2008-05-14 14:34:13     Memory Protection

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2008-05-14 14:34:13     Memory Protection

Henning Manteuffel (GERMANY)

Message: 55833   


I connected an FPGA to the Blackfin address/data bus for accelerating arithmetic computations.


Is there a way to unprotect certain addresses in user space so that the FPGA can be accessed directly without a device driver? Changing entries in the DCPLB address and data registers did not work, an exception is still thrown.






2008-05-15 10:19:57     Re: Memory Protection

Mike Frysinger (UNITED STATES)

Message: 55862   


by default, all the async memory banks are usable from userspace, so there isnt anything for you to change.  i just tested by setting a pointer to 0x20000000 and reading data frorm userspace and it worked fine.


please post the crash message you're getting as well as information about your system (kernel/toolchain version/etc...)




2008-05-22 08:20:14     Re: Memory Protection

Henning Manteuffel (GERMANY)

Message: 56140   


I used the wrong toolchain (2007R1.1). Downgrading to 2007R1 eleminated the error. The toolchain seemed to be too new for the kernel.






2008-05-22 10:13:08     Re: Memory Protection


Message: 56146   




Toolchain, kernel and bootloader are three pieces of the same puzzle. You can

not just upgrade/downgrade one - you need to do all three.




Why do I need to use the same version of toolchain / kernel / uClibc /

U-boot / uClinux-dist?