/*
 * Copyright (c) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup genericipc
 * @{
 */
/** @file
 */

#ifndef KERN_IPC_H_
#define KERN_IPC_H_

/** Length of data being transfered with IPC call
 *
 * The uspace may not be able to utilize full length
 *
 */
#define IPC_CALL_LEN  6

/** Maximum active async calls per thread */
#ifdef CONFIG_DEBUG
	#define IPC_MAX_ASYNC_CALLS  4
#else
	#define IPC_MAX_ASYNC_CALLS  4000
#endif

/* Flags for calls */

/** This is answer to a call */
#define IPC_CALL_ANSWERED  (1 << 0)

/** Answer will not be passed to userspace, will be discarded */
#define IPC_CALL_DISCARD_ANSWER  (1 << 1)

/** Call was forwarded */
#define IPC_CALL_FORWARDED  (1 << 2)

/** Identify connect_me_to answer */
#define IPC_CALL_CONN_ME_TO  (1 << 3)

/** Interrupt notification */
#define IPC_CALL_NOTIF  (1 << 4)


/** Bits used in call hashes.
 *
 * The addresses are aligned at least to 4 that is why we can use the 2 least
 * significant bits of the call address.
 *
 */

/** Type of this call is 'answer' */
#define IPC_CALLID_ANSWERED  1

/** Type of this call is 'notification' */
#define IPC_CALLID_NOTIFICATION  2

/* Return values from sys_ipc_call_async(). */
#define IPC_CALLRET_FATAL      -1
#define IPC_CALLRET_TEMPORARY  -2


/* Macros for manipulating calling data */
#define IPC_SET_RETVAL(data, retval)  ((data).args[0] = (retval))
#define IPC_SET_METHOD(data, val)     ((data).args[0] = (val))
#define IPC_SET_ARG1(data, val)       ((data).args[1] = (val))
#define IPC_SET_ARG2(data, val)       ((data).args[2] = (val))
#define IPC_SET_ARG3(data, val)       ((data).args[3] = (val))
#define IPC_SET_ARG4(data, val)       ((data).args[4] = (val))
#define IPC_SET_ARG5(data, val)       ((data).args[5] = (val))

#define IPC_GET_METHOD(data)  ((data).args[0])
#define IPC_GET_RETVAL(data)  ((data).args[0])

#define IPC_GET_ARG1(data)  ((data).args[1])
#define IPC_GET_ARG2(data)  ((data).args[2])
#define IPC_GET_ARG3(data)  ((data).args[3])
#define IPC_GET_ARG4(data)  ((data).args[4])
#define IPC_GET_ARG5(data)  ((data).args[5])

/* Well known phone descriptors */
#define PHONE_NS  0

/* Forwarding flags. */
#define IPC_FF_NONE  0

/**
 * The call will be routed as though it was initially sent via the phone used to
 * forward it. This feature is intended to support the situation in which the
 * forwarded call needs to be handled by the same connection fibril as any other
 * calls that were initially sent by the forwarder to the same destination. This
 * flag has no imapct on routing replies.
 *
 */
#define IPC_FF_ROUTE_FROM_ME  (1 << 0)

/** System-specific methods - only through special syscalls
 * These methods have special behaviour
 *
 */

/** Clone connection.
 *
 * The calling task clones one of its phones for the callee.
 *
 * - ARG1 - The caller sets ARG1 to the phone of the cloned connection.
 *        - The callee gets the new phone from ARG1.
 *
 * - on answer, the callee acknowledges the new connection by sending EOK back
 *   or the kernel closes it
 *
 */
#define IPC_M_CONNECTION_CLONE  1

/** Protocol for CONNECT - ME
 *
 * Through this call, the recipient learns about the new cloned connection. 
 *
 * - ARG5 - the kernel sets ARG5 to contain the hash of the used phone
 * - on asnwer, the callee acknowledges the new connection by sending EOK back
 *   or the kernel closes it
 *
 */
#define IPC_M_CONNECT_ME  2

/** Protocol for CONNECT - TO - ME
 *
 * Calling process asks the callee to create a callback connection,
 * so that it can start initiating new messages.
 *
 * The protocol for negotiating is:
 * - sys_connect_to_me - sends a message IPC_M_CONNECT_TO_ME
 * - recipient         - upon receipt tries to allocate new phone
 *                       - if it fails, responds with ELIMIT
 *                     - passes call to userspace. If userspace
 *                       responds with error, phone is deallocated and
 *                       error is sent back to caller. Otherwise 
 *                       the call is accepted and the response is sent back.
 *                     - the allocated phoneid is passed to userspace 
 *                       (on the receiving side) as ARG5 of the call.
 *
 */
#define IPC_M_CONNECT_TO_ME  3

/** Protocol for CONNECT - ME - TO
 *
 * Calling process asks the callee to create for him a new connection.
 * E.g. the caller wants a name server to connect him to print server.
 *
 * The protocol for negotiating is:
 * - sys_connect_me_to - send a synchronous message to name server
 *                       indicating that it wants to be connected to some
 *                       service
 *                     - arg1/2/3 are user specified, arg5 contains
 *                       address of the phone that should be connected
 *                       (TODO: it leaks to userspace)
 *  - recipient        -  if ipc_answer == 0, then accept connection
 *                     -  otherwise connection refused
 *                     -  recepient may forward message.
 *
 */
#define IPC_M_CONNECT_ME_TO  4

/** This message is sent to answerbox when the phone is hung up
 *
 */
#define IPC_M_PHONE_HUNGUP  5

