/*
 * remote_buf.c Remotely accessible, circular buffer implementation.
 *
 * Authors : Alain Greiner  (2016,2017,2018,2019,2020)
 *
 * Copyright (c) UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-MKH.
 *
 * ALMOS-MKH 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; version 2.0 of the License.
 *
 * ALMOS-MKH 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 ALMOS-MKH; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <hal_kernel_types.h>
#include <hal_irqmask.h>
#include <hal_remote.h>
#include <hal_uspace.h>
#include <bits.h>
#include <memcpy.h>
#include <kmem.h>
#include <remote_buf.h>

/////////////////////////////////////////
error_t remote_buf_init( xptr_t   buf_xp,
                         uint32_t size )
{
    kmem_req_t     req;
    uint8_t      * data;

    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    // allocate the data buffer
    if( size == 0 )
    {
        data = NULL;
    }
    else if( size >= CONFIG_PPM_PAGE_SIZE )
    {
        req.type  = KMEM_PPM;
        req.order = bits_log2( size >> CONFIG_PPM_PAGE_SHIFT );
        req.flags = AF_NONE;
        data = kmem_remote_alloc( buf_cxy , &req );

        if( data == NULL )  return -1;
    }
    else
    {
        req.type  = KMEM_KCM;
        req.order = bits_log2( size );
        req.flags = AF_NONE;
        data = kmem_remote_alloc( buf_cxy , &req );

        if( data == NULL )  return -1;
    }

    // initialize buffer descriptor
    hal_remote_s32( XPTR( buf_cxy , &buf_ptr->size ) , size );
    hal_remote_s32( XPTR( buf_cxy , &buf_ptr->ptw  ) , 0 );
    hal_remote_s32( XPTR( buf_cxy , &buf_ptr->ptr  ) , 0 );
    hal_remote_s32( XPTR( buf_cxy , &buf_ptr->sts  ) , 0 );
    hal_remote_spt( XPTR( buf_cxy , &buf_ptr->data ) , data );

    return 0;

}  // end remote_buf_init()

/////////////////////////////////////////
void remote_buf_destroy( xptr_t  buf_xp )
{
    kmem_req_t   req;

    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    uint32_t size = hal_remote_l32( XPTR( buf_cxy , &buf_ptr->size ));

    // release memory allocated to data buffer if required
    if( size == 0 )
    {
        return;
    }
    else if( size >= CONFIG_PPM_PAGE_SIZE )
    {
        req.type  = KMEM_PPM;
        req.ptr   = hal_remote_lpt( XPTR( buf_cxy , &buf_ptr->data ) );
        kmem_remote_free( buf_cxy , &req );
    }
    else
    {
        req.type  = KMEM_KCM;
        req.ptr   = hal_remote_lpt( XPTR( buf_cxy , &buf_ptr->data ) );
        kmem_remote_free( buf_cxy , &req );
    }
}

/////////////////////////////////////////
void remote_buf_reset( xptr_t    buf_xp )
{
    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    hal_remote_s32( XPTR( buf_cxy , &buf_ptr->ptw ) , 0 );
    hal_remote_s32( XPTR( buf_cxy , &buf_ptr->ptr ) , 0 );
    hal_remote_s32( XPTR( buf_cxy , &buf_ptr->sts ) , 0 );
}

/////////////////////////////////////////////////
error_t remote_buf_get_to_user( xptr_t    buf_xp,
                                uint8_t * u_buf, 
                                uint32_t  nbytes )
{
    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    // build relevant extended pointers
    xptr_t sts_xp  = XPTR( buf_cxy , &buf_ptr->sts );
    xptr_t ptr_xp  = XPTR( buf_cxy , &buf_ptr->ptr );
    xptr_t size_xp = XPTR( buf_cxy , &buf_ptr->size );
    xptr_t data_xp = XPTR( buf_cxy , &buf_ptr->data );

    // get relevant infos from remote buffer descriptor
    uint32_t  sts  = hal_remote_l32( sts_xp );
    uint32_t  ptr  = hal_remote_l32( ptr_xp );
    uint32_t  size = hal_remote_l32( size_xp );
    uint8_t * data = hal_remote_lpt( data_xp );

    // check enough bytes in buffer
    if( nbytes > sts ) return -1;

    // move nbytes 
    if( (ptr + nbytes) <= size)  // no wrap around => one move
    {
        hal_copy_to_uspace( u_buf,
                            XPTR( buf_cxy , data + ptr ),
                            nbytes );
    }
    else                         // wrap around => two moves
    {
        uint32_t bytes_1 = size - ptr;
        uint32_t bytes_2 = nbytes - bytes_1;
     
        hal_copy_to_uspace( u_buf,
                            XPTR( buf_cxy , data + ptr ),
                            bytes_1 );

        hal_copy_to_uspace( u_buf + bytes_1,
                            XPTR( buf_cxy , data ),
                            bytes_2 );
    }

    // update ptr in buffer descriptor
    hal_remote_s32( ptr_xp , (ptr + nbytes) % size );

    // atomically update sts
    hal_remote_atomic_add( sts_xp , -nbytes );

    return 0;

}  // end remote_buf_get_to_user()

///////////////////////////////////////////////////
error_t remote_buf_get_to_kernel( xptr_t    buf_xp,
                                  uint8_t * k_buf,
                                  uint32_t  nbytes )
{
    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    // build relevant extended pointers
    xptr_t sts_xp  = XPTR( buf_cxy , &buf_ptr->sts );
    xptr_t ptr_xp  = XPTR( buf_cxy , &buf_ptr->ptr );
    xptr_t size_xp = XPTR( buf_cxy , &buf_ptr->size );
    xptr_t data_xp = XPTR( buf_cxy , &buf_ptr->data );

