2.6.x kernels & PCI-to-PCMCIA bridges [again]

[Russell King]

On Wed, Jun 30, 2004 at 09:31:56PM +0900, Komuro wrote:
> We assume that mem->sys_start is 0x0a0000000
> and we want mem->card_start = 0. 
> Note that 0x0a0000000 is 32bit number.
> 
> ((mem->card_start - mem->sys_start) >> 12) & 0x3fff
> = ((0 - 0x0a0000000) >> 12 ) & 0x3fff
> = (0x60000000 >> 12) & 0x3fff
> = 0x60000 & 0x3fff
> = 0  
> strange and wrong!

strange and correct.  Work it back to the original relationship given
in the data sheet.

	26-bit card address = memory address + 26-bit offset address

which is:

	                    = 0xa0000000 + 0x00000000

And 0xa0000000 as a 26-bit address is 0x00000000.  This happens to
be your card_start.

Therefore, your example _is_ correct.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core