diff mbox

[v2,3/7] mhi_bus: core: add support for data transfer

Message ID 1531166894-30984-4-git-send-email-sdias@codeaurora.org (mailing list archive)
State Not Applicable, archived
Delegated to: Andy Gross
Headers show

Commit Message

Sujeev Dias July 9, 2018, 8:08 p.m. UTC
Add support for transferring data between external
modem and MHI host using MHI protocol.

Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
Reviewed-by: Tony Truong <truong@codeaurora.org>
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
---
 drivers/bus/mhi/core/mhi_init.c     |  76 +++-
 drivers/bus/mhi/core/mhi_internal.h |   8 -
 drivers/bus/mhi/core/mhi_main.c     | 803 +++++++++++++++++++++++++++++++++++-
 include/linux/mhi.h                 |  78 ++++
 4 files changed, 950 insertions(+), 15 deletions(-)

Comments

Greg KH July 10, 2018, 6:29 a.m. UTC | #1
On Mon, Jul 09, 2018 at 01:08:10PM -0700, Sujeev Dias wrote:
> +static void mhi_add_ring_element(struct mhi_controller *mhi_cntrl,
> +				 struct mhi_ring *ring)
> +{
> +	ring->wp += ring->el_size;
> +	if (ring->wp >= (ring->base + ring->len))
> +		ring->wp = ring->base;
> +	/* smp update */
> +	smp_wmb();

Why do this?  You need to comment the heck out of odd stuff like this.

Also, why are you using your own ring buffer code?  What's wrong with
the code that is in the kernel already for this type of thing?

thanks,

greg k-h
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diff mbox

Patch

diff --git a/drivers/bus/mhi/core/mhi_init.c b/drivers/bus/mhi/core/mhi_init.c
index 7b3d12a..43a700d 100644
--- a/drivers/bus/mhi/core/mhi_init.c
+++ b/drivers/bus/mhi/core/mhi_init.c
@@ -548,6 +548,66 @@  int mhi_init_chan_ctxt(struct mhi_controller *mhi_cntrl,
 	return 0;
 }
 
+int mhi_device_configure(struct mhi_device *mhi_dev,
+			 enum dma_data_direction dir,
+			 struct mhi_buf *cfg_tbl,
+			 int elements)
+{
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_chan *mhi_chan;
+	struct mhi_event_ctxt *er_ctxt;
+	struct mhi_chan_ctxt *ch_ctxt;
+	int er_index, chan;
+
+	switch (dir) {
+	case DMA_TO_DEVICE:
+		mhi_chan = mhi_dev->ul_chan;
+		break;
+	case DMA_BIDIRECTIONAL:
+	case DMA_FROM_DEVICE:
+	case DMA_NONE:
+		mhi_chan = mhi_dev->dl_chan;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	er_index = mhi_chan->er_index;
+	chan = mhi_chan->chan;
+
+	for (; elements > 0; elements--, cfg_tbl++) {
+		/* update event context array */
+		if (!strcmp(cfg_tbl->name, "ECA")) {
+			er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[er_index];
+			if (sizeof(*er_ctxt) != cfg_tbl->len) {
+				dev_err(mhi_cntrl->dev,
+					"Invalid ECA size, expected:%zu actual%zu\n",
+					sizeof(*er_ctxt), cfg_tbl->len);
+				return -EINVAL;
+			}
+			memcpy((void *)er_ctxt, cfg_tbl->buf, sizeof(*er_ctxt));
+			continue;
+		}
+
+		/* update channel context array */
+		if (!strcmp(cfg_tbl->name, "CCA")) {
+			ch_ctxt = &mhi_cntrl->mhi_ctxt->chan_ctxt[chan];
+			if (cfg_tbl->len != sizeof(*ch_ctxt)) {
+				dev_err(mhi_cntrl->dev,
+					"Invalid CCA size, expected:%zu actual:%zu\n",
+					sizeof(*ch_ctxt), cfg_tbl->len);
+				return -EINVAL;
+			}
+			memcpy((void *)ch_ctxt, cfg_tbl->buf, sizeof(*ch_ctxt));
+			continue;
+		}
+
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int of_parse_ev_cfg(struct mhi_controller *mhi_cntrl,
 			   struct device_node *of_node)
 {
@@ -1067,6 +1127,9 @@  static int mhi_driver_probe(struct device *dev)
 	struct mhi_event *mhi_event;
 	struct mhi_chan *ul_chan = mhi_dev->ul_chan;
 	struct mhi_chan *dl_chan = mhi_dev->dl_chan;
+	bool auto_start = false;
+	int ret;
+
 
 	if (ul_chan) {
 		/* lpm notification require status_cb */
@@ -1078,6 +1141,7 @@  static int mhi_driver_probe(struct device *dev)
 
 		ul_chan->xfer_cb = mhi_drv->ul_xfer_cb;
 		mhi_dev->status_cb = mhi_drv->status_cb;
+		auto_start = ul_chan->auto_start;
 	}
 
 	if (dl_chan) {
@@ -1101,9 +1165,15 @@  static int mhi_driver_probe(struct device *dev)
 
 		/* ul & dl uses same status cb */
 		mhi_dev->status_cb = mhi_drv->status_cb;
+		auto_start = (auto_start || dl_chan->auto_start);
 	}
 
-	return mhi_drv->probe(mhi_dev, mhi_dev->id);
+	ret = mhi_drv->probe(mhi_dev, mhi_dev->id);
+
+	if (!ret && auto_start)
+		mhi_prepare_for_transfer(mhi_dev);
+
+	return ret;
 }
 
 static int mhi_driver_remove(struct device *dev)
@@ -1141,6 +1211,10 @@  static int mhi_driver_remove(struct device *dev)
 		ch_state[dir] = mhi_chan->ch_state;
 		mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
 		write_unlock_irq(&mhi_chan->lock);
+
+		/* reset the channel */
+		if (!mhi_chan->offload_ch)
+			mhi_reset_chan(mhi_cntrl, mhi_chan);
 	}
 
