2009-10-29 09:06:15     ssync instruction before and after flash access

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2009-10-29 09:06:15     ssync instruction before and after flash access

Appalayagari Sreedhar (INDIA)

Message: 81865   

 

Hi,

 

I am working with the BF527 custom board with parallel nor flash interfaced to AMS0#.

 

I observed that in BF533 Ezkit flash driver code.

 

there is a ssync instruction (__builtin_bfin_ssync() ) before and after the flash read and write access. is it mandatory to put this ssync instruction before and after the flash access is there any particular reason for this?

 

My understanding is that is required for only MMR access.

 

Thank you.

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2009-10-29 09:16:18     Re: ssync instruction before and after flash access

Mike Frysinger (UNITED STATES)

Message: 81866   

 

SSYNC's force all pending system writes to complete.  it isnt just an MMR issue.

 

perhaps the bf533-ezkit flash driver uses more SSYNC's than is strictly, but no one really cares as this driver isnt intended for reuse and that flash part is not recommended.

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2009-10-29 09:38:08     Re: ssync instruction before and after flash access

Appalayagari Sreedhar (INDIA)

Message: 81868   

 

Hi Mike,

 

For write case it is ok ,but for the read case do we really need to place the ssync instruction before and after the flash access?

 

Thank you.

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2009-10-29 09:47:22     Re: ssync instruction before and after flash access

Mike Frysinger (UNITED STATES)

Message: 81869   

 

probably not, but again, we arent going to spend any time optimizing this driver

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