/*
 * Copyright (c) 2020 Demant
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/kernel.h>
#include <soc.h>
#include <zephyr/sys/byteorder.h>

#include "hal/cpu.h"
#include "hal/ccm.h"

#include "util/util.h"
#include "util/mem.h"
#include "util/memq.h"
#include "util/mfifo.h"
#include "util/mayfly.h"
#include "util/dbuf.h"

#include "pdu.h"
#include "hal/ticker.h"

#include "lll.h"
#include "lll/lll_adv_types.h"
#include "lll_adv.h"
#include "lll/lll_adv_pdu.h"
#include "lll_adv_iso.h"
#include "lll/lll_df_types.h"
#include "lll_sync.h"
#include "lll_sync_iso.h"
#include "lll_conn.h"
#include "lll_conn_iso.h"
#include "lll_iso_tx.h"

#if !defined(CONFIG_BT_LL_SW_LLCP_LEGACY)
#include "ull_tx_queue.h"
#endif

#include "isoal.h"

#include "ull_adv_types.h"
#include "ull_sync_types.h"
#include "ull_iso_types.h"
#include "ull_conn_iso_types.h"
#include "ull_internal.h"
#include "ull_iso_internal.h"

#include "ull_adv_internal.h"
#include "ull_conn_internal.h"
#include "ull_sync_iso_internal.h"
#include "ull_conn_iso_internal.h"
#include "ull_conn_types.h"
#include "ull_llcp.h"

#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_DRIVER)
#define LOG_MODULE_NAME bt_ctlr_ull_iso
#include "common/log.h"
#include "hal/debug.h"

#if defined(CONFIG_BT_CTLR_CONN_ISO_STREAMS)
#define BT_CTLR_CONN_ISO_STREAMS CONFIG_BT_CTLR_CONN_ISO_STREAMS
#else /* !CONFIG_BT_CTLR_CONN_ISO_STREAMS */
#define BT_CTLR_CONN_ISO_STREAMS 0
#endif /* !CONFIG_BT_CTLR_CONN_ISO_STREAMS */

#if defined(CONFIG_BT_CTLR_SYNC_ISO_STREAM_COUNT)
#define BT_CTLR_SYNC_ISO_STREAMS (CONFIG_BT_CTLR_SYNC_ISO_STREAM_COUNT)
#else /* !CONFIG_BT_CTLR_SYNC_ISO_STREAM_COUNT */
#define BT_CTLR_SYNC_ISO_STREAMS 0
#endif /* CONFIG_BT_CTLR_SYNC_ISO_STREAM_COUNT */

static int init_reset(void);

#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
static isoal_status_t ll_iso_pdu_alloc(struct isoal_pdu_buffer *pdu_buffer);
static isoal_status_t ll_iso_pdu_write(struct isoal_pdu_buffer *pdu_buffer,
				       const size_t   offset,
				       const uint8_t *sdu_payload,
				       const size_t   consume_len);
static isoal_status_t ll_iso_pdu_emit(struct node_tx_iso *node_tx,
				      const uint16_t handle);
#if defined(CONFIG_BT_CTLR_CONN_ISO)
static isoal_status_t ll_iso_pdu_release(struct node_tx_iso *node_tx,
					 const uint16_t handle,
					 const isoal_status_t status);
#endif /* CONFIG_BT_CTLR_CONN_ISO */
#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */

/* Allocate data path pools for RX/TX directions for each stream */
#define BT_CTLR_ISO_STREAMS ((2 * (BT_CTLR_CONN_ISO_STREAMS)) + \
			     BT_CTLR_SYNC_ISO_STREAMS)
#if BT_CTLR_ISO_STREAMS
static struct ll_iso_datapath datapath_pool[BT_CTLR_ISO_STREAMS];
#endif /* BT_CTLR_ISO_STREAMS */

static void *datapath_free;

#if defined(CONFIG_BT_CTLR_SYNC_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
#define NODE_RX_HEADER_SIZE (offsetof(struct node_rx_pdu, pdu))
/* ISO LL conformance tests require a PDU size of maximum 251 bytes + header */
#define ISO_RX_BUFFER_SIZE (2 + 251)

/* Declare the ISO rx node RXFIFO. This is a composite pool-backed MFIFO for
 * rx_nodes. The declaration constructs the following data structures:
 * - mfifo_iso_rx:    FIFO with pointers to PDU buffers
 * - mem_iso_rx:      Backing data pool for PDU buffer elements
 * - mem_link_iso_rx: Pool of memq_link_t elements
 *
 * Two extra links are reserved for use by the ll_iso_rx and ull_iso_rx memq.
 */
static RXFIFO_DEFINE(iso_rx, NODE_RX_HEADER_SIZE + ISO_RX_BUFFER_SIZE,
			     CONFIG_BT_CTLR_ISO_RX_BUFFERS, 2);

static MEMQ_DECLARE(ll_iso_rx);
#if defined(CONFIG_BT_CTLR_ISO_VENDOR_DATA_PATH)
static MEMQ_DECLARE(ull_iso_rx);
static void iso_rx_demux(void *param);
#endif /* CONFIG_BT_CTLR_ISO_VENDOR_DATA_PATH */
#endif /* CONFIG_BT_CTLR_SYNC_ISO) || CONFIG_BT_CTLR_CONN_ISO */

#define ISO_TEST_PACKET_COUNTER_SIZE 4U

#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
void ll_iso_link_tx_release(void *link);
void ll_iso_tx_mem_release(void *node_tx);

#define NODE_TX_BUFFER_SIZE MROUND(offsetof(struct node_tx_iso, pdu) + \
				   offsetof(struct pdu_iso, payload) + \
				   CONFIG_BT_CTLR_ISO_TX_BUFFER_SIZE)

#define ISO_TEST_TX_BUFFER_SIZE 32U

static struct {
	void *free;
	uint8_t pool[NODE_TX_BUFFER_SIZE * CONFIG_BT_CTLR_ISO_TX_BUFFERS];
} mem_iso_tx;

static struct {
	void *free;
	uint8_t pool[sizeof(memq_link_t) * CONFIG_BT_CTLR_ISO_TX_BUFFERS];
} mem_link_iso_tx;

#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */

/* Must be implemented by vendor */
__weak bool ll_data_path_configured(uint8_t data_path_dir,
				    uint8_t data_path_id)
{
	ARG_UNUSED(data_path_dir);
	ARG_UNUSED(data_path_id);

	return false;
}

uint8_t ll_read_iso_tx_sync(uint16_t handle, uint16_t *seq,
			    uint32_t *timestamp, uint32_t *offset)
{
#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)

	if (IS_CIS_HANDLE(handle)) {
		struct ll_iso_datapath *dp = NULL;
		struct ll_conn_iso_stream *cis;

		cis = ll_conn_iso_stream_get(handle);

		if (cis) {
			dp = cis->hdr.datapath_in;
		}

		if (dp &&
			isoal_tx_get_sync_info(dp->source_hdl, seq,
					timestamp, offset) == ISOAL_STATUS_OK) {
			return BT_HCI_ERR_SUCCESS;
		}

		return BT_HCI_ERR_CMD_DISALLOWED;

	} else if (IS_ADV_ISO_HANDLE(handle)) {
		/* FIXME: Do something similar to connected */

		return BT_HCI_ERR_CMD_DISALLOWED;
	}

	return BT_HCI_ERR_UNKNOWN_CONN_ID;
#else
	ARG_UNUSED(handle);
	ARG_UNUSED(seq);
	ARG_UNUSED(timestamp);
	ARG_UNUSED(offset);

	return BT_HCI_ERR_CMD_DISALLOWED;
#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */
}

/* Must be implemented by vendor */
__weak bool ll_data_path_sink_create(struct ll_iso_datapath *datapath,
				     isoal_sink_sdu_alloc_cb *sdu_alloc,
				     isoal_sink_sdu_emit_cb *sdu_emit,
				     isoal_sink_sdu_write_cb *sdu_write)
{
	ARG_UNUSED(datapath);