 	/* destroy the device */
diff --git a/drivers/bus/mhi/core/mhi_internal.h b/drivers/bus/mhi/core/mhi_internal.h
index 0091245..1167d75 100644
--- a/drivers/bus/mhi/core/mhi_internal.h
+++ b/drivers/bus/mhi/core/mhi_internal.h
@@ -243,7 +243,6 @@  enum mhi_cmd_type {
 	MHI_CMD_TYPE_RESET = 16,
 	MHI_CMD_TYPE_STOP = 17,
 	MHI_CMD_TYPE_START = 18,
-	MHI_CMD_TYPE_TSYNC = 24,
 };
 
 /* no operation command */
@@ -268,12 +267,6 @@  enum mhi_cmd_type {
 #define MHI_TRE_CMD_START_DWORD1(chid) ((chid << 24) | \
 					(MHI_CMD_TYPE_START << 16))
 
-/* time sync cfg command */
-#define MHI_TRE_CMD_TSYNC_CFG_PTR (0)
-#define MHI_TRE_CMD_TSYNC_CFG_DWORD0 (0)
-#define MHI_TRE_CMD_TSYNC_CFG_DWORD1(er) ((MHI_CMD_TYPE_TSYNC << 16) | \
-					  (er << 24))
-
 #define MHI_TRE_GET_CMD_CHID(tre) (((tre)->dword[1] >> 24) & 0xFF)
 #define MHI_TRE_GET_CMD_TYPE(tre) (((tre)->dword[1] >> 16) & 0xFF)
 
@@ -300,7 +293,6 @@  enum mhi_cmd_type {
 enum MHI_CMD {
 	MHI_CMD_RESET_CHAN,
 	MHI_CMD_START_CHAN,
-	MHI_CMD_TIMSYNC_CFG,
 };
 
 enum MHI_PKT_TYPE {
diff --git a/drivers/bus/mhi/core/mhi_main.c b/drivers/bus/mhi/core/mhi_main.c
index 81cda31..3e7077a8 100644
--- a/drivers/bus/mhi/core/mhi_main.c
+++ b/drivers/bus/mhi/core/mhi_main.c
@@ -159,23 +159,46 @@  enum MHI_STATE mhi_get_m_state(struct mhi_controller *mhi_cntrl)
 int mhi_map_single_no_bb(struct mhi_controller *mhi_cntrl,
 			 struct mhi_buf_info *buf_info)
 {
-	return -ENOMEM;
+	buf_info->p_addr = dma_map_single(mhi_cntrl->dev, buf_info->v_addr,
+					  buf_info->len, buf_info->dir);
+	if (dma_mapping_error(mhi_cntrl->dev, buf_info->p_addr))
+		return -ENOMEM;
+
+	return 0;
 }
 
 int mhi_map_single_use_bb(struct mhi_controller *mhi_cntrl,
 			  struct mhi_buf_info *buf_info)
 {
-	return -ENOMEM;
+	void *buf = mhi_alloc_coherent(mhi_cntrl, buf_info->len,
+				       &buf_info->p_addr, GFP_ATOMIC);
+
+	if (!buf)
+		return -ENOMEM;
+
+	if (buf_info->dir == DMA_TO_DEVICE)
+		memcpy(buf, buf_info->v_addr, buf_info->len);
+
+	buf_info->bb_addr = buf;
+
+	return 0;
 }
 
 void mhi_unmap_single_no_bb(struct mhi_controller *mhi_cntrl,
 			    struct mhi_buf_info *buf_info)
 {
+	dma_unmap_single(mhi_cntrl->dev, buf_info->p_addr, buf_info->len,
+			 buf_info->dir);
 }
 
 void mhi_unmap_single_use_bb(struct mhi_controller *mhi_cntrl,
 			    struct mhi_buf_info *buf_info)
 {
+	if (buf_info->dir == DMA_FROM_DEVICE)
+		memcpy(buf_info->v_addr, buf_info->bb_addr, buf_info->len);
+
+	mhi_free_coherent(mhi_cntrl, buf_info->len, buf_info->bb_addr,
+			  buf_info->p_addr);
 }
 
 int mhi_queue_sclist(struct mhi_device *mhi_dev,
@@ -196,6 +219,41 @@  int mhi_queue_nop(struct mhi_device *mhi_dev,
 	return -EINVAL;
 }
 
+static void mhi_add_ring_element(struct mhi_controller *mhi_cntrl,
+				 struct mhi_ring *ring)
+{
+	ring->wp += ring->el_size;
+	if (ring->wp >= (ring->base + ring->len))
+		ring->wp = ring->base;
+	/* smp update */
+	smp_wmb();
+}
+
+static void mhi_del_ring_element(struct mhi_controller *mhi_cntrl,
+				 struct mhi_ring *ring)
+{
+	ring->rp += ring->el_size;
+	if (ring->rp >= (ring->base + ring->len))
+		ring->rp = ring->base;
+	/* smp update */
+	smp_wmb();
+}
+
+static int get_nr_avail_ring_elements(struct mhi_controller *mhi_cntrl,
+				      struct mhi_ring *ring)
+{
+	int nr_el;
+
+	if (ring->wp < ring->rp)
+		nr_el = ((ring->rp - ring->wp) / ring->el_size) - 1;
+	else {
+		nr_el = (ring->rp - ring->base) / ring->el_size;
+		nr_el += ((ring->base + ring->len - ring->wp) /
+			  ring->el_size) - 1;
+	}
+	return nr_el;
+}
+
 static void *mhi_to_virtual(struct mhi_ring *ring, dma_addr_t addr)
 {
 	return (addr - ring->iommu_base) + ring->base;
@@ -231,13 +289,97 @@  static void mhi_recycle_ev_ring_element(struct mhi_controller *mhi_cntrl,
 	smp_wmb();
 }
 
