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//==========================================================================

//

//      io/iosys.c

//

//      I/O Subsystem + Device Table support

//

//==========================================================================

// ####ECOSGPLCOPYRIGHTBEGIN####                                            

// -------------------------------------------                              

// This file is part of eCos, the Embedded Configurable Operating System.   

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under    

// the terms of the GNU General Public License as published by the Free     

// Software Foundation; either version 2 or (at your option) any later      

// version.                                                                 

//

// eCos is distributed in the hope that it will be useful, but WITHOUT      

// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or    

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License    

// for more details.                                                        

//

// You should have received a copy of the GNU General Public License        

// along with eCos; if not, write to the Free Software Foundation, Inc.,    

// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.            

//

// As a special exception, if other files instantiate templates or use      

// macros or inline functions from this file, or you compile this file      

// and link it with other works to produce a work based on this file,       

// this file does not by itself cause the resulting work to be covered by   

// the GNU General Public License. However the source code for this file    

// must still be made available in accordance with section (3) of the GNU   

// General Public License v2.                                               

//

// This exception does not invalidate any other reasons why a work based    

// on this file might be covered by the GNU General Public License.         

// -------------------------------------------                              

// ####ECOSGPLCOPYRIGHTEND####                                              

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   gthomas

// Contributors:  gthomas

// Date:        1999-02-04

// Purpose:     Device I/O Support

// Description: 

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include <pkgconf/io.h>

#include <cyg/io/io.h>

#include <cyg/io/devtab.h>

#include <cyg/infra/diag.h>

//extern void cyg_io_init(void) CYGBLD_ATTRIB_CONSTRUCTOR

//  CYG_INIT_PRIORITY(CYG_INIT_BEFORE(LIBC));

// Checks that two strings are "equivalent" device names

// 'n1' is a string from the user

// 'n2' is a name in a device table entry

// 'cyg_io_compare()' will return true IFF

//    n1 == n2, for all characters

//    n2 ends in '/' and matches n1 up to the terminating '/'

// 'ptr' will get a pointer to the residual string.

static bool

cyg_io_compare(const char *n1, const char *n2, const char **ptr)

{

    while (*n1 && *n2) {

        if (*n1++ != *n2++) {

            return false;

        }

    }

    if (*n1) {

        // See if the devtab name is is a substring

        if (*(n2-1) == '/') {

            *ptr = n1;

            return true;

        }

    }

    if (*n1 || *n2) {

        return false;

    }

    *ptr = n1;

    return true;

}

//

// This function is called during system initialization.  The purpose is

// to step through all devices linked into the system, calling their

// "init" entry points.  

//

void

cyg_io_init(void)

{

    static int _init = false;

    cyg_devtab_entry_t *t;

    if (_init) return;

    for (t = &__DEVTAB__[0]; t != &__DEVTAB_END__; t++) {

#ifdef CYGDBG_IO_INIT

        diag_printf("Init device '%s'\n", t->name);

#endif

        if (t->init(t)) {

            t->status |= CYG_DEVTAB_STATUS_AVAIL;

        } else {

            // What to do if device init fails?

            // Device not [currently] available

            t->status &= ~CYG_DEVTAB_STATUS_AVAIL;

        }

    }

    _init = true;

}

//

// Look up the devtab entry for a named device and return its handle.

// If the device is found and it has a "lookup" function, call that

// function to allow the device/driver to perform any necessary

// initializations.

//

Cyg_ErrNo

cyg_io_lookup(const char *name, cyg_io_handle_t *handle)

{

    union devtab_entry_handle_union {

        cyg_devtab_entry_t *st;

        cyg_io_handle_t h;

    } stunion;

    cyg_devtab_entry_t *t;

    Cyg_ErrNo res;

    const char *name_ptr;

    for (t = &__DEVTAB__[0]; t != &__DEVTAB_END__; t++) {

        if (cyg_io_compare(name, t->name, &name_ptr)) {

            // FUTURE: Check 'avail'/'online' here

            if (t->dep_name) {

                res = cyg_io_lookup(t->dep_name, &stunion.h);

                if (res != ENOERR) {

                    return res;

                }

            } else {

                stunion.st = NULL;

            }

            if (t->lookup) {

                // This indirection + the name pointer allows the lookup routine

                // to return a different 'devtab' handle.  This will provide for

                // 'pluggable' devices, file names, etc.

                res = (t->lookup)(&t, stunion.st, name_ptr);

                if (res != ENOERR) {

                    return res;

                }

            }

            *handle = (cyg_io_handle_t)t;

            return ENOERR;

        }

    }

    return -ENOENT;  // Not found

}

//

// 'write' data to a device.

//

Cyg_ErrNo

cyg_io_write(cyg_io_handle_t handle, const void *buf, cyg_uint32 *len)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    // Validate request

    if (!t->handlers->write) {

        return -EDEVNOSUPP;

    }

    // Special check.  If length is zero, this just verifies that the 

    // 'write' method exists for the given device.

    if (NULL != len && 0 == *len) {

        return ENOERR;

    }

    return t->handlers->write(handle, buf, len);

}

//

// 'read' data from a device.

