dev_ctxt)) {
@@ -864,9 +894,10 @@ int mhi_initiate_m3(struct mhi_device_ctxt *mhi_dev_ctxt)
 	int r = 0, abort_m3 = 0;
 
 	mhi_log(MHI_MSG_INFO,
-		"Entered MHI state %d, Pending M0 %d Pending M3 %d\n",
-		mhi_dev_ctxt->mhi_state, mhi_dev_ctxt->flags.pending_M0,
-					mhi_dev_ctxt->flags.pending_M3);
+		"Entered MHI state %s, Pending M0 %d Pending M3 %d\n",
+		TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+		mhi_dev_ctxt->flags.pending_M0,
+		mhi_dev_ctxt->flags.pending_M3);
 	mutex_lock(&mhi_dev_ctxt->pm_lock);
 	switch (mhi_dev_ctxt->mhi_state) {
 	case MHI_STATE_RESET:
@@ -881,47 +912,53 @@ int mhi_initiate_m3(struct mhi_device_ctxt *mhi_dev_ctxt)
 	case MHI_STATE_M0:
 	case MHI_STATE_M1:
 	case MHI_STATE_M2:
+		write_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
 		mhi_log(MHI_MSG_INFO,
 			"Triggering wake out of M2\n");
-		write_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
 		mhi_dev_ctxt->flags.pending_M3 = 1;
 		if ((atomic_read(&mhi_dev_ctxt->flags.m2_transition)) == 0) {
 			mhi_log(MHI_MSG_INFO,
 				"M2 transition not set\n");
 			mhi_assert_device_wake(mhi_dev_ctxt);
 		}
-		write_unlock_irqrestore(&mhi_dev_ctxt->xfer_lock, flags);
-		r = wait_event_interruptible_timeout(
+
+		if (mhi_dev_ctxt->mhi_state == MHI_STATE_M2) {
+			write_unlock_irqrestore(&mhi_dev_ctxt->xfer_lock,
+				flags);
+			r = wait_event_interruptible_timeout(
 				*mhi_dev_ctxt->mhi_ev_wq.m0_event,
-				mhi_dev_ctxt->mhi_state == MHI_STATE_M0 ||
-				mhi_dev_ctxt->mhi_state == MHI_STATE_M1,
+				mhi_dev_ctxt->mhi_state == MHI_STATE_M0,
 				msecs_to_jiffies(MHI_MAX_RESUME_TIMEOUT));
-		if (0 == r || -ERESTARTSYS == r) {
-			mhi_log(MHI_MSG_CRITICAL,
-				"MDM failed to come out of M2.\n");
-			mhi_dev_ctxt->counters.m2_event_timeouts++;
-			r = -EAGAIN;
-			goto exit;
+			write_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
+			if (0 == r || -ERESTARTSYS == r) {
+				mhi_log(MHI_MSG_CRITICAL,
+					"MDM failed to come out of M2.\n");
+				mhi_dev_ctxt->counters.m2_event_timeouts++;
+				r = -EAGAIN;
+				goto unlock;
+			}
 		}
 		break;
 	case MHI_STATE_M3:
 		mhi_log(MHI_MSG_INFO,
-			"MHI state %d, link state %d.\n",
-				mhi_dev_ctxt->mhi_state,
-				mhi_dev_ctxt->flags.link_up);
+			"MHI state %s, link state %d.\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+			mhi_dev_ctxt->flags.link_up);
 		if (mhi_dev_ctxt->flags.link_up)
 			r = -EAGAIN;
 		else
 			r = 0;
 		goto exit;
 	default:
+		write_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
 		mhi_log(MHI_MSG_INFO,
-			"MHI state %d, link state %d.\n",
-				mhi_dev_ctxt->mhi_state,
-				mhi_dev_ctxt->flags.link_up);
+			"MHI state %s, link state %d.\n",
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
+			mhi_dev_ctxt->flags.link_up);
 		break;
 	}
-	while (atomic_read(&mhi_dev_ctxt->counters.outbound_acks)) {
+
+	if (atomic_read(&mhi_dev_ctxt->counters.outbound_acks)) {
 		mhi_log(MHI_MSG_INFO,
 			"There are still %d acks pending from device\n",
 			atomic_read(&mhi_dev_ctxt->counters.outbound_acks));
@@ -929,25 +966,23 @@ int mhi_initiate_m3(struct mhi_device_ctxt *mhi_dev_ctxt)
 			__pm_relax(&mhi_dev_ctxt->w_lock);
 		abort_m3 = 1;
 		r = -EAGAIN;
-		goto exit;
+		goto unlock;
 	}
 
 	if (atomic_read(&mhi_dev_ctxt->flags.data_pending)) {
 		abort_m3 = 1;
 		r = -EAGAIN;
-		goto exit;
+		goto unlock;
 	}
-	write_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
+
 	if (mhi_dev_ctxt->flags.pending_M0) {
-		write_unlock_irqrestore(&mhi_dev_ctxt->xfer_lock, flags);
 		r = -EAGAIN;
-		goto exit;
+		goto unlock;
 	}
 	mhi_dev_ctxt->flags.pending_M3 = 1;
 