+static bool mhi_is_ring_full(struct mhi_controller *mhi_cntrl,
+			     struct mhi_ring *ring)
+{
+	void *tmp = ring->wp + ring->el_size;
+
+	if (tmp >= (ring->base + ring->len))
+		tmp = ring->base;
+
+	return (tmp == ring->rp);
+}
+
 int mhi_queue_skb(struct mhi_device *mhi_dev,
 		  struct mhi_chan *mhi_chan,
 		  void *buf,
 		  size_t len,
 		  enum MHI_FLAGS mflags)
 {
-	return -EINVAL;
+	struct sk_buff *skb = buf;
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_ring *tre_ring = &mhi_chan->tre_ring;
+	struct mhi_ring *buf_ring = &mhi_chan->buf_ring;
+	struct mhi_buf_info *buf_info;
+	struct mhi_tre *mhi_tre;
+	bool assert_wake = false;
+	int ret;
+
+	if (mhi_is_ring_full(mhi_cntrl, tre_ring))
+		return -ENOMEM;
+
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	if (unlikely(MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))) {
+		read_unlock_bh(&mhi_cntrl->pm_lock);
+		return -EIO;
+	}
+
+	/* we're in M3 or transitioning to M3 */
+	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
+		mhi_cntrl->runtime_get(mhi_cntrl, mhi_cntrl->priv_data);
+		mhi_cntrl->runtime_put(mhi_cntrl, mhi_cntrl->priv_data);
+	}
+
+	/*
+	 * For UL channels always assert WAKE until work is done,
+	 * For DL channels only assert if MHI is in a LPM
+	 */
+	if (mhi_chan->dir == DMA_TO_DEVICE ||
+	    (mhi_chan->dir == DMA_FROM_DEVICE &&
+	     mhi_cntrl->pm_state != MHI_PM_M0)) {
+		assert_wake = true;
+		mhi_cntrl->wake_get(mhi_cntrl, false);
+	}
+
+	/* generate the tre */
+	buf_info = buf_ring->wp;
+	buf_info->v_addr = skb->data;
+	buf_info->cb_buf = skb;
+	buf_info->wp = tre_ring->wp;
+	buf_info->dir = mhi_chan->dir;
+	buf_info->len = len;
+	ret = mhi_cntrl->map_single(mhi_cntrl, buf_info);
+	if (ret)
+		goto map_error;
+
+	mhi_tre = tre_ring->wp;
+	mhi_tre->ptr = MHI_TRE_DATA_PTR(buf_info->p_addr);
+	mhi_tre->dword[0] = MHI_TRE_DATA_DWORD0(buf_info->len);
+	mhi_tre->dword[1] = MHI_TRE_DATA_DWORD1(1, 1, 0, 0);
+
+	/* increment WP */
+	mhi_add_ring_element(mhi_cntrl, tre_ring);
+	mhi_add_ring_element(mhi_cntrl, buf_ring);
+
+	if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state))) {
+		read_lock_bh(&mhi_chan->lock);
+		mhi_ring_chan_db(mhi_cntrl, mhi_chan);
+		read_unlock_bh(&mhi_chan->lock);
+	}
+
+	if (mhi_chan->dir == DMA_FROM_DEVICE && assert_wake)
+		mhi_cntrl->wake_put(mhi_cntrl, true);
+
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+	return 0;
+
+map_error:
+	if (assert_wake)
+		mhi_cntrl->wake_put(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+	return ret;
 }
 
 int mhi_gen_tre(struct mhi_controller *mhi_cntrl,
@@ -247,7 +389,41 @@  int mhi_gen_tre(struct mhi_controller *mhi_cntrl,
 		size_t buf_len,
 		enum MHI_FLAGS flags)
 {
-	return -EINVAL;
+	struct mhi_ring *buf_ring, *tre_ring;
+	struct mhi_tre *mhi_tre;
+	struct mhi_buf_info *buf_info;
+	int eot, eob, chain, bei;
+	int ret;
+
+	buf_ring = &mhi_chan->buf_ring;
+	tre_ring = &mhi_chan->tre_ring;
+
+	buf_info = buf_ring->wp;
+	buf_info->v_addr = buf;
+	buf_info->cb_buf = cb;
+	buf_info->wp = tre_ring->wp;
+	buf_info->dir = mhi_chan->dir;
+	buf_info->len = buf_len;
+
+	ret = mhi_cntrl->map_single(mhi_cntrl, buf_info);
+	if (ret)
+		return ret;
+
+	eob = !!(flags & MHI_EOB);
+	eot = !!(flags & MHI_EOT);
+	chain = !!(flags & MHI_CHAIN);
+	bei = !!(mhi_chan->intmod);
+
+	mhi_tre = tre_ring->wp;
+	mhi_tre->ptr = MHI_TRE_DATA_PTR(buf_info->p_addr);
+	mhi_tre->dword[0] = MHI_TRE_DATA_DWORD0(buf_len);
+	mhi_tre->dword[1] = MHI_TRE_DATA_DWORD1(bei, eot, eob, chain);
+
+	/* increment WP */
+	mhi_add_ring_element(mhi_cntrl, tre_ring);
+	mhi_add_ring_element(mhi_cntrl, buf_ring);
+
+	return 0;
 }
 
