path: root/include/drm/display/drm_dp_mst_helper.h

/*
 * Copyright © 2014 Red Hat.
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */
#ifndef _DRM_DP_MST_HELPER_H_
#define _DRM_DP_MST_HELPER_H_

#include <linux/types.h>
#include <drm/display/drm_dp_helper.h>
#include <drm/drm_atomic.h>
#include <drm/drm_fixed.h>

#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
#include <linux/stackdepot.h>
#include <linux/timekeeping.h>

enum drm_dp_mst_topology_ref_type {
	DRM_DP_MST_TOPOLOGY_REF_GET,
	DRM_DP_MST_TOPOLOGY_REF_PUT,
};

struct drm_dp_mst_topology_ref_history {
	struct drm_dp_mst_topology_ref_entry {
		enum drm_dp_mst_topology_ref_type type;
		int count;
		ktime_t ts_nsec;
		depot_stack_handle_t backtrace;
	} *entries;
	int len;
};
#endif /* IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS) */

enum drm_dp_mst_payload_allocation {
	DRM_DP_MST_PAYLOAD_ALLOCATION_NONE,
	DRM_DP_MST_PAYLOAD_ALLOCATION_LOCAL,
	DRM_DP_MST_PAYLOAD_ALLOCATION_DFP,
	DRM_DP_MST_PAYLOAD_ALLOCATION_REMOTE,
};

struct drm_dp_mst_branch;

/**
 * struct drm_dp_mst_port - MST port
 * @port_num: port number
 * @input: if this port is an input port. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @mcs: message capability status - DP 1.2 spec. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @ddps: DisplayPort Device Plug Status - DP 1.2. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @pdt: Peer Device Type. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @ldps: Legacy Device Plug Status. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @dpcd_rev: DPCD revision of device on this port. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @num_sdp_streams: Number of simultaneous streams. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @num_sdp_stream_sinks: Number of stream sinks. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @full_pbn: Max possible bandwidth for this port. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @next: link to next port on this branch device
 * @aux: i2c aux transport to talk to device connected to this port, protected
 * by &drm_dp_mst_topology_mgr.base.lock.
 * @passthrough_aux: parent aux to which DSC pass-through requests should be
 * sent, only set if DSC pass-through is possible.
 * @parent: branch device parent of this port
 * @connector: DRM connector this port is connected to. Protected by
 * &drm_dp_mst_topology_mgr.base.lock.
 * @mgr: topology manager this port lives under.
 *
 * This structure represents an MST port endpoint on a device somewhere
 * in the MST topology.
 */
struct drm_dp_mst_port {
	/**
	 * @topology_kref: refcount for this port's lifetime in the topology,
	 * only the DP MST helpers should need to touch this
	 */
	struct kref topology_kref;

	/**
	 * @malloc_kref: refcount for the memory allocation containing this
	 * structure. See drm_dp_mst_get_port_malloc() and
	 * drm_dp_mst_put_port_malloc().
	 */
	struct kref malloc_kref;

#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
	/**
	 * @topology_ref_history: A history of each topology
	 * reference/dereference. See CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS.
	 */
	struct drm_dp_mst_topology_ref_history topology_ref_history;
#endif

	u8 port_num;
	bool input;
	bool mcs;
	bool ddps;
	u8 pdt;
	bool ldps;
	u8 dpcd_rev;
	u8 num_sdp_streams;
	u8 num_sdp_stream_sinks;
	uint16_t full_pbn;
	struct list_head next;
	/**
	 * @mstb: the branch device connected to this port, if there is one.
	 * This should be considered protected for reading by
	 * &drm_dp_mst_topology_mgr.lock. There are two exceptions to this:
	 * &drm_dp_mst_topology_mgr.up_req_work and
	 * &drm_dp_mst_topology_mgr.work, which do not grab
	 * &drm_dp_mst_topology_mgr.lock during reads but are the only
	 * updaters of this list and are protected from writing concurrently
	 * by &drm_dp_mst_topology_mgr.probe_lock.
	 */
	struct drm_dp_mst_branch *mstb;
	struct drm_dp_aux aux; /* i2c bus for this port? */
	struct drm_dp_aux *passthrough_aux;
	struct drm_dp_mst_branch *parent;

	struct drm_connector *connector;
	struct drm_dp_mst_topology_mgr *mgr;