	*sdu_alloc = NULL;
	*sdu_emit  = NULL;
	*sdu_write = NULL;

	return false;
}

/* Could be implemented by vendor */
__weak bool ll_data_path_source_create(uint16_t handle,
				       struct ll_iso_datapath *datapath,
				       isoal_source_pdu_alloc_cb *pdu_alloc,
				       isoal_source_pdu_write_cb *pdu_write,
				       isoal_source_pdu_emit_cb *pdu_emit,
				       isoal_source_pdu_release_cb *pdu_release)
{
	ARG_UNUSED(handle);
	ARG_UNUSED(datapath);
	ARG_UNUSED(pdu_alloc);
	ARG_UNUSED(pdu_write);
	ARG_UNUSED(pdu_emit);
	ARG_UNUSED(pdu_release);

	return false;
}

static inline bool path_is_vendor_specific(uint8_t path_id)
{
	return (path_id >= BT_HCI_DATAPATH_ID_VS &&
		path_id <= BT_HCI_DATAPATH_ID_VS_END);
}

uint8_t ll_setup_iso_path(uint16_t handle, uint8_t path_dir, uint8_t path_id,
			  uint8_t coding_format, uint16_t company_id,
			  uint16_t vs_codec_id, uint32_t controller_delay,
			  uint8_t codec_config_len, uint8_t *codec_config)
{
	ARG_UNUSED(controller_delay);
	ARG_UNUSED(codec_config_len);
	ARG_UNUSED(codec_config);

	if (path_id == BT_HCI_DATAPATH_ID_DISABLED) {
		return 0;
	}

#if defined(CONFIG_BT_CTLR_SYNC_ISO)
	if (path_dir != BT_HCI_DATAPATH_DIR_CTLR_TO_HOST) {
		/* FIXME: workaround to succeed datapath setup for ISO
		 *        broadcaster until Tx datapath is implemented, in the
		 *        future.
		 */
		return BT_HCI_ERR_SUCCESS;
	}
#endif /* CONFIG_BT_CTLR_SYNC_ISO */

#if defined(CONFIG_BT_CTLR_SYNC_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
#if defined(CONFIG_BT_CTLR_CONN_ISO)
	isoal_source_handle_t source_handle;
	uint8_t max_octets;
#endif /* CONFIG_BT_CTLR_CONN_ISO */
	isoal_sink_handle_t sink_handle;
	uint32_t stream_sync_delay;
	uint32_t group_sync_delay;
	uint8_t flush_timeout;
	uint16_t iso_interval;
	uint32_t sdu_interval;
	uint8_t  burst_number;
	isoal_status_t err;
	uint8_t framed;
	uint8_t role;

#if defined(CONFIG_BT_CTLR_CONN_ISO)
	struct ll_iso_datapath *dp_in = NULL;
	struct ll_iso_datapath *dp_out = NULL;

	struct ll_conn_iso_stream *cis = NULL;
	struct ll_conn_iso_group *cig = NULL;

	if (IS_CIS_HANDLE(handle)) {
		struct ll_conn *conn;

		cis = ll_conn_iso_stream_get(handle);
		if (!cis->group) {
			/* CIS does not belong to a CIG */
			return BT_HCI_ERR_UNKNOWN_CONN_ID;
		}

		conn = ll_connected_get(cis->lll.acl_handle);
		if (conn) {
			/* If we're still waiting for accept/response from
			 * host, path setup is premature and we must return
			 * disallowed status.
			 */
#if defined(CONFIG_BT_CTLR_PERIPHERAL_ISO)
#if defined(CONFIG_BT_LL_SW_LLCP_LEGACY)
			const uint8_t cis_waiting = (conn->llcp_cis.state ==
						     LLCP_CIS_STATE_RSP_WAIT);
#else
			const uint8_t cis_waiting = ull_cp_cc_awaiting_reply(conn);
#endif
			if (cis_waiting) {
				return BT_HCI_ERR_CMD_DISALLOWED;
			}
#endif /* CONFIG_BT_CTLR_PERIPHERAL_ISO */
		}

		cig = cis->group;
		dp_in = cis->hdr.datapath_in;
		dp_out = cis->hdr.datapath_out;
	}

	/* If the Host attempts to set a data path with a Connection Handle
	 * that does not exist or that is not for a CIS or a BIS, the Controller
	 * shall return the error code Unknown Connection Identifier (0x02)
	 */
	if (!cis) {
		return BT_HCI_ERR_UNKNOWN_CONN_ID;
	}

	if ((path_dir == BT_HCI_DATAPATH_DIR_HOST_TO_CTLR  && dp_in) ||
	    (path_dir == BT_HCI_DATAPATH_DIR_CTLR_TO_HOST && dp_out)) {
		/* Data path has been set up, can only do setup once */
		return BT_HCI_ERR_CMD_DISALLOWED;
	}

	if (path_is_vendor_specific(path_id) &&
	    !ll_data_path_configured(path_dir, path_id)) {
		/* Data path must be configured prior to setup */
		return BT_HCI_ERR_CMD_DISALLOWED;
	}

	/* If Codec_Configuration_Length non-zero and Codec_ID set to
	 * transparent air mode, the Controller shall return the error code
	 * Invalid HCI Command Parameters (0x12).
	 */
	if (codec_config_len && vs_codec_id == BT_HCI_CODING_FORMAT_TRANSPARENT) {
		return BT_HCI_ERR_INVALID_PARAM;
	}
#endif /* CONFIG_BT_CTLR_CONN_ISO */

#if defined(CONFIG_BT_CTLR_SYNC_ISO)
	struct lll_sync_iso_stream *stream;
	uint16_t stream_handle;

	if (handle < BT_CTLR_SYNC_ISO_STREAM_HANDLE_BASE) {
		return BT_HCI_ERR_CMD_DISALLOWED;
	}
	stream_handle = LL_BIS_SYNC_IDX_FROM_HANDLE(handle);

	stream = ull_sync_iso_stream_get(stream_handle);
	if (!stream || stream->dp) {
		return BT_HCI_ERR_CMD_DISALLOWED;
	}
#endif /* CONFIG_BT_CTLR_SYNC_ISO */

	/* Allocate and configure datapath */
	struct ll_iso_datapath *dp = mem_acquire(&datapath_free);
	if (!dp) {
		return BT_HCI_ERR_CMD_DISALLOWED;
	}

	dp->path_dir = path_dir;
	dp->path_id = path_id;
	dp->coding_format = coding_format;
	dp->company_id = company_id;

	/* TODO dp->sync_delay    = controller_delay; ?*/

	flush_timeout = 0;
	stream_sync_delay = 0;
	group_sync_delay = 0;

#if defined(CONFIG_BT_CTLR_CONN_ISO)
	role = cig->lll.role;
	iso_interval = cig->iso_interval;
	stream_sync_delay = cis->sync_delay;
	group_sync_delay = cig->sync_delay;
	framed = cis->framed;

	if (path_dir == BT_HCI_DATAPATH_DIR_CTLR_TO_HOST) {
		/* Create sink for RX data path */
		burst_number  = cis->lll.rx.burst_number;
		flush_timeout = cis->lll.rx.flush_timeout;
		max_octets    = cis->lll.rx.max_octets;

		if (role) {
			/* peripheral */
			sdu_interval = cig->c_sdu_interval;
		} else {
			/* central */
			sdu_interval = cig->p_sdu_interval;
		}

		cis->hdr.datapath_out = dp;

		if (path_id == BT_HCI_DATAPATH_ID_HCI) {
			/* Not vendor specific, thus alloc and emit functions known */
			err = isoal_sink_create(handle, role, framed,
						burst_number, flush_timeout,
						sdu_interval, iso_interval,
						stream_sync_delay, group_sync_delay,
						sink_sdu_alloc_hci, sink_sdu_emit_hci,
						sink_sdu_write_hci, &sink_handle);
		} else {
			/* Set up vendor specific data path */
			isoal_sink_sdu_alloc_cb sdu_alloc;
			isoal_sink_sdu_emit_cb  sdu_emit;
			isoal_sink_sdu_write_cb sdu_write;