 int mhi_queue_buf(struct mhi_device *mhi_dev,
@@ -256,7 +432,61 @@  int mhi_queue_buf(struct mhi_device *mhi_dev,
 		  size_t len,
 		  enum MHI_FLAGS mflags)
 {
-	return -EINVAL;
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_ring *tre_ring;
+	unsigned long flags;
+	bool assert_wake = false;
+	int ret;
+
+	/*
+	 * this check here only as a guard, it's always
+	 * possible mhi can enter error while executing rest of function,
+	 * which is not fatal so we do not need to hold pm_lock
+	 */
+	if (unlikely(MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)))
+		return -EIO;
+
+	/* we're in M3 or transitioning to M3 */
+	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
+		mhi_cntrl->runtime_get(mhi_cntrl, mhi_cntrl->priv_data);
+		mhi_cntrl->runtime_put(mhi_cntrl, mhi_cntrl->priv_data);
+	}
+
+	tre_ring = &mhi_chan->tre_ring;
+	if (mhi_is_ring_full(mhi_cntrl, tre_ring))
+		return -ENOMEM;
+
+	ret = mhi_chan->gen_tre(mhi_cntrl, mhi_chan, buf, buf, len, mflags);
+	if (unlikely(ret))
+		return ret;
+
+	read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
+
+	/*
+	 * For UL channels always assert WAKE until work is done,
+	 * For DL channels only assert if MHI is in a LPM
+	 */
+	if (mhi_chan->dir == DMA_TO_DEVICE ||
+	    (mhi_chan->dir == DMA_FROM_DEVICE &&
+	     mhi_cntrl->pm_state != MHI_PM_M0)) {
+		assert_wake = true;
+		mhi_cntrl->wake_get(mhi_cntrl, false);
+	}
+
+	if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state))) {
+		unsigned long flags;
+
+		read_lock_irqsave(&mhi_chan->lock, flags);
+		mhi_ring_chan_db(mhi_cntrl, mhi_chan);
+		read_unlock_irqrestore(&mhi_chan->lock, flags);
+	}
+
+	if (mhi_chan->dir == DMA_FROM_DEVICE && assert_wake)
+		mhi_cntrl->wake_put(mhi_cntrl, true);
+
+	read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags);
+
+	return 0;
 }
 
