syntheth.c

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//==========================================================================
//
//      syntheth.c
//
//      Network device driver for the synthetic target
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 2002, 2003 Bart Veer
//
// 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.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 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.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting the
// copyright holder(s).
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):    bartv
// Contributors: bartv
// Date:         2002-08-07
//
//####DESCRIPTIONEND####
//==========================================================================

#include <pkgconf/devs_eth_ecosynth.h>

#include <cyg/infra/cyg_type.h>
#include <cyg/infra/cyg_ass.h>
#include <cyg/hal/hal_arch.h>
#include <cyg/infra/diag.h>
#include <cyg/hal/drv_api.h>
#include <errno.h>
#include <string.h>

#define __ECOS 1
#include <sys/types.h>
#include <cyg/io/eth/netdev.h>
#include <cyg/io/eth/eth_drv.h>
#include <cyg/io/eth/eth_drv_stats.h>

#ifdef CYGPKG_NET
# include <net/if.h>
#else
# define IFF_PROMISC 0
#endif

#include <cyg/hal/hal_io.h>
#include "protocol.h"

// ----------------------------------------------------------------------------
// Device instances. The synthetic target ethernet package can support
// up to four ethernet devices, eth0 to eth3. A synth_eth structure
// holds the data that is specific to a given device. Each device
// needs an instance of this structure, followed by ETH_DRV_SC and
// NETDEVTAB_ENTRY macros. Another macro SYNTH_ETH_INSTANCE takes
// care of all that, to avoid unnecessary duplication of code here.
//
// NOTE: unfortunately this involves duplicating the eth_hwr_funs
// structure. This could be eliminated but it would require bypassing
// the ETH_DRV_SC macro.

#define ETHERNET_MINTU 14
#define ETHERNET_MAXTU 1514


typedef struct synth_eth {
    int             synth_id;           // Device id within the auxiliary
    int             up;                 // Has there been a call to start()?
    int             in_send;            // Detect recursive calls
    int             tx_done;
    unsigned long   tx_key;             // Allow mbuf's to be freed
    volatile int    rx_pending;         // There is pending data.
    int             rx_len;             // Length of buffered data.
    unsigned char   MAC[6];             // Obtained from the underlying ethernet device
    cyg_vector_t    interrupt;          // Interrupt number allocated by the auxiliary
    int             multi_supported;    // Does the driver support multicasting?
    cyg_handle_t    interrupt_handle;   // Allow the ISR and DSR to be installed.
    cyg_interrupt   interrupt_data;
    unsigned char   tx_data[ETHERNET_MAXTU];
    unsigned char   rx_data[ETHERNET_MAXTU];
} synth_eth;

#define SYNTH_ETH_INSTANCE( _number_)           \
static synth_eth synth_eth##_number_ = {        \
    synth_id:   -1,                             \
    up:          1,                             \
    in_send:     0,                             \
    tx_done:     0,                             \
    tx_key:      0L,                            \
    rx_pending:  0,                             \
    rx_len:      0,                             \
    MAC:         { 0, 0, 0, 0, 0, 0 },          \
    interrupt:   0,                             \
    interrupt_handle: 0                         \
};                                              \
ETH_DRV_SC(synth_eth_sc##_number_,              \
           (void*) &synth_eth##_number_,        \
           "eth" #_number_,                     \
           synth_eth_start,                     \
           synth_eth_stop,                      \
           synth_eth_ioctl,                     \
           synth_eth_can_send,                  \
           synth_eth_send,                      \
           synth_eth_recv,                      \
           synth_eth_deliver,                   \
           synth_eth_poll,                      \
           synth_eth_intvector);                \
NETDEVTAB_ENTRY(synth_eth_netdev##_number_,     \
                "synth_eth" #_number_,          \
                synth_eth_init,                 \
                &synth_eth_sc##_number_);

