Re: [ECOS] RedBoot gets() implimentation question

[Gary Thomas <gthomas@cambridge.redhat.com>]

On 19-Jan-2001 Grant Edwards wrote:
> On Thu, Jan 18, 2001 at 04:08:52PM -0700, Gary Thomas wrote:
> 
>> > That means that network polling stops and TCP sockets (and
>> > associated timers) go dead between between the time the first
>> > character is received and the newline is received?  [I don't
>> > think that's a problem, but it's something to keep in mind.]
>> 
>> Correct.  This was a design choice - avoid the overhead of polling
>> for potential new TCP connections (all that's really going on here)
>> once data starts coming in.
> 
> You must be able to type a lot faster than me.  ;)
> 
>> > I'm also curious about the inner loop:
>> > 
>> >             mon_set_read_char_timeout(50);
>> >             while (timeout > 0) {
>> >                 res = mon_read_char_with_timeout(&c);
>> >                 if (res) {
>> >                     // Got a character
>> >                     break;
>> >                 }
>> >                 timeout -= 50;
>> >             }
>> > 
>> > Would the following be equivalent?
>> > 
>> >             mon_set_read_char_timeout(timeout);
>> >             res = mon_read_char_with_timeout(&c);
>> 
>> Yes and no.  Yes - the overall timeout would be the same.  No since
>> we want to go back and check for new TCP connections as often as is
>> reasonable.
> 
> I can't figure out where the check for TCP connections is done.
> Is mon_read_char_with_timeout() supposed to call __tcp_poll()
> in some way that I've broken?  My tests with ping seem to
> verify that on my board TCP polling is done once every 250ms
> (the value of timeout) while waiting for the first character of
> a command line.

No, it actually only happens in "main.c" while RedBoot is waiting for
the command line itself.

    while (true) {
        if (prompt) {
            printf("RedBoot> ");
            prompt = false;
        }
        res = gets(line, sizeof(line), 250);
        if (res == _GETS_TIMEOUT) {
            // No input arrived
#ifdef CYGPKG_REDBOOT_NETWORKING
            if (have_net) {
                // Check for incoming TCP debug connection
                net_io_test();
            }
#endif
        } else {
            if (res == _GETS_GDB) {
                // Special case of '$' - need to start GDB protocol
                CYGACC_CALL_IF_SET_CONSOLE_COMM(cur);
#ifdef HAL_ARCH_PROGRAM_NEW_STACK
                HAL_ARCH_PROGRAM_NEW_STACK(breakpoint);
#else
                breakpoint();  // Get GDB stubs started, with a proper environment, etc.
#endif
            } else {
                if (strlen(line) > 0) {
                    if ((cmd = parse(line, &argc, &argv[0])) != (struct cmd *)0) {
                        (cmd->fun)(argc, argv);
                    } else {
                        printf("** Error: Illegal command: \"%s\"\n", argv[0]);
                    }
                }
                prompt = true;
            }
        }
    }