			/* Request vendor sink callbacks for path */
			if (ll_data_path_sink_create(dp, &sdu_alloc, &sdu_emit, &sdu_write)) {
				err = isoal_sink_create(handle, role, framed,
							burst_number, flush_timeout,
							sdu_interval, iso_interval,
							stream_sync_delay, group_sync_delay,
							sdu_alloc, sdu_emit, sdu_write,
							&sink_handle);
			} else {
				return BT_HCI_ERR_CMD_DISALLOWED;
			}
		}

		if (!err) {
			dp->sink_hdl = sink_handle;
			isoal_sink_enable(sink_handle);
		} else {
			return BT_HCI_ERR_CMD_DISALLOWED;
		}
	} else  {
		/* path_dir == BT_HCI_DATAPATH_DIR_HOST_TO_CTLR */
		burst_number  = cis->lll.tx.burst_number;
		flush_timeout = cis->lll.tx.flush_timeout;
		max_octets    = cis->lll.tx.max_octets;

		if (role) {
			/* peripheral */
			sdu_interval = cig->p_sdu_interval;
		} else {
			/* central */
			sdu_interval = cig->c_sdu_interval;
		}

		cis->hdr.datapath_in = dp;

		/* Create source for TX data path */
		isoal_source_pdu_alloc_cb   pdu_alloc;
		isoal_source_pdu_write_cb   pdu_write;
		isoal_source_pdu_emit_cb    pdu_emit;
		isoal_source_pdu_release_cb pdu_release;

		/* Set default callbacks assuming not vendor specific
		 * or that the vendor specific path is the same.
		 */
		pdu_alloc   = ll_iso_pdu_alloc;
		pdu_write   = ll_iso_pdu_write;
		pdu_emit    = ll_iso_pdu_emit;
		pdu_release = ll_iso_pdu_release;

		if (path_is_vendor_specific(path_id)) {
			if (!ll_data_path_source_create(handle, dp,
							&pdu_alloc, &pdu_write,
							&pdu_emit, &pdu_release)) {
				return BT_HCI_ERR_CMD_DISALLOWED;
			}
		}

		err = isoal_source_create(handle, role, framed,
					  burst_number, flush_timeout, max_octets,
					  sdu_interval, iso_interval,
					  stream_sync_delay, group_sync_delay,
					  pdu_alloc, pdu_write, pdu_emit,
					  pdu_release, &source_handle);

		if (!err) {
			dp->source_hdl = source_handle;
			isoal_source_enable(source_handle);
		} else {
			return BT_HCI_ERR_CMD_DISALLOWED;
		}
	}
#endif /* CONFIG_BT_CTLR_CONN_ISO */

#if defined(CONFIG_BT_CTLR_SYNC_ISO)
	struct ll_sync_iso_set *sync_iso;
	struct lll_sync_iso *lll_iso;

	sync_iso = ull_sync_iso_by_stream_get(stream_handle);
	lll_iso = &sync_iso->lll;

	role = 1U; /* FIXME: Set role from LLL struct */
	framed = 0;
	burst_number = lll_iso->bn;
	sdu_interval = lll_iso->sdu_interval;
	iso_interval = lll_iso->iso_interval;

	if (path_id == BT_HCI_DATAPATH_ID_HCI) {
		/* Not vendor specific, thus alloc and emit functions known */
		err = isoal_sink_create(handle, role, framed,
					burst_number, flush_timeout,
					sdu_interval, iso_interval,
					stream_sync_delay, group_sync_delay,
					sink_sdu_alloc_hci, sink_sdu_emit_hci,
					sink_sdu_write_hci, &sink_handle);
	} else {
		/* Set up vendor specific data path */
		isoal_sink_sdu_alloc_cb sdu_alloc;
		isoal_sink_sdu_emit_cb  sdu_emit;
		isoal_sink_sdu_write_cb sdu_write;

		/* Request vendor sink callbacks for path */
		if (ll_data_path_sink_create(dp, &sdu_alloc, &sdu_emit, &sdu_write)) {
			err = isoal_sink_create(handle, role, framed,
						burst_number, flush_timeout,
						sdu_interval, iso_interval,
						stream_sync_delay, group_sync_delay,
						sdu_alloc, sdu_emit, sdu_write,
						&sink_handle);
		} else {
			ull_iso_datapath_release(dp);

			return BT_HCI_ERR_CMD_DISALLOWED;
		}
	}

	if (!err) {
		stream->dp = dp;

		dp->sink_hdl = sink_handle;
		isoal_sink_enable(sink_handle);
	} else {
		ull_iso_datapath_release(dp);

		return BT_HCI_ERR_CMD_DISALLOWED;
	}
#endif /* CONFIG_BT_CTLR_SYNC_ISO */
#endif /* CONFIG_BT_CTLR_SYNC_ISO || CONFIG_BT_CTLR_CONN_ISO */

	return 0;
}

uint8_t ll_remove_iso_path(uint16_t handle, uint8_t path_dir)
{
	struct ll_iso_datapath *dp = NULL;

#if defined(CONFIG_BT_CTLR_CONN_ISO)
	struct ll_conn_iso_stream *cis = NULL;
	struct ll_iso_stream_hdr *hdr = NULL;

	if (IS_CIS_HANDLE(handle)) {
		cis = ll_conn_iso_stream_get(handle);
		hdr = &cis->hdr;
	}

	/* If the Host issues this command with a Connection_Handle that does not exist
	 * or is not for a CIS or a BIS, the Controller shall return the error code Unknown
	 * Connection Identifier (0x02).
	 */
	if (!cis) {
		return BT_HCI_ERR_UNKNOWN_CONN_ID;
	}

	if (path_dir == BT_HCI_DATAPATH_DIR_HOST_TO_CTLR) {
		dp = hdr->datapath_in;
		if (dp) {
			isoal_source_destroy(dp->source_hdl);

			hdr->datapath_in = NULL;
			ull_iso_datapath_release(dp);
		}
	} else if (path_dir == BT_HCI_DATAPATH_DIR_CTLR_TO_HOST) {
		dp = hdr->datapath_out;
		if (dp) {
			isoal_sink_destroy(dp->sink_hdl);

			hdr->datapath_out = NULL;
			ull_iso_datapath_release(dp);
		}
	} else {
		/* Reserved for future use */
		return BT_HCI_ERR_CMD_DISALLOWED;
	}
#endif /* CONFIG_BT_CTLR_CONN_ISO */

