2008-03-29 00:00:01     a quetion about cache and l1-ram

2008-03-29 00:00:01     a quetion about cache and l1-ram

david wang (CHINA)

Message: 53281   

Hi, all

  I've a question for a long time. In my case, I want to use both l1-text and l1-data in my kernel driver, and also want to enable I-CACHE and D-CACHE to make my userspace application running faster. I do this by using __attribute__((section(.l1.data))) and __attribute__((section(.l1.text)))  in my driver, and by selecting I-CACHE and D-CACHE( only use BANK A) enable  in  making menuconfig. It works fine to me for a long time( from Dec 2007),  until I upgrade the kernel and toolchain to 2008-r1-rc8. It'll will corrupt each time when the userspace program running reporting NULL POINTER error. It seems the driver codes not in the correct l1 address. But even when I disable both cache the situation is the same.

  My question is, is it possible to allocate memory manually by defining code with __attribute__((section(l1.text))  when cache (I-CACHE and D-CACHE)  is enable? if I allocate a large data in l1, how will the cache works? I'm very confused with this problem. Thanks for any help!

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2008-03-29 00:10:12     Re: a quetion about cache and l1-ram

Mike Frysinger (UNITED STATES)

Message: 53287    please read the documentation:

http://docs.blackfin.uclinux.org/doku.php?id=using_l1_memory