source: trunk/kernel/kern/kernel_init.c @ 113

/*
 * kernel_init.c - kernel parallel initialization
 * 
 * Authors :  Mohamed Lamine Karaoui (2015)
 *            Alain Greiner  (2016,2017)
 *
 * Copyright (c) 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 <kernel_config.h>
#include <errno.h>
#include <hal_types.h>
#include <hal_special.h>
#include <hal_context.h>
#include <barrier.h>
#include <remote_barrier.h>
#include <core.h>
#include <list.h>
#include <xlist.h>
#include <thread.h>
#include <scheduler.h>
#include <kmem.h>
#include <cluster.h>
#include <string.h>
#include <memcpy.h>
#include <ppm.h>
#include <page.h>
#include <chdev.h>
#include <boot_info.h>
#include <dqdt.h>
#include <dev_icu.h>
#include <dev_mmc.h>
#include <dev_dma.h>
#include <dev_iob.h>
#include <dev_ioc.h>
#include <dev_txt.h>
#include <dev_pic.h>
#include <printk.h>
#include <vfs.h>
#include <hal_drivers.h>
#include <devfs.h>
#include <mapper.h>
#include <soclib_tty.h>

#define KERNEL_INIT_SYNCHRO  0xA5A5B5B5

///////////////////////////////////////////////////////////////////////////////////////////
// All these global variables are replicated in all clusters.
// They are initialised by the kernel_init() function.
//
// WARNING : The section names have been defined to control the base addresses of the 
// boot_info structure and the idle thread descriptors, through the kernel.ld script:
// - the boot_info structure is build by the bootloader, and used by kernel_init.
//   it must be first object in the kdata segment.
// - the array of idle threads descriptors must be placed on the first page boundary after
//   the boot_info structure in the kdata segment.
///////////////////////////////////////////////////////////////////////////////////////////

// This variable defines the local boot_info structure
__attribute__((section(".kinfo")))
boot_info_t          boot_info;

// This variable defines the "idle" threads descriptors array
__attribute__((section(".kidle")))
char                  idle_threads[CONFIG_THREAD_DESC_SIZE *
                                   CONFIG_MAX_LOCAL_CORES]   CONFIG_PPM_PAGE_ALIGNED;

// This variable defines the local cluster manager 
__attribute__((section(".kdata")))
cluster_t            cluster_manager                         CONFIG_CACHE_LINE_ALIGNED;

// This variables define the kernel process0 descriptor
__attribute__((section(".kdata")))
process_t            process_zero                            CONFIG_CACHE_LINE_ALIGNED;

// This variable defines extended pointers on the distributed chdevs
__attribute__((section(".kdata")))
chdev_directory_t    chdev_dir                               CONFIG_CACHE_LINE_ALIGNED;

// This variable contains the input IRQ indexes for the PIC device
__attribute__((section(".kdata")))
chdev_pic_input_t    chdev_pic_input                         CONFIG_CACHE_LINE_ALIGNED;

// This variable contains the input IRQ indexes for the ICU device
__attribute__((section(".kdata")))
chdev_icu_input_t    chdev_icu_input                         CONFIG_CACHE_LINE_ALIGNED;

// This variable defines the local cluster identifier
__attribute__((section(".kdata")))
cxy_t                local_cxy                               CONFIG_CACHE_LINE_ALIGNED;

// This variable defines the TXT0 chdev descriptor 
__attribute__((section(".kdata")))
chdev_t              txt0_chdev                              CONFIG_CACHE_LINE_ALIGNED;

// This variable is used for CP0 cores sychronisation in kernel_init()
__attribute__((section(".kdata")))
remote_barrier_t     global_barrier                          CONFIG_CACHE_LINE_ALIGNED;

// This variable is used for local cores sychronisation in kernel_init()
__attribute__((section(".kdata")))
barrier_t            local_barrier                           CONFIG_CACHE_LINE_ALIGNED;

// This variable defines the array of supported File System contexts 
__attribute__((section(".kdata")))
vfs_ctx_t            fs_context[FS_TYPES_NR]                 CONFIG_CACHE_LINE_ALIGNED;