	/**
	 * @cached_edid: for DP logical ports - make tiling work by ensuring
	 * that the EDID for all connectors is read immediately.
	 */
	const struct drm_edid *cached_edid;

	/**
	 * @fec_capable: bool indicating if FEC can be supported up to that
	 * point in the MST topology.
	 */
	bool fec_capable;
};

/* sideband msg header - not bit struct */
struct drm_dp_sideband_msg_hdr {
	u8 lct;
	u8 lcr;
	u8 rad[8];
	bool broadcast;
	bool path_msg;
	u8 msg_len;
	bool somt;
	bool eomt;
	bool seqno;
};

struct drm_dp_sideband_msg_rx {
	u8 chunk[48];
	u8 msg[256];
	u8 curchunk_len;
	u8 curchunk_idx; /* chunk we are parsing now */
	u8 curchunk_hdrlen;
	u8 curlen; /* total length of the msg */
	bool have_somt;
	bool have_eomt;
	struct drm_dp_sideband_msg_hdr initial_hdr;
};

/**
 * struct drm_dp_mst_branch - MST branch device.
 * @rad: Relative Address to talk to this branch device.
 * @lct: Link count total to talk to this branch device.
 * @num_ports: number of ports on the branch.
 * @port_parent: pointer to the port parent, NULL if toplevel.
 * @mgr: topology manager for this branch device.
 * @link_address_sent: if a link address message has been sent to this device yet.
 * @guid: guid for DP 1.2 branch device. port under this branch can be
 * identified by port #.
 *
 * This structure represents an MST branch device, there is one
 * primary branch device at the root, along with any other branches connected
 * to downstream port of parent branches.
 */
struct drm_dp_mst_branch {
	/**
	 * @topology_kref: refcount for this branch device's lifetime in the
	 * topology, only the DP MST helpers should need to touch this
	 */
	struct kref topology_kref;

	/**
	 * @malloc_kref: refcount for the memory allocation containing this
	 * structure. See drm_dp_mst_get_mstb_malloc() and
	 * drm_dp_mst_put_mstb_malloc().
	 */
	struct kref malloc_kref;

#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
	/**
	 * @topology_ref_history: A history of each topology
	 * reference/dereference. See CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS.
	 */
	struct drm_dp_mst_topology_ref_history topology_ref_history;
#endif

	/**
	 * @destroy_next: linked-list entry used by
	 * drm_dp_delayed_destroy_work()
	 */
	struct list_head destroy_next;

	u8 rad[8];
	u8 lct;
	int num_ports;

	/**
	 * @ports: the list of ports on this branch device. This should be
	 * considered protected for reading by &drm_dp_mst_topology_mgr.lock.
	 * There are two exceptions to this:
	 * &drm_dp_mst_topology_mgr.up_req_work and
	 * &drm_dp_mst_topology_mgr.work, which do not grab
	 * &drm_dp_mst_topology_mgr.lock during reads but are the only
	 * updaters of this list and are protected from updating the list
	 * concurrently by @drm_dp_mst_topology_mgr.probe_lock
	 */
	struct list_head ports;

	struct drm_dp_mst_port *port_parent;
	struct drm_dp_mst_topology_mgr *mgr;

	bool link_address_sent;

	/* global unique identifier to identify branch devices */
	u8 guid[16];
};


struct drm_dp_nak_reply {
	u8 guid[16];
	u8 reason;
	u8 nak_data;
};

struct drm_dp_link_address_ack_reply {
	u8 guid[16];
	u8 nports;
	struct drm_dp_link_addr_reply_port {
		bool input_port;
		u8 peer_device_type;
		u8 port_number;
		bool mcs;
		bool ddps;
		bool legacy_device_plug_status;
		u8 dpcd_revision;
		u8 peer_guid[16];
		u8 num_sdp_streams;
		u8 num_sdp_stream_sinks;
	} ports[16];
};

struct drm_dp_remote_dpcd_read_ack_reply {
	u8 port_number;
	u8 num_bytes;
	u8 bytes[255];
};

struct drm_dp_remote_dpcd_write_ack_reply {
	u8 port_number;
};

struct drm_dp_remote_dpcd_write_nak_reply {
	u8 port_number;
	u8 reason;
	u8 bytes_written_before_failure;
};

struct drm_dp_remote_i2c_read_ack_reply {
	u8 port_number;
	u8 num_bytes;
	u8 bytes[255];
};

struct drm_dp_remote_i2c_read_nak_reply {
	u8 port_number;
	u8 nak_reason;
	u8 i2c_nak_transaction;
};

struct drm_dp_remote_i2c_write_ack_reply {
	u8 port_number;
};

struct drm_dp_query_stream_enc_status_ack_reply {
	/* Bit[23:16]- Stream Id */
	u8 stream_id;