//

Cyg_ErrNo

cyg_io_read(cyg_io_handle_t handle, void *buf, cyg_uint32 *len)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    // Validate request

    if (!t->handlers->read) {

        return -EDEVNOSUPP;

    }

    // Special check.  If length is zero, this just verifies that the 

    // 'read' method exists for the given device.

    if (NULL != len && 0 == *len) {

        return ENOERR;

    }

    return t->handlers->read(handle, buf, len);

}

//

// 'write' blocks to a device. The len and the position are in terms

// of blocks, not bytes like the cyg_io_write.

//

Cyg_ErrNo

cyg_io_bwrite(cyg_io_handle_t handle, const void *buf, cyg_uint32 *len, cyg_uint32 pos)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    // Validate request

    if (!t->handlers->bwrite) {

        return -EDEVNOSUPP;

    }

    // Special check.  If length is zero, this just verifies that the 

    // 'bwrite' method exists for the given device.

    if (NULL != len && 0 == *len) {

        return ENOERR;

    }

    return t->handlers->bwrite(handle, buf, len, pos);

}

//

// 'read' blocks from a device. The len and the position are in terms of

// blocks, not bytes like the cyg_io_read.

//

Cyg_ErrNo

cyg_io_bread(cyg_io_handle_t handle, void *buf, cyg_uint32 *len, cyg_uint32 pos)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    // Validate request

    if (!t->handlers->bread) {

        return -EDEVNOSUPP;

    }

    // Special check.  If length is zero, this just verifies that the 

    // 'bread' method exists for the given device.

    if (NULL != len && 0 == *len) {

        return ENOERR;

    }

    return t->handlers->bread(handle, buf, len, pos);

}

//

// Check device for available input or space for output

//

cyg_bool

cyg_io_select(cyg_io_handle_t handle, cyg_uint32 which, CYG_ADDRWORD info)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    // Validate request

    if (!t->handlers->select) {

        return -EDEVNOSUPP;

    }

    return t->handlers->select( handle, which, info );

}

//

// Get the configuration of a device.

//

Cyg_ErrNo

cyg_io_get_config(cyg_io_handle_t handle, cyg_uint32 key, void *buf, cyg_uint32 *len)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    // Validate request

    if (!t->handlers->get_config) {

        return -EDEVNOSUPP;

    }

    // Special check.  If length is zero, this just verifies that the 

    // 'get_config' method exists for the given device.

    if (NULL != len && 0 == *len) {

        return ENOERR;

    }

    return t->handlers->get_config(handle, key, buf, len);

}

//

// Change the configuration of a device.

//

Cyg_ErrNo

cyg_io_set_config(cyg_io_handle_t handle, cyg_uint32 key, const void *buf, cyg_uint32 *len)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    // Validate request

    if (!t->handlers->set_config) {

        return -EDEVNOSUPP;

    }

    // Special check.  If length is zero, this just verifies that the 

    // 'set_config' method exists for the given device.

    if (NULL != len && 0 == *len) {

        return ENOERR;

    }

    return t->handlers->set_config(handle, key, buf, len);

}

/*---------------------------------------------------------------------------*/

// Default functions for devio tables

Cyg_ErrNo cyg_devio_cwrite(cyg_io_handle_t handle, const void *buf, cyg_uint32 *len)

{

    return -EDEVNOSUPP;

}

Cyg_ErrNo cyg_devio_cread(cyg_io_handle_t handle, void *buf, cyg_uint32 *len)

{

    return -EDEVNOSUPP;

}

Cyg_ErrNo cyg_devio_bwrite(cyg_io_handle_t handle, const void *buf,

                        cyg_uint32 *len, cyg_uint32 pos)

{

    return -EDEVNOSUPP;

}

Cyg_ErrNo cyg_devio_bread(cyg_io_handle_t handle, void *buf,

                       cyg_uint32 *len, cyg_uint32 pos)

{

    return -EDEVNOSUPP;

}

Cyg_ErrNo

cyg_devio_select(cyg_io_handle_t handle, cyg_uint32 which, CYG_ADDRWORD info)

{

    CYG_UNUSED_PARAM(cyg_io_handle_t, handle);

    CYG_UNUSED_PARAM(cyg_uint32, which);

    CYG_UNUSED_PARAM(CYG_ADDRWORD, info);

    return -EDEVNOSUPP;

}

Cyg_ErrNo

cyg_devio_get_config(cyg_io_handle_t handle, cyg_uint32 key,

                     void* buf, cyg_uint32* len)

{

    CYG_UNUSED_PARAM(cyg_io_handle_t, handle);

    CYG_UNUSED_PARAM(cyg_uint32, key);

    CYG_UNUSED_PARAM(void*, buf);

    CYG_UNUSED_PARAM(cyg_uint32*, len);

    return -EDEVNOSUPP;

}

Cyg_ErrNo

cyg_devio_set_config(cyg_io_handle_t handle, cyg_uint32 key,

                     void* buf, cyg_uint32* len)

{

    CYG_UNUSED_PARAM(cyg_io_handle_t, handle);

    CYG_UNUSED_PARAM(cyg_uint32, key);

    CYG_UNUSED_PARAM(void*, buf);

    CYG_UNUSED_PARAM(cyg_uint32*, len);

    return -EDEVNOSUPP;

}

/*---------------------------------------------------------------------------*/

/* End of io/iosys.c */