view packages/redboot/current/src/main.c @ 2257:467fd46113f3

* src/fs/fileio.c (do_list): Use getcwd for current directory, rather than "." which may not be implemented in the FS. * src/parse.c (redboot_exec): Conditionalise use of __mem_fault_handler to only be when stubs are included. (error_handler): Ditto for this function. * src/main.c (cyg_start): Conditionalise use of __mem_fault_handler to only be when stubs are included. (do_go): Ditto. (error_handler): Ditto for this function. * src/fs/fileio.c (do_mkdir, do_deldir, do_del, do_write): Added some extra argument checking to these functions. * src/fs/fileio.c (do_mount): Only support -f with "legacy" flash block devices. Clear mount table on failure. (do_move): Silence rename undefined warning. (do_write): Silence warnings. (do_info): Support longer device names. * src/decompress.c (ZLIB_COMPRESSION_OVERHEAD): Increase substantially if jffs2 is present. * src/fs/fileio.c: Fixed some bugs in handling of mounts. The strings used in the mount table must be copied, otherwise the mount table is corrupted by later commands. Also toughened up some error testing. * doc/redboot_cmds.sgml: Added file mode documentation to load command. * doc/redboot_cmds.sgml: Added documentation of filesystem access commands. * src/fs/fileio.c (do_write): Added O_TRUNC to the open call to ensure that the file is resized to fit the new data. * src/fs/fileio.c: Significantly reorganized to present an interface similar to the fis commands. Added a variety of command to manipulate files and directories in a filesystem. * src/parse.c: Added redboot_exec() to provide an internal interface for executing RedBoot commands. Added err_printf() which allows an error message to be printed before longjumping out to an enclosing call to redboot_exec(). Where redboot_exec() is not involved, it just behaves like diag_printf(). * src/main.c: Removed unnecessary delay during startup. Changed diag_printf() in do_go() into err_printf(). * src/load.c: Changed some calls to diag_printf() to err_printf(). * src/net/net_io.c: Changed init priority to RedBoot_INIT_NET. * include/redboot.h: Added some extra initialization priorities. Added prototypes for redboot_exec() and err_printf().
author jlarmour
date Thu, 20 Jul 2006 20:27:47 +0000
parents 5c5e93c863ac
children 6cbecf3cc2e4
line wrap: on
line source

//==========================================================================
//
//      main.c
//
//      RedBoot main routine
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004 Red Hat, Inc.
// Copyright (C) 2002, 2003, 2004 Gary Thomas
// Copyright (C) 2003, 2004, 2005, 2006 eCosCentric Limited
//
// 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.
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):    gthomas
// Contributors: gthomas, tkoeller, eCosCentric
// Date:         2000-07-14
// Purpose:      
// Description:  
//              
// This code is part of RedBoot (tm).
//
//####DESCRIPTIONEND####
//
//==========================================================================

#define  DEFINE_VARS
#include <redboot.h>
#include <cyg/hal/hal_arch.h>
#include <cyg/hal/hal_intr.h>
#include <cyg/hal/hal_if.h>
#include <cyg/hal/hal_cache.h>
#include CYGHWR_MEMORY_LAYOUT_H

#ifdef CYGPKG_IO_ETH_DRIVERS
#include <cyg/io/eth/eth_drv.h>            // Logical driver interfaces
#endif

#include <cyg/hal/hal_tables.h>
#include <cyg/infra/cyg_ass.h>         // assertion macros
#include <cyg/infra/cyg_type.h>
#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
#ifdef CYGBLD_HAL_PLATFORM_STUB_H
#include CYGBLD_HAL_PLATFORM_STUB_H
#else
#include <cyg/hal/plf_stub.h>
#endif
// GDB interfaces
extern void breakpoint(void);
#endif

// Builtin Self Test (BIST)
externC void bist(void);

// Path to code run from a go command or to GDB stubs
static void trampoline(unsigned long entry);

// Return path for code run from a go command or for GDB stubs
static void return_to_redboot(int status);

// Address of area where current context is saved before executing
// trampoline procedure
static void * saved_context;

// Status returned after trampoline execution
static int return_status;
 