	/* Bit[15]- Signed */
	bool reply_signed;

	/* Bit[10:8]- Stream Output Sink Type */
	bool unauthorizable_device_present;
	bool legacy_device_present;
	bool query_capable_device_present;

	/* Bit[12:11]- Stream Output CP Type */
	bool hdcp_1x_device_present;
	bool hdcp_2x_device_present;

	/* Bit[4]- Stream Authentication */
	bool auth_completed;

	/* Bit[3]- Stream Encryption */
	bool encryption_enabled;

	/* Bit[2]- Stream Repeater Function Present */
	bool repeater_present;

	/* Bit[1:0]- Stream State */
	u8 state;
};

#define DRM_DP_MAX_SDP_STREAMS 16
struct drm_dp_allocate_payload {
	u8 port_number;
	u8 number_sdp_streams;
	u8 vcpi;
	u16 pbn;
	u8 sdp_stream_sink[DRM_DP_MAX_SDP_STREAMS];
};

struct drm_dp_allocate_payload_ack_reply {
	u8 port_number;
	u8 vcpi;
	u16 allocated_pbn;
};

struct drm_dp_connection_status_notify {
	u8 guid[16];
	u8 port_number;
	bool legacy_device_plug_status;
	bool displayport_device_plug_status;
	bool message_capability_status;
	bool input_port;
	u8 peer_device_type;
};

struct drm_dp_remote_dpcd_read {
	u8 port_number;
	u32 dpcd_address;
	u8 num_bytes;
};

struct drm_dp_remote_dpcd_write {
	u8 port_number;
	u32 dpcd_address;
	u8 num_bytes;
	u8 *bytes;
};

#define DP_REMOTE_I2C_READ_MAX_TRANSACTIONS 4
struct drm_dp_remote_i2c_read {
	u8 num_transactions;
	u8 port_number;
	struct drm_dp_remote_i2c_read_tx {
		u8 i2c_dev_id;
		u8 num_bytes;
		u8 *bytes;
		u8 no_stop_bit;
		u8 i2c_transaction_delay;
	} transactions[DP_REMOTE_I2C_READ_MAX_TRANSACTIONS];
	u8 read_i2c_device_id;
	u8 num_bytes_read;
};

struct drm_dp_remote_i2c_write {
	u8 port_number;
	u8 write_i2c_device_id;
	u8 num_bytes;
	u8 *bytes;
};

struct drm_dp_query_stream_enc_status {
	u8 stream_id;
	u8 client_id[7];	/* 56-bit nonce */
	u8 stream_event;
	bool valid_stream_event;
	u8 stream_behavior;
	u8 valid_stream_behavior;
};

/* this covers ENUM_RESOURCES, POWER_DOWN_PHY, POWER_UP_PHY */
struct drm_dp_port_number_req {
	u8 port_number;
};

struct drm_dp_enum_path_resources_ack_reply {
	u8 port_number;
	bool fec_capable;
	u16 full_payload_bw_number;
	u16 avail_payload_bw_number;
};

/* covers POWER_DOWN_PHY, POWER_UP_PHY */
struct drm_dp_port_number_rep {
	u8 port_number;
};

struct drm_dp_query_payload {
	u8 port_number;
	u8 vcpi;
};

struct drm_dp_resource_status_notify {
	u8 port_number;
	u8 guid[16];
	u16 available_pbn;
};

struct drm_dp_query_payload_ack_reply {
	u8 port_number;
	u16 allocated_pbn;
};

struct drm_dp_sideband_msg_req_body {
	u8 req_type;
	union ack_req {
		struct drm_dp_connection_status_notify conn_stat;
		struct drm_dp_port_number_req port_num;
		struct drm_dp_resource_status_notify resource_stat;

		struct drm_dp_query_payload query_payload;
		struct drm_dp_allocate_payload allocate_payload;

		struct drm_dp_remote_dpcd_read dpcd_read;
		struct drm_dp_remote_dpcd_write dpcd_write;