///////////////////////////////////////////////////////////////////////////////////////////
// This function displays the ALMOS_MKH banner.
///////////////////////////////////////////////////////////////////////////////////////////
static void print_banner( uint32_t nclusters , uint32_t ncores )
{ 
    printk("\n"
           "                    _        __    __     _____     ______         __    __    _   __   _     _   \n"
           "          /\\       | |      |  \\  /  |   / ___ \\   / _____|       |  \\  /  |  | | / /  | |   | |  \n"
           "         /  \\      | |      |   \\/   |  | /   \\ | | /             |   \\/   |  | |/ /   | |   | |  \n"
           "        / /\\ \\     | |      | |\\  /| |  | |   | | | |_____   ___  | |\\  /| |  |   /    | |___| |  \n"
           "       / /__\\ \\    | |      | | \\/ | |  | |   | | \\_____  \\ |___| | | \\/ | |  |   \\    |  ___  |  \n"
           "      / ______ \\   | |      | |    | |  | |   | |       | |       | |    | |  | |\\ \\   | |   | |  \n"
           "     / /      \\ \\  | |____  | |    | |  | \\___/ |  _____/ |       | |    | |  | | \\ \\  | |   | |  \n"
           "    /_/        \\_\\ |______| |_|    |_|   \\_____/  |______/        |_|    |_|  |_|  \\_\\ |_|   |_|  \n"
           "\n\n\t\t Advanced Locality Management Operating System / Multi Kernel Hybrid\n"
           "\n\n\t\t\t Version 0.0   :   %d clusters   /   %d cores per cluster\n\n", nclusters , ncores ); 
}


///////////////////////////////////////////////////////////////////////////////////////////
// This static function initializes the TXT0 chdev descriptor, associated to the "kernel 
// terminal", and shared by all kernel instances for debug messages. It also register it
// in the chdev directory, containing extended pointers on all chdevs.
// The global variable txt0_chdev is replicated in all clusters, but only the chdev
// allocated in I/O cluster is used by ALMOS-MKH.
// Therefore, this function must be called by a thread running in the I/O cluster.
// As this TXT0 chdev supports only the TXT_SYNC_WRITE command,  we don't create
// a server thread,  we don't allocate a WTI, and we don't initialize the waiting queue.
///////////////////////////////////////////////////////////////////////////////////////////
// @ info    : pointer on the local boot-info structure.
///////////////////////////////////////////////////////////////////////////////////////////
static void txt0_device_init( boot_info_t * info )
{
    boot_device_t * dev_tbl;         // pointer on array of devices in boot_info
        uint32_t        dev_nr;          // actual number of devices in this cluster
        xptr_t          base;            // remote pointer on segment base
    uint32_t        type;            // peripheral type
    uint32_t        func;            // device functionnal index
    uint32_t        impl;            // device implementation index
        uint32_t        i;               // device index in dev_tbl
        uint32_t        x;               // X cluster coordinate
        uint32_t        y;               // Y cluster coordinate

    // get number of peripherals and base of devices array from boot_info
        dev_nr      = info->ext_dev_nr;
    dev_tbl     = info->ext_dev;

    // loop on external peripherals to find TXT device
        for( i = 0 ; i < dev_nr ; i++ )
        {
        base        = dev_tbl[i].base;
        type        = dev_tbl[i].type;
        func        = FUNC_FROM_TYPE( type );
        impl        = IMPL_FROM_TYPE( type );

        if (func == DEV_FUNC_TXT ) 
        {
            // initialize basic fields
            txt0_chdev.func     = func;
            txt0_chdev.impl     = impl;
            txt0_chdev.channel  = 0;
            txt0_chdev.is_rx    = 0;
            txt0_chdev.base     = base;

            // initialize lock
            remote_spinlock_init( XPTR( local_cxy , &txt0_chdev.wait_lock ) );

            // TODO use generic device initialisation
            // hal_drivers_txt_init( &txt0_chdev );

            if( impl == IMPL_TXT_TTY )
            {
                txt0_chdev.cmd = &soclib_tty_cmd;
                txt0_chdev.isr = &soclib_tty_isr;
                soclib_tty_init( &txt0_chdev );
            }

            // initialize the replicated chdev_dir[x][y] structures
            for( x = 0 ; x < info->x_size ; x++ )
            {
                for( y = 0 ; y < info->y_size ; y++ )
                {
                    cxy_t  cxy = (x<<info->y_width) + y;
                    hal_remote_swd( XPTR( cxy , &chdev_dir.txt[0] ) ,
                                    XPTR( local_cxy , &txt0_chdev ) );
                }
            }

                    kinit_dmsg("\n[INFO] %s : core[%x][0] created TXT0 chdev"
                       " / paddr = %l at cycle %d\n",
                       __FUNCTION__ , local_cxy , chdev_func_str( func ),
                       XPTR(local_cxy , &txt0_chdev) , hal_get_cycles() );
        }

        } // end loop on devices

}  // end txt0_device_init()