// CLI command processing (defined in this file)
RedBoot_cmd("version", 
            "Display RedBoot version information",
            "",
            do_version
    );
RedBoot_cmd("help", 
            "Help about help?", 
            "[<topic>]",
            do_help 
    );

static char go_usage[] = "[-w <timeout>] [-c] "
#ifdef CYGPKG_IO_ETH_DRIVERS
                      "[-n] "
#endif
                      "[entry]";

RedBoot_cmd("go", 
            "Execute code at a location", 
            go_usage,
            do_go 
    );
#ifdef HAL_PLATFORM_RESET
RedBoot_cmd("reset", 
            "Reset the system", 
            "",
            do_reset 
    );
#endif
#ifdef CYGSEM_REDBOOT_VARIABLE_BAUD_RATE
RedBoot_cmd("baudrate", 
            "Set/Query the system console baud rate", 
            "[-b <rate>]",
            do_baud_rate
    );
#endif

// Define table boundaries
CYG_HAL_TABLE_BEGIN( __RedBoot_INIT_TAB__, RedBoot_inits );
CYG_HAL_TABLE_END( __RedBoot_INIT_TAB_END__, RedBoot_inits );
extern struct init_tab_entry __RedBoot_INIT_TAB__[], __RedBoot_INIT_TAB_END__;

CYG_HAL_TABLE_BEGIN( __RedBoot_CMD_TAB__, RedBoot_commands );
CYG_HAL_TABLE_END( __RedBoot_CMD_TAB_END__, RedBoot_commands );
extern struct cmd __RedBoot_CMD_TAB__[], __RedBoot_CMD_TAB_END__;

CYG_HAL_TABLE_BEGIN( __RedBoot_IDLE_TAB__, RedBoot_idle );
CYG_HAL_TABLE_END( __RedBoot_IDLE_TAB_END__, RedBoot_idle );
extern struct idle_tab_entry __RedBoot_IDLE_TAB__[], __RedBoot_IDLE_TAB_END__;

#ifdef HAL_ARCH_PROGRAM_NEW_STACK
extern void HAL_ARCH_PROGRAM_NEW_STACK(void *fun);
#endif

// 
// [Null] Builtin [Power On] Self Test
//
void bist(void) CYGBLD_ATTRIB_WEAK;

void
bist(void) 
{
}

//
// 'version' command
//
void
do_version(int argc, char *argv[])
{
#if CYGBLD_REDBOOT_MAX_MEM_SEGMENTS > 1
    int seg;
#endif
#ifdef CYGPKG_REDBOOT_FLASH
    externC void _flash_info(void);
#endif
    char *version = CYGACC_CALL_IF_MONITOR_VERSION();

    diag_printf(version);
#ifdef HAL_PLATFORM_CPU
    diag_printf("Platform: %s (%s) %s\n", HAL_PLATFORM_BOARD, HAL_PLATFORM_CPU, HAL_PLATFORM_EXTRA);
#endif
    diag_printf("Copyright (C) 2000, 2001, 2002, 2003, 2004 Red Hat, Inc.\n");
    diag_printf("Copyright (C) 2003, 2004, 2005, 2006 eCosCentric Limited\n\n");
    diag_printf("RAM: %p-%p, ", (void*)ram_start, (void*)ram_end);
    diag_printf("[%p-%p]", mem_segments[0].start, mem_segments[0].end);
    diag_printf(" available\n");
#if CYGBLD_REDBOOT_MAX_MEM_SEGMENTS > 1
    for (seg = 1;  seg < CYGBLD_REDBOOT_MAX_MEM_SEGMENTS;  seg++) {
        if (mem_segments[seg].start != NO_MEMORY) {
            diag_printf("     %p-%p, ", mem_segments[seg].start, mem_segments[seg].end);
            diag_printf("[%p-%p]", mem_segments[seg].start, mem_segments[seg].end);
            diag_printf(" available\n");
        }
    }
#endif
#ifdef CYGPKG_REDBOOT_FLASH
    _flash_info();
#endif
}

