2011-01-12 12:13:39     question about CONFIG_NR_DRAM_BANKS

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2011-01-12 12:13:39     question about CONFIG_NR_DRAM_BANKS

Matt Prewett (UNITED STATES)

Message: 97404   

 

I am working on some boards which use BF524 and Micron MT48H16M16LF.  On most of these boards, the ADDR18/ADDR19 pins on the BF524 are connected to the SDRAM's BA0/BA1 pins (respectively).  I have u-boot running and booting the application loader file without any issues.

 

On one (older) variation of these boards, the SDRAM BA0/BA1 pins are not connected to anything.  We can run the application with the default (VDSP) bootloader as long as we force the linker to use bank 0.  However, u-boot seems to have an issue with this board.  When I load the application into SDRAM and then run bootldr at that address, I get "No ldr image at address...".  I know the transmitted files are good because bootldr accepts them on the newer boards.

 

In trying to avoid potential bank addressing pitfalls, I tried loady/bootldr at address 0x00100000 and even 0x0.  This approach worked on the newer boards but I get "No ldr image at address" on the older boards.

 

I was looking through the u-boot source code and I see many boards have a "Physical Memory Map" area where they define CONFIG_NR_DRAM_BANKS and many of the boards have this defined as 1.  Could I use this approach to tell u-boot to not use bank addressing between the BF524 and the SDRAM?

 

-Matt

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2011-01-12 12:18:48     Re: question about CONFIG_NR_DRAM_BANKS

Mike Frysinger (UNITED STATES)

Message: 97405   

 

there is no support for CONFIG_NR_DRAM_BANKS in the Blackfin port

 

u-boot itself runs at the top of SDRAM.  if you want to force only usage of a certain bank, change your CONFIG_MEM_SIZE to however much RAM you want to use.

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2011-01-12 12:38:28     Re: question about CONFIG_NR_DRAM_BANKS

Matt Prewett (UNITED STATES)

Message: 97406   

 

I'm using a 32MB SDRAM device which is organized as 4 Meg x 16 x 4 banks so I think I would need to set CONFIG_MEM_SIZE to 8 in order to remain in bank 0.  I see some code that tests for 16, 32, 64, etc.  Do you know a low value like 8 is supported?

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2011-01-12 12:43:50     Re: question about CONFIG_NR_DRAM_BANKS

Mike Frysinger (UNITED STATES)

Message: 97407   

 

might be simpler to set CONFIG_SYS_MAX_RAM_SIZE to '8 * 1024 * 1024'

 

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2011-01-12 14:19:56     Re: question about CONFIG_NR_DRAM_BANKS

Matt Prewett (UNITED STATES)

Message: 97408   

 

That worked.  Thanks so much!!!

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