		struct drm_dp_remote_i2c_read i2c_read;
		struct drm_dp_remote_i2c_write i2c_write;

		struct drm_dp_query_stream_enc_status enc_status;
	} u;
};

struct drm_dp_sideband_msg_reply_body {
	u8 reply_type;
	u8 req_type;
	union ack_replies {
		struct drm_dp_nak_reply nak;
		struct drm_dp_link_address_ack_reply link_addr;
		struct drm_dp_port_number_rep port_number;

		struct drm_dp_enum_path_resources_ack_reply path_resources;
		struct drm_dp_allocate_payload_ack_reply allocate_payload;
		struct drm_dp_query_payload_ack_reply query_payload;

		struct drm_dp_remote_dpcd_read_ack_reply remote_dpcd_read_ack;
		struct drm_dp_remote_dpcd_write_ack_reply remote_dpcd_write_ack;
		struct drm_dp_remote_dpcd_write_nak_reply remote_dpcd_write_nack;

		struct drm_dp_remote_i2c_read_ack_reply remote_i2c_read_ack;
		struct drm_dp_remote_i2c_read_nak_reply remote_i2c_read_nack;
		struct drm_dp_remote_i2c_write_ack_reply remote_i2c_write_ack;

		struct drm_dp_query_stream_enc_status_ack_reply enc_status;
	} u;
};

/* msg is queued to be put into a slot */
#define DRM_DP_SIDEBAND_TX_QUEUED 0
/* msg has started transmitting on a slot - still on msgq */
#define DRM_DP_SIDEBAND_TX_START_SEND 1
/* msg has finished transmitting on a slot - removed from msgq only in slot */
#define DRM_DP_SIDEBAND_TX_SENT 2
/* msg has received a response - removed from slot */
#define DRM_DP_SIDEBAND_TX_RX 3
#define DRM_DP_SIDEBAND_TX_TIMEOUT 4

struct drm_dp_sideband_msg_tx {
	u8 msg[256];
	u8 chunk[48];
	u8 cur_offset;
	u8 cur_len;
	struct drm_dp_mst_branch *dst;
	struct list_head next;
	int seqno;
	int state;
	bool path_msg;
	struct drm_dp_sideband_msg_reply_body reply;
};

/* sideband msg handler */
struct drm_dp_mst_topology_mgr;
struct drm_dp_mst_topology_cbs {
	/* create a connector for a port */
	struct drm_connector *(*add_connector)(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, const char *path);
	/*
	 * Checks for any pending MST interrupts, passing them to MST core for
	 * processing, the same way an HPD IRQ pulse handler would do this.
	 * If provided MST core calls this callback from a poll-waiting loop
	 * when waiting for MST down message replies. The driver is expected
	 * to guard against a race between this callback and the driver's HPD
	 * IRQ pulse handler.
	 */
	void (*poll_hpd_irq)(struct drm_dp_mst_topology_mgr *mgr);
};

#define to_dp_mst_topology_state(x) container_of(x, struct drm_dp_mst_topology_state, base)

/**
 * struct drm_dp_mst_atomic_payload - Atomic state struct for an MST payload
 *
 * The primary atomic state structure for a given MST payload. Stores information like current
 * bandwidth allocation, intended action for this payload, etc.
 */
struct drm_dp_mst_atomic_payload {
	/** @port: The MST port assigned to this payload */
	struct drm_dp_mst_port *port;

	/**
	 * @vc_start_slot: The time slot that this payload starts on. Because payload start slots
	 * can't be determined ahead of time, the contents of this value are UNDEFINED at atomic
	 * check time. This shouldn't usually matter, as the start slot should never be relevant for
	 * atomic state computations.
	 *
	 * Since this value is determined at commit time instead of check time, this value is
	 * protected by the MST helpers ensuring that async commits operating on the given topology
	 * never run in parallel. In the event that a driver does need to read this value (e.g. to
	 * inform hardware of the starting timeslot for a payload), the driver may either:
	 *
	 * * Read this field during the atomic commit after
	 *   drm_dp_mst_atomic_wait_for_dependencies() has been called, which will ensure the
	 *   previous MST states payload start slots have been copied over to the new state. Note
	 *   that a new start slot won't be assigned/removed from this payload until
	 *   drm_dp_add_payload_part1()/drm_dp_remove_payload_part2() have been called.
	 * * Acquire the MST modesetting lock, and then wait for any pending MST-related commits to
	 *   get committed to hardware by calling drm_crtc_commit_wait() on each of the
	 *   &drm_crtc_commit structs in &drm_dp_mst_topology_state.commit_deps.
	 *
	 * If neither of the two above solutions suffice (e.g. the driver needs to read the start
	 * slot in the middle of an atomic commit without waiting for some reason), then drivers
	 * should cache this value themselves after changing payloads.
	 */
	s8 vc_start_slot;

