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

[Stephen Warren <swarren@wwwdotorg.org>]

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?

> +		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');
> +	}
> +}