 /* destroy specific device */
@@ -389,6 +619,154 @@  void mhi_create_devices(struct mhi_controller *mhi_cntrl)
 			mhi_dealloc_device(mhi_cntrl, mhi_dev);
 	}
 }
+
+static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
+			    struct mhi_tre *event,
+			    struct mhi_chan *mhi_chan)
+{
+	struct mhi_ring *buf_ring, *tre_ring;
+	u32 ev_code;
+	struct mhi_result result;
+	unsigned long flags = 0;
+
+	ev_code = MHI_TRE_GET_EV_CODE(event);
+	buf_ring = &mhi_chan->buf_ring;
+	tre_ring = &mhi_chan->tre_ring;
+
+	result.transaction_status = (ev_code == MHI_EV_CC_OVERFLOW) ?
+		-EOVERFLOW : 0;
+
+	/*
+	 * if it's a DB Event then we need to grab the lock
+	 * with preemption disable and as a write because we
+	 * have to update db register and another thread could
+	 * be doing same.
+	 */
+	if (ev_code >= MHI_EV_CC_OOB)
+		write_lock_irqsave(&mhi_chan->lock, flags);
+	else
+		read_lock_bh(&mhi_chan->lock);
+
+	if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED)
+		goto end_process_tx_event;
+
+	switch (ev_code) {
+	case MHI_EV_CC_OVERFLOW:
+	case MHI_EV_CC_EOB:
+	case MHI_EV_CC_EOT:
+	{
+		dma_addr_t ptr = MHI_TRE_GET_EV_PTR(event);
+		struct mhi_tre *local_rp, *ev_tre;
+		void *dev_rp;
+		struct mhi_buf_info *buf_info;
+		u16 xfer_len;
+
+		/* Get the TRB this event points to */
+		ev_tre = mhi_to_virtual(tre_ring, ptr);
+
+		/* device rp after servicing the TREs */
+		dev_rp = ev_tre + 1;
+		if (dev_rp >= (tre_ring->base + tre_ring->len))
+			dev_rp = tre_ring->base;
+
+		result.dir = mhi_chan->dir;
+
+		/* local rp */
+		local_rp = tre_ring->rp;
+		while (local_rp != dev_rp) {
+			buf_info = buf_ring->rp;
+			/* if it's last tre get len from the event */
+			if (local_rp == ev_tre)
+				xfer_len = MHI_TRE_GET_EV_LEN(event);
+			else
+				xfer_len = buf_info->len;
+
+			mhi_cntrl->unmap_single(mhi_cntrl, buf_info);
+
+			result.buf_addr = buf_info->cb_buf;
+			result.bytes_xferd = xfer_len;
+			mhi_del_ring_element(mhi_cntrl, buf_ring);
+			mhi_del_ring_element(mhi_cntrl, tre_ring);
+			local_rp = tre_ring->rp;
+
+			/* notify client */
+			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+
+			if (mhi_chan->dir == DMA_TO_DEVICE) {
+				read_lock_bh(&mhi_cntrl->pm_lock);
+				mhi_cntrl->wake_put(mhi_cntrl, false);
+				read_unlock_bh(&mhi_cntrl->pm_lock);
+			}
+
+			/*
+			 * recycle the buffer if buffer is pre-allocated,
+			 * if there is error, not much we can do apart from
+			 * dropping the packet
+			 */
+			if (mhi_chan->pre_alloc) {
+				if (mhi_queue_buf(mhi_chan->mhi_dev, mhi_chan,
+						  buf_info->cb_buf,
+						  buf_info->len, MHI_EOT)) {
+					dev_err(mhi_cntrl->dev,
+						"Error recycling buffer for chan:%d\n",
+						mhi_chan->chan);
+					kfree(buf_info->cb_buf);
+				}
+			}
+		}
+		break;
+	} /* CC_EOT */
+	case MHI_EV_CC_OOB:
+	case MHI_EV_CC_DB_MODE:
+	{
+		unsigned long flags;
+
+		mhi_chan->db_cfg.db_mode = 1;
+		read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
+		if (tre_ring->wp != tre_ring->rp &&
+		    MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state)) {
+			mhi_ring_chan_db(mhi_cntrl, mhi_chan);
+		}
+		read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags);
+		break;
+	}
+	case MHI_EV_CC_BAD_TRE:
+	default:
+		dev_err(mhi_cntrl->dev, "Unknown event 0x%x\n", ev_code);
+		break;
+	} /* switch(MHI_EV_READ_CODE(EV_TRB_CODE,event)) */
+
+end_process_tx_event:
+	if (ev_code >= MHI_EV_CC_OOB)
+		write_unlock_irqrestore(&mhi_chan->lock, flags);
+	else
+		read_unlock_bh(&mhi_chan->lock);
+
+	return 0;
+}
+
+static void mhi_process_cmd_completion(struct mhi_controller *mhi_cntrl,
+				       struct mhi_tre *tre)
+{
+	dma_addr_t ptr = MHI_TRE_GET_EV_PTR(tre);
+	struct mhi_cmd *cmd_ring = &mhi_cntrl->mhi_cmd[PRIMARY_CMD_RING];
+	struct mhi_ring *mhi_ring = &cmd_ring->ring;
+	struct mhi_tre *cmd_pkt;
+	struct mhi_chan *mhi_chan;
+	u32 chan;
+
+	cmd_pkt = mhi_to_virtual(mhi_ring, ptr);
+
+	chan = MHI_TRE_GET_CMD_CHID(cmd_pkt);
+	mhi_chan = &mhi_cntrl->mhi_chan[chan];
+	write_lock_bh(&mhi_chan->lock);
+	mhi_chan->ccs = MHI_TRE_GET_EV_CODE(tre);
+	complete(&mhi_chan->completion);
+	write_unlock_bh(&mhi_chan->lock);
+
+	mhi_del_ring_element(mhi_cntrl, mhi_ring);
+}
+
 int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
 			     struct mhi_event *mhi_event,
 			     u32 event_quota)
@@ -457,6 +835,7 @@  int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
 			break;
 		}
 		case MHI_PKT_TYPE_CMD_COMPLETION_EVENT:
+			mhi_process_cmd_completion(mhi_cntrl, local_rp);
 			break;
 		case MHI_PKT_TYPE_EE_EVENT:
 		{
@@ -513,11 +892,52 @@  int mhi_process_data_event_ring(struct mhi_controller *mhi_cntrl,
 				struct mhi_event *mhi_event,
 				u32 event_quota)
 {
-	return -EIO;
+	struct mhi_tre *dev_rp, *local_rp;
+	struct mhi_ring *ev_ring = &mhi_event->ring;
+	struct mhi_event_ctxt *er_ctxt =
+		&mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index];
+	int count = 0;
+	u32 chan;
+	struct mhi_chan *mhi_chan;
+
+	if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state)))
+		return -EIO;
+
+	dev_rp = mhi_to_virtual(ev_ring, er_ctxt->rp);
+	local_rp = ev_ring->rp;
+
+	while (dev_rp != local_rp && event_quota > 0) {
+		enum MHI_PKT_TYPE type = MHI_TRE_GET_EV_TYPE(local_rp);
+
+		if (likely(type == MHI_PKT_TYPE_TX_EVENT)) {
+			chan = MHI_TRE_GET_EV_CHID(local_rp);
+			mhi_chan = &mhi_cntrl->mhi_chan[chan];
+			parse_xfer_event(mhi_cntrl, local_rp, mhi_chan);
+			event_quota--;
+		}
+
+		mhi_recycle_ev_ring_element(mhi_cntrl, ev_ring);
+		local_rp = ev_ring->rp;
+		dev_rp = mhi_to_virtual(ev_ring, er_ctxt->rp);
+		count++;
+	}
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state)))
+		mhi_ring_er_db(mhi_event);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+	return count;
 }
 
 void mhi_ev_task(unsigned long data)
 {
+	struct mhi_event *mhi_event = (struct mhi_event *)data;
+	struct mhi_controller *mhi_cntrl = mhi_event->mhi_cntrl;
+
+	/* process all pending events */
+	spin_lock_bh(&mhi_event->lock);
+	mhi_event->process_event(mhi_cntrl, mhi_event, U32_MAX);
+	spin_unlock_bh(&mhi_event->lock);
 }
 
 void mhi_ctrl_ev_task(unsigned long data)
@@ -609,6 +1029,361 @@  irqreturn_t mhi_intvec_handlr(int irq_number, void *dev)
 	return IRQ_WAKE_THREAD;
 }
 
