[U-Boot] [PATCH 4/5] tegra: Provide tegra_pre_console_panic() for early panics

[Simon Glass]

Hi Stephen,

On Mon, Mar 19, 2012 at 2:16 PM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 03/19/2012 02:27 PM, Simon Glass wrote:
>> This function is made available to board which want to display a message
>> when a panic() occurs before the console is set up. This would otherwise
>> result in a silent hang or reboot.
>>
>> Boards should call tegra_pre_console_panic() and pass the UARTs which
>> are available and safe for a message, as well as the selected clock and
>> serial multiplier values. Defaults are available as
>> CONFIG_DEFAULT_NS16550_CLK and CONFIG_DEFAULT_NS16550_MULT.
> ...
>> diff --git a/arch/arm/cpu/armv7/tegra2/board.c b/arch/arm/cpu/armv7/tegra2/board.c
> ...
>> +void tegra_pre_console_panic(int uart_ids, unsigned clock_freq,
>> +                          unsigned multiplier, const char *str)
>> +{
>> +     int baudrate, divisor;
>> +     const u32 *uart_addr;
>> +
>> +     /* Enable all permitted UARTs */
>> +     tegra_setup_uarts(uart_ids);
>
> That call honors uart_ids. ...
>
>> +     /*
>> +      * Now send the string out all the selected  UARTs. We don't try all
>> +      * possible configurations, but this could be added if required.
>> +      */
>> +     baudrate = CONFIG_BAUDRATE;
>> +     divisor = (clock_freq + (baudrate * (multiplier / 2))) /
>> +                     (multiplier * baudrate);
>> +
>> +     for (uart_addr = uart_reg_addr; *uart_addr; uart_addr++) {
>
> Shouldn't this loop also honor uart_ids, and skip sending data to UARTS
> not in uart_ids? Sure, they aren't set up above, but perhaps they were
> set up elsewhere in the code and hence are capable of sending out data
> anyway?

No, my intent was to use the same value but I overlooked it. I will fix this.

>
>> +             NS16550_t regs = (NS16550_t)*uart_addr;
>> +             const char *s;
>> +
>> +             NS16550_init(regs, divisor);
>> +             for (s = str; *s; s++) {
>> +                     NS16550_putc(regs, *s);
>> +                     if (*s == '\n')
>> +                             NS16550_putc(regs, '\r');
>> +             }
>> +             NS16550_putc(regs, '\n');
>> +             NS16550_putc(regs, '\r');
>> +     }
>> +}

Regards,
Simon