///////////////////////////////////////////////////////////////////////////////////////////
// This static function allocates memory for the chdev (channel_device) descriptors
// associated to the internal peripherals contained in the local cluster. These internal
// devices (ICU, MMC, DMA) chdev descriptors are placed in the local cluster.
// It initialises these device descriptors as specified by the boot_info_t structure,
// including the dynamic linking with the driver for the specified implementation.
// Finally, all copies of the devices directory are initialised.
///////////////////////////////////////////////////////////////////////////////////////////
// @ info    : pointer on the local boot-info structure.
///////////////////////////////////////////////////////////////////////////////////////////
static void internal_devices_init( boot_info_t * info )
{
    boot_device_t * dev;             // pointer on boot_info device (ICU/MMC/DMA)
        uint32_t        x;               // X cluster coordinate
        uint32_t        y;               // Y cluster coordinate
        chdev_t       * chdev_ptr;       // local pointer on chdev descriptor
    xptr_t          chdev_xp;        // extended pointer on chdev descriptor

    ///////////  ICU   //////////

    dev = &info->dev_icu;

    assert( ((info->cores_nr == 0) || (dev->channels != 0)) , __FUNCTION__ ,
            "ICU device must exist in cluster containing cores" );
        
    assert( (dev->channels == 1) , __FUNCTION__ ,
            "channels number must be 1 for ICU device" );

    assert( (FUNC_FROM_TYPE( dev->type ) == DEV_FUNC_ICU ) , __FUNCTION__ ,
            " inconsistent ICU  device type");

    // create one chdev in local cluster
    chdev_ptr = chdev_create( FUNC_FROM_TYPE( dev->type ),
                              IMPL_FROM_TYPE( dev->type ),
                              0,                              // channel
                              false,                          // TX
                              dev->base );

    assert( (chdev_ptr != NULL) , __FUNCTION__ , "cannot allocate ICU chdev" );
            
    // get extended pointer on chdev descriptor 
    chdev_xp = XPTR( local_cxy , chdev_ptr );

    // make ICU specific initialisation 
    // TODO remove these three parameters
    dev_icu_init( chdev_ptr , dev->param0 , dev->param1 , dev->param2 );

    // initialize the ICU field in the chdev_dir[x][y] structures
    // replicated in all clusters, and containing extended pointers 
    // on all remotely accessible devices 
    for( x = 0 ; x < info->x_size ; x++ )
    {
        for( y = 0 ; y < info->y_size ; y++ )
        {
            cxy_t  cxy = (x<<info->y_width) + y;
            hal_remote_swd( XPTR( cxy , &chdev_dir.icu[local_cxy] ) , chdev_xp );
        }
    }

    // initialize the entries of the local chdev_icu_input structure
    // defining how internal peripherals are connected to ICU 
    uint32_t   id;
    uint8_t    valid;
    uint32_t   src_type;
    uint8_t    src_ch;
    uint32_t   src_func;
    for( id = 0 ; id < CONFIG_MAX_HWIS_PER_ICU ; id++ )
    {
        valid    = dev->irq[id].valid;
        src_type = dev->irq[id].dev_type;
        src_ch   = dev->irq[id].channel;
        src_func = FUNC_FROM_TYPE( src_type );

        if( valid ) // only valid local IRQs are registered
        {
            if     ( src_func == DEV_FUNC_MMC ) chdev_icu_input.mmc = id;
            else if( src_func == DEV_FUNC_DMA ) chdev_icu_input.dma[src_ch] = id;
            else assert( false , __FUNCTION__ , "illegal source device for ICU input" );
        }
    }

    kinit_dmsg("\n[INFO] %s : core[%x][0] created ICU chdev at cycle %d\n",
               __FUNCTION__ , local_cxy , hal_get_cycles() );

    /////////// MMC internal chdev ///////////  

    dev = &info->dev_mmc;

    if( dev->channels != 0 )   // MMC device is defined
    {
        assert( (dev->channels == 1) , __FUNCTION__ , 
            "channels number must be 1 for MMC device" );

        assert( (FUNC_FROM_TYPE( dev->type ) == DEV_FUNC_MMC ) , __FUNCTION__ ,
            " inconsistent MMC device type");

        // create one chdev in local cluster
        chdev_ptr = chdev_create( FUNC_FROM_TYPE( dev->type ),
                                  IMPL_FROM_TYPE( dev->type ),
                                  0,                              // channel
                                  false,                          // TX
                                  dev->base );

        assert( (chdev_ptr != NULL) , __FUNCTION__ , "cannot allocate MMC chdev" );
            
        // get extended pointer on chdev descriptor 
        chdev_xp = XPTR( local_cxy , chdev_ptr );

        // make MMC specific initialisation
        dev_mmc_init( chdev_ptr );     