#ifdef CYGVAR_DEVS_ETH_ECOSYNTH_ETH0
SYNTH_ETH_INSTANCE(0);
#endif
#ifdef CYGVAR_DEVS_ETH_ECOSYNTH_ETH1
SYNTH_ETH_INSTANCE(1);
#endif
#ifdef CYGVAR_DEVS_ETH_ECOSYNTH_ETH2
SYNTH_ETH_INSTANCE(2);
#endif
#ifdef CYGVAR_DEVS_ETH_ECOSYNTH_ETH3
SYNTH_ETH_INSTANCE(3);
#endif

// ----------------------------------------------------------------------------
// Data transmits.
//
// The eCos application will just send the data to the auxiliary,
// which will in turn pass it on to the rawether utility. There is no
// need for any response. Flow control is implicit: if the eCos
// application tries to send ethernet packets too quickly then those
// get passed on to the auxiliary, which in turn will pass them on to
// the rawether process. If rawether is still busy with the previous
// packet then the auxiliary will block on a pipe write, and in turn
// the eCos application will block. As long as rawether manages to
// complete its operations reasonably quickly these blocks should not
// be noticeable to the user.
//
// So can_send() should always return true for an interface that is up
// and running. The send operation needs to take the sg list, turn it
// into a single buffer, and transmit it to the auxiliary. At that
// point the transmission is already complete so eth_drv_dsr() should
// be called to call deliver() and release the buffer.
//
// However there are some complications. The first is polled operation,
// where eth_drv_dsr() is a no-op and should not really be called at
// all because there are no interrupts going off. The second is that
// calling eth_drv_dsr() directly will cause recursive operation:
// send() -> dsr -> can_send()/send() -> ...
// This is a bad idea, so can_send() has to check that we are not
// already inside a send(). Data transmission will proceed merrily
// once the send has returned.

static int
synth_eth_can_send(struct eth_drv_sc* sc)
{
    synth_eth*  eth = (synth_eth*)(sc->driver_private);
    return synth_auxiliary_running && eth->up && !eth->in_send && !eth->tx_done;
}

static void
synth_eth_send(struct eth_drv_sc* sc,
               struct eth_drv_sg* sg_list, int sg_len, int total_len,
               unsigned long key)
{
    synth_eth*  eth = (synth_eth*)(sc->driver_private);

    CYG_PRECONDITION((total_len >= ETHERNET_MINTU) && (total_len <= ETHERNET_MAXTU), "Only normal-sized ethernet packets are supported");
    CYG_PRECONDITION(!eth->in_send && !eth->tx_done, "Ethernet device must not still be in use for transmits");

    eth->in_send = 1;
    eth->tx_key  = key;
    if (synth_auxiliary_running && eth->up) {
        int i;
        unsigned char* buf = eth->tx_data;
        for (i = 0; i < sg_len; i++) {
            memcpy(buf, (void*) sg_list[i].buf, sg_list[i].len);
            buf += sg_list[i].len;
            CYG_LOOP_INVARIANT(buf <= &(eth->tx_data[ETHERNET_MAXTU]), "sg list must not exceed ethernet MTU");
        }
        CYG_POSTCONDITION(buf == &(eth->tx_data[total_len]), "sg list lengths should match total_len");

        synth_auxiliary_xchgmsg(eth->synth_id, SYNTH_ETH_TX, 0, 0, eth->tx_data, total_len,
                                (void*) 0, (unsigned char*)0, (int*)0, 0);
    }

    // The transfer has now completed, one way or another, so inform
    // the higher-level code immediately.
    eth->tx_done = 1;
    eth_drv_dsr(eth->interrupt, 0, (cyg_addrword_t) sc);
    eth->in_send = 0;
}

// ----------------------------------------------------------------------------
// Receives.
//
// These are rather more complicated because there are real interrupts
// involved, and polling needs to be supported as well. The actual
// transfer of data from auxiliary to eCos happens inside deliver(),
// and the data is buffered up in the synth_eth structure. All that
// needs to be done here is scatter the existing data into the
// sg_list. If higher-level code has run out of space then the
// sg_list may contain null pointers.

static void