	/** @vcpi: The Virtual Channel Payload Identifier */
	u8 vcpi;
	/**
	 * @time_slots:
	 * The number of timeslots allocated to this payload from the source DP Tx to
	 * the immediate downstream DP Rx
	 */
	int time_slots;
	/** @pbn: The payload bandwidth for this payload */
	int pbn;

	/** @delete: Whether or not we intend to delete this payload during this atomic commit */
	bool delete : 1;
	/** @dsc_enabled: Whether or not this payload has DSC enabled */
	bool dsc_enabled : 1;

	/** @payload_allocation_status: The allocation status of this payload */
	enum drm_dp_mst_payload_allocation payload_allocation_status;

	/** @next: The list node for this payload */
	struct list_head next;
};

/**
 * struct drm_dp_mst_topology_state - DisplayPort MST topology atomic state
 *
 * This struct represents the atomic state of the toplevel DisplayPort MST manager
 */
struct drm_dp_mst_topology_state {
	/** @base: Base private state for atomic */
	struct drm_private_state base;

	/** @mgr: The topology manager */
	struct drm_dp_mst_topology_mgr *mgr;

	/**
	 * @pending_crtc_mask: A bitmask of all CRTCs this topology state touches, drivers may
	 * modify this to add additional dependencies if needed.
	 */
	u32 pending_crtc_mask;
	/**
	 * @commit_deps: A list of all CRTC commits affecting this topology, this field isn't
	 * populated until drm_dp_mst_atomic_wait_for_dependencies() is called.
	 */
	struct drm_crtc_commit **commit_deps;
	/** @num_commit_deps: The number of CRTC commits in @commit_deps */
	size_t num_commit_deps;

	/** @payload_mask: A bitmask of allocated VCPIs, used for VCPI assignments */
	u32 payload_mask;
	/** @payloads: The list of payloads being created/destroyed in this state */
	struct list_head payloads;

	/** @total_avail_slots: The total number of slots this topology can handle (63 or 64) */
	u8 total_avail_slots;
	/** @start_slot: The first usable time slot in this topology (1 or 0) */
	u8 start_slot;

	/**
	 * @pbn_div: The current PBN divisor for this topology. The driver is expected to fill this
	 * out itself.
	 */
	fixed20_12 pbn_div;
};

#define to_dp_mst_topology_mgr(x) container_of(x, struct drm_dp_mst_topology_mgr, base)

/**
 * struct drm_dp_mst_topology_mgr - DisplayPort MST manager
 *
 * This struct represents the toplevel displayport MST topology manager.
 * There should be one instance of this for every MST capable DP connector
 * on the GPU.
 */
struct drm_dp_mst_topology_mgr {
	/**
	 * @base: Base private object for atomic
	 */
	struct drm_private_obj base;

	/**
	 * @dev: device pointer for adding i2c devices etc.
	 */
	struct drm_device *dev;
	/**
	 * @cbs: callbacks for connector addition and destruction.
	 */
	const struct drm_dp_mst_topology_cbs *cbs;
	/**
	 * @max_dpcd_transaction_bytes: maximum number of bytes to read/write
	 * in one go.
	 */
	int max_dpcd_transaction_bytes;
	/**
	 * @aux: AUX channel for the DP MST connector this topolgy mgr is
	 * controlling.
	 */
	struct drm_dp_aux *aux;
	/**
	 * @max_payloads: maximum number of payloads the GPU can generate.
	 */
	int max_payloads;
	/**
	 * @conn_base_id: DRM connector ID this mgr is connected to. Only used
	 * to build the MST connector path value.
	 */
	int conn_base_id;

	/**
	 * @up_req_recv: Message receiver state for up requests.
	 */
	struct drm_dp_sideband_msg_rx up_req_recv;

	/**
	 * @down_rep_recv: Message receiver state for replies to down
	 * requests.
	 */
	struct drm_dp_sideband_msg_rx down_rep_recv;