#if defined(CONFIG_BT_CTLR_SYNC_ISO)
	struct lll_sync_iso_stream *stream;
	uint16_t stream_handle;

	if (path_dir != BT_HCI_DATAPATH_DIR_CTLR_TO_HOST) {
		return BT_HCI_ERR_CMD_DISALLOWED;
	}

	if (handle < BT_CTLR_SYNC_ISO_STREAM_HANDLE_BASE) {
		return BT_HCI_ERR_CMD_DISALLOWED;
	}
	stream_handle = LL_BIS_SYNC_IDX_FROM_HANDLE(handle);

	stream = ull_sync_iso_stream_get(stream_handle);
	if (!stream) {
		return BT_HCI_ERR_CMD_DISALLOWED;
	}

	dp = stream->dp;
	if (dp) {
		isoal_sink_destroy(dp->sink_hdl);

		stream->dp = NULL;
		isoal_sink_destroy(dp->sink_hdl);
		ull_iso_datapath_release(dp);
	}
#endif /* CONFIG_BT_CTLR_SYNC_ISO */

	if (!dp) {
		/* Datapath was not previously set up */
		return BT_HCI_ERR_CMD_DISALLOWED;
	}

	return 0;
}

#if defined(CONFIG_BT_CTLR_SYNC_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
/* The sdu_alloc function is called before combining PDUs into an SDU. Here we
 * store the paylaod number associated with the first PDU, for unframed usecase.
 */
static isoal_status_t ll_iso_test_sdu_alloc(const struct isoal_sink *sink_ctx,
					    const struct isoal_pdu_rx *valid_pdu,
					    struct isoal_sdu_buffer *sdu_buffer)
{
	uint16_t handle;

	handle = sink_ctx->session.handle;

	if (IS_CIS_HANDLE(handle)) {
		if (!sink_ctx->session.framed) {
			struct ll_conn_iso_stream *cis;

			cis = ll_iso_stream_connected_get(sink_ctx->session.handle);
			LL_ASSERT(cis);

			/* For unframed, SDU counter is the payload number */
			cis->hdr.test_mode.rx_sdu_counter =
				(uint32_t)valid_pdu->meta->payload_number;
		}
	} else if (IS_SYNC_ISO_HANDLE(handle)) {
		/* FIXME: Implement for sync receiver */
		LL_ASSERT(false);
	}

	return sink_sdu_alloc_hci(sink_ctx, valid_pdu, sdu_buffer);
}

/* The sdu_emit function is called whenever an SDU is combined and ready to be sent
 * further in the data path. This injected implementation performs statistics on
 * the SDU and then discards it.
 */
static isoal_status_t ll_iso_test_sdu_emit(const struct isoal_sink             *sink_ctx,
					   const struct isoal_emitted_sdu_frag *sdu_frag,
					   const struct isoal_emitted_sdu      *sdu)
{
	isoal_status_t status;
	struct net_buf *buf;
	uint16_t handle;

	handle = sink_ctx->session.handle;
	buf = (struct net_buf *)sdu_frag->sdu.contents.dbuf;

	if (IS_CIS_HANDLE(handle)) {
		struct ll_conn_iso_stream *cis;
		isoal_sdu_len_t length;
		uint32_t sdu_counter;
		uint8_t framed;

		cis = ll_iso_stream_connected_get(sink_ctx->session.handle);
		LL_ASSERT(cis);

		length = sink_ctx->sdu_production.sdu_written;
		framed = sink_ctx->session.framed;

		/* In BT_HCI_ISO_TEST_ZERO_SIZE_SDU mode, all SDUs must have length 0 and there is
		 * no sdu_counter field. In the other modes, the first 4 bytes must contain a
		 * packet counter, which is used as SDU counter. The sdu_counter is extracted
		 * regardless of mode as a sanity check, unless the length does not allow it.
		 */
		if (length >= ISO_TEST_PACKET_COUNTER_SIZE) {
			sdu_counter = sys_get_le32(buf->data);
		} else {
			sdu_counter = 0U;
		}

		switch (sdu_frag->sdu.status) {
		case ISOAL_SDU_STATUS_VALID:
			if (framed && cis->hdr.test_mode.rx_sdu_counter == 0U) {
				/* BT 5.3, Vol 6, Part B, section 7.2:
				 * When using framed PDUs the expected value of the SDU counter
				 * shall be initialized with the value of the SDU counter of the
				 * first valid received SDU.
				 */
				cis->hdr.test_mode.rx_sdu_counter = sdu_counter;
			}

			switch (cis->hdr.test_mode.rx_payload_type) {
			case BT_HCI_ISO_TEST_ZERO_SIZE_SDU:
				if (length == 0) {
					cis->hdr.test_mode.received_cnt++;
				} else {
					cis->hdr.test_mode.failed_cnt++;
				}
				break;

			case BT_HCI_ISO_TEST_VARIABLE_SIZE_SDU:
				if ((length >= ISO_TEST_PACKET_COUNTER_SIZE) &&
				    (length <= cis->c_max_sdu) &&
				    (sdu_counter == cis->hdr.test_mode.rx_sdu_counter)) {
					cis->hdr.test_mode.received_cnt++;
				} else {
					cis->hdr.test_mode.failed_cnt++;
				}
				break;

			case BT_HCI_ISO_TEST_MAX_SIZE_SDU:
				if ((length == cis->c_max_sdu) &&
				    (sdu_counter == cis->hdr.test_mode.rx_sdu_counter)) {
					cis->hdr.test_mode.received_cnt++;
				} else {
					cis->hdr.test_mode.failed_cnt++;
				}
				break;

			default:
				LL_ASSERT(0);
				return ISOAL_STATUS_ERR_SDU_EMIT;
			}
			break;

		case ISOAL_SDU_STATUS_ERRORS:
		case ISOAL_SDU_STATUS_LOST_DATA:
			cis->hdr.test_mode.missed_cnt++;
			break;
		}

		if (framed) {
			cis->hdr.test_mode.rx_sdu_counter++;
		}

		status = ISOAL_STATUS_OK;

	} else if (IS_SYNC_ISO_HANDLE(handle)) {
		/* FIXME: Implement for sync receiver */
		status = ISOAL_STATUS_ERR_SDU_EMIT;
	} else {
		/* Handle is out of range */
		status = ISOAL_STATUS_ERR_SDU_EMIT;
	}

	net_buf_unref(buf);

	return status;
}

uint8_t ll_iso_receive_test(uint16_t handle, uint8_t payload_type)
{
	isoal_sink_handle_t sink_handle;
	struct ll_iso_datapath *dp;
	uint32_t sdu_interval;
	isoal_status_t err;
	uint8_t status;

	status = BT_HCI_ERR_SUCCESS;

	if (IS_CIS_HANDLE(handle)) {
		struct ll_conn_iso_stream *cis;
		struct ll_conn_iso_group *cig;

		cis = ll_iso_stream_connected_get(handle);
		if (!cis) {
			/* CIS is not connected */
			return BT_HCI_ERR_UNKNOWN_CONN_ID;
		}

		if (cis->lll.rx.burst_number == 0) {
			/* CIS is not configured for RX */
			return BT_HCI_ERR_UNSUPP_FEATURE_PARAM_VAL;
		}

		if (cis->hdr.datapath_out) {
			/* Data path already set up */
			return BT_HCI_ERR_CMD_DISALLOWED;
		}

		if (payload_type > BT_HCI_ISO_TEST_MAX_SIZE_SDU) {
			return BT_HCI_ERR_INVALID_LL_PARAM;
		}

		/* Allocate and configure test datapath */
		dp = mem_acquire(&datapath_free);
		if (!dp) {
			return BT_HCI_ERR_CMD_DISALLOWED;
		}

		dp->path_dir = BT_HCI_DATAPATH_DIR_CTLR_TO_HOST;
		dp->path_id  = BT_HCI_DATAPATH_ID_HCI;

		cis->hdr.datapath_out = dp;
		cig = cis->group;

		if (cig->lll.role == BT_HCI_ROLE_PERIPHERAL) {
			/* peripheral */
			sdu_interval = cig->c_sdu_interval;
		} else {
			/* central */
			sdu_interval = cig->p_sdu_interval;
		}

		err = isoal_sink_create(handle, cig->lll.role, cis->framed,
					cis->lll.rx.burst_number, cis->lll.rx.flush_timeout,
					sdu_interval, cig->iso_interval,
					cis->sync_delay, cig->sync_delay,
					ll_iso_test_sdu_alloc, ll_iso_test_sdu_emit,
					sink_sdu_write_hci, &sink_handle);
		if (err) {
			/* Error creating test source - cleanup source and datapath */
			isoal_sink_destroy(sink_handle);
			ull_iso_datapath_release(dp);
			cis->hdr.datapath_out = NULL;

			return BT_HCI_ERR_CMD_DISALLOWED;
		}

		dp->sink_hdl = sink_handle;
		isoal_sink_enable(sink_handle);

