[uClinux-dev] RE: How to use SRAM as driver buffer?

Fang Vincent-r65806 Vincent.Fang at freescale.com
Mon Aug 15 21:50:01 EDT 2005


I think this problem goes to this:
Make uClinux support discontinues memory, or different regions in memory. One region is for default allocation, and the other is for user specific allocation. We need modify page frames and virtual address conversion, add a new malloc function. Is this a correct way? 


Best Regards,
Vincent Fang


-----Original Message-----
From: Fang Vincent-r65806 
Sent: Monday, August 15, 2005 3:50 PM
To: uClinux-dev
Subject: How to use SRAM as driver buffer?

 I'm using SDRAM as IDE driver buffer. That is, in the read()/write() system calls, a buffer pointer located in SDRAM was used as the "buf" parameter. Due to performance, I need to use buffer in SRAM. It works for some driver like USB driver, when I pass a pointer in SDRAM (0x20000000 for example). But for IDE driver, file system is in the path. uClinux only initiated page frames for SDRAM, so uClinux can't find the page frame of address in SDRAM. At last the IDE driver got a wrong buffer_head, and can't fill the buffer in SRAM. 
Is there any way to use SRAM just as SDRAM?  Thanks for any advise.

Best Regards,
Vincent Fang

 




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