        // initialize the MMC field in the chdev_dir[x][y] structures
        // replicated in all clusters, and containing extended pointers 
        // on all remotely accessible devices 
        for( x = 0 ; x < info->x_size ; x++ )
        {
            for( y = 0 ; y < info->y_size ; y++ )
            {
                cxy_t  cxy = (x<<info->y_width) + y;
                hal_remote_swd( XPTR( cxy , &chdev_dir.mmc[local_cxy] ) , chdev_xp );
            }
        }

        kinit_dmsg("\n[INFO] %s : core[%x][0] created MMC chdev at cycle %d\n",
                   __FUNCTION__ , local_cxy , hal_get_cycles() );
    }

    /////////// DMA internal chdevs //////////

    dev = &info->dev_dma;

    if( dev->channels != 0 )   // DMA device is defined
    {
        assert( (FUNC_FROM_TYPE( dev->type ) == DEV_FUNC_DMA ) , __FUNCTION__ ,
                " inconsistent DMA  device type");

        // create one chdev per channel in local cluster
        uint32_t channel;
        for( channel = 0 ; channel < dev->channels ; channel++ )
        { 
            chdev_ptr = chdev_create( FUNC_FROM_TYPE( dev->type ),
                                      IMPL_FROM_TYPE( dev->type ),
                                      channel,                        // channel
                                      false,                          // TX
                                      dev->base );

            assert( (chdev_ptr != NULL) , __FUNCTION__ , "cannot allocate DMA chdev" );
            
            // get extended pointer on channel descriptor 
            chdev_xp = XPTR( local_cxy , chdev_ptr );

            // make DMA specific initialisation
            dev_dma_init( chdev_ptr );     

            // initialize only the DMA[channel] field in the local chdev_dir[x][y]
            // structure because the DMA device is not remotely accessible.
            chdev_dir.dma[channel] = chdev_xp;

            kinit_dmsg("\n[INFO] %s : core[%x][0] created DMA[%d] chdev at cycle %d\n",
                       __FUNCTION__ , local_cxy , channel , hal_get_cycles() );
        }
    } 
}  // end internal_devices_init()

///////////////////////////////////////////////////////////////////////////////////////////
// This static function allocates memory for the chdev descriptors associated 
// to the external (shared) peripherals contained in the local cluster. These external
// devices (IOB, IOC, TXT, NIC, etc ) are distributed on all clusters. 
// It initialises these device descriptors as specified by the boot_info_t structure,
// including the dynamic linking with the driver for the specified implementation.
// Finally, all copies of the devices directory are initialised.
//
// The number of channel_devices depends on the device functionnal type.
// There is three nested loops to build the full set of external channel_devices:
// - loop on external devices.
// - loop on channels for multi-channels devices.
// - loop on directions (RX/TX) for NIC device.
// The set of channel_devices is indexed by the chdev_gid global index, that is used
// to select the cluster containing a given chdev[func,channel,direction].
// All clusters scan the full set of chdevs, but only the cluster matching
// (chdev_gid % (x_size*y_size)) create the corresponding chdev. 
//
// TODO check that cluster IO contains a PIC [AG]
// TODO make a default initialisation for the chdev_dir structure (XPTR_NULL )  [AG]
///////////////////////////////////////////////////////////////////////////////////////////
// @ info    : pointer on the local boot-info structure.
///////////////////////////////////////////////////////////////////////////////////////////
static void external_devices_init( boot_info_t * info )
{
    boot_device_t * dev_tbl;         // pointer on array of devices in boot_info
        uint32_t        dev_nr;          // actual number of devices in this cluster
        xptr_t          base;            // remote pointer on segment base
    uint32_t        type;            // peripheral type
    uint32_t        func;            // device functionnal index
    uint32_t        impl;            // device implementation index
        uint32_t        i;               // device index in dev_tbl
        uint32_t        x;               // X cluster coordinate
        uint32_t        y;               // Y cluster coordinate
        uint32_t        channels_nr;     // number of channels
        uint32_t        channel;         // channel index
        uint32_t        directions_nr;   // number of directions 
        uint32_t        direction;       // direction index
        uint32_t        p0;              // device parameter 0
        uint32_t        p1;              // device parameter 1
        uint32_t        p2;              // device parameter 2
        uint32_t        p3;              // device parameter 3
    uint32_t        first_channel;   // used in loop on channels

        chdev_t       * chdev;           // local pointer on one channel_device descriptor
    xptr_t          chdev_xp;        // extended pointer on channel_device descriptor
    uint32_t        chdev_gid = 0;   // global index of channel_device descriptor

    // get number of peripherals and base of devices array from boot_info
        dev_nr      = info->ext_dev_nr;
    dev_tbl     = info->ext_dev;

    // loop on external peripherals
        for( i = 0 ; i < dev_nr ; i++ )
        {
        base        = dev_tbl[i].base;
        type        = dev_tbl[i].type;
        channels_nr = dev_tbl[i].channels;
        p0          = dev_tbl[i].param0;
        p1          = dev_tbl[i].param1;
        p2          = dev_tbl[i].param2;
        p3          = dev_tbl[i].param3;

        func     = FUNC_FROM_TYPE( type );
        impl     = IMPL_FROM_TYPE( type );

