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/*

 * 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        4

/** 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)

/** This call will not be freed on error */

#define IPC_CALL_STATIC_ALLOC   (1 << 1)

/** Answer will not be passed to userspace, will be discarded */

#define IPC_CALL_DISCARD_ANSWER (1 << 2)

/** Call was forwarded */

#define IPC_CALL_FORWARDED  (1 << 3)

/** Identify connect_me_to answer */

#define IPC_CALL_CONN_ME_TO (1 << 4)

/** Interrupt notification */

#define IPC_CALL_NOTIF      (1 << 5)

/*

 * 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_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])

/* Well known phone descriptors */

#define PHONE_NS    0

/* System-specific methods - only through special syscalls

 * These methods have special behaviour

 */

/** 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

 * - sys_wait_for_call - 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 ARG3 of the call.

 *                     - the caller obtains taskid of the called thread

 */

#define IPC_M_CONNECT_TO_ME 1

/** 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 are user specified, arg3 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. Forwarding

 *                        system message

 *

 */

#define IPC_M_CONNECT_ME_TO 2

/** This message is sent to answerbox when the phone

 * is hung up

 */

#define IPC_M_PHONE_HUNGUP  3

/** 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_AS_AREA_SEND  4   

/** 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_AS_AREA_RECV  5   

/** Send data to another address space over IPC.

 * - ARG1 - destination address space virtual address, may be overriden by the

 *      recipient

 * - ARG2 - source address space virtual address

 * - ARG3 - 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

 * - ARG3 - final size of data to be copied

 */

#define IPC_M_DATA_SEND     6

/* Well-known methods */

#define IPC_M_LAST_SYSTEM   511

#define IPC_M_PING      512

/* User methods */

#define FIRST_USER_METHOD   1024

#ifdef KERNEL

#define IPC_MAX_PHONES  16

#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 {

    SPINLOCK_DECLARE(lock);

    link_t link;

    struct answerbox *callee;

    ipc_phone_state_t state;

    atomic_t active_calls;

} phone_t;

typedef struct answerbox {

    SPINLOCK_DECLARE(lock);

    struct task *task;

    waitq_t wq;

    /** 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;

    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;

    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_SEND. */

    uint8_t *buffer;

} call_t;

extern void ipc_init(void);

extern call_t * ipc_wait_for_call(answerbox_t *box, uint32_t usec, int flags);

extern void ipc_answer(answerbox_t *box, call_t *request);

extern int ipc_call(phone_t *phone, call_t *call);

extern void ipc_call_sync(phone_t *phone, call_t *request);

extern void ipc_phone_init(phone_t *phone);

extern void ipc_phone_connect(phone_t *phone, answerbox_t *box);

extern void ipc_call_free(call_t *call);

extern call_t * ipc_call_alloc(int flags);

extern void ipc_answerbox_init(answerbox_t *box);

extern void ipc_call_static_init(call_t *call);

extern void task_print_list(void);

extern int ipc_forward(call_t *call, phone_t *newphone, answerbox_t *oldbox);

extern void ipc_cleanup(void);

extern int ipc_phone_hangup(phone_t *phone);

extern void ipc_backsend_err(phone_t *phone, call_t *call, unative_t err);

extern void ipc_print_task(task_id_t taskid);

extern answerbox_t *ipc_phone_0;

#endif

#endif

/** @}

 */