    // get relevant infos from remote buffer descriptor
    uint32_t  sts  = hal_remote_l32( sts_xp );
    uint32_t  ptr  = hal_remote_l32( ptr_xp );
    uint32_t  size = hal_remote_l32( size_xp );
    uint8_t * data = hal_remote_lpt( data_xp );

    // check enough bytes in buffer
    if( nbytes > sts ) return -1;

    // move nbytes 
    if( (ptr + nbytes) <= size)  // no wrap around => one move
    {
        hal_remote_memcpy( XPTR( local_cxy , k_buf ),
                           XPTR( buf_cxy   , data + ptr ),
                           nbytes );
    }
    else                         // wrap around => two moves
    {
        uint32_t bytes_1 = size - ptr;
        uint32_t bytes_2 = nbytes - bytes_1;
     
        hal_remote_memcpy( XPTR( local_cxy , k_buf ),
                           XPTR( buf_cxy   , data + ptr ),
                           bytes_1 );

        hal_remote_memcpy( XPTR( local_cxy , k_buf + bytes_1 ),
                           XPTR( buf_cxy   , data ),
                           bytes_2 );
    }

    // update ptr in buffer descriptor
    hal_remote_s32( ptr_xp , (ptr + nbytes) % size );

    // atomically update sts
    hal_remote_atomic_add( sts_xp , -nbytes );

    return 0;

}  // end remote_buf_get_to_user()

///////////////////////////////////////////////////
error_t remote_buf_put_from_user( xptr_t    buf_xp,
                                  uint8_t * u_buf,
                                  uint32_t  nbytes )
{
    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    // build relevant extended pointers
    xptr_t sts_xp  = XPTR( buf_cxy , &buf_ptr->sts );
    xptr_t ptw_xp  = XPTR( buf_cxy , &buf_ptr->ptw );
    xptr_t size_xp = XPTR( buf_cxy , &buf_ptr->size );
    xptr_t data_xp = XPTR( buf_cxy , &buf_ptr->data );

    // get relevant infos from remote buffer descriptor
    uint32_t  sts  = hal_remote_l32( sts_xp );
    uint32_t  ptw  = hal_remote_l32( ptw_xp );
    uint32_t  size = hal_remote_l32( size_xp );
    uint8_t * data = hal_remote_lpt( data_xp );

    // check enough space in buffer
    if( nbytes > (size - sts) ) return -1;

    // move nbytes 
    if( (ptw + nbytes) <= size)  // no wrap around => one move
    {
        hal_copy_from_uspace( XPTR( buf_cxy , data + ptw ),
                              u_buf,
                              nbytes );
    }
    else                         // wrap around => two moves
    {
        uint32_t bytes_1 = size - ptw;
        uint32_t bytes_2 = nbytes - bytes_1;
     
        hal_copy_from_uspace( XPTR( buf_cxy , data + ptw ),
                              u_buf,
                              bytes_1 );

        hal_copy_from_uspace( XPTR( buf_cxy , data ),
                              u_buf + bytes_1,
                              bytes_2 );
    }

    // update ptw in buffer descriptor
    hal_remote_s32( ptw_xp , (ptw + nbytes) % size );

    // atomically update sts
    hal_remote_atomic_add( sts_xp , nbytes );

    return 0;

}  // end remote_buf_put_from_user()

/////////////////////////////////////////////////////
error_t remote_buf_put_from_kernel( xptr_t    buf_xp,
                                    uint8_t * k_buf, 
                                    uint32_t  nbytes )
{
    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    // build relevant extended pointers
    xptr_t sts_xp  = XPTR( buf_cxy , &buf_ptr->sts );
    xptr_t ptw_xp  = XPTR( buf_cxy , &buf_ptr->ptw );
    xptr_t size_xp = XPTR( buf_cxy , &buf_ptr->size );
    xptr_t data_xp = XPTR( buf_cxy , &buf_ptr->data );

    // get relevant infos from remote buffer descriptor
    uint32_t  sts  = hal_remote_l32( sts_xp );
    uint32_t  ptw  = hal_remote_l32( ptw_xp );
    uint32_t  size = hal_remote_l32( size_xp );
    uint8_t * data = hal_remote_lpt( data_xp );

    // check enough space in buffer
    if( nbytes > (size - sts) ) return -1;

    // move nbytes 
    if( (ptw + nbytes) <= size)  // no wrap around => one move
    {
        hal_remote_memcpy( XPTR( buf_cxy   , data + ptw ),
                           XPTR( local_cxy , k_buf ),
                           nbytes );
    }
    else                         // wrap around => two moves
    {
        uint32_t bytes_1 = size - ptw;
        uint32_t bytes_2 = nbytes - bytes_1;
     
        hal_remote_memcpy( XPTR( buf_cxy   , data + ptw ),
                           XPTR( local_cxy , k_buf ),
                           bytes_1 );

        hal_remote_memcpy( XPTR( buf_cxy   , data ),
                           XPTR( local_cxy , k_buf + bytes_1 ),
                           bytes_2 );
    }

    // update ptw in buffer descriptor
    hal_remote_s32( ptw_xp , (ptw + nbytes) % size );

    // atomically update sts
    hal_remote_atomic_add( sts_xp , nbytes );

    return 0;

}  // end remote_buf_put_from_kernel()

////////////////////////////////////////////
uint32_t remote_buf_status( xptr_t  buf_xp )
{
    remote_buf_t * buf_ptr = GET_PTR( buf_xp );
    cxy_t          buf_cxy = GET_CXY( buf_xp );

    return hal_remote_l32( XPTR( buf_cxy , &buf_ptr->sts ) );
    
}  // end remote_buf_status()


