synth_intr.c

eCos操作系统源码

        request[SYNTH_REQUEST_TXLEN_OFFSET + 1]     = (txlen >>  8) & 0x0FF;
        request[SYNTH_REQUEST_TXLEN_OFFSET + 2]     = (txlen >> 16) & 0x0FF;
        request[SYNTH_REQUEST_TXLEN_OFFSET + 3]     = (txlen >> 24) & 0x0FF;
        request[SYNTH_REQUEST_RXLEN_OFFSET + 0]     = (rxlen >>  0) & 0x0FF;
        request[SYNTH_REQUEST_RXLEN_OFFSET + 1]     = (rxlen >>  8) & 0x0FF;
        request[SYNTH_REQUEST_RXLEN_OFFSET + 2]     = (rxlen >> 16) & 0x0FF;
        request[SYNTH_REQUEST_RXLEN_OFFSET + 3]     = ((rxlen >> 24) & 0x0FF) | (((int*)0 != result) ? 0x080 : 0);

        // sizeof(synth_auxiliary_request) < PIPE_BUF (4096) so a single write should be atomic,
        // subject only to incoming clock or SIGIO or child-related signals.
        do {
            rc = cyg_hal_sys_write(to_aux, (const void*) &request, SYNTH_REQUEST_LENGTH);
        } while (-CYG_HAL_SYS_EINTR == rc);

        // Is there any more data to be sent?
        if (0 < txlen) {
            int sent    = 0;
            CYG_LOOP_INVARIANT(synth_auxiliary_running, "The auxiliary cannot just disappear");
        
            while (sent < txlen) {
                rc = cyg_hal_sys_write(to_aux, (const void*) &(txdata[sent]), txlen - sent);
                if (-CYG_HAL_SYS_EINTR == rc) {
                    continue;
                } else if (rc < 0) {
                    diag_printf("Internal error: unexpected result %d when sending buffer to auxiliary.\n", rc);
                    diag_printf("              : this application is exiting immediately.\n");
                    cyg_hal_sys_exit(1);
                } else {
                    sent += rc;
                }
            }
            CYG_ASSERT(sent <= txlen, "Amount of data sent should not exceed requested size");
        }

        // The auxiliary can now process this entire request. Is a reply expected?
        if ((int*)0 != result) {
            // The basic reply is also only a small number of bytes, so should be atomic.
            do {
                rc = cyg_hal_sys_read(from_aux, (void*) &reply, SYNTH_REPLY_LENGTH);
            } while (-CYG_HAL_SYS_EINTR == rc);
            if (rc <= 0) {
                if (rc < 0) {
                    diag_printf("Internal error: unexpected result %d when receiving data from auxiliary.\n", rc);
                } else {
                    diag_printf("Internal error: EOF detected on pipe from auxiliary.\n");
                }
                diag_printf("              : this application is exiting immediately.\n");
                cyg_hal_sys_exit(1);
            }
            CYG_ASSERT(SYNTH_REPLY_LENGTH == rc, "The correct amount of data should have been read");

            // Replies are packed in Tcl and assumed to be two 32-bit
            // little-endian integers.
            *result   = (reply[SYNTH_REPLY_RESULT_OFFSET + 3] << 24) |
                (reply[SYNTH_REPLY_RESULT_OFFSET + 2] << 16) |
                (reply[SYNTH_REPLY_RESULT_OFFSET + 1] <<  8) |
                (reply[SYNTH_REPLY_RESULT_OFFSET + 0] <<  0);
            reply_rxlen = (reply[SYNTH_REPLY_RXLEN_OFFSET + 3] << 24) |
                (reply[SYNTH_REPLY_RXLEN_OFFSET + 2] << 16) |
                (reply[SYNTH_REPLY_RXLEN_OFFSET + 1] <<  8) |
                (reply[SYNTH_REPLY_RXLEN_OFFSET + 0] <<  0);
        
            CYG_ASSERT(reply_rxlen <= rxlen, "The auxiliary should not be sending more data than was requested.");
        
            if ((int*)0 != actual_rxlen) {
                *actual_rxlen  = reply_rxlen;
            }
            if (reply_rxlen) {
                int received = 0;
            
                while (received < reply_rxlen) {
                    rc = cyg_hal_sys_read(from_aux, (void*) &(rxdata[received]), reply_rxlen - received);
                    if (-CYG_HAL_SYS_EINTR == rc) {
                        continue;
                    } else if (rc <= 0) {
                        if (rc < 0) {
                            diag_printf("Internal error: unexpected result %d when receiving data from auxiliary.\n", rc);
                        } else {
                            diag_printf("Internal error: EOF detected on pipe from auxiliary.\n");
                        }
                        diag_printf("              : this application is exiting immediately.\n");
                    } else {
                        received += rc;
                    }
                }
                CYG_ASSERT(received == reply_rxlen, "Amount received should be exact");
            }
        }
    }