        // There is one chdev per direction for NIC
        if (func == DEV_FUNC_NIC) directions_nr = 2;
        else                      directions_nr = 1;

        // The TXT0 chdev has already been created
        if (func == DEV_FUNC_TXT) first_channel = 1;
        else                      first_channel = 0;

        // do nothing for ROM, that does not require a device descriptor.
        if( func == DEV_FUNC_ROM ) continue;

        // check external device functionnal type
        if( (func != DEV_FUNC_IOB) &&
            (func != DEV_FUNC_PIC) &&
            (func != DEV_FUNC_IOC) &&
            (func != DEV_FUNC_TXT) &&
            (func != DEV_FUNC_NIC) &&
            (func != DEV_FUNC_FBF) ) 
        {
            assert( false , __FUNCTION__ , "undefined external peripheral type" );
        }

        // loops on channels 
        for( channel = first_channel ; channel < channels_nr ; channel++ )
        { 
            // loop on directions
            for( direction = 0 ; direction < directions_nr ; direction++ )
            {
                // get target cluster for chdev[func,channel,direction]
                uint32_t offset     = chdev_gid % ( info->x_size * info->y_size );
                uint32_t cx         = offset / info->y_size;
                uint32_t cy         = offset % info->y_size;
                uint32_t target_cxy = (cx<<info->y_width) + cy;

                // allocate and initialize a local chdev
                // if local cluster matches target cluster
                if( target_cxy == local_cxy )
                {
                    chdev = chdev_create( func,
                                          impl,
                                          channel,
                                          direction,
                                          base );

                    assert( (chdev != NULL), __FUNCTION__ , 
                            "cannot allocate external device" );

                    // get extended pointer on chdev
                    chdev_xp = XPTR( local_cxy , chdev );

                    // make device type specific initialisation
                    // the number of parameters depends on the device type
                    // TODO : remove the parameters that  must be provided by the drivers
                    if     ( func == DEV_FUNC_IOB ) dev_iob_init( chdev );
                    else if( func == DEV_FUNC_IOC ) dev_ioc_init( chdev );
                    else if( func == DEV_FUNC_TXT ) dev_txt_init( chdev );
                    else if( func == DEV_FUNC_NIC ) dev_nic_init( chdev );
                    else if( func == DEV_FUNC_PIC ) dev_pic_init( chdev , p0 );
                    else if( func == DEV_FUNC_FBF ) dev_fbf_init( chdev , p0 , p1 );
                    else
                    {
                        assert( false , __FUNCTION__ , "undefined device type" );
                    }

                    // all external (shared) devices are remotely accessible 
                    // initialize the replicated chdev_dir[x][y] structures
                    // defining the extended pointers on chdev descriptors 
                    xptr_t * entry;    
                
                    if( func == DEV_FUNC_IOB ) entry  = &chdev_dir.iob;
                    if( func == DEV_FUNC_PIC ) entry  = &chdev_dir.pic;
                    if( func == DEV_FUNC_TXT ) entry  = &chdev_dir.txt[channel];
                    if( func == DEV_FUNC_IOC ) entry  = &chdev_dir.ioc[channel];
                    if( func == DEV_FUNC_FBF ) entry  = &chdev_dir.fbf[channel];
                    if( func == DEV_FUNC_NIC ) entry  = &chdev_dir.nic_tx[channel];
  
                    for( x = 0 ; x < info->x_size ; x++ )
                    {
                        for( y = 0 ; y < info->y_size ; y++ )
                        {
                            cxy_t  cxy = (x<<info->y_width) + y;
                            hal_remote_swd( XPTR( cxy , entry ) , chdev_xp );
                        }
                    }

                            kinit_dmsg("\n[INFO] %s : core[%x][0] create chdev %s[%d] at cycle %d\n",
                               __FUNCTION__ , local_cxy , chdev_func_str( func ),
                               channel , hal_get_cycles() );

                }  // end if match

                // increment chdev global index (matching or not)
                chdev_gid++;

            } // end loop on directions

        }  // end loop on channels

        // initialize the entries of the local chdev_pic_input structure
        // defining how external peripherals are connected to PIC 
        if( func == DEV_FUNC_PIC )  
        {
            uint32_t   id;
            uint8_t    valid;
            uint32_t   dev_type;
            uint8_t    channel;
            uint8_t    is_rx;