+int mhi_send_cmd(struct mhi_controller *mhi_cntrl,
+		 struct mhi_chan *mhi_chan,
+		 enum MHI_CMD cmd)
+{
+	struct mhi_tre *cmd_tre = NULL;
+	struct mhi_cmd *mhi_cmd = &mhi_cntrl->mhi_cmd[PRIMARY_CMD_RING];
+	struct mhi_ring *ring = &mhi_cmd->ring;
+	int chan = 0;
+
+	if (mhi_chan)
+		chan = mhi_chan->chan;
+
+	spin_lock_bh(&mhi_cmd->lock);
+	if (!get_nr_avail_ring_elements(mhi_cntrl, ring)) {
+		spin_unlock_bh(&mhi_cmd->lock);
+		return -ENOMEM;
+	}
+
+	/* prepare the cmd tre */
+	cmd_tre = ring->wp;
+	switch (cmd) {
+	case MHI_CMD_RESET_CHAN:
+		cmd_tre->ptr = MHI_TRE_CMD_RESET_PTR;
+		cmd_tre->dword[0] = MHI_TRE_CMD_RESET_DWORD0;
+		cmd_tre->dword[1] = MHI_TRE_CMD_RESET_DWORD1(chan);
+		break;
+	case MHI_CMD_START_CHAN:
+		cmd_tre->ptr = MHI_TRE_CMD_START_PTR;
+		cmd_tre->dword[0] = MHI_TRE_CMD_START_DWORD0;
+		cmd_tre->dword[1] = MHI_TRE_CMD_START_DWORD1(chan);
+		break;
+	}
+
+	/* queue to hardware */
+	mhi_add_ring_element(mhi_cntrl, ring);
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state)))
+		mhi_ring_cmd_db(mhi_cntrl, mhi_cmd);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+	spin_unlock_bh(&mhi_cmd->lock);
+
+	return 0;
+}
+
+static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl,
+				    struct mhi_chan *mhi_chan)
+{
+	int ret;
+
+	dev_info(mhi_cntrl->dev, "Entered: unprepare channel:%d\n",
+		 mhi_chan->chan);
+
+	/* no more processing events for this channel */
+	mutex_lock(&mhi_chan->mutex);
+	write_lock_irq(&mhi_chan->lock);
+	if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED) {
+		write_unlock_irq(&mhi_chan->lock);
+		mutex_unlock(&mhi_chan->mutex);
+		return;
+	}
+
+	mhi_chan->ch_state = MHI_CH_STATE_DISABLED;
+	write_unlock_irq(&mhi_chan->lock);
+
+	reinit_completion(&mhi_chan->completion);
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
+		read_unlock_bh(&mhi_cntrl->pm_lock);
+		goto error_invalid_state;
+	}
+
+	mhi_cntrl->wake_get(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+	mhi_cntrl->runtime_get(mhi_cntrl, mhi_cntrl->priv_data);
+	mhi_cntrl->runtime_put(mhi_cntrl, mhi_cntrl->priv_data);
+	ret = mhi_send_cmd(mhi_cntrl, mhi_chan, MHI_CMD_RESET_CHAN);
+	if (ret)
+		goto error_completion;
+
+	/* even if it fails we will still reset */
+	ret = wait_for_completion_timeout(&mhi_chan->completion,
+				msecs_to_jiffies(mhi_cntrl->timeout_ms));
+	if (!ret || mhi_chan->ccs != MHI_EV_CC_SUCCESS)
+		dev_err(mhi_cntrl->dev,
+			"Failed to receive cmd completion, still resetting\n");
+
+error_completion:
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	mhi_cntrl->wake_put(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+error_invalid_state:
+	if (!mhi_chan->offload_ch) {
+		mhi_reset_chan(mhi_cntrl, mhi_chan);
+		mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
+	}
+	dev_info(mhi_cntrl->dev, "chan:%d successfully resetted\n",
+		 mhi_chan->chan);
+	mutex_unlock(&mhi_chan->mutex);
+}
+
+static int __mhi_prepare_channel(struct mhi_controller *mhi_cntrl,
+				 struct mhi_chan *mhi_chan)
+{
+	int ret = 0;
+
+	dev_info(mhi_cntrl->dev, "Entered: preparing channel:%d\n",
+		 mhi_chan->chan);
+
+	if (mhi_cntrl->ee != mhi_chan->ee)
+		return -ENOTCONN;
+
+	mutex_lock(&mhi_chan->mutex);
+	/* client manages channel context for offload channels */
+	if (!mhi_chan->offload_ch) {
+		ret = mhi_init_chan_ctxt(mhi_cntrl, mhi_chan);
+		if (ret)
+			goto error_init_chan;
+	}
+
+	reinit_completion(&mhi_chan->completion);
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
+		read_unlock_bh(&mhi_cntrl->pm_lock);
+		ret = -EIO;
+		goto error_pm_state;
+	}
+
+	mhi_cntrl->wake_get(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+	mhi_cntrl->runtime_get(mhi_cntrl, mhi_cntrl->priv_data);
+	mhi_cntrl->runtime_put(mhi_cntrl, mhi_cntrl->priv_data);
+
+	ret = mhi_send_cmd(mhi_cntrl, mhi_chan, MHI_CMD_START_CHAN);
+	if (ret)
+		goto error_send_cmd;
+
+	ret = wait_for_completion_timeout(&mhi_chan->completion,
+				msecs_to_jiffies(mhi_cntrl->timeout_ms));
+	if (!ret || mhi_chan->ccs != MHI_EV_CC_SUCCESS) {
+		ret = -EIO;
+		goto error_send_cmd;
+	}
+
+	write_lock_irq(&mhi_chan->lock);
+	mhi_chan->ch_state = MHI_CH_STATE_ENABLED;
+	write_unlock_irq(&mhi_chan->lock);
+
+	/* pre allocate buffer for xfer ring */
+	if (mhi_chan->pre_alloc) {
+		int nr_el = get_nr_avail_ring_elements(mhi_cntrl,
+						       &mhi_chan->tre_ring);
+		size_t len = mhi_cntrl->buffer_len;
+
+		while (nr_el--) {
+			void *buf;
+
+			buf = kmalloc(len, GFP_KERNEL);
+			if (!buf) {
+				ret = -ENOMEM;
+				goto error_pre_alloc;
+			}
+
+			/* prepare transfer descriptors */
+			ret = mhi_chan->gen_tre(mhi_cntrl, mhi_chan, buf, buf,
+						len, MHI_EOT);
+			if (ret) {
+				kfree(buf);
+				goto error_pre_alloc;
+			}
+		}
+
+		read_lock_bh(&mhi_cntrl->pm_lock);
+		if (MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state)) {
+			read_lock_irq(&mhi_chan->lock);
+			mhi_ring_chan_db(mhi_cntrl, mhi_chan);
+			read_unlock_irq(&mhi_chan->lock);
+		}
+		read_unlock_bh(&mhi_cntrl->pm_lock);
+	}
+
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	mhi_cntrl->wake_put(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+	mutex_unlock(&mhi_chan->mutex);
+
+	dev_info(mhi_cntrl->dev, "Chan:%d successfully moved to start state\n",
+		 mhi_chan->chan);