//
// This function is called when RedBoot is idle (waiting for user
// input).  It will call any registered "idle" routines, e.g. scan
// for incoming network connections, blank an LCD screen, etc.
//
void
do_idle(bool is_idle)
{
    struct idle_tab_entry *idle_entry;

    for (idle_entry = __RedBoot_IDLE_TAB__; 
         idle_entry != &__RedBoot_IDLE_TAB_END__;  idle_entry++) {
        (*idle_entry->fun)(is_idle);
    }
}

// Wrapper used by diag_printf()
static void
_mon_write_char(char c, void **param)
{
    if (c == '\n') {
        mon_write_char('\r');
    }
    mon_write_char(c);
}

//
// Handle illegal memory accesses (and other abort conditions)
//
static hal_jmp_buf error_jmpbuf;
#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
__externC void* volatile __mem_fault_handler;

static void error_handler(void)
{
    hal_longjmp(error_jmpbuf, 1);
}
#endif


//
// This is the main entry point for RedBoot
//

void
cyg_start(void)
{
    int res = 0;
    bool prompt = true;
    static char line[CYGPKG_REDBOOT_MAX_CMD_LINE];
    char *command;
    struct cmd *cmd;
    int cur;
    struct init_tab_entry *init_entry;
    extern char RedBoot_version[];
#if CYGBLD_REDBOOT_MAX_MEM_SEGMENTS > 1
    int seg;
#endif

    // Export version information
    CYGACC_CALL_IF_MONITOR_VERSION_SET(RedBoot_version);

    CYGACC_CALL_IF_MONITOR_RETURN_SET(return_to_redboot);

    // Make sure the channels are properly initialized.
    diag_init_putc(_mon_write_char);
    hal_if_diag_init();

    // Force console to output raw text - but remember the old setting
    // so it can be restored if interaction with a debugger is
    // required.
    cur = CYGACC_CALL_IF_SET_CONSOLE_COMM(CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT);
    CYGACC_CALL_IF_SET_CONSOLE_COMM(CYGNUM_HAL_VIRTUAL_VECTOR_DEBUG_CHANNEL);
#ifdef CYGPKG_REDBOOT_ANY_CONSOLE
    console_selected = false;
#endif
    console_echo = true;

    ram_start = (unsigned char *)CYGMEM_REGION_ram;
    ram_end = (unsigned char *)(CYGMEM_REGION_ram+CYGMEM_REGION_ram_SIZE);
#ifdef HAL_MEM_REAL_REGION_TOP
    {
        unsigned char *ram_end_tmp = ram_end;
        ram_end = HAL_MEM_REAL_REGION_TOP( ram_end_tmp );
    }
#endif
#ifdef CYGMEM_SECTION_heap1
    workspace_start = (unsigned char *)CYGMEM_SECTION_heap1;
    workspace_end = (unsigned char *)(CYGMEM_SECTION_heap1+CYGMEM_SECTION_heap1_SIZE);
#else
    workspace_start = (unsigned char *)CYGMEM_REGION_ram;
    workspace_end = (unsigned char *)(CYGMEM_REGION_ram+CYGMEM_REGION_ram_SIZE);
#endif

    if ( ram_end < workspace_end ) {
        // when *less* SDRAM is installed than the possible maximum,
        // but the heap1 region remains greater...
        workspace_end = ram_end;
    }

    workspace_end_init=workspace_end;

    // Nothing has ever been loaded into memory
    entry_address = (unsigned long)NO_MEMORY;

    bist();

#if defined(CYGPRI_REDBOOT_ZLIB_FLASH) && defined(CYGOPT_REDBOOT_FIS_ZLIB_COMMON_BUFFER)
    fis_zlib_common_buffer =
    workspace_end -= CYGNUM_REDBOOT_FIS_ZLIB_COMMON_BUFFER_SIZE;
#endif

#ifdef CYGFUN_REDBOOT_BOOT_SCRIPT
    script_timeout = CYGNUM_REDBOOT_BOOT_SCRIPT_DEFAULT_TIMEOUT;
#endif

    for (init_entry = __RedBoot_INIT_TAB__; init_entry != &__RedBoot_INIT_TAB_END__;  init_entry++) {
        (*init_entry->fun)();
    }

    mem_segments[0].start = workspace_start;
    mem_segments[0].end = workspace_end;
#if CYGBLD_REDBOOT_MAX_MEM_SEGMENTS > 1
    for (seg = 1;  seg < CYGBLD_REDBOOT_MAX_MEM_SEGMENTS;  seg++) {
        cyg_plf_memory_segment(seg, &mem_segments[seg].start, &mem_segments[seg].end);
    }
#endif