            // loop on PIC inputs
            for( id = 0 ; id < CONFIG_MAX_IRQS_PER_PIC ; id++ )
            {
                valid     = dev_tbl[i].irq[id].valid;
                dev_type  = dev_tbl[i].irq[id].dev_type;
                channel   = dev_tbl[i].irq[id].channel;
                is_rx     = dev_tbl[i].irq[id].is_rx;

                if( valid )  // only valid inputs are registered
                {
                    uint32_t * index;  // local pointer on one entry
                    uint16_t dev_func = FUNC_FROM_TYPE( dev_type );

                    if( dev_func == DEV_FUNC_TXT )
                    {
                        index = &chdev_pic_input.txt[channel];
                    }
                    else if( dev_func == DEV_FUNC_IOC )
                    {
                        index = &chdev_pic_input.ioc[channel]; 
                    }
                    else if( (dev_func == DEV_FUNC_NIC) && (is_rx == 0) )
                    {
                        index = &chdev_pic_input.nic_tx[channel]; 
                    }
                    else if( (dev_func == DEV_FUNC_NIC) && (is_rx != 0) )
                    {
                        index = &chdev_pic_input.nic_rx[channel]; 
                    }
                    else
                    {
                        assert( false , __FUNCTION__ , "illegal source device for PIC input" );
                    }                   

                    // set entry in local structure
                    *index = id; 
                }
            } // end loop on PIC inputs
        } // end PIC
        } // end loop on devices
}  // end external_devices_init()


///////////////////////////////////////////////////////////////////////////////////////////
// This static function returns the identifiers of the calling core.
///////////////////////////////////////////////////////////////////////////////////////////
// @ info    : pointer on boot_info structure.
// @ lid     : [out] core local index in cluster.
// @ cxy     : [out] cluster identifier.
// @ lid     : [out] core global identifier (hardware).
// @ return 0 if success / return EINVAL if not found.
///////////////////////////////////////////////////////////////////////////////////////////
static error_t get_core_identifiers( boot_info_t * info,
                                     lid_t       * lid,
                                     cxy_t       * cxy,
                                     gid_t       * gid )
{
        uint32_t   i;
    gid_t      global_id;

    // get global identifier from hardware register
    global_id = hal_get_gid(); 

    // makes an associative search in boot_info to get (cxy,lid) from global_id
    for( i = 0 ; i < info->cores_nr ; i++ )
    {
        if( global_id == info->core[i].gid )
        {
            *lid = info->core[i].lid;
            *cxy = info->core[i].cxy;
            *gid = global_id;
            return 0;
        }
    }
    return EINVAL;
}

///////////////////////////////////////////////////////////////////////////////////////////
// This function is the entry point for the kernel initialisation.
// It is executed by all cores in all clusters, but only core[0], called CP0,
// initializes the shared resources such as the cluster manager, or the local peripherals.
// To comply with the multi-kernels paradigm, it accesses only local cluster memory, using
// only information contained in the local boot_info_t structure, set by the bootloader.
// Only CP0 in cluster 0 print the log messages.
///////////////////////////////////////////////////////////////////////////////////////////
// @ info    : pointer on the local boot-info structure.
///////////////////////////////////////////////////////////////////////////////////////////
void kernel_init( boot_info_t * info )
{
    lid_t        core_lid = -1;      // running core local index
    cxy_t        core_cxy = -1;      // running core cluster identifier
    gid_t        core_gid;           // running core hardware identifier 
    cluster_t  * cluster;            // pointer on local cluster manager
    core_t     * core;               // pointer on running core descriptor
    thread_t   * thread;             // pointer on idle thread descriptor
    error_t      error;

    // all cores get and check core identifiers
    error = get_core_identifiers( info,
                                  &core_lid,
                                  &core_cxy,
                                  &core_gid );

    // CP0 initialise cluster identifier
    if( core_lid == 0 ) local_cxy = info->cxy;

    // each core get pointer on its private idle thread descriptor
        thread = (thread_t *)( idle_threads + (core_lid * CONFIG_THREAD_DESC_SIZE) );

    // each core registers this thread pointer in hardware register 
    hal_set_current_thread( thread );

    // CP0 in I/O cluster initialises TXT0 chdev descriptor
    if( (core_lid == 0) && (core_cxy == info->io_cxy) ) txt0_device_init( info );

    /////////////////////////////////////////////////////////////////////////////////
    // global & local synchro to protect access to TXT0 terminal
    if( core_lid == 0 ) remote_barrier( XPTR( info->io_cxy , &global_barrier ), 
                                        (info->x_size * info->y_size) );
    barrier_wait( &local_barrier , info->cores_nr );
    /////////////////////////////////////////////////////////////////////////////////

    if( (core_lid ==  0) && (local_cxy == info->io_cxy) ) 
    {
        kinit_dmsg("\n[INFO] %s : core[%x][%d] exit barrier 0 at cycle %d\n",
                   __FUNCTION__ , core_cxy , core_lid , hal_get_cycles() );
    }