    HAL_RESTORE_INTERRUPTS(old_isrstate);
}

// Instantiate a device. This takes arguments such as
// devs/eth/synth/ecosynth, current, ethernet, eth0, and 200x100 If
// the package and version are NULL strings then the device being
// initialized is application-specific and does not belong to any
// particular package.
int
synth_auxiliary_instantiate(const char* pkg, const char* version, const char* devtype, const char* devinst, const char* devdata)
{
    int         result = -1;
    char        buf[512 + 1];
    const char* str;
    int         index;

    CYG_ASSERT((const char*)0 != devtype, "Device instantiations must specify a valid device type");
    CYG_ASSERT((((const char*)0 != pkg) && ((const char*)0 != version)) || \
               (((const char*)0 == pkg) && ((const char*)0 == version)), "If a package is specified then the version must be supplied as well");
    
    index = 0;
    str = pkg;
    if ((const char*)0 == str) {
        str = "";
    }
    while ( (index < 512) && ('\0' != *str) ) {
        buf[index++] = *str++;
    }
    if (index < 512) buf[index++] = '\0';
    str = version;
    if ((const char*)0 == str) {
        str = "";
    }
    while ((index < 512) && ('\0' != *str) ) {
        buf[index++] = *str++;
    }
    if (index < 512) buf[index++] = '\0';
    for (str = devtype; (index < 512) && ('\0' != *str); ) {
        buf[index++] = *str++;
    }
    if (index < 512) buf[index++] = '\0';
    if ((const char*)0 != devinst) {
        for (str = devinst; (index < 512) && ('\0' != *str); ) {
            buf[index++] = *str++;
        }
    }
    if (index < 512) buf[index++] = '\0';
    if ((const char*)0 != devdata) {
        for (str = devdata; (index < 512) && ('\0' != *str); ) {
            buf[index++] = *str++;
        }
    }
    if (index < 512) {
        buf[index++] = '\0';
    } else {
        diag_printf("Internal error: buffer overflow constructing instantiate request for auxiliary.\n");
        diag_printf("              : this application is exiting immediately.\n");
        cyg_hal_sys_exit(1);
    }

    if (synth_auxiliary_running) {
        synth_auxiliary_xchgmsg(SYNTH_DEV_AUXILIARY, SYNTH_AUXREQ_INSTANTIATE, 0, 0,
                                buf, index,
                                &result, 
                                (unsigned char*) 0, (int *) 0, 0);
    }
    return result;
}

// ----------------------------------------------------------------------------
// SIGPIPE and SIGCHLD are special, related to the auxiliary process.
//
// A SIGPIPE can only happen when the application is writing to the
// auxiliary, which only happens inside synth_auxiliary_xchgmsg() (this
// assumes that no other code is writing down a pipe, e.g. to interact
// with a process other than the standard I/O auxiliary). Either the
// auxiliary has explicitly closed the pipe, which it is not supposed
// to do, or more likely it has exited. Either way, there is little
// point in continuing - unless we already know that the system is
// shutting down.
static void
synth_pipe_sighandler(int sig)
{
    CYG_ASSERT(CYG_HAL_SYS_SIGPIPE == sig, "The right signal handler should be invoked");
    if (synth_auxiliary_running) {
        synth_auxiliary_running   = false;
        diag_printf("Internal error: communication with the I/O auxiliary has been lost.\n");
        diag_printf("              : this application is exiting immediately.\n");
        cyg_hal_sys_exit(1);
    }
}

// Similarly it is assumed that there will be no child processes other than
// the auxiliary. Therefore a SIGCHLD indicates that the auxiliary has
// terminated unexpectedly. This is bad: normal termination involves
// the application exiting and the auxiliary terminating in response,
// not the other way around.
//
// As a special case, if it is known that the auxiliary is not currently
// usable then the signal is ignored. This copes with the situation where
// the auxiliary has just been fork()'d but has failed to initialize, or
// alternatively where the whole system is in the process of shutting down
// cleanly and it happens that the auxiliary got there first.
static void
synth_chld_sighandler(int sig)
{
    CYG_ASSERT(CYG_HAL_SYS_SIGCHLD == sig, "The right signal handler should be invoked");
    if (synth_auxiliary_running) {
        synth_auxiliary_running   = false;
        diag_printf("Internal error: the I/O auxiliary has terminated unexpectedly.\n");
        diag_printf("              : this application is exiting immediately.\n");
        cyg_hal_sys_exit(1);
    }
}

// ----------------------------------------------------------------------------
// Initialization

void
synth_hardware_init(void)
{
    struct cyg_hal_sys_sigaction action;
    struct cyg_hal_sys_sigset_t  blocked;
    int i;

