text: /*
   * Copyright (C) ST-Ericsson AB 2010
   * Author:	Sjur Brendeland / sjur.brandeland@stericsson.com
   * License terms: GNU General Public License (GPL) version 2
   */
  
  #ifndef CAIF_LAYER_H_
  #define CAIF_LAYER_H_
  
  #include <linux/list.h>
  
  struct cflayer;
  struct cfpkt;
  struct cfpktq;
  struct caif_payload_info;
  struct caif_packet_funcs;
  
  #define CAIF_LAYER_NAME_SZ 16
  
  /**
   * caif_assert() - Assert function for CAIF.
   * @assert: expression to evaluate.
   *
   * This function will print a error message and a do WARN_ON if the
   * assertion failes. Normally this will do a stack up at the current location.
   */
  #define caif_assert(assert)					\
  do {								\
  	if (!(assert)) {					\
  		pr_err("caif:Assert detected:'%s'\n", #assert); \
  		WARN_ON(!(assert));				\
  	}							\
  } while (0)
  
  /**
   * enum caif_ctrlcmd - CAIF Stack Control Signaling sent in layer.ctrlcmd().
   *
   * @CAIF_CTRLCMD_FLOW_OFF_IND:		Flow Control is OFF, transmit function
   *					should stop sending data
   *
   * @CAIF_CTRLCMD_FLOW_ON_IND:		Flow Control is ON, transmit function
   *					can start sending data
   *
   * @CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:	Remote end modem has decided to close
   *					down channel
   *
   * @CAIF_CTRLCMD_INIT_RSP:		Called initially when the layer below
   *					has finished initialization
   *
   * @CAIF_CTRLCMD_DEINIT_RSP:		Called when de-initialization is
   *					complete
   *
   * @CAIF_CTRLCMD_INIT_FAIL_RSP:		Called if initialization fails
   *
   * @_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND:	CAIF Link layer temporarily cannot
   *					send more packets.
   * @_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND:	Called if CAIF Link layer is able
   *					to send packets again.
   * @_CAIF_CTRLCMD_PHYIF_DOWN_IND:	Called if CAIF Link layer is going
   *					down.
   *
   * These commands are sent upwards in the CAIF stack to the CAIF Client.
   * They are used for signaling originating from the modem or CAIF Link Layer.
   * These are either responses (*_RSP) or events (*_IND).
   */
  enum caif_ctrlcmd {
  	CAIF_CTRLCMD_FLOW_OFF_IND,
  	CAIF_CTRLCMD_FLOW_ON_IND,
  	CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND,
  	CAIF_CTRLCMD_INIT_RSP,
  	CAIF_CTRLCMD_DEINIT_RSP,
  	CAIF_CTRLCMD_INIT_FAIL_RSP,
  	_CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
  	_CAIF_CTRLCMD_PHYIF_FLOW_ON_IND,
  	_CAIF_CTRLCMD_PHYIF_DOWN_IND,
  };
  
  /**
   * enum caif_modemcmd -	 Modem Control Signaling, sent from CAIF Client
   *			 to the CAIF Link Layer or modem.
   *
   * @CAIF_MODEMCMD_FLOW_ON_REQ:		Flow Control is ON, transmit function
   *					can start sending data.
   *
   * @CAIF_MODEMCMD_FLOW_OFF_REQ:		Flow Control is OFF, transmit function
   *					should stop sending data.
   *
   * @_CAIF_MODEMCMD_PHYIF_USEFULL:	Notify physical layer that it is in use
   *
   * @_CAIF_MODEMCMD_PHYIF_USELESS:	Notify physical layer that it is
   *					no longer in use.
   *
   * These are requests sent 'downwards' in the stack.
   * Flow ON, OFF can be indicated to the modem.
   */
  enum caif_modemcmd {
  	CAIF_MODEMCMD_FLOW_ON_REQ = 0,
  	CAIF_MODEMCMD_FLOW_OFF_REQ = 1,
  	_CAIF_MODEMCMD_PHYIF_USEFULL = 3,
  	_CAIF_MODEMCMD_PHYIF_USELESS = 4
  };
  
  /**
   * enum caif_direction - CAIF Packet Direction.
   * Indicate if a packet is to be sent out or to be received in.
   * @CAIF_DIR_IN:		Incoming packet received.
   * @CAIF_DIR_OUT:		Outgoing packet to be transmitted.
   */
  enum caif_direction {
  	CAIF_DIR_IN = 0,
  	CAIF_DIR_OUT = 1
  };
  
  /**
   * struct cflayer - CAIF Stack layer.
   * Defines the framework for the CAIF Core Stack.
   * @up:		Pointer up to the layer above.
   * @dn:		Pointer down to the layer below.
   * @node:	List node used when layer participate in a list.
   * @receive:	Packet receive function.
   * @transmit:	Packet transmit funciton.
   * @ctrlcmd:	Used for control signalling upwards in the stack.
   * @modemcmd:	Used for control signaling downwards in the stack.
   * @prio:	Priority of this layer.
   * @id:		The identity of this layer
   * @type:	The type of this layer
   * @name:	Name of the layer.
   *
   *  This structure defines the layered structure in CAIF.
   *
   *  It defines CAIF layering structure, used by all CAIF Layers and the
   *  layers interfacing CAIF.
   *
   *  In order to integrate with CAIF an adaptation layer on top of the CAIF stack
   *  and PHY layer below the CAIF stack
   *  must be implemented. These layer must follow the design principles below.
   *
   *  Principles for layering of protocol layers:
   *    - All layers must use this structure. If embedding it, then place this
   *	structure first in the layer specific structure.
   *
   *    - Each layer should not depend on any others layer's private data.
   *
   *    - In order to send data upwards do
   *	layer->up->receive(layer->up, packet);
   *
   *    - In order to send data downwards do
   *	layer->dn->transmit(layer->dn, info, packet);
   */
  struct cflayer {
  	struct cflayer *up;
  	struct cflayer *dn;
  	struct list_head node;
  
