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Re: RedBoot gets() implimentation question
- To: Grant Edwards <grante at visi dot com>
- Subject: Re: [ECOS] RedBoot gets() implimentation question
- From: Gary Thomas <gthomas at cambridge dot redhat dot com>
- Date: Fri, 19 Jan 2001 08:43:21 -0700 (MST)
- Cc: ecos-discuss at sources dot redhat dot com
- Organization: Red Hat, Inc.
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;
}
}
}