	/**
	 * @lock: protects @mst_state, @mst_primary, @dpcd, and
	 * @payload_id_table_cleared.
	 */
	struct mutex lock;

	/**
	 * @probe_lock: Prevents @work and @up_req_work, the only writers of
	 * &drm_dp_mst_port.mstb and &drm_dp_mst_branch.ports, from racing
	 * while they update the topology.
	 */
	struct mutex probe_lock;

	/**
	 * @mst_state: If this manager is enabled for an MST capable port. False
	 * if no MST sink/branch devices is connected.
	 */
	bool mst_state : 1;

	/**
	 * @payload_id_table_cleared: Whether or not we've cleared the payload
	 * ID table for @mst_primary. Protected by @lock.
	 */
	bool payload_id_table_cleared : 1;

	/**
	 * @payload_count: The number of currently active payloads in hardware. This value is only
	 * intended to be used internally by MST helpers for payload tracking, and is only safe to
	 * read/write from the atomic commit (not check) context.
	 */
	u8 payload_count;

	/**
	 * @next_start_slot: The starting timeslot to use for new VC payloads. This value is used
	 * internally by MST helpers for payload tracking, and is only safe to read/write from the
	 * atomic commit (not check) context.
	 */
	u8 next_start_slot;

	/**
	 * @mst_primary: Pointer to the primary/first branch device.
	 */
	struct drm_dp_mst_branch *mst_primary;

	/**
	 * @dpcd: Cache of DPCD for primary port.
	 */
	u8 dpcd[DP_RECEIVER_CAP_SIZE];
	/**
	 * @sink_count: Sink count from DEVICE_SERVICE_IRQ_VECTOR_ESI0.
	 */
	u8 sink_count;

	/**
	 * @funcs: Atomic helper callbacks
	 */
	const struct drm_private_state_funcs *funcs;

	/**
	 * @qlock: protects @tx_msg_downq and &drm_dp_sideband_msg_tx.state
	 */
	struct mutex qlock;

	/**
	 * @tx_msg_downq: List of pending down requests
	 */
	struct list_head tx_msg_downq;

	/**
	 * @tx_waitq: Wait to queue stall for the tx worker.
	 */
	wait_queue_head_t tx_waitq;
	/**
	 * @work: Probe work.
	 */
	struct work_struct work;
	/**
	 * @tx_work: Sideband transmit worker. This can nest within the main
	 * @work worker for each transaction @work launches.
	 */
	struct work_struct tx_work;

	/**
	 * @destroy_port_list: List of to be destroyed connectors.
	 */
	struct list_head destroy_port_list;
	/**
	 * @destroy_branch_device_list: List of to be destroyed branch
	 * devices.
	 */
	struct list_head destroy_branch_device_list;
	/**
	 * @delayed_destroy_lock: Protects @destroy_port_list and
	 * @destroy_branch_device_list.
	 */
	struct mutex delayed_destroy_lock;

	/**
	 * @delayed_destroy_wq: Workqueue used for delayed_destroy_work items.
	 * A dedicated WQ makes it possible to drain any requeued work items
	 * on it.
	 */
	struct workqueue_struct *delayed_destroy_wq;

	/**
	 * @delayed_destroy_work: Work item to destroy MST port and branch
	 * devices, needed to avoid locking inversion.
	 */
	struct work_struct delayed_destroy_work;

	/**
	 * @up_req_list: List of pending up requests from the topology that
	 * need to be processed, in chronological order.
	 */
	struct list_head up_req_list;
	/**
	 * @up_req_lock: Protects @up_req_list
	 */
	struct mutex up_req_lock;
	/**
	 * @up_req_work: Work item to process up requests received from the
	 * topology. Needed to avoid blocking hotplug handling and sideband
	 * transmissions.
	 */
	struct work_struct up_req_work;

#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
	/**
	 * @topology_ref_history_lock: protects
	 * &drm_dp_mst_port.topology_ref_history and
	 * &drm_dp_mst_branch.topology_ref_history.
	 */
	struct mutex topology_ref_history_lock;
#endif
};

int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
				 struct drm_device *dev, struct drm_dp_aux *aux,
				 int max_dpcd_transaction_bytes,
				 int max_payloads, int conn_base_id);

void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);