		/* Enable Receive Test Mode */
		cis->hdr.test_mode.rx_enabled = 1;
		cis->hdr.test_mode.rx_payload_type = payload_type;

	} else if (IS_SYNC_ISO_HANDLE(handle)) {
		/* FIXME: Implement for sync receiver */
		status = BT_HCI_ERR_CMD_DISALLOWED;
	} else {
		/* Handle is out of range */
		status = BT_HCI_ERR_UNKNOWN_CONN_ID;
	}

	return status;
}

uint8_t ll_iso_read_test_counters(uint16_t handle, uint32_t *received_cnt,
				  uint32_t *missed_cnt,
				  uint32_t *failed_cnt)
{
	uint8_t status;

	*received_cnt = 0U;
	*missed_cnt   = 0U;
	*failed_cnt   = 0U;

	status = BT_HCI_ERR_SUCCESS;

	if (IS_CIS_HANDLE(handle)) {
		struct ll_conn_iso_stream *cis;

		cis = ll_iso_stream_connected_get(handle);
		if (!cis) {
			/* CIS is not connected */
			return BT_HCI_ERR_UNKNOWN_CONN_ID;
		}

		if (!cis->hdr.test_mode.rx_enabled) {
			/* ISO receive Test is not active */
			return BT_HCI_ERR_UNSUPP_FEATURE_PARAM_VAL;
		}

		/* Return SDU statistics */
		*received_cnt = cis->hdr.test_mode.received_cnt;
		*missed_cnt   = cis->hdr.test_mode.missed_cnt;
		*failed_cnt   = cis->hdr.test_mode.failed_cnt;

	} else if (IS_SYNC_ISO_HANDLE(handle)) {
		/* FIXME: Implement for sync receiver */
		status = BT_HCI_ERR_CMD_DISALLOWED;
	} else {
		/* Handle is out of range */
		status = BT_HCI_ERR_UNKNOWN_CONN_ID;
	}

	return status;
}

#if defined(CONFIG_BT_CTLR_READ_ISO_LINK_QUALITY)
uint8_t ll_read_iso_link_quality(uint16_t  handle,
				 uint32_t *tx_unacked_packets,
				 uint32_t *tx_flushed_packets,
				 uint32_t *tx_last_subevent_packets,
				 uint32_t *retransmitted_packets,
				 uint32_t *crc_error_packets,
				 uint32_t *rx_unreceived_packets,
				 uint32_t *duplicate_packets)
{
	ARG_UNUSED(handle);
	ARG_UNUSED(tx_unacked_packets);
	ARG_UNUSED(tx_flushed_packets);
	ARG_UNUSED(tx_last_subevent_packets);
	ARG_UNUSED(retransmitted_packets);
	ARG_UNUSED(crc_error_packets);
	ARG_UNUSED(rx_unreceived_packets);
	ARG_UNUSED(duplicate_packets);

	return BT_HCI_ERR_CMD_DISALLOWED;
}
#endif /* CONFIG_BT_CTLR_READ_ISO_LINK_QUALITY */

#endif /* CONFIG_BT_CTLR_SYNC_ISO || CONFIG_BT_CTLR_CONN_ISO */

#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
static isoal_status_t ll_iso_test_pdu_release(struct node_tx_iso *node_tx,
					      const uint16_t handle,
					      const isoal_status_t status)
{
	/* Release back to memory pool */
	if (node_tx->link) {
		ll_iso_link_tx_release(node_tx->link);
	}
	ll_iso_tx_mem_release(node_tx);

	return ISOAL_STATUS_OK;
}

#if defined(CONFIG_BT_CTLR_CONN_ISO)
void ll_iso_transmit_test_send_sdu(uint16_t handle, uint32_t ticks_at_expire)
{
	isoal_source_handle_t source_handle;
	struct isoal_sdu_tx sdu;
	isoal_status_t err;
	uint8_t tx_buffer[ISO_TEST_TX_BUFFER_SIZE];
	uint16_t remaining_tx;
	uint32_t sdu_counter;

	if (IS_CIS_HANDLE(handle)) {
		struct isoal_pdu_production *pdu_production;
		struct ll_conn_iso_stream *cis;
		struct ll_conn_iso_group *cig;
		struct isoal_source *source;
		uint32_t rand_max_sdu;
		uint8_t rand_8;

		cis = ll_iso_stream_connected_get(handle);
		LL_ASSERT(cis);

		if (!cis->hdr.test_mode.tx_enabled) {
			/* Transmit Test Mode not enabled */
			return;
		}

		cig = cis->group;
		source_handle = cis->hdr.datapath_in->source_hdl;

		switch (cis->hdr.test_mode.tx_payload_type) {
		case BT_HCI_ISO_TEST_ZERO_SIZE_SDU:
			remaining_tx = 0;
			break;

		case BT_HCI_ISO_TEST_VARIABLE_SIZE_SDU:
			/* Randomize the length [4..p_max_sdu] */
			lll_rand_get(&rand_8, sizeof(rand_8));
			rand_max_sdu = rand_8 * (cis->p_max_sdu - ISO_TEST_PACKET_COUNTER_SIZE);
			remaining_tx = ISO_TEST_PACKET_COUNTER_SIZE + (rand_max_sdu >> 8);
			break;

		case BT_HCI_ISO_TEST_MAX_SIZE_SDU:
			LL_ASSERT(cis->p_max_sdu > ISO_TEST_PACKET_COUNTER_SIZE);
			remaining_tx = cis->p_max_sdu;
			break;

		default:
			LL_ASSERT(0);
			return;
		}

		if (remaining_tx > ISO_TEST_TX_BUFFER_SIZE) {
			sdu.sdu_state = BT_ISO_START;
		} else {
			sdu.sdu_state = BT_ISO_SINGLE;
		}

		/* Configure SDU similarly to one delivered via HCI */
		sdu.dbuf = tx_buffer;
		sdu.grp_ref_point = cig->cig_ref_point;
		sdu.target_event = cis->lll.event_count +
					(cis->lll.tx.flush_timeout > 1U ? 0U : 1U);
		sdu.iso_sdu_length = remaining_tx;

		/* Send all SDU fragments */
		do {
			sdu.time_stamp = HAL_TICKER_TICKS_TO_US(ticks_at_expire);
			sdu.size = MIN(remaining_tx, ISO_TEST_TX_BUFFER_SIZE);
			memset(tx_buffer, 0, sdu.size);

			/* If this is the first fragment of a framed SDU, inject the SDU
			 * counter.
			 */
			if ((sdu.size >= ISO_TEST_PACKET_COUNTER_SIZE) &&
			    ((sdu.sdu_state == BT_ISO_START) || (sdu.sdu_state == BT_ISO_SINGLE))) {
				if (cis->framed) {
					sdu_counter = (uint32_t)cis->hdr.test_mode.tx_sdu_counter;
				} else {
					/* Unframed. Get the next payload counter.
					 *
					 * BT 5.3, Vol 6, Part B, Section 7.1:
					 * When using unframed PDUs, the SDU counter shall be equal
					 * to the payload counter.
					 */
					source = isoal_source_get(source_handle);
					pdu_production = &source->pdu_production;

					sdu_counter = MAX(pdu_production->payload_number,
							  (sdu.target_event *
							   cis->lll.tx.burst_number));
				}

				sys_put_le32(sdu_counter, tx_buffer);
			}

			/* Send to ISOAL */
			err = isoal_tx_sdu_fragment(source_handle, &sdu);
			LL_ASSERT(!err);

			remaining_tx -= sdu.size;

			if (remaining_tx > ISO_TEST_TX_BUFFER_SIZE) {
				sdu.sdu_state = BT_ISO_CONT;
			} else {
				sdu.sdu_state = BT_ISO_END;
			}
		} while (remaining_tx);

		cis->hdr.test_mode.tx_sdu_counter++;

