[U-Boot] [PATCH] Add bootcount to AT91

[Tom]

Anders Darander wrote:
> From: Anders Darander <ad at datarespons.se>
> 



> Use AT91_GPBR 3 as a bootcount register.
> 
> Signed-off-by: Anders Darander <ad at datarespons.se>
> ---
>  cpu/arm926ejs/at91/cpu.c |   28 ++++++++++++++++++++++++++++
>  1 files changed, 28 insertions(+), 0 deletions(-)
> 
> diff --git a/cpu/arm926ejs/at91/cpu.c b/cpu/arm926ejs/at91/cpu.c
> index f2f7b62..09c1376 100644
> --- a/cpu/arm926ejs/at91/cpu.c
> +++ b/cpu/arm926ejs/at91/cpu.c
> @@ -31,6 +31,11 @@
>  #define AT91_MAIN_CLOCK 0
>  #endif
>  
> +/* The at91sam9260 has 4 GPBR (0-3), we'll use the last one, nr 3,
> + * to keep track of the bootcount. */

multi-line comments are
/*
  *Comment lines
  */

> +#define AT91_GPBR_BOOTCOUNT_REGISTER 3
> +#define AT91_BOOTCOUNT_ADDRESS (AT91_GPBR + 4*AT91_GPBR_BOOTCOUNT_REGISTER)
> +
>  int arch_cpu_init(void)
>  {
>  	return at91_clock_init(AT91_MAIN_CLOCK);
> @@ -52,3 +57,26 @@ int print_cpuinfo(void)
>  	return 0;
>  }
>  #endif
> +
> +#ifdef CONFIG_BOOTCOUNT_LIMIT
> +
> +void bootcount_store (ulong a)
> +{
> +	volatile ulong *save_addr =
> +		(volatile ulong *)(AT91_BASE_SYS + AT91_BOOTCOUNT_ADDRESS);
> +
> +	*save_addr = (BOOTCOUNT_MAGIC & 0xffff0000) | a;

implied length of a is 16 bits.
the  parameter type passed in should be explicitly cast/masked to u16.

I see sharing the 32 bits this way is how mpc5xxx does it..

But

mpc8260, mpc83xx, mpc8xx, ppc4xx, ipx store the bootcount_magic and the
parameter as 2 32bit values.

Is there a memory limitation on why you can not follow what most of the others
are doing ? If there is, please add the explanation as a comment.

Thank you for pinging me,
Tom