/**
 * enum drm_dp_mst_mode - sink's MST mode capability
 */
enum drm_dp_mst_mode {
	/**
	 * @DRM_DP_SST: The sink does not support MST nor single stream sideband
	 * messaging.
	 */
	DRM_DP_SST,
	/**
	 * @DRM_DP_MST: Sink supports MST, more than one stream and single
	 * stream sideband messaging.
	 */
	DRM_DP_MST,
	/**
	 * @DRM_DP_SST_SIDEBAND_MSG: Sink supports only one stream and single
	 * stream sideband messaging.
	 */
	DRM_DP_SST_SIDEBAND_MSG,
};

enum drm_dp_mst_mode drm_dp_read_mst_cap(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state);

int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr,
				    const u8 *esi,
				    u8 *ack,
				    bool *handled);
void drm_dp_mst_hpd_irq_send_new_request(struct drm_dp_mst_topology_mgr *mgr);

int
drm_dp_mst_detect_port(struct drm_connector *connector,
		       struct drm_modeset_acquire_ctx *ctx,
		       struct drm_dp_mst_topology_mgr *mgr,
		       struct drm_dp_mst_port *port);

const struct drm_edid *drm_dp_mst_edid_read(struct drm_connector *connector,
					    struct drm_dp_mst_topology_mgr *mgr,
					    struct drm_dp_mst_port *port);
struct edid *drm_dp_mst_get_edid(struct drm_connector *connector,
				 struct drm_dp_mst_topology_mgr *mgr,
				 struct drm_dp_mst_port *port);

fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
				    int link_rate, int link_lane_count);

int drm_dp_calc_pbn_mode(int clock, int bpp);

void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap);

int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
			     struct drm_dp_mst_topology_state *mst_state,
			     struct drm_dp_mst_atomic_payload *payload);
int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
			     struct drm_dp_mst_atomic_payload *payload);
void drm_dp_remove_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
				 struct drm_dp_mst_topology_state *mst_state,
				 struct drm_dp_mst_atomic_payload *payload);
void drm_dp_remove_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
				 struct drm_dp_mst_topology_state *mst_state,
				 const struct drm_dp_mst_atomic_payload *old_payload,
				 struct drm_dp_mst_atomic_payload *new_payload);

int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr);

void drm_dp_mst_dump_topology(struct seq_file *m,
			      struct drm_dp_mst_topology_mgr *mgr);

void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
int __must_check
drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
			       bool sync);

ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
			     unsigned int offset, void *buffer, size_t size);
ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
			      unsigned int offset, void *buffer, size_t size);

int drm_dp_mst_connector_late_register(struct drm_connector *connector,
				       struct drm_dp_mst_port *port);
void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
					   struct drm_dp_mst_port *port);

struct drm_dp_mst_topology_state *
drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
				  struct drm_dp_mst_topology_mgr *mgr);
struct drm_dp_mst_topology_state *
drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state,
				      struct drm_dp_mst_topology_mgr *mgr);
struct drm_dp_mst_topology_state *
drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
				      struct drm_dp_mst_topology_mgr *mgr);
struct drm_dp_mst_atomic_payload *
drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
				 struct drm_dp_mst_port *port);
bool drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr,
					  struct drm_dp_mst_port *port,
					  struct drm_dp_mst_port *parent);
int __must_check
drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
			      struct drm_dp_mst_topology_mgr *mgr,
			      struct drm_dp_mst_port *port, int pbn);
int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
				 struct drm_dp_mst_port *port,
				 int pbn, bool enable);
int __must_check
drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state,
				  struct drm_dp_mst_topology_mgr *mgr);
int __must_check
drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
				 struct drm_dp_mst_topology_mgr *mgr,
				 struct drm_dp_mst_port *port);
void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state);
int __must_check drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state);
int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
				 struct drm_dp_mst_port *port, bool power_up);
int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
		struct drm_dp_mst_port *port,
		struct drm_dp_query_stream_enc_status_ack_reply *status);
int __must_check drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state,
					     struct drm_dp_mst_topology_mgr *mgr,
					     struct drm_dp_mst_topology_state *mst_state,
					     struct drm_dp_mst_port **failing_port);
int __must_check drm_dp_mst_atomic_check(struct drm_atomic_state *state);
int __must_check drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
						   struct drm_dp_mst_topology_mgr *mgr);

void drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port);
void drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port);

static inline
bool drm_dp_mst_port_is_logical(struct drm_dp_mst_port *port)
{
	return port->port_num >= DP_MST_LOGICAL_PORT_0;
}

struct drm_dp_aux *drm_dp_mst_aux_for_parent(struct drm_dp_mst_port *port);
struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port);

static inline struct drm_dp_mst_topology_state *
to_drm_dp_mst_topology_state(struct drm_private_state *state)
{
	return container_of(state, struct drm_dp_mst_topology_state, base);
}

extern const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs;