 	mhi_set_m_state(mhi_dev_ctxt, MHI_STATE_M3);
 	write_unlock_irqrestore(&mhi_dev_ctxt->xfer_lock, flags);
-
 	mhi_log(MHI_MSG_INFO,
 			"Waiting for M3 completion.\n");
 	r = wait_event_interruptible_timeout(*mhi_dev_ctxt->mhi_ev_wq.m3_event,
@@ -970,16 +1005,20 @@ int mhi_initiate_m3(struct mhi_device_ctxt *mhi_dev_ctxt)
 	r = mhi_set_bus_request(mhi_dev_ctxt, 0);
 	if (r)
 		mhi_log(MHI_MSG_INFO, "Failed to set bus freq ret %d\n", r);
-exit:
+	goto exit;
+unlock:
+	mhi_dev_ctxt->flags.pending_M3 = 0;
 	if (abort_m3) {
-		write_lock_irqsave(&mhi_dev_ctxt->xfer_lock, flags);
 		atomic_inc(&mhi_dev_ctxt->flags.data_pending);
 		write_unlock_irqrestore(&mhi_dev_ctxt->xfer_lock, flags);
-		ring_all_chan_dbs(mhi_dev_ctxt);
+		ring_all_chan_dbs(mhi_dev_ctxt, false);
 		ring_all_cmd_dbs(mhi_dev_ctxt);
 		atomic_dec(&mhi_dev_ctxt->flags.data_pending);
 		mhi_deassert_device_wake(mhi_dev_ctxt);
+	} else {
+		write_unlock_irqrestore(&mhi_dev_ctxt->xfer_lock, flags);
 	}
+exit:
 	mhi_dev_ctxt->flags.pending_M3 = 0;
 	mutex_unlock(&mhi_dev_ctxt->pm_lock);
 	return r;
diff --git a/drivers/platform/msm/mhi/mhi_sys.c b/drivers/platform/msm/mhi/mhi_sys.c
index b8652770275e..3316b2694896 100644
--- a/drivers/platform/msm/mhi/mhi_sys.c
+++ b/drivers/platform/msm/mhi/mhi_sys.c
@@ -34,6 +34,18 @@ MODULE_PARM_DESC(mhi_msg_lvl, "dbg lvl");
 module_param(mhi_ipc_log_lvl, uint, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(mhi_ipc_log_lvl, "dbg lvl");
 
+const char * const mhi_states_str[MHI_STATE_LIMIT] = {
+	"RESET",
+	"READY",
+	"M0",
+	"M1",
+	"M2",
+	"M3",
+	"Reserved: 0x06",
+	"BHI",
+	"SYS_ERR",
+};
+
 static ssize_t mhi_dbgfs_chan_read(struct file *fp, char __user *buf,
 				size_t count, loff_t *offp)
 {
@@ -225,9 +237,9 @@ static ssize_t mhi_dbgfs_state_read(struct file *fp, char __user *buf,
 	amnt_copied =
 	scnprintf(mhi_dev_ctxt->chan_info,
 			MHI_LOG_SIZE,
-			"%s %u %s %d %s %d %s %d %s %d %s %d %s %d %s %d %s %d %s %d %s %d, %s, %d, %s %d\n",
+			"%s %s %s %d %s %d %s %d %s %d %s %d %s %d %s %d %s %d %s %d %s %d\n",
 			"Our State:",
-			mhi_dev_ctxt->mhi_state,
+			TO_MHI_STATE_STR(mhi_dev_ctxt->mhi_state),
 			"M0->M1:",
 			mhi_dev_ctxt->counters.m0_m1,
 			"M0<-M1:",
@@ -244,10 +256,6 @@ static ssize_t mhi_dbgfs_state_read(struct file *fp, char __user *buf,
 			mhi_dev_ctxt->counters.m3_event_timeouts,
 			"M0_ev_TO:",
 			mhi_dev_ctxt->counters.m0_event_timeouts,
-			"MSI_d:",
-			mhi_dev_ctxt->counters.msi_disable_cntr,
-			"MSI_e:",
-			mhi_dev_ctxt->counters.msi_enable_cntr,
 			"outstanding_acks:",
 			atomic_read(&mhi_dev_ctxt->counters.outbound_acks),
 			"LPM:",
diff --git a/drivers/platform/msm/mhi/mhi_sys.h b/drivers/platform/msm/mhi/mhi_sys.h
index 765fd46ef2dd..a948a2354de7 100644
--- a/drivers/platform/msm/mhi/mhi_sys.h
+++ b/drivers/platform/msm/mhi/mhi_sys.h
@@ -46,6 +46,10 @@ extern void *mhi_ipc_log;
 			       "[%s] " _msg, __func__, ##__VA_ARGS__);	\
 } while (0)
 
+extern const char * const mhi_states_str[MHI_STATE_LIMIT];
+#define TO_MHI_STATE_STR(state) (((state) >= MHI_STATE_LIMIT) ? \
+				 "INVALID_STATE" : mhi_states_str[state])
+
 irqreturn_t mhi_msi_handlr(int msi_number, void *dev_id);
 
 struct mhi_meminfo {