Questions regarding serial console on MPC8260ADS under Linux

Arun Dharankar ADharankar at attbi.com
Sun Apr 13 09:26:36 EST 2003


Hello...

1. After making sure that the stty/termio settings on the console port
    have "brkint", I tried sending a break (kermit, minicom and reverse
    telnet on BDI). The break does not seem to generate SIGINT.

    What could I be missing, or doing wrong? Or is my understanding
    incorrect of the brkint termio flag?


2. I would like to use the SAK/sysrq on the serial console. One thing
    seems to be missing is ASYNC_SAK flag in the ser_info_t->flags.
    So, I added it in the 8260_io/uart.c:startup(...). Also, made sure
    that /proc/sys/kernel/sysrq has "1" in it. With this much, I tried sending
    a break on the console followed by "t" (and other SAK feature keys).
    No luck.

    Could this be related to (1) above? What about the missing flag
    ASYNC_SAK in the ser_info_t info struct?


3. During Linux kernel bootup, ppc_md.progress(...) is called in a number
    of places. This is before the serial console is initialized. On the
    8260 configuration, the ppc_md.progress(...) is NULL. Has this been
    been fixed by anyone for the 8260 configuration?

    On the board I use, PPCBoot is the bootloader/monitor. So, I copied
    over the serial_putc()/serial_puts() routines to uart.c (ofcourse, the
    modified to use the same DPRAM settings/addresses as used by
    PPCBoot.

    With BDI, I can see that this ppc_md.progress()-->serial_puts()-->
    serial_putc() is called. But,
     volatile cbd_t tbdf = (cbd_t *)&im->im_dprambase[up->smc_tbase];
    Seems to cause an exception in machine_init() the first time it is
    called.  Also, up does point to 0xf0000040 (in IMAP/IMMR).

    My guess is that this is do with the address translations which are
    not setup at this instance during startup. I am not sure how to fix
    this - if this is the case.  How do I get this to work?


Best regards,
-Arun.


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