/** Send as_area over IPC.
 * - ARG1 - source as_area base address
 * - ARG2 - size of source as_area (filled automatically by kernel)
 * - ARG3 - flags of the as_area being sent
 *
 * on answer, the recipient must set:
 * - ARG1 - dst as_area base adress
 *
 */
#define IPC_M_SHARE_OUT  6

/** Receive as_area over IPC.
 * - ARG1 - destination as_area base address
 * - ARG2 - destination as_area size
 * - ARG3 - user defined argument
 *
 * on answer, the recipient must set:
 *
 * - ARG1 - source as_area base address
 * - ARG2 - flags that will be used for sharing
 *
 */
#define IPC_M_SHARE_IN  7

/** Send data to another address space over IPC.
 * - ARG1 - source address space virtual address
 * - ARG2 - size of data to be copied, may be overriden by the recipient
 *
 * on answer, the recipient must set:
 *
 * - ARG1 - final destination address space virtual address
 * - ARG2 - final size of data to be copied
 *
 */
#define IPC_M_DATA_WRITE  8

/** Receive data from another address space over IPC.
 * - ARG1 - destination virtual address in the source address space
 * - ARG2 - size of data to be received, may be cropped by the recipient 
 *
 * on answer, the recipient must set:
 *
 * - ARG1 - source virtual address in the destination address space
 * - ARG2 - final size of data to be copied
 *
 */
#define IPC_M_DATA_READ  9

/** Debug the recipient.
 * - ARG1 - specifies the debug method (from udebug_method_t)
 * - other arguments are specific to the debug method
 *
 */
#define IPC_M_DEBUG_ALL  10

/* Well-known methods */
#define IPC_M_LAST_SYSTEM  511
#define IPC_M_PING         512

/* User methods */
#define IPC_FIRST_USER_METHOD  1024

#ifdef KERNEL

#define IPC_MAX_PHONES  32

#include <synch/spinlock.h>
#include <synch/mutex.h>
#include <synch/waitq.h>

struct answerbox;
struct task;

typedef enum {
	/** Phone is free and can be allocated */
	IPC_PHONE_FREE = 0,
	/** Phone is connecting somewhere */
	IPC_PHONE_CONNECTING,
	/** Phone is connected */
	IPC_PHONE_CONNECTED,
	/** Phone is hung up, waiting for answers to come */
	IPC_PHONE_HUNGUP,
	/** Phone was hungup from server */
	IPC_PHONE_SLAMMED
} ipc_phone_state_t;

/** Structure identifying phone (in TASK structure) */
typedef struct {
	mutex_t lock;
	link_t link;
	struct answerbox *callee;
	ipc_phone_state_t state;
	atomic_t active_calls;
} phone_t;

typedef struct answerbox {
	IRQ_SPINLOCK_DECLARE(lock);
	
	struct task *task;
	
	waitq_t wq;
	
	/** Linkage for the list of task's synchronous answerboxes. */
	link_t sync_box_link;
	
	/** Phones connected to this answerbox. */
	link_t connected_phones;
	/** Received calls. */
	link_t calls;
	link_t dispatched_calls;  /* Should be hash table in the future */
	
	/** Answered calls. */
	link_t answers;
	
	IRQ_SPINLOCK_DECLARE(irq_lock);
	
	/** Notifications from IRQ handlers. */
	link_t irq_notifs;
	/** IRQs with notifications to this answerbox. */
	link_t irq_head;
} answerbox_t;

typedef struct {
	unative_t args[IPC_CALL_LEN];
	phone_t *phone;
} ipc_data_t;

typedef struct {
	link_t link;
	
	unsigned int flags;
	
	/** Identification of the caller. */
	struct task *sender;
	
	/*
	 * The caller box is different from sender->answerbox
	 * for synchronous calls.
	 *
	 */
	answerbox_t *callerbox;
	
	/** Private data to internal IPC. */
	unative_t priv;
	
	/** Data passed from/to userspace. */
	ipc_data_t data;
	
	/** Buffer for IPC_M_DATA_WRITE and IPC_M_DATA_READ. */
	uint8_t *buffer;
	
	/*
	 * The forward operation can masquerade the caller phone. For those
	 * cases, we must keep it aside so that the answer is processed
	 * correctly.
	 *
	 */
	phone_t *caller_phone;
} call_t;

extern answerbox_t *ipc_phone_0;

extern void ipc_init(void);

extern call_t *ipc_call_alloc(unsigned int);
extern void ipc_call_free(call_t *);

extern int ipc_call(phone_t *, call_t *);
extern int ipc_call_sync(phone_t *, call_t *);
extern call_t * ipc_wait_for_call(answerbox_t *, uint32_t, unsigned int);
extern int ipc_forward(call_t *, phone_t *, answerbox_t *, unsigned int);
extern void ipc_answer(answerbox_t *, call_t *);

extern void ipc_phone_init(phone_t *);
extern void ipc_phone_connect(phone_t *, answerbox_t *);
extern int ipc_phone_hangup(phone_t *);

extern void ipc_answerbox_init(answerbox_t *, struct task *);

extern void ipc_cleanup(void);
extern void ipc_backsend_err(phone_t *, call_t *, unative_t);
extern void ipc_answerbox_slam_phones(answerbox_t *, bool);
extern void ipc_cleanup_call_list(link_t *);

extern void ipc_print_task(task_id_t);

#endif /* KERNEL */

#endif

/** @}
 */