[U-Boot] [PATCHv2] common/memsize.c: Simplify RAM size detection

[Hannes Schmelzer <hannes@schmelzer.or.at>]

On 02.02.2016 21:15, Eddy Petri?or wrote:
> The case of memory of size 0 is not that different from a memory of any other
> size, so we remove the duplicate code and treat the small differences when it
> is the case.
>
> Signed-off-by: Eddy Petri?or <eddy.petrisor@gmail.com>
> ---
>
> v2: Removed patman stuff from commit message
>
>   common/memsize.c | 47 +++++++++++++++++++++--------------------------
>   1 file changed, 21 insertions(+), 26 deletions(-)
>
> diff --git a/common/memsize.c b/common/memsize.c
> index 0fb9ba5..5c0d279 100644
> --- a/common/memsize.c
> +++ b/common/memsize.c
> @@ -33,38 +33,28 @@ long get_ram_size(long *base, long maxsize)
>   	long           size;
>   	int            i = 0;
>   
> -	for (cnt = (maxsize / sizeof(long)) >> 1; cnt > 0; cnt >>= 1) {
> +	for (cnt = (maxsize / sizeof(long)) >> 1; cnt >= 0; cnt >>= 1) {
>   		addr = base + cnt;	/* pointer arith! */
>   		sync();
> -		save[i++] = *addr;
> +		save[i] = *addr;
>   		sync();
> -		*addr = ~cnt;
> -	}
> -
> -	addr = base;
> -	sync();
> -	save[i] = *addr;
> -	sync();
> -	*addr = 0;
> -
> -	sync();
> -	if ((val = *addr) != 0) {
> -		/* Restore the original data before leaving the function. */
> -		sync();
> -		*addr = save[i];
> -		for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
> -			addr  = base + cnt;
> -			sync();
> -			*addr = save[--i];
> +		if (cnt) {
> +			i++;
> +			*addr = ~cnt;
> +		} else {
> +			*addr = 0;
>   		}
> -		return (0);
>   	}
>   
> -	for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
> +	sync();
> +	cnt = 0;
> +	do {
>   		addr = base + cnt;	/* pointer arith! */
>   		val = *addr;
> -		*addr = save[--i];
> -		if (val != ~cnt) {
> +		*addr = save[i--];
> +		sync();
> +		if (((cnt == 0) && (val != 0)) ||
> +		    ((cnt != 0) && (val != ~cnt))) {
>   			size = cnt * sizeof(long);
>   			/*
>   			 * Restore the original data
> @@ -74,11 +64,16 @@ long get_ram_size(long *base, long maxsize)
>   			     cnt < maxsize / sizeof(long);
>   			     cnt <<= 1) {
>   				addr  = base + cnt;
> -				*addr = save[--i];
> +				*addr = save[i--];
>   			}
>   			return (size);
>   		}
> -	}
> +
> +		if (cnt)
> +			cnt = cnt << 1;
> +		else
> +			cnt = 1;
> +	} while (cnt < maxsize / sizeof(long));
>   
>   	return (maxsize);
>   }
Hi Eddy,

this commit breaks my BuR AM335x boards.
The board stucks at boot:

U-Boot 2016.03-rc1-00195-g437cc77-dirty (Feb 09 2016 - 09:25:51 +0100)

initcall: 8080a384
U-Boot code: 80800000 -> 8083A6F4  BSS: -> 8088433C
initcall: 8080a174
initcall: 8080a3f0
I2C: ready
initcall: 8080a3d8
DRAM:  initcall: 80800784

has anybody else experience on am335x boards with this ?

best regards,
Hannes