/**
 * __drm_dp_mst_state_iter_get - private atomic state iterator function for
 * macro-internal use
 * @state: &struct drm_atomic_state pointer
 * @mgr: pointer to the &struct drm_dp_mst_topology_mgr iteration cursor
 * @old_state: optional pointer to the old &struct drm_dp_mst_topology_state
 * iteration cursor
 * @new_state: optional pointer to the new &struct drm_dp_mst_topology_state
 * iteration cursor
 * @i: int iteration cursor, for macro-internal use
 *
 * Used by for_each_oldnew_mst_mgr_in_state(),
 * for_each_old_mst_mgr_in_state(), and for_each_new_mst_mgr_in_state(). Don't
 * call this directly.
 *
 * Returns:
 * True if the current &struct drm_private_obj is a &struct
 * drm_dp_mst_topology_mgr, false otherwise.
 */
static inline bool
__drm_dp_mst_state_iter_get(struct drm_atomic_state *state,
			    struct drm_dp_mst_topology_mgr **mgr,
			    struct drm_dp_mst_topology_state **old_state,
			    struct drm_dp_mst_topology_state **new_state,
			    int i)
{
	struct __drm_private_objs_state *objs_state = &state->private_objs[i];

	if (objs_state->ptr->funcs != &drm_dp_mst_topology_state_funcs)
		return false;

	*mgr = to_dp_mst_topology_mgr(objs_state->ptr);
	if (old_state)
		*old_state = to_dp_mst_topology_state(objs_state->old_state);
	if (new_state)
		*new_state = to_dp_mst_topology_state(objs_state->new_state);

	return true;
}

/**
 * for_each_oldnew_mst_mgr_in_state - iterate over all DP MST topology
 * managers in an atomic update
 * @__state: &struct drm_atomic_state pointer
 * @mgr: &struct drm_dp_mst_topology_mgr iteration cursor
 * @old_state: &struct drm_dp_mst_topology_state iteration cursor for the old
 * state
 * @new_state: &struct drm_dp_mst_topology_state iteration cursor for the new
 * state
 * @__i: int iteration cursor, for macro-internal use
 *
 * This iterates over all DRM DP MST topology managers in an atomic update,
 * tracking both old and new state. This is useful in places where the state
 * delta needs to be considered, for example in atomic check functions.
 */
#define for_each_oldnew_mst_mgr_in_state(__state, mgr, old_state, new_state, __i) \
	for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
		for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), &(old_state), &(new_state), (__i)))

/**
 * for_each_old_mst_mgr_in_state - iterate over all DP MST topology managers
 * in an atomic update
 * @__state: &struct drm_atomic_state pointer
 * @mgr: &struct drm_dp_mst_topology_mgr iteration cursor
 * @old_state: &struct drm_dp_mst_topology_state iteration cursor for the old
 * state
 * @__i: int iteration cursor, for macro-internal use
 *
 * This iterates over all DRM DP MST topology managers in an atomic update,
 * tracking only the old state. This is useful in disable functions, where we
 * need the old state the hardware is still in.
 */
#define for_each_old_mst_mgr_in_state(__state, mgr, old_state, __i) \
	for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
		for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), &(old_state), NULL, (__i)))

/**
 * for_each_new_mst_mgr_in_state - iterate over all DP MST topology managers
 * in an atomic update
 * @__state: &struct drm_atomic_state pointer
 * @mgr: &struct drm_dp_mst_topology_mgr iteration cursor
 * @new_state: &struct drm_dp_mst_topology_state iteration cursor for the new
 * state
 * @__i: int iteration cursor, for macro-internal use
 *
 * This iterates over all DRM DP MST topology managers in an atomic update,
 * tracking only the new state. This is useful in enable functions, where we
 * need the new state the hardware should be in when the atomic commit
 * operation has completed.
 */
#define for_each_new_mst_mgr_in_state(__state, mgr, new_state, __i) \
	for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
		for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), NULL, &(new_state), (__i)))

#endif