    // all cores check core identifiers
    if( error )
    {
        nolock_printk("\n[PANIC] in %s : illegal core identifiers"
               " gid = %x / cxy = %x / lid = %d\n",
               __FUNCTION__ , core_lid , core_cxy , core_lid );
        hal_core_sleep();
    }

    // CP0 initializes the local cluster manager (cores and memory allocators)
    if( core_lid == 0 )
    {
        error = cluster_init( info );

        if( error )
        {
            nolock_printk("\n[PANIC] in %s : cannot initialise cluster manager in cluster %x",
                   __FUNCTION__ , local_cxy );
            hal_core_sleep();
        }
    }

    /////////////////////////////////////////////////////////////////////////////////
    // global & local synchro, to protect access to cluster manager
    if( core_lid == 0 ) remote_barrier( XPTR( info->io_cxy , &global_barrier ), 
                                        (info->x_size * info->y_size) );
    barrier_wait( &local_barrier , info->cores_nr );
    /////////////////////////////////////////////////////////////////////////////////

    if( (core_lid ==  0) && (local_cxy == info->io_cxy) ) 
    {
        kinit_dmsg("\n[INFO] %s : core[%x][%d] exit barrier 1 at cycle %d\n",
                   __FUNCTION__ , core_cxy , core_lid , hal_get_cycles() );
    }

    // all cores get pointer on local cluster manager and on core descriptor
    cluster = &cluster_manager;
        core    = &cluster->core_tbl[core_lid];

    // CP0 initializes the process_zero descriptor
    if( core_lid == 0 ) process_reference_init( &process_zero , 0 , XPTR_NULL );

    // CP0 allocates and initialises the internal peripheral chdev descriptors.
    // Each CP0[cxy] scan the set of its internal (private) peripherals,
    // and allocate memory for the corresponding chdev descriptors.
    if( core_lid == 0 ) internal_devices_init( info );
        
    // CP0 allocates one WTI mailbbox per core for Inter Processor Interrupt
    // this must be done after ICU chdev initialisation, by CP0 only, and before
    // external devices initialisation to enforce the rule :
    // "The WTI index for the IPI routed to core[lid] is lid"
    if( core_lid == 1 )
    {
        uint32_t  wti_id;
        uint32_t  lid;
        for( lid = 0 ; lid < LOCAL_CLUSTER->cores_nr ; lid++ )
        {
            wti_id = dev_icu_wti_alloc();

            if( wti_id != lid )
            {
                nolock_printk("\n[PANIC] in %s : WTI index for IPI = %d / core_lid = %d",
                              __FUNCTION__ , wti_id , lid );
                hal_core_sleep();
            }

            dev_icu_enable_irq( lid , WTI_TYPE , wti_id , NULL );
        }
    }

    // All CP0s contribute to initialise external peripheral chdev descriptors.
    // Each CP0[cxy] scan the set of external (shared) peripherals (but the TXT0),
    // and allocates memory for the chdev descriptors that must be placed
    // on the (cxy) cluster according to the global index value.  
    if( core_lid == 0 ) external_devices_init( info );

    /////////////////////////////////////////////////////////////////////////////////
    // global &local synchro to protect access to peripherals
    if( core_lid == 0 ) remote_barrier( XPTR( info->io_cxy , &global_barrier ), 
                                        (info->x_size * info->y_size) );
    barrier_wait( &local_barrier , info->cores_nr );
    /////////////////////////////////////////////////////////////////////////////////

    if( (core_lid ==  0) && (local_cxy == info->io_cxy) ) 
    {
        kinit_dmsg("\n[INFO] %s : core[%x][%d] exit barrier 2 at cycle %d\n", 
                   __FUNCTION__ , core_cxy , core_lid , hal_get_cycles() );
    }

    error = thread_kernel_init( thread,
                                THREAD_IDLE, 
                                &thread_idle_func, 
                                NULL,
                                core_lid );
    if( error )
    {
        nolock_printk("\n[PANIC] in %s : core[%x][%d] cannot initialize idle thread\n",
                      __FUNCTION__ , local_cxy , core_lid );
        hal_core_sleep();
    }

    // register idle thread in scheduler
    core->scheduler.idle = thread;

    // activate the idle thread
    thread_unblock( XPTR( local_cxy , thread ) , THREAD_BLOCKED_GLOBAL );

    if( (core_lid ==  0) && (local_cxy == info->io_cxy) ) 
    {
        kinit_dmsg("\n[INFO] %s : core[%x][%d] created idle thread %x at cycle %d\n",
                   __FUNCTION__ , core_cxy , core_lid , thread , hal_get_cycles());
    }