    // Set up a sigprocmask to block all signals except the ones we
    // particularly want to handle. However do not block the tty
    // signals - the ability to ctrl-C a program is important.
    CYG_HAL_SYS_SIGFILLSET(&blocked);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGILL);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGBUS);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGFPE);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGSEGV);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGPIPE);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGCHLD);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGALRM);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGIO);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGHUP);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGINT);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGQUIT);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGTERM);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGCONT);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGSTOP);
    CYG_HAL_SYS_SIGDELSET(&blocked, CYG_HAL_SYS_SIGTSTP);
        
    if (0 != cyg_hal_sys_sigprocmask(CYG_HAL_SYS_SIG_SETMASK, &blocked, (cyg_hal_sys_sigset_t*) 0)) {
        CYG_FAIL("Failed to initialize sigprocmask");
    }

    // Now set up the VSR and ISR statics
    synth_VSR = &synth_default_vsr;
    for (i = 0; i < CYGNUM_HAL_ISR_COUNT; i++) {
        synth_isr_handlers[i].isr       = &synth_default_isr;
        synth_isr_handlers[i].data      = (CYG_ADDRWORD) 0;
        synth_isr_handlers[i].obj       = (CYG_ADDRESS) 0;
        synth_isr_handlers[i].pri       = CYGNUM_HAL_ISR_COUNT;
    }

    // Install signal handlers for SIGIO and SIGALRM, the two signals
    // that may cause the VSR to run. SA_NODEFER is important: it
    // means that the current signal will not be blocked while the
    // signal handler is running. Combined with a mask of 0, it means
    // that the sigprocmask does not change when a signal handler is
    // invoked, giving eCos the flexibility to switch to other threads
    // instead of having the signal handler return immediately.
    action.hal_mask     = 0;
    action.hal_flags    = CYG_HAL_SYS_SA_NODEFER;
    action.hal_bogus    = (void (*)(int)) 0;
    action.hal_handler  = &synth_alrm_sighandler;
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGALRM, &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGALRM");
    }
    action.hal_handler  = &synth_io_sighandler;
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGIO, &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGIO");
    }

    // Install handlers for the various exceptions. For now these also
    // operate with unchanged sigprocmasks, allowing nested
    // exceptions. It is not clear that this is entirely a good idea,
    // but in practice these exceptions will usually be handled by gdb
    // anyway.
    action.hal_handler  = &synth_exception_sighandler;
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGILL,  &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGILL");
    }
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGBUS,  &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGBUS");
    }
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGFPE,  &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGFPE");
    }
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGSEGV,  &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGSEGV");
    }

    // Also cope with SIGCHLD and SIGPIPE. SIGCHLD indicates that the
    // auxiliary has terminated, which is a bad thing. SIGPIPE
    // indicates that a write to the auxiliary has terminated, but
    // the error condition was caught at a different stage.
    action.hal_handler = &synth_pipe_sighandler;
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGPIPE,  &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGPIPE");
    }
    action.hal_handler = &synth_chld_sighandler;
    action.hal_flags  |= CYG_HAL_SYS_SA_NOCLDSTOP | CYG_HAL_SYS_SA_NOCLDWAIT;
    if (0 != cyg_hal_sys_sigaction(CYG_HAL_SYS_SIGCHLD,  &action, (struct cyg_hal_sys_sigaction*) 0)) {
        CYG_FAIL("Failed to install signal handler for SIGCHLD");
    }

    // Start up the auxiliary process.
    synth_start_auxiliary();
    
    // All done. At this stage interrupts are still disabled, no ISRs
    // have been installed, and the clock is not yet ticking.
    // Exceptions can come in and will be processed normally. SIGIO
    // and SIGALRM could come in, but nothing has yet been done
    // to make that happen.
}

// Second-stage hardware init. This is called after all C++ static
// constructors have been run, which should mean that all device
// drivers have been initialized and will have performed appropriate
// interactions with the I/O auxiliary. There should now be a
// message exchange with the auxiliary to let it know that there will
// not be any more devices, allowing it to remove unwanted frames,
// run the user's mainrc.tcl script, and so on. Also this is the
// time that the various toplevels get mapped on to the display.
//
// This request blocks until the auxiliary is ready. The return value
// indicates whether or not any errors occurred on the auxiliary side,
// and that those errors have not been suppressed using --keep-going

void
synth_hardware_init2(void)
{
    if (synth_auxiliary_running) {
        int result;
        synth_auxiliary_xchgmsg(SYNTH_DEV_AUXILIARY, SYNTH_AUXREQ_CONSTRUCTORS_DONE,
                               0, 0, (const unsigned char*) 0, 0,
                               &result,
                               (unsigned char*) 0, (int*) 0, 0);
        if ( !result ) {
            cyg_hal_sys_exit(1);
        }
    }
}