  	/*
  	 *  receive() - Receive Function (non-blocking).
  	 *  Contract: Each layer must implement a receive function passing the
  	 *  CAIF packets upwards in the stack.
  	 *	Packet handling rules:
  	 *	      - The CAIF packet (cfpkt) ownership is passed to the
  	 *		called receive function. This means that the the
  	 *		packet cannot be accessed after passing it to the
  	 *		above layer using up->receive().
  	 *
  	 *	      - If parsing of the packet fails, the packet must be
  	 *		destroyed and negative error code returned
  	 *		from the function.
  	 *		EXCEPTION: If the framing layer (cffrml) returns
  	 *			-EILSEQ, the packet is not freed.
  	 *
  	 *	      - If parsing succeeds (and above layers return OK) then
  	 *		      the function must return a value >= 0.
  	 *
  	 *  Returns result < 0 indicates an error, 0 or positive value
  	 *	     indicates success.
  	 *
  	 *  @layr: Pointer to the current layer the receive function is
  	 *		implemented for (this pointer).
  	 *  @cfpkt: Pointer to CaifPacket to be handled.
  	 */
  	int (*receive)(struct cflayer *layr, struct cfpkt *cfpkt);
  
  	/*
  	 *  transmit() - Transmit Function (non-blocking).
  	 *  Contract: Each layer must implement a transmit function passing the
  	 *	CAIF packet downwards in the stack.
  	 *	Packet handling rules:
  	 *	      - The CAIF packet (cfpkt) ownership is passed to the
  	 *		transmit function. This means that the the packet
  	 *		cannot be accessed after passing it to the below
  	 *		layer using dn->transmit().
  	 *
  	 *	      - Upon error the packet ownership is still passed on,
  	 *		so the packet shall be freed where error is detected.
  	 *		Callers of the transmit function shall not free packets,
  	 *		but errors shall be returned.
  	 *
  	 *	      - Return value less than zero means error, zero or
  	 *		greater than zero means OK.
  	 *
  	 *  Returns result < 0 indicates an error, 0 or positive value
  	 *		indicates success.
  	 *
  	 *  @layr:	Pointer to the current layer the receive function
  	 *		isimplemented for (this pointer).
  	 *  @cfpkt:	 Pointer to CaifPacket to be handled.
  	 */
  	int (*transmit) (struct cflayer *layr, struct cfpkt *cfpkt);
  
  	/*
  	 *  cttrlcmd() - Control Function upwards in CAIF Stack  (non-blocking).
  	 *  Used for signaling responses (CAIF_CTRLCMD_*_RSP)
  	 *  and asynchronous events from the modem  (CAIF_CTRLCMD_*_IND)
  	 *
  	 *  @layr:	Pointer to the current layer the receive function
  	 *		is implemented for (this pointer).
  	 *  @ctrl:	Control Command.
  	 */
  	void (*ctrlcmd) (struct cflayer *layr, enum caif_ctrlcmd ctrl,
  			 int phyid);
  
  	/*
  	 *  modemctrl() - Control Function used for controlling the modem.
  	 *  Used to signal down-wards in the CAIF stack.
  	 *  Returns 0 on success, < 0 upon failure.
  	 *
  	 *  @layr:	Pointer to the current layer the receive function
  	 *		is implemented for (this pointer).
  	 *  @ctrl:  Control Command.
  	 */
  	int (*modemcmd) (struct cflayer *layr, enum caif_modemcmd ctrl);
  
  	unsigned short prio;
  	unsigned int id;
  	unsigned int type;
  	char name[CAIF_LAYER_NAME_SZ];
  };
  
  /**
   * layer_set_up() - Set the up pointer for a specified layer.
   *  @layr: Layer where up pointer shall be set.
   *  @above: Layer above.
   */
  #define layer_set_up(layr, above) ((layr)->up = (struct cflayer *)(above))
  
  /**
   *  layer_set_dn() - Set the down pointer for a specified layer.
   *  @layr:  Layer where down pointer shall be set.
   *  @below: Layer below.
   */
  #define layer_set_dn(layr, below) ((layr)->dn = (struct cflayer *)(below))
  
  /**
   * struct dev_info - Physical Device info information about physical layer.
   * @dev:	Pointer to native physical device.
   * @id:		Physical ID of the physical connection used by the
   *		logical CAIF connection. Used by service layers to
   *		identify their physical id to Caif MUX (CFMUXL)so
   *		that the MUX can add the correct physical ID to the
   *		packet.
   */
  struct dev_info {
  	void *dev;
  	unsigned int id;
  };
  
  /**
   * struct caif_payload_info - Payload information embedded in packet (sk_buff).
   *
   * @dev_info:	Information about the receiving device.
   *
   * @hdr_len:	Header length, used to align pay load on 32bit boundary.
   *
   * @channel_id: Channel ID of the logical CAIF connection.
   *		Used by mux to insert channel id into the caif packet.
   */
  struct caif_payload_info {
  	struct dev_info *dev_info;
  	unsigned short hdr_len;
  	unsigned short channel_id;
  };
  
  #endif	/* CAIF_LAYER_H_ */
  