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About anomaly 05000263 in BF537 and expanding RAM

Question asked by juangdp on Nov 15, 2013
Latest reply on Nov 18, 2013 by Aaronwu

Hello, I was trying to expand the RAM of my Blackfin 537 from 64 MB to (at least) 128 MB, and I modified the u-boot and the kernel to achieve this. But when I thougt I got it, I found about this anomaly 05000263, and discovered that even with 64 MB, total RAM was limited to 56 MB.

 

I looked for information on the Internet, and found these pages:

http://docs.blackfin.uclinux.org/doku.php?id=faq#folder_32 

http://ez.analog.com/docs/DOC-3733

http://www.analog.com/static/imported-files/ic_anom/ADSP-BF531_BF532_BF533_anomaly_RevG.pdf

 

My blackfin is rev 0.2, so according to these, it is impossible to get more than 56-60 MB, because it is limited by the code in the kernel to avoid hardware loop errors:

 

#if (defined(CONFIG_BFIN_ICACHE) && ANOMALY_05000263)

    /* Due to a Hardware Anomaly we need to limit the size of usable instruction memory to max 60MB, 56

     * if HUNT_FOR_ZERO is on 05000263 - Hardware loop corrupted when taking an ICPLB exception

     */

#if (defined(CONFIG_DEBUG_HUNT_FOR_ZERO))

    if (memory_end >= 56 * 1024 * 1024)

        memory_end = 56 * 1024 * 1024;

#endif                /* CONFIG_DEBUG_HUNT_FOR_ZERO */

    printk(KERN_NOTICE "Warning: limiting memory to %liMB due to hardware anomaly 05000263\n", memory_end >> 20);

#endif            

 

I think it is plain that I can't use more than 64 (56) MB in my system, but I wonder what will happen if I remove those limitations in the code and recompile. What kind of errorsor malfunctioning may I see?

I did it, recompile removing the limitation, and at first everything seemed to be perfect, my system said it has 128 MB, and I could reserve much more memory in my application than before. But I finally encountered some problems when executing my application, such as "Data access CPLB miss"

 

What kind of errors may I see? There is really no chance to expand the RAM beyond the 64 MB safely?

If I use rev 0.3 and do the same process, will the problem be totally fixed and everything be ok?

 

Thanks you for your attention.

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