+
+	return 0;
+
+error_send_cmd:
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	mhi_cntrl->wake_put(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+error_pm_state:
+	if (!mhi_chan->offload_ch)
+		mhi_deinit_chan_ctxt(mhi_cntrl, mhi_chan);
+
+error_init_chan:
+	mutex_unlock(&mhi_chan->mutex);
+
+	return ret;
+
+error_pre_alloc:
+
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	mhi_cntrl->wake_put(mhi_cntrl, false);
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+
+	mutex_unlock(&mhi_chan->mutex);
+	__mhi_unprepare_channel(mhi_cntrl, mhi_chan);
+
+	return ret;
+}
+
+void mhi_reset_chan(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan)
+{
+	struct mhi_tre *dev_rp, *local_rp;
+	struct mhi_event_ctxt *er_ctxt;
+	struct mhi_event *mhi_event;
+	struct mhi_ring *ev_ring, *buf_ring, *tre_ring;
+	unsigned long flags;
+	int chan = mhi_chan->chan;
+	struct mhi_result result;
+
+	/* nothing to reset, client don't queue buffers */
+	if (mhi_chan->offload_ch)
+		return;
+
+	read_lock_bh(&mhi_cntrl->pm_lock);
+	mhi_event = &mhi_cntrl->mhi_event[mhi_chan->er_index];
+	ev_ring = &mhi_event->ring;
+	er_ctxt = &mhi_cntrl->mhi_ctxt->er_ctxt[mhi_chan->er_index];
+
+	/* mark all stale events related to channel as STALE event */
+	spin_lock_irqsave(&mhi_event->lock, flags);
+	dev_rp = mhi_to_virtual(ev_ring, er_ctxt->rp);
+	if (!mhi_event->mhi_chan) {
+		local_rp = ev_ring->rp;
+		while (dev_rp != local_rp) {
+			if (MHI_TRE_GET_EV_TYPE(local_rp) ==
+			    MHI_PKT_TYPE_TX_EVENT &&
+			    chan == MHI_TRE_GET_EV_CHID(local_rp))
+				local_rp->dword[1] = MHI_TRE_EV_DWORD1(chan,
+						MHI_PKT_TYPE_STALE_EVENT);
+			local_rp++;
+			if (local_rp == (ev_ring->base + ev_ring->len))
+				local_rp = ev_ring->base;
+		}
+	} else {
+		/* dedicated event ring so move the ptr to end */
+		ev_ring->rp = dev_rp;
+		ev_ring->wp = ev_ring->rp - ev_ring->el_size;
+		if (ev_ring->wp < ev_ring->base)
+			ev_ring->wp = ev_ring->base + ev_ring->len -
+				ev_ring->el_size;
+		if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl->pm_state)))
+			mhi_ring_er_db(mhi_event);
+	}
+
+	spin_unlock_irqrestore(&mhi_event->lock, flags);
+
+	/* reset any pending buffers */
+	buf_ring = &mhi_chan->buf_ring;
+	tre_ring = &mhi_chan->tre_ring;
+	result.transaction_status = -ENOTCONN;
+	result.bytes_xferd = 0;
+	while (tre_ring->rp != tre_ring->wp) {
+		struct mhi_buf_info *buf_info = buf_ring->rp;
+
+		if (mhi_chan->dir == DMA_TO_DEVICE)
+			mhi_cntrl->wake_put(mhi_cntrl, false);
+
+		mhi_cntrl->unmap_single(mhi_cntrl, buf_info);
+		mhi_del_ring_element(mhi_cntrl, buf_ring);
+		mhi_del_ring_element(mhi_cntrl, tre_ring);
+
+		if (mhi_chan->pre_alloc) {
+			kfree(buf_info->cb_buf);
+		} else {
+			result.buf_addr = buf_info->cb_buf;
+			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+		}
+	}
+
+	read_unlock_bh(&mhi_cntrl->pm_lock);
+}
+
+/* move channel to start state */
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev)
+{
+	int ret, dir;
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_chan *mhi_chan;
+
+	for (dir = 0; dir < 2; dir++) {
+		mhi_chan = dir ? mhi_dev->dl_chan : mhi_dev->ul_chan;
+
+		if (!mhi_chan)
+			continue;
+
+		ret = __mhi_prepare_channel(mhi_cntrl, mhi_chan);
+		if (ret)
+			goto error_open_chan;
+	}
+
+	return 0;
+
+error_open_chan:
+	for (--dir; dir >= 0; dir--) {
+		mhi_chan = dir ? mhi_dev->dl_chan : mhi_dev->ul_chan;
+
+		if (!mhi_chan)
+			continue;
+
+		__mhi_unprepare_channel(mhi_cntrl, mhi_chan);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(mhi_prepare_for_transfer);
+
+void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev)
+{
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_chan *mhi_chan;
+	int dir;
+
+	for (dir = 0; dir < 2; dir++) {
+		mhi_chan = dir ? mhi_dev->ul_chan : mhi_dev->dl_chan;
+
+		if (!mhi_chan)
+			continue;
+
+		__mhi_unprepare_channel(mhi_cntrl, mhi_chan);
+	}
+}
+EXPORT_SYMBOL(mhi_unprepare_from_transfer);
+
+int mhi_get_no_free_descriptors(struct mhi_device *mhi_dev,
+				enum dma_data_direction dir)
+{
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
+		mhi_dev->ul_chan : mhi_dev->dl_chan;
+	struct mhi_ring *tre_ring = &mhi_chan->tre_ring;
+
+	return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
+}
+EXPORT_SYMBOL(mhi_get_no_free_descriptors);
+
 static int __mhi_bdf_to_controller(struct device *dev, void *tmp)
 {
 	struct mhi_device *mhi_dev = to_mhi_device(dev);
@@ -646,3 +1421,19 @@  struct mhi_controller *mhi_bdf_to_controller(u32 domain,
 	return mhi_dev->mhi_cntrl;
 }
 EXPORT_SYMBOL(mhi_bdf_to_controller);
+
+int mhi_poll(struct mhi_device *mhi_dev,
+	     u32 budget)
+{
+	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_chan *mhi_chan = mhi_dev->dl_chan;
+	struct mhi_event *mhi_event = &mhi_cntrl->mhi_event[mhi_chan->er_index];
+	int ret;
+
+	spin_lock_bh(&mhi_event->lock);
+	ret = mhi_event->process_event(mhi_cntrl, mhi_event, budget);
+	spin_unlock_bh(&mhi_event->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(mhi_poll);
diff --git a/include/linux/mhi.h b/include/linux/mhi.h
index ed7cea8..308d12b 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -326,6 +326,29 @@  static inline void *mhi_device_get_devdata(struct mhi_device *mhi_dev)
 	return mhi_dev->priv_data;
 }
 
