Dear Gerd Hoffmann,
In message <1413910153-5907-1-git-send-email-kra...@redhat.com> you wrote:
> The original memory sizing code in get_ram_size clobbers the word
> at the base address, but forgets to restore it.
The funny thing is that it avtually works on some boards. Do you have
an explanation for that?
> - long save[32];
> + long save[32], save_base;
Why do you need another variable? The original code stores the value
as last entry in save[] - what's wrong with that?
> + save_base = base[0];
> + sync ();
You add this code here, but...
> for (cnt = (maxsize / sizeof (long)) >> 1; cnt > 0; cnt >>= 1) {
> addr = base + cnt; /* pointer arith! */
> sync ();
> @@ -43,8 +46,6 @@ long get_ram_size(long *base, long maxsize)
>
> addr = base;
> sync ();
> - save[i] = *addr;
> - sync ();
...remove it's equivalent here. Why would your code be any better
than the existing one?
> - *addr = save[i];
> for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
> addr = base + cnt;
> sync ();
> *addr = save[--i];
> }
> + base[0] = save_base;
Same here - the line you removed above does the very same as the one
you add here. In which way is the new code supposed to be different
or even better?
> @@ -73,10 +74,12 @@ long get_ram_size(long *base, long maxsize)
> addr = base + cnt;
> *addr = save[--i];
> }
> + base[0] = save_base;
> return (size);
> }
> }
>
> + base[0] = save_base;
> return (maxsize);
Agreed here. These two make sense to me. I still wonder why it works
on the boards I used for testing, while it's failing on yours.
Which exit path are you taking? The one at the end of the function,
i. e. "return (maxsize)" ? What happens if you double the memory
size to be checked?
I'll resend a slightly reworked patch in a minute; could you please
test if this works for you, too?
Thanks.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de
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