    // CP0 in all clusters initializes cooperatively VFS and DEVFS 
    if( (core_lid == 0)  )
    {
        xptr_t  root_inode_xp;

        // initialize root File System (must be FATFS in this implementation)
        if( CONFIG_VFS_ROOT_IS_FATFS )
        {
            root_inode_xp = fatfs_init();
        }
        else
        {
            nolock_printk("\n[PANIC] in %s : root FS must be FATFS\n", __FUNCTION__ );
            hal_core_sleep();
        }

        if( root_inode_xp == XPTR_NULL )
        {
            nolock_printk("\n[PANIC] in %s : core[%x][%d] cannot initialize file system\n",
                   __FUNCTION__ , local_cxy , core_lid );
            hal_core_sleep();
        }

        // register VFS root inode in process_zero
        process_zero.vfs_root_xp = root_inode_xp;
        process_zero.vfs_cwd_xp  = root_inode_xp;

        // mount the DEVFS File system
            devfs_mount( root_inode_xp , "dev" );
    }


    // CP0 in I/O cluster creates the process_init and print banner
    if( (core_lid ==  0) && (local_cxy == info->io_cxy) ) 
    {
        process_init_create();

        print_banner( (info->x_size * info->y_size) , info->cores_nr );

        kinit_dmsg("\n\n*** memory fooprint of main kernet objects ***\n"
                   " - thread descriptor  : %d bytes\n"
                   " - process descriptor : %d bytes\n"
                   " - cluster manager    : %d bytes\n"
                   " - chdev descriptor   : %d bytes\n"
                   " - core descriptor    : %d bytes\n"
                   " - scheduler          : %d bytes\n"
                   " - rpc fifo           : %d bytes\n"
                   " - page descriptor    : %d bytes\n"
                   " - mapper root        : %d bytes\n"
                   " - ppm manager        : %d bytes\n"
                   " - kcm manager        : %d bytes\n"
                   " - khm manager        : %d bytes\n"
                   " - vmm manager        : %d bytes\n"
                   " - gpt root           : %d bytes\n"
                   " - list item          : %d bytes\n"
                   " - xlist item         : %d bytes\n"
                   " - spinlock           : %d bytes\n"
                   " - remote spinlock    : %d bytes\n"
                   " - rwlock             : %d bytes\n"
                   " - remote rwlock      : %d bytes\n",
                   sizeof( thread_t          ), 
                   sizeof( process_t         ),
                   sizeof( cluster_t         ),
                   sizeof( chdev_t           ),
                   sizeof( core_t            ),
                   sizeof( scheduler_t       ),
                   sizeof( rpc_fifo_t        ),
                   sizeof( page_t            ),
                   sizeof( mapper_t          ),
                   sizeof( ppm_t             ),
                   sizeof( kcm_t             ),
                   sizeof( khm_t             ),
                   sizeof( vmm_t             ),
                   sizeof( gpt_t             ),
                   sizeof( list_entry_t      ),
                   sizeof( xlist_entry_t     ),
                   sizeof( spinlock_t        ),
                   sizeof( remote_spinlock_t ),
                   sizeof( rwlock_t          ),
                   sizeof( remote_rwlock_t   ));
    }

    /////////////////////////////////////////////////////////////////////////////////
    // global syncho to protect access to File System
    if( core_lid == 0 ) remote_barrier( XPTR( info->io_cxy , &global_barrier ),
                                        (info->x_size * info->y_size) );
    barrier_wait( &local_barrier , info->cores_nr );
    /////////////////////////////////////////////////////////////////////////////////

    if( (core_lid ==  0) && (local_cxy == info->io_cxy) ) 
    {
        kinit_dmsg("\n[INFO] %s : core[%x][%d] exit barrier 3 at cycle %d\n", 
                   __FUNCTION__ , core_cxy , core_lid , hal_get_cycles() );
    }

    // each core activates its private PTI IRQ 
    dev_icu_set_period( core_lid , CONFIG_SCHED_TICK_PERIOD );
    dev_icu_enable_irq( core_lid , PTI_TYPE , core_lid , NULL );

    // each core get its private IRQ masks values
    uint32_t hwi_mask;
    uint32_t wti_mask;
    uint32_t pti_mask;
    dev_icu_get_masks( core_lid , &hwi_mask , &wti_mask , &pti_mask );

    thread_dmsg("\n[INFO] %s : core[%x][%d] complete kernel init at cycle %d\n"
                "   hwi_mask = %x / wti_mask = %x / pti_mask = %x\n",
                    __FUNCTION__ , local_cxy , core_lid , hal_get_cycles() ,
                    hwi_mask , wti_mask , pti_mask );

    // each core jump to idle thread
    thread_idle_func();

} // end kernel_init()