	} else if (IS_ADV_ISO_HANDLE(handle)) {
		/* FIXME: Implement for broadcaster */
	} else {
		LL_ASSERT(0);
	}
}
#endif /* CONFIG_BT_CTLR_CONN_ISO */

uint8_t ll_iso_transmit_test(uint16_t handle, uint8_t payload_type)
{
	isoal_source_handle_t source_handle;
	struct ll_iso_datapath *dp;
	uint32_t sdu_interval;
	isoal_status_t err;
	uint8_t status;

	status = BT_HCI_ERR_SUCCESS;

	if (IS_CIS_HANDLE(handle)) {
		struct ll_conn_iso_stream *cis;
		struct ll_conn_iso_group *cig;

		cis = ll_iso_stream_connected_get(handle);
		if (!cis) {
			/* CIS is not connected */
			return BT_HCI_ERR_UNKNOWN_CONN_ID;
		}

		if (cis->lll.tx.burst_number == 0U) {
			/* CIS is not configured for TX */
			return BT_HCI_ERR_UNSUPP_FEATURE_PARAM_VAL;
		}

		if (cis->hdr.datapath_in) {
			/* Data path already set up */
			return BT_HCI_ERR_CMD_DISALLOWED;
		}

		if (payload_type > BT_HCI_ISO_TEST_MAX_SIZE_SDU) {
			return BT_HCI_ERR_INVALID_LL_PARAM;
		}

		/* Allocate and configure test datapath */
		dp = mem_acquire(&datapath_free);
		if (!dp) {
			return BT_HCI_ERR_CMD_DISALLOWED;
		}

		dp->path_dir = BT_HCI_DATAPATH_DIR_HOST_TO_CTLR;
		dp->path_id  = BT_HCI_DATAPATH_ID_HCI;

		cis->hdr.datapath_in = dp;
		cig = cis->group;

		if (cig->lll.role == BT_HCI_ROLE_PERIPHERAL) {
			/* peripheral */
			sdu_interval = cig->c_sdu_interval;
		} else {
			/* central */
			sdu_interval = cig->p_sdu_interval;
		}

		/* Setup the test source */
		err = isoal_source_create(handle, cig->lll.role, cis->framed,
					  cis->lll.rx.burst_number, cis->lll.rx.flush_timeout,
					  cis->lll.rx.max_octets, sdu_interval, cig->iso_interval,
					  cis->sync_delay, cig->sync_delay,
					  ll_iso_pdu_alloc, ll_iso_pdu_write, ll_iso_pdu_emit,
					  ll_iso_test_pdu_release, &source_handle);

		if (err) {
			/* Error creating test source - cleanup source and datapath */
			isoal_source_destroy(source_handle);
			ull_iso_datapath_release(dp);
			cis->hdr.datapath_in = NULL;

			return BT_HCI_ERR_CMD_DISALLOWED;
		}

		dp->source_hdl = source_handle;
		isoal_source_enable(source_handle);

		/* Enable Transmit Test Mode */
		cis->hdr.test_mode.tx_enabled = 1;
		cis->hdr.test_mode.tx_payload_type = payload_type;

	} else if (IS_ADV_ISO_HANDLE(handle)) {
		struct lll_adv_iso_stream *stream;
		uint16_t stream_handle;

		stream_handle = LL_BIS_ADV_IDX_FROM_HANDLE(handle);
		stream = ull_adv_iso_stream_get(stream_handle);
		if (!stream) {
			return BT_HCI_ERR_UNKNOWN_CONN_ID;
		}

		/* FIXME: Implement use of common header in stream to enable code sharing
		 * between CIS and BIS for test commands (and other places).
		 */
		status = BT_HCI_ERR_CMD_DISALLOWED;
	} else {
		/* Handle is out of range */
		status = BT_HCI_ERR_UNKNOWN_CONN_ID;
	}

	return status;
}
#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */

uint8_t ll_iso_test_end(uint16_t handle, uint32_t *received_cnt,
			uint32_t *missed_cnt, uint32_t *failed_cnt)
{
	uint8_t status;

	*received_cnt = 0U;
	*missed_cnt   = 0U;
	*failed_cnt   = 0U;

	status = BT_HCI_ERR_SUCCESS;

	if (IS_CIS_HANDLE(handle)) {
		struct ll_conn_iso_stream *cis;

		cis = ll_iso_stream_connected_get(handle);
		if (!cis) {
			/* CIS is not connected */
			return BT_HCI_ERR_UNKNOWN_CONN_ID;
		}

		if (!cis->hdr.test_mode.rx_enabled && !cis->hdr.test_mode.tx_enabled) {
			/* Test Mode is not active */
			return BT_HCI_ERR_UNSUPP_FEATURE_PARAM_VAL;
		}

		if (cis->hdr.test_mode.rx_enabled) {
			isoal_sink_destroy(cis->hdr.datapath_out->sink_hdl);
			ull_iso_datapath_release(cis->hdr.datapath_out);
			cis->hdr.datapath_out = NULL;

			/* Return SDU statistics */
			*received_cnt = cis->hdr.test_mode.received_cnt;
			*missed_cnt   = cis->hdr.test_mode.missed_cnt;
			*failed_cnt   = cis->hdr.test_mode.failed_cnt;
		}

		if (cis->hdr.test_mode.tx_enabled) {
			/* Tear down source and datapath */
			isoal_source_destroy(cis->hdr.datapath_in->source_hdl);
			ull_iso_datapath_release(cis->hdr.datapath_in);
			cis->hdr.datapath_in = NULL;
		}

		/* Disable Test Mode */
		(void)memset(&cis->hdr.test_mode, 0U, sizeof(cis->hdr.test_mode));

	} else if (IS_ADV_ISO_HANDLE(handle)) {
		/* FIXME: Implement for broadcaster */
		status = BT_HCI_ERR_CMD_DISALLOWED;
	} else if (IS_SYNC_ISO_HANDLE(handle)) {
		/* FIXME: Implement for sync receiver */
		status = BT_HCI_ERR_CMD_DISALLOWED;
	} else {
		/* Handle is out of range */
		status = BT_HCI_ERR_UNKNOWN_CONN_ID;
	}

	return status;
}

#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
void *ll_iso_tx_mem_acquire(void)
{
	return mem_acquire(&mem_iso_tx.free);
}

void ll_iso_tx_mem_release(void *node_tx)
{
	mem_release(node_tx, &mem_iso_tx.free);
}

int ll_iso_tx_mem_enqueue(uint16_t handle, void *node_tx, void *link)
{
	if (IS_ENABLED(CONFIG_BT_CTLR_CONN_ISO) &&
	    IS_CIS_HANDLE(handle)) {
		struct ll_conn_iso_stream *cis;

		cis = ll_conn_iso_stream_get(handle);
		memq_enqueue(link, node_tx, &cis->lll.memq_tx.tail);

	} else if (IS_ENABLED(CONFIG_BT_CTLR_ADV_ISO) &&
		   IS_ADV_ISO_HANDLE(handle)) {
		struct lll_adv_iso_stream *stream;
		uint16_t stream_handle;

		/* FIXME: When hci_iso_handle uses ISOAL, link is provided and
		 * this code should be removed.
		 */
		link = mem_acquire(&mem_link_iso_tx.free);
		LL_ASSERT(link);

		stream_handle = LL_BIS_ADV_IDX_FROM_HANDLE(handle);
		stream = ull_adv_iso_stream_get(stream_handle);
		memq_enqueue(link, node_tx, &stream->memq_tx.tail);