#ifdef CYGSEM_REDBOOT_PLF_STARTUP

    cyg_plf_redboot_startup();
#endif
    do_version(0,0);

#ifdef CYGFUN_REDBOOT_BOOT_SCRIPT
# ifdef CYGDAT_REDBOOT_DEFAULT_BOOT_SCRIPT
    if (!script) {
      script = CYGDAT_REDBOOT_DEFAULT_BOOT_SCRIPT;
    }
# endif
    if (script) {
        // Give the guy a chance to abort any boot script
        unsigned char *hold_script = script;
        int script_timeout_ms = script_timeout * CYGNUM_REDBOOT_BOOT_SCRIPT_TIMEOUT_RESOLUTION;
        diag_printf("== Executing boot script in %d.%03d seconds - enter ^C to abort\n", 
                    script_timeout_ms/1000, script_timeout_ms%1000);
        script = (unsigned char *)0;
        res = _GETS_CTRLC;  // Treat 0 timeout as ^C
        while (script_timeout_ms >= CYGNUM_REDBOOT_CLI_IDLE_TIMEOUT) {
            res = _rb_gets(line, sizeof(line), CYGNUM_REDBOOT_CLI_IDLE_TIMEOUT);
            if (res >= _GETS_OK) {
                diag_printf("== Executing boot script in %d.%03d seconds - enter ^C to abort\n", 
                            script_timeout_ms/1000, script_timeout_ms%1000);
                continue;  // Ignore anything but ^C
            }
            if (res != _GETS_TIMEOUT) break;
            script_timeout_ms -= CYGNUM_REDBOOT_CLI_IDLE_TIMEOUT;
        }
        if (res == _GETS_CTRLC) {
            script = (unsigned char *)0;  // Disable script
        } else {
            script = hold_script;  // Re-enable script
        }
    }
#endif
    CYG_ASSERT(workspace_start < workspace_end, 
               "negative workspace size");
    while (true) {
        if (prompt) {
            diag_printf("RedBoot> ");
            prompt = false;
        }
#if CYGNUM_REDBOOT_CMD_LINE_EDITING != 0
        cmd_history = true;  // Enable history collection
#endif
        res = _rb_gets(line, sizeof(line), CYGNUM_REDBOOT_CLI_IDLE_TIMEOUT);
#if CYGNUM_REDBOOT_CMD_LINE_EDITING != 0
        cmd_history = false;  // Enable history collection
#endif
        if (res == _GETS_TIMEOUT) {
            // No input arrived
        } else {
#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
            if (res == _GETS_GDB) {
		int dbgchan;
                hal_virtual_comm_table_t *__chan;
                int i;
                // Special case of '$' - need to start GDB protocol
                gdb_active = true;
                // Mask interrupts on all channels
                for (i = 0;  i < CYGNUM_HAL_VIRTUAL_VECTOR_NUM_CHANNELS;  i++) {
                    CYGACC_CALL_IF_SET_CONSOLE_COMM(i);
                    __chan = CYGACC_CALL_IF_CONSOLE_PROCS();
                    CYGACC_COMM_IF_CONTROL( *__chan, __COMMCTL_IRQ_DISABLE );
                }
    
                CYGACC_CALL_IF_SET_CONSOLE_COMM(cur);

                // set up a temporary context that will take us to the trampoline
                HAL_THREAD_INIT_CONTEXT((CYG_ADDRWORD)workspace_end,
                                        breakpoint, trampoline,0);