+/**
+ * mhi_queue_transfer - Queue a buffer to hardware
+ * All transfers are asyncronous transfers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Data direction
+ * @buf: Data buffer (skb for hardware channels)
+ * @len: Size in bytes
+ * @mflags: Interrupt flags for the device
+ */
+static inline int mhi_queue_transfer(struct mhi_device *mhi_dev,
+				     enum dma_data_direction dir,
+				     void *buf,
+				     size_t len,
+				     enum MHI_FLAGS mflags)
+{
+	if (dir == DMA_TO_DEVICE)
+		return mhi_dev->ul_xfer(mhi_dev, mhi_dev->ul_chan, buf, len,
+					mflags);
+	else
+		return mhi_dev->dl_xfer(mhi_dev, mhi_dev->dl_chan, buf, len,
+					mflags);
+}
+
 static inline void *mhi_controller_get_devdata(struct mhi_controller *mhi_cntrl)
 {
 	return mhi_cntrl->priv_data;
@@ -349,6 +372,21 @@  static inline void mhi_free_controller(struct mhi_controller *mhi_cntrl)
 void mhi_driver_unregister(struct mhi_driver *mhi_drv);
 
 /**
+ * mhi_device_configure - configure ECA or CCA context
+ * For offload channels that client manage, call this
+ * function to configure channel context or event context
+ * array associated with the channel
+ * @mhi_div: Device associated with the channels
+ * @dir: Direction of the channel
+ * @mhi_buf: Configuration data
+ * @elements: # of configuration elements
+ */
+int mhi_device_configure(struct mhi_device *mhi_div,
+			 enum dma_data_direction dir,
+			 struct mhi_buf *mhi_buf,
+			 int elements);
+
+/**
  * mhi_device_get - disable all low power modes
  * Only disables lpm, does not immediately exit low power mode
  * if controller already in a low power mode
@@ -371,6 +409,46 @@  static inline void mhi_free_controller(struct mhi_controller *mhi_cntrl)
 void mhi_device_put(struct mhi_device *mhi_dev);
 
 /**
+ * mhi_prepare_for_transfer - setup channel for data transfer
+ * Moves both UL and DL channel from RESET to START state
+ * @mhi_dev: Device associated with the channels
+ */
+int mhi_prepare_for_transfer(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_unprepare_from_transfer -unprepare the channels
+ * Moves both UL and DL channels to RESET state
+ * @mhi_dev: Device associated with the channels
+ */
+void mhi_unprepare_from_transfer(struct mhi_device *mhi_dev);
+
+/**
+ * mhi_get_no_free_descriptors - Get transfer ring length
+ * Get # of TD available to queue buffers
+ * @mhi_dev: Device associated with the channels
+ * @dir: Direction of the channel
+ */
+int mhi_get_no_free_descriptors(struct mhi_device *mhi_dev,
+				enum dma_data_direction dir);
+
+/**
+ * mhi_poll - poll for any available data to consume
+ * This is only applicable for DL direction
+ * @mhi_dev: Device associated with the channels
+ * @budget: In descriptors to service before returning
+ */
+int mhi_poll(struct mhi_device *mhi_dev, u32 budget);
+
+/**
+ * mhi_ioctl - user space IOCTL support for MHI channels
+ * Native support for setting  TIOCM
+ * @mhi_dev: Device associated with the channels
+ * @cmd: IOCTL cmd
+ * @arg: Optional parameter, iotcl cmd specific
+ */
+long mhi_ioctl(struct mhi_device *mhi_dev, unsigned int cmd, unsigned long arg);
+
+/**
  * mhi_alloc_controller - Allocate mhi_controller structure
  * Allocate controller structure and additional data for controller
  * private data. You may get the private data pointer by calling