text: /*
   * 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/drm_dp_helper.h>
  #include <drm/drm_atomic.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) */
  
  struct drm_dp_mst_branch;
  
  /**
   * struct drm_dp_vcpi - Virtual Channel Payload Identifier
   * @vcpi: Virtual channel ID.
   * @pbn: Payload Bandwidth Number for this channel
   * @aligned_pbn: PBN aligned with slot size
   * @num_slots: number of slots for this PBN
   */
  struct drm_dp_vcpi {
  	int vcpi;
  	int pbn;
  	int aligned_pbn;
  	int num_slots;
  };
  
  /**
   * 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.
   * @parent: branch device parent of this port
   * @vcpi: Virtual Channel Payload info for 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_mst_branch *parent;
  
  	struct drm_dp_vcpi vcpi;
  	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.
  	 */
  	struct edid *cached_edid;
  	/**
  	 * @has_audio: Tracks whether the sink connector to this port is
  	 * audio-capable.
  	 */
  	bool has_audio;
  
  	/**
  	 * @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 DP_MAX_PAYLOAD (sizeof(unsigned long) * 8)
  
  #define DP_PAYLOAD_LOCAL 1
  #define DP_PAYLOAD_REMOTE 2
  #define DP_PAYLOAD_DELETE_LOCAL 3
  
  struct drm_dp_payload {
  	int payload_state;
  	int start_slot;
  	int num_slots;
  	int vcpi;
  };
  
  #define to_dp_mst_topology_state(x) container_of(x, struct drm_dp_mst_topology_state, base)
  
  struct drm_dp_vcpi_allocation {
  	struct drm_dp_mst_port *port;
  	int vcpi;
  	int pbn;
  	bool dsc_enabled;
  	struct list_head next;
  };
  
  struct drm_dp_mst_topology_state {
  	struct drm_private_state base;
  	struct list_head vcpis;
  	struct drm_dp_mst_topology_mgr *mgr;
  	u8 total_avail_slots;
  	u8 start_slot;
  };
  
  #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;
  	/**
  	 * @max_lane_count: maximum number of lanes the GPU can drive.
  	 */
  	int max_lane_count;
  	/**
  	 * @max_link_rate: maximum link rate per lane GPU can output, in kHz.
  	 */
  	int max_link_rate;
  	/**
  	 * @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;
  
  	/**
  	 * @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;
  	/**
  	 * @pbn_div: PBN to slots divisor.
  	 */
  	int pbn_div;
  
  	/**
  	 * @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;
  
  	/**
  	 * @payload_lock: Protect payload information.
  	 */
  	struct mutex payload_lock;
  	/**
  	 * @proposed_vcpis: Array of pointers for the new VCPI allocation. The
  	 * VCPI structure itself is &drm_dp_mst_port.vcpi, and the size of
  	 * this array is determined by @max_payloads.
  	 */
  	struct drm_dp_vcpi **proposed_vcpis;
  	/**
  	 * @payloads: Array of payloads. The size of this array is determined
  	 * by @max_payloads.
  	 */
  	struct drm_dp_payload *payloads;
  	/**
  	 * @payload_mask: Elements of @payloads actually in use. Since
  	 * reallocation of active outputs isn't possible gaps can be created by
  	 * disabling outputs out of order compared to how they've been enabled.
  	 */
  	unsigned long payload_mask;
  	/**
  	 * @vcpi_mask: Similar to @payload_mask, but for @proposed_vcpis.
  	 */
  	unsigned long vcpi_mask;
  
  	/**
  	 * @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 max_lane_count, int max_link_rate,
  				 int conn_base_id);
  
  void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
  
  bool 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(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled);
  
  
  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);
  
  struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
  
  int 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, bool dsc);
  
  bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
  			      struct drm_dp_mst_port *port, int pbn, int slots);
  
  int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
  
  
  void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
  
  void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap);
  
  void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
  				struct drm_dp_mst_port *port);
  
  
  int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
  			   int pbn);
  
  
  int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr, int start_slot);
  
  
  int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr);
  
  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);
  int __must_check
  drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
  			      struct drm_dp_mst_topology_mgr *mgr,
  			      struct drm_dp_mst_port *port, int pbn,
  			      int pbn_div);
  int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
  				 struct drm_dp_mst_port *port,
  				 int pbn, int pbn_div,
  				 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_vcpi_slots(struct drm_atomic_state *state,
  				 struct drm_dp_mst_topology_mgr *mgr,
  				 struct drm_dp_mst_port *port);
  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(struct drm_atomic_state *state);
  
  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);
  
  struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port);
  
  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
  