[U-Boot] valid RAM region on a 256MB fails occasionally

Hi !

I am trying to run a u-boot.bin from the RAM as a standalone application and occationally my board hangs and resets. i found the place it breaks but dont have any clue why..

After the u-boot.img is loaded, i get the cmd prompt and run run the u-boot.bin from by boot partition of emmc U-Boot# fatload mmc 1:1 0x84000000 u-boot.bin reading u-boot.bin 388959 bytes read in 44 ms (8.4 MiB/s) U-Boot# go 0x84000000 ## Starting application at 0x84000000 ...

Here the u-boot.bin starts and runs fine most of the time. occationally i get the following and system hangs and resets.

RAM Configuration: Bank #0: 80000000 DRAM: 1 GiB

I have a 256M lpDDR Ram on our custom board and for some reason u-boot calculates the wrong (1Gb) on the bad cases..

Here is the file it reports the calculated RAM size.. u-boot-2015.07/common/memsize.c.

I added some debug prints and here are the outputs for a valid case and occational bad reset..

function modified: ---------------------

long get_ram_size(long *base, long maxsize) { volatile long *addr; long save[32]; long cnt; long val; long size; int i = 0;

printf("The value of base is %ld and max value is %ld and size of long is %d \n", *base, maxsize, sizeof(long));

for (cnt = (maxsize / sizeof(long)) >> 1; cnt > 0; cnt >>= 1) { addr = base + cnt; /* pointer arith! */ printf("address= %ld ", *addr); sync(); save[i++] = *addr; printf("save[%d]=%ld \n", i, *addr); sync(); *addr = ~cnt; } printf("The address val is %ld ", *addr); addr = base; sync(); save[i] = *addr; sync(); *addr = 0; printf("save[%d]=%ld \n", i, *addr); sync(); if ((val = *addr) != 0) { /* Restore the original data before leaving the function. */ puts(" The value of addr is 0 \n"); sync(); *addr = save[i]; for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) { addr = base + cnt; sync(); *addr = save[--i]; } puts("Returning zero size !!!"); return (0); }

for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) { addr = base + cnt; /* pointer arith! */ val = *addr; *addr = save[--i];

printf("base=%ld , val=%ld , address,save[%d]=%ld, cnt=%ld and ~cnt=%ld \n",*base, val,i,*addr,cnt,~cnt);

if (val != ~cnt) { size = cnt * sizeof(long);

printf("calulated size is %ld \n!!!!", size); /* * Restore the original data * before leaving the function. */ for (cnt <<= 1; cnt < maxsize / sizeof(long); cnt <<= 1) { addr = base + cnt; *addr = save[--i]; }

printf("returning cal size %ld \n!!!!", size); return (size); } }

puts("returning max size!!!!"); return (maxsize); }

Bad Case: ---------------- http://u-boot.10912.n7.nabble.com/file/n226040/bad.jpg

Good Case: --------------

http://u-boot.10912.n7.nabble.com/file/n226040/good.jpg

I get a value even after the valid RAM range and this happens randomly.. I have caches enabled in both the u-boot.img and u-boot.bin. please let me know if i am missing anything..

Thanks, Harsha

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