                // switch context to trampoline (get GDB stubs started)
                HAL_THREAD_SWITCH_CONTEXT(&saved_context, &workspace_end);

                gdb_active = false;

		dbgchan = CYGACC_CALL_IF_SET_DEBUG_COMM(CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT);
		CYGACC_CALL_IF_SET_CONSOLE_COMM(dbgchan);
            } else 
#endif // CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
            {
                expand_aliases(line, sizeof(line));
		command = (char *)&line;
                if ((*command == '#') || (*command == '=')) {
                    // Special cases
                    if (*command == '=') {
                        // Print line on console
                        diag_printf("%s\n", &line[2]);
                    }
                } else {
                    while (strlen(command) > 0) {                    
                        if ((cmd = parse(&command, &argc, &argv[0])) != (struct cmd *)0) {
                            // Try to handle aborts - messy because of the stack unwinding...
#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
                            __mem_fault_handler = error_handler;
#endif
                            if (hal_setjmp(error_jmpbuf)) {
                                diag_printf("** command abort - illegal memory access?\n");
                            } else {
                                (cmd->fun)(argc, argv);
                            }
#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
                            __mem_fault_handler = 0;
#endif
                        } else {
                            diag_printf("** Error: Illegal command: \"%s\"\n", argv[0]);
                        }
                    }
                }
                prompt = true;
            }
        }
    }
}

void
show_help(struct cmd *cmd, struct cmd *cmd_end, char *which, char *pre)
{
    bool show;
    int len = 0;

    if (which) {
        len = strlen(which);
    }
    while (cmd != cmd_end) {
        show = true;
        if (which && (strncasecmp(which, cmd->str, len) != 0)) {
            show = false;
        }
        if (show) {
            diag_printf("%s\n  %s %s %s\n", cmd->help, pre, cmd->str, cmd->usage);
            if ((cmd->sub_cmds != (struct cmd *)0) && (which != (char *)0)) {
                show_help(cmd->sub_cmds, cmd->sub_cmds_end, 0, cmd->str);
            }
        }
        cmd++;
    }
}

void
do_help(int argc, char *argv[])
{
    struct cmd *cmd;
    char *which = (char *)0;

    if (!scan_opts(argc, argv, 1, 0, 0, (void *)&which, OPTION_ARG_TYPE_STR, "<topic>")) {
        diag_printf("Invalid argument\n");
        return;
    }
    cmd = __RedBoot_CMD_TAB__;
    show_help(cmd, &__RedBoot_CMD_TAB_END__, which, "");
    return;
}

static void
trampoline(unsigned long entry)
{
    typedef void code_fun(void);
    code_fun *fun = (code_fun *)entry;
    unsigned long oldints;

    HAL_DISABLE_INTERRUPTS(oldints);

#ifdef HAL_ARCH_PROGRAM_NEW_STACK
    HAL_ARCH_PROGRAM_NEW_STACK(fun);
#else
    (*fun)();
#endif

    HAL_THREAD_LOAD_CONTEXT(&saved_context);
}

static void
return_to_redboot(int status)
{
    CYGARC_HAL_SAVE_GP();

    return_status = status;
    HAL_THREAD_LOAD_CONTEXT(&saved_context);
    // never returns

    // need this to balance above CYGARC_HAL_SAVE_GP on
    // some platforms. It will never run, though.
    CYGARC_HAL_RESTORE_GP();
}

void
do_go(int argc, char *argv[])
{
    int i, cur, num_options;
    unsigned long entry;
    unsigned long oldints;
    bool wait_time_set;
    int  wait_time, res;
    bool cache_enabled = false;
#ifdef CYGPKG_IO_ETH_DRIVERS
    bool stop_net = false;
#endif
    struct option_info opts[3];
    char line[8];
    hal_virtual_comm_table_t *__chan;

#ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS
    __mem_fault_handler = 0; // Let GDB handle any faults directly
#endif
    entry = entry_address;  // Default from last 'load' operation
    init_opts(&opts[0], 'w', true, OPTION_ARG_TYPE_NUM, 
              (void *)&wait_time, (bool *)&wait_time_set, "wait timeout");
    init_opts(&opts[1], 'c', false, OPTION_ARG_TYPE_FLG, 
              (void *)&cache_enabled, (bool *)0, "go with caches enabled");
    num_options = 2;
#ifdef CYGPKG_IO_ETH_DRIVERS
    init_opts(&opts[2], 'n', false, OPTION_ARG_TYPE_FLG, 
              (void *)&stop_net, (bool *)0, "go with network driver stopped");
    num_options++;
#endif