	} else {
		return -EINVAL;
	}

	return 0;
}
#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */

int ull_iso_init(void)
{
	int err;

	err = init_reset();
	if (err) {
		return err;
	}

	return 0;
}

int ull_iso_reset(void)
{
	int err;

	err = init_reset();
	if (err) {
		return err;
	}

	return 0;
}

#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
void ull_iso_lll_ack_enqueue(uint16_t handle, struct node_tx_iso *node_tx)
{
	struct ll_iso_datapath *dp = NULL;

	if (IS_ENABLED(CONFIG_BT_CTLR_CONN_ISO) && IS_CIS_HANDLE(handle)) {
		struct ll_conn_iso_stream *cis;

		cis = ll_conn_iso_stream_get(handle);
		dp  = cis->hdr.datapath_in;

		if (dp) {
			isoal_tx_pdu_release(dp->source_hdl, node_tx);
		}
	} else if (IS_ENABLED(CONFIG_BT_CTLR_ADV_ISO) && IS_ADV_ISO_HANDLE(handle)) {
		/* Process as TX ack. TODO: Can be unified with CIS and use
		 * ISOAL.
		 */
		ll_tx_ack_put(handle, (void *)node_tx);
		ll_rx_sched();
	} else {
		LL_ASSERT(0);
	}
}

void ull_iso_lll_event_prepare(uint16_t handle, uint64_t event_count)
{
	if (IS_CIS_HANDLE(handle)) {
		struct ll_iso_datapath *dp = NULL;
		struct ll_conn_iso_stream *cis;

		cis = ll_iso_stream_connected_get(handle);

		if (cis) {
			dp  = cis->hdr.datapath_in;
		}

		if (dp) {
			isoal_tx_event_prepare(dp->source_hdl, event_count);
		}
	} else if (IS_ADV_ISO_HANDLE(handle)) {
		/* Send event deadline trigger to ISO-AL.
		 * TODO: Can be unified with CIS implementation.
		 */
	} else {
		LL_ASSERT(0);
	}
}
#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */

#if defined(CONFIG_BT_CTLR_SYNC_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
void *ull_iso_pdu_rx_alloc_peek(uint8_t count)
{
	if (count > MFIFO_AVAIL_COUNT_GET(iso_rx)) {
		return NULL;
	}

	return MFIFO_DEQUEUE_PEEK(iso_rx);
}

void *ull_iso_pdu_rx_alloc(void)
{
	return MFIFO_DEQUEUE(iso_rx);
}

#if defined(CONFIG_BT_CTLR_ISO_VENDOR_DATA_PATH)
void ull_iso_rx_put(memq_link_t *link, void *rx)
{
	/* Enqueue the Rx object */
	memq_enqueue(link, rx, &memq_ull_iso_rx.tail);
}

void ull_iso_rx_sched(void)
{
	static memq_link_t link;
	static struct mayfly mfy = {0, 0, &link, NULL, iso_rx_demux};

	/* Kick the ULL (using the mayfly, tailchain it) */
	mayfly_enqueue(TICKER_USER_ID_LLL, TICKER_USER_ID_ULL_HIGH, 1, &mfy);
}

#if defined(CONFIG_BT_CTLR_CONN_ISO)
static void iso_rx_cig_ref_point_update(struct ll_conn_iso_group *cig,
					const struct ll_conn_iso_stream *cis,
					const struct node_rx_iso_meta  *meta)
{
	uint32_t cig_sync_delay;
	uint32_t cis_sync_delay;
	uint64_t event_count;
	uint8_t burst_number;
	uint8_t role;

	role = cig->lll.role;
	cig_sync_delay = cig->sync_delay;
	cis_sync_delay = cis->sync_delay;
	burst_number = cis->lll.rx.burst_number;
	event_count = cis->lll.event_count;

	if (role) {
		/* Peripheral */

		/* Check if this is the first payload received for this cis in
		 * this event
		 */
		if (meta->payload_number == (burst_number * event_count)) {
			/* Update the CIG reference point based on the CIS
			 * anchor point
			 */
			cig->cig_ref_point = meta->timestamp + cis_sync_delay -
					     cig_sync_delay;
		}
	}
}
#endif /* CONFIG_BT_CTLR_CONN_ISO */

static void iso_rx_demux(void *param)
{
#if defined(CONFIG_BT_CTLR_CONN_ISO)
	struct ll_conn_iso_stream *cis;
	struct ll_conn_iso_group *cig;
	struct ll_iso_datapath *dp;
	struct node_rx_pdu *rx_pdu;
#endif /* CONFIG_BT_CTLR_CONN_ISO */
	struct node_rx_hdr *rx;
	memq_link_t *link;

	do {
		link = memq_peek(memq_ull_iso_rx.head, memq_ull_iso_rx.tail,
				 (void **)&rx);
		if (link) {
			/* Demux Rx objects */
			switch (rx->type) {
			case NODE_RX_TYPE_RELEASE:
				(void)memq_dequeue(memq_ull_iso_rx.tail,
						   &memq_ull_iso_rx.head, NULL);
				ll_iso_rx_put(link, rx);
				ll_rx_sched();
				break;

			case NODE_RX_TYPE_ISO_PDU:
				/* Remove from receive-queue; ULL has received this now */
				(void)memq_dequeue(memq_ull_iso_rx.tail, &memq_ull_iso_rx.head,
						   NULL);

#if defined(CONFIG_BT_CTLR_CONN_ISO)
				rx_pdu = (struct node_rx_pdu *)rx;
				cis = ll_conn_iso_stream_get(rx_pdu->hdr.handle);
				cig = cis->group;
				dp  = cis->hdr.datapath_out;

				iso_rx_cig_ref_point_update(cig, cis, &rx_pdu->hdr.rx_iso_meta);

				if (dp && dp->path_id != BT_HCI_DATAPATH_ID_HCI) {
					/* If vendor specific datapath pass to ISO AL here,
					 * in case of HCI destination it will be passed in
					 * HCI context.
					 */
					struct isoal_pdu_rx pckt_meta = {
						.meta = &rx_pdu->hdr.rx_iso_meta,
						.pdu  = (struct pdu_iso *)&rx_pdu->pdu[0]
					};

					/* Pass the ISO PDU through ISO-AL */
					const isoal_status_t err =
						isoal_rx_pdu_recombine(dp->sink_hdl, &pckt_meta);

					LL_ASSERT(err == ISOAL_STATUS_OK); /* TODO handle err */
				}
#endif /* CONFIG_BT_CTLR_CONN_ISO */

				/* Let ISO PDU start its long journey upwards */
				ll_iso_rx_put(link, rx);
				ll_rx_sched();
				break;

			default:
				LL_ASSERT(0);
				break;
			}
		}
	} while (link);
}
#endif /* CONFIG_BT_CTLR_ISO_VENDOR_DATA_PATH */

void ll_iso_rx_put(memq_link_t *link, void *rx)
{
	/* Enqueue the Rx object */
	memq_enqueue(link, rx, &memq_ll_iso_rx.tail);
}

void *ll_iso_rx_get(void)
{
	struct node_rx_hdr *rx;
	memq_link_t *link;

	link = memq_peek(memq_ll_iso_rx.head, memq_ll_iso_rx.tail, (void **)&rx);
	while (link) {
		/* Do not send up buffers to Host thread that are
		 * marked for release
		 */
		if (rx->type == NODE_RX_TYPE_RELEASE) {
			(void)memq_dequeue(memq_ll_iso_rx.tail,
						&memq_ll_iso_rx.head, NULL);
			mem_release(link, &mem_link_iso_rx.free);
			mem_release(rx, &mem_iso_rx.free);
			RXFIFO_ALLOC(iso_rx, 1);

			link = memq_peek(memq_ll_iso_rx.head, memq_ll_iso_rx.tail, (void **)&rx);
			continue;
		}
		return rx;
	}

	return NULL;
}

void ll_iso_rx_dequeue(void)
{
	struct node_rx_hdr *rx = NULL;
	memq_link_t *link;

	link = memq_dequeue(memq_ll_iso_rx.tail, &memq_ll_iso_rx.head,
			    (void **)&rx);
	LL_ASSERT(link);

	mem_release(link, &mem_link_iso_rx.free);

