Re: [kvm-unit-tests PATCH 18/18] arm/arm64: uart0_init: check /chosen/stdout-path

[Paolo Bonzini <pbonzini@redhat.com>]

On 06/11/2015 01:24, Andrew Jones wrote:
> Arguably all of uart0_init() is unnecessary, as we're pretty sure
> that the address we initialize uart0_base to is correct. We go
> through the motions of finding the uart anyway though, because it's
> easy. It's also easy to check chosen/stdout-path first, so let's do
> that too. But, just to make all this stuff is a little less unnecessary,
> let's add a warning when we do actually find an address that doesn't
> match our initializer.
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  lib/arm/io.c | 36 +++++++++++++++++++++++++++---------
>  1 file changed, 27 insertions(+), 9 deletions(-)
> 
> diff --git a/lib/arm/io.c b/lib/arm/io.c
> index 8b1501886736a..a08d394e4aa1c 100644
> --- a/lib/arm/io.c
> +++ b/lib/arm/io.c
> @@ -19,12 +19,14 @@ extern void halt(int code);
>  /*
>   * Use this guess for the pl011 base in order to make an attempt at
>   * having earlier printf support. We'll overwrite it with the real
> - * base address that we read from the device tree later.
> + * base address that we read from the device tree later. This is
> + * the address we expect QEMU's mach-virt machine type to put in
> + * its generated device tree.
>   */
> -#define QEMU_MACH_VIRT_PL011_BASE 0x09000000UL
> +#define UART_EARLY_BASE 0x09000000UL
>  
>  static struct spinlock uart_lock;
> -static volatile u8 *uart0_base = (u8 *)QEMU_MACH_VIRT_PL011_BASE;
> +static volatile u8 *uart0_base = (u8 *)UART_EARLY_BASE;
>  
>  static void uart0_init(void)
>  {
> @@ -32,16 +34,32 @@ static void uart0_init(void)
>  	struct dt_pbus_reg base;
>  	int ret;
>  
> -	ret = dt_pbus_get_base_compatible(compatible, &base);
> -	assert(ret == 0 || ret == -FDT_ERR_NOTFOUND);
> +	ret = dt_get_default_console_node();
> +	assert(ret >= 0 || ret == -FDT_ERR_NOTFOUND);
>  
> -	if (ret) {
> -		printf("%s: %s not found in the device tree, aborting...\n",
> -			__func__, compatible);
> -		abort();
> +	if (ret == -FDT_ERR_NOTFOUND) {
> +
> +		ret = dt_pbus_get_base_compatible(compatible, &base);
> +		assert(ret == 0 || ret == -FDT_ERR_NOTFOUND);
> +
> +		if (ret) {
> +			printf("%s: %s not found in the device tree, "
> +				"aborting...\n",
> +				__func__, compatible);
> +			abort();
> +		}
> +
> +	} else {
> +		assert(dt_pbus_translate_node(ret, 0, &base) == 0);
>  	}
>  
>  	uart0_base = ioremap(base.addr, base.size);
> +
> +	if (uart0_base != (u8 *)UART_EARLY_BASE) {
> +		printf("WARNING: early print support may not work. "
> +		       "Found uart at %p, but early base is %p.\n",
> +			uart0_base, (u8 *)UART_EARLY_BASE);
> +	}
>  }
>  
>  void io_init(void)
> 

Applied, thanks.

Paolo