    CYG_ASSERT(num_options <= NUM_ELEMS(opts), "Too many options");

    if (!scan_opts(argc, argv, 1, opts, num_options, (void *)&entry, OPTION_ARG_TYPE_NUM, "starting address"))
    {
        return;
    }
    if (entry == (unsigned long)NO_MEMORY) {
        err_printf("No entry point known - aborted\n");
        return;
    }
    if (wait_time_set) {
        int script_timeout_ms = wait_time * 1000;
#ifdef CYGSEM_REDBOOT_FLASH_CONFIG
        unsigned char *hold_script = script;
        script = (unsigned char *)0;
#endif
        diag_printf("About to start execution at %p - abort with ^C within %d seconds\n",
                    (void *)entry, wait_time);
        while (script_timeout_ms >= CYGNUM_REDBOOT_CLI_IDLE_TIMEOUT) {
            res = _rb_gets(line, sizeof(line), CYGNUM_REDBOOT_CLI_IDLE_TIMEOUT);
            if (res == _GETS_CTRLC) {
#ifdef CYGSEM_REDBOOT_FLASH_CONFIG
                script = hold_script;  // Re-enable script
#endif
                return;
            }
            script_timeout_ms -= CYGNUM_REDBOOT_CLI_IDLE_TIMEOUT;
        }
    }

    // Mask interrupts on all channels
    cur = CYGACC_CALL_IF_SET_CONSOLE_COMM(CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT);
    for (i = 0;  i < CYGNUM_HAL_VIRTUAL_VECTOR_NUM_CHANNELS;  i++) {
	CYGACC_CALL_IF_SET_CONSOLE_COMM(i);
	__chan = CYGACC_CALL_IF_CONSOLE_PROCS();
	CYGACC_COMM_IF_CONTROL( *__chan, __COMMCTL_IRQ_DISABLE );
    }
    CYGACC_CALL_IF_SET_CONSOLE_COMM(cur);

    __chan = CYGACC_CALL_IF_CONSOLE_PROCS();
    CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_ENABLE_LINE_FLUSH);

#ifdef CYGPKG_IO_ETH_DRIVERS
    if (stop_net)
	eth_drv_stop();
#endif
	
    HAL_DISABLE_INTERRUPTS(oldints);
    HAL_DCACHE_SYNC();
    if (!cache_enabled) {
	HAL_ICACHE_DISABLE();
	HAL_DCACHE_DISABLE();
	HAL_DCACHE_SYNC();
    }
    HAL_ICACHE_INVALIDATE_ALL();
    HAL_DCACHE_INVALIDATE_ALL();
    // set up a temporary context that will take us to the trampoline
    HAL_THREAD_INIT_CONTEXT((CYG_ADDRWORD)workspace_end, 
                            entry, trampoline, 0);

    // switch context to trampoline
    HAL_THREAD_SWITCH_CONTEXT(&saved_context, &workspace_end);

    // we get back here by way of return_to_redboot()

    // undo the changes we made before switching context
    if (!cache_enabled) {
	HAL_ICACHE_ENABLE();
	HAL_DCACHE_ENABLE();
    }

    CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_DISABLE_LINE_FLUSH);

    HAL_RESTORE_INTERRUPTS(oldints);

    diag_printf("\nProgram completed with status %d\n", return_status);
}

#ifdef HAL_PLATFORM_RESET
void
do_reset(int argc, char *argv[])
{
    diag_printf("... Resetting.");
    CYGACC_CALL_IF_DELAY_US(2*100000);
    diag_printf("\n");
    CYGACC_CALL_IF_RESET();
    diag_printf("!! oops, RESET not working on this platform\n");
}
#endif