	/* Handle object specific clean up */
	switch (rx->type) {
	case NODE_RX_TYPE_ISO_PDU:
		break;
	default:
		LL_ASSERT(0);
		break;
	}
}

void ll_iso_rx_mem_release(void **node_rx)
{
	struct node_rx_hdr *rx;

	rx = *node_rx;
	while (rx) {
		struct node_rx_hdr *rx_free;

		rx_free = rx;
		rx = rx->next;

		switch (rx_free->type) {
		case NODE_RX_TYPE_ISO_PDU:
			mem_release(rx_free, &mem_iso_rx.free);
			break;
		default:
			/* Ignore other types as node may have been initialized due to
			 * race with HCI reset.
			 */
			break;
		}
	}

	*node_rx = rx;

	RXFIFO_ALLOC(iso_rx, UINT8_MAX);
}
#endif /* CONFIG_BT_CTLR_SYNC_ISO) || CONFIG_BT_CTLR_CONN_ISO */

void ull_iso_datapath_release(struct ll_iso_datapath *dp)
{
	mem_release(dp, &datapath_free);
}

#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
void ll_iso_link_tx_release(void *link)
{
	mem_release(link, &mem_link_iso_tx.free);
}

/**
 * Allocate a PDU from the LL and store the details in the given buffer. Allocation
 * is not expected to fail as there must always be sufficient PDU buffers. Any
 * failure will trigger the assert.
 * @param[in]  pdu_buffer Buffer to store PDU details in
 * @return     Error status of operation
 */
static isoal_status_t ll_iso_pdu_alloc(struct isoal_pdu_buffer *pdu_buffer)
{
	struct node_tx_iso *node_tx;

	node_tx = ll_iso_tx_mem_acquire();
	if (!node_tx) {
		BT_ERR("Tx Buffer Overflow");
		/* TODO: Report overflow to HCI and remove assert
		 * data_buf_overflow(evt, BT_OVERFLOW_LINK_ISO)
		 */
		LL_ASSERT(0);
		return ISOAL_STATUS_ERR_PDU_ALLOC;
	}

	node_tx->link = NULL;

	/* node_tx handle will be required to emit the PDU later */
	pdu_buffer->handle = (void *)node_tx;
	pdu_buffer->pdu    = (void *)node_tx->pdu;

	/* Use TX buffer size as the limit here. Actual size will be decided in
	 * the ISOAL based on the minimum of the buffer size and the respective
	 * Max_PDU_C_To_P or Max_PDU_P_To_C.
	 */
	pdu_buffer->size = CONFIG_BT_CTLR_ISO_TX_BUFFER_SIZE;

	return ISOAL_STATUS_OK;
}

/**
 * Write the given SDU payload to the target PDU buffer at the given offset.
 * @param[in,out]  pdu_buffer  Target PDU buffer
 * @param[in]      pdu_offset  Offset / current write position within PDU
 * @param[in]      sdu_payload Location of source data
 * @param[in]      consume_len Length of data to copy
 * @return         Error status of write operation
 */
static isoal_status_t ll_iso_pdu_write(struct isoal_pdu_buffer *pdu_buffer,
				       const size_t  pdu_offset,
				       const uint8_t *sdu_payload,
				       const size_t  consume_len)
{
	ARG_UNUSED(pdu_offset);
	ARG_UNUSED(consume_len);

	LL_ASSERT(pdu_buffer);
	LL_ASSERT(pdu_buffer->pdu);
	LL_ASSERT(sdu_payload);

	if ((pdu_offset + consume_len) > pdu_buffer->size) {
		/* Exceeded PDU buffer */
		return ISOAL_STATUS_ERR_UNSPECIFIED;
	}

	/* Copy source to destination at given offset */
	memcpy(&pdu_buffer->pdu->payload[pdu_offset], sdu_payload, consume_len);

	return ISOAL_STATUS_OK;
}

/**
 * Emit the encoded node to the transmission queue
 * @param node_tx TX node to enqueue
 * @param handle  CIS/BIS handle
 * @return        Error status of enqueue operation
 */
static isoal_status_t ll_iso_pdu_emit(struct node_tx_iso *node_tx,
				      const uint16_t handle)
{
	memq_link_t *link;

	link = mem_acquire(&mem_link_iso_tx.free);
	LL_ASSERT(link);

	if (ll_iso_tx_mem_enqueue(handle, node_tx, link)) {
		return ISOAL_STATUS_ERR_PDU_EMIT;
	}

	return ISOAL_STATUS_OK;
}

#if defined(CONFIG_BT_CTLR_CONN_ISO)
/**
 * Release the given payload back to the memory pool.
 * @param node_tx TX node to release or forward
 * @param handle  CIS/BIS handle
 * @param status  Reason for release
 * @return        Error status of release operation
 */
static isoal_status_t ll_iso_pdu_release(struct node_tx_iso *node_tx,
					 const uint16_t handle,
					 const isoal_status_t status)
{
	if (status == ISOAL_STATUS_OK) {
		/* Process as TX ack */
		ll_tx_ack_put(handle, (void *)node_tx);
		ll_rx_sched();
	} else {
		/* Release back to memory pool */
		if (node_tx->link) {
			ll_iso_link_tx_release(node_tx->link);
		}
		ll_iso_tx_mem_release(node_tx);
	}

	return ISOAL_STATUS_OK;
}
#endif /* CONFIG_BT_CTLR_CONN_ISO */
#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */

static int init_reset(void)
{
#if defined(CONFIG_BT_CTLR_SYNC_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
	memq_link_t *link;

	RXFIFO_INIT(iso_rx);

	/* Acquire a link to initialize ull rx memq */
	link = mem_acquire(&mem_link_iso_rx.free);
	LL_ASSERT(link);

#if defined(CONFIG_BT_CTLR_ISO_VENDOR_DATA_PATH)
	/* Initialize ull rx memq */
	MEMQ_INIT(ull_iso_rx, link);
#endif /* CONFIG_BT_CTLR_ISO_VENDOR_DATA_PATH */

	/* Acquire a link to initialize ll_iso_rx memq */
	link = mem_acquire(&mem_link_iso_rx.free);
	LL_ASSERT(link);

	/* Initialize ll_iso_rx memq */
	MEMQ_INIT(ll_iso_rx, link);

	RXFIFO_ALLOC(iso_rx, UINT8_MAX);
#endif /* CONFIG_BT_CTLR_SYNC_ISO) || CONFIG_BT_CTLR_CONN_ISO */

#if defined(CONFIG_BT_CTLR_ADV_ISO) || defined(CONFIG_BT_CTLR_CONN_ISO)
	/* Initialize tx pool. */
	mem_init(mem_iso_tx.pool, NODE_TX_BUFFER_SIZE,
		 CONFIG_BT_CTLR_ISO_TX_BUFFERS, &mem_iso_tx.free);

	/* Initialize tx link pool. */
	mem_init(mem_link_iso_tx.pool, sizeof(memq_link_t),
		 CONFIG_BT_CTLR_ISO_TX_BUFFERS,
		 &mem_link_iso_tx.free);
#endif /* CONFIG_BT_CTLR_ADV_ISO || CONFIG_BT_CTLR_CONN_ISO */

#if BT_CTLR_ISO_STREAMS
	/* Initialize ISO Datapath pool */
	mem_init(datapath_pool, sizeof(struct ll_iso_datapath),
		 sizeof(datapath_pool) / sizeof(struct ll_iso_datapath), &datapath_free);
#endif /* BT_CTLR_ISO_STREAMS */

	/* Initialize ISO Adaptation Layer */
	isoal_init();

	return 0;
}