#ifdef CYGSEM_REDBOOT_VARIABLE_BAUD_RATE
#ifdef CYGSEM_REDBOOT_FLASH_CONFIG
#include <flash_config.h>
#endif

static int
set_comm_baud_rate(hal_virtual_comm_table_t *chan, int rate)
{
    int current_rate;

    current_rate = CYGACC_COMM_IF_CONTROL(*chan, __COMMCTL_GETBAUD);
    if (rate != current_rate)
        return CYGACC_COMM_IF_CONTROL(*chan, __COMMCTL_SETBAUD, rate);

    return 0;
}

int
set_console_baud_rate(int rate)
{
    int ret = -1;
#ifdef CYGPKG_REDBOOT_ANY_CONSOLE
    if (!console_selected) {
        int cur = CYGACC_CALL_IF_SET_CONSOLE_COMM(CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT);
        int i;
        // Set baud for all channels
        for (i = 0;  i < CYGNUM_HAL_VIRTUAL_VECTOR_COMM_CHANNELS;  i++) {
            CYGACC_CALL_IF_SET_CONSOLE_COMM(i);
	    ret = set_comm_baud_rate(CYGACC_CALL_IF_CONSOLE_PROCS(), rate);
	    if (ret < 0)
		break;
        }
        CYGACC_CALL_IF_SET_CONSOLE_COMM(cur);
    } else
#endif
    ret = set_comm_baud_rate(CYGACC_CALL_IF_CONSOLE_PROCS(), rate);

    if (ret < 0)
	diag_printf("Setting console baud rate to %d failed\n", rate);

    return ret;
}

static void
_sleep(int ms)
{
    int i;
    for (i = 0;  i < ms;  i++) {
        CYGACC_CALL_IF_DELAY_US((cyg_int32)1000);
    }
}

void
do_baud_rate(int argc, char *argv[])
{
    int new_rate, ret, old_rate;
    bool new_rate_set;
    hal_virtual_comm_table_t *__chan;
    struct option_info opts[1];
#ifdef CYGSEM_REDBOOT_FLASH_CONFIG
    struct config_option opt;
#endif

    init_opts(&opts[0], 'b', true, OPTION_ARG_TYPE_NUM, 
              (void *)&new_rate, (bool *)&new_rate_set, "new baud rate");
    if (!scan_opts(argc, argv, 1, opts, 1, 0, 0, "")) {
        return;
    }
    __chan = CYGACC_CALL_IF_CONSOLE_PROCS();
    if (new_rate_set) {
        diag_printf("Baud rate will be changed to %d - update your settings\n", new_rate);
        _sleep(500);  // Give serial time to flush
        old_rate = CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_GETBAUD);
        ret = set_console_baud_rate(new_rate);
        if (ret < 0) {
            if (old_rate > 0) {
                // Try to restore
                set_console_baud_rate(old_rate);
                _sleep(500);  // Give serial time to flush
                diag_printf("\nret = %d\n", ret);
            }
            return;  // Couldn't set the desired rate
        }
        // Make sure this new rate works or back off to previous value
        // Sleep for a few seconds, then prompt to see if it works
        _sleep(3000);  // Give serial time to flush
        if (!verify_action_with_timeout(5000, "Baud rate changed to %d", new_rate)) {
            _sleep(500);  // Give serial time to flush
            set_console_baud_rate(old_rate);
            _sleep(500);  // Give serial time to flush
            return;
        }
#ifdef CYGSEM_REDBOOT_FLASH_CONFIG
        opt.type = CONFIG_INT;
        opt.enable = (char *)0;
        opt.enable_sense = 1;
        opt.key = "console_baud_rate";
        opt.dflt = new_rate;
        flash_add_config(&opt, true);
#endif
    } else {
        ret = CYGACC_COMM_IF_CONTROL(*__chan, __COMMCTL_GETBAUD);
        diag_printf("Baud rate = ");
        if (ret <= 0) {
            diag_printf("unknown\n");
        } else {
            diag_printf("%d\n", ret);
        }
    }
}
#endif

//
// Validate an address to see if it is within any known RAM area
//
bool
valid_address(unsigned char *addr)
{
    int seg;

    for (seg = 0;  seg < CYGBLD_REDBOOT_MAX_MEM_SEGMENTS;  seg++) {
        if (mem_segments[seg].start != NO_MEMORY) {
            if ((addr >= mem_segments[seg].start) && (addr < mem_segments[seg].end)) {
                return true;
            }
        }
    }
    return false;
}