thanks，you are right, it really init the chip through UBL.
BUT, there is also one question:
DM9000a 's driver has 8 bit accessing function:
#define CONFIG_DM9000_BASE 0x04000000
#define DM9000_IO CONFIG_DM9000_BASE
#define DM9000_DATA (CONFIG_DM9000_BASE+2) // (BA1,it's the 16bit
least significant bit (effective) )
#define DM9000_outb(d,r) ( *(volatile u8 *)r = d )
#define DM9000_inb(r) (*(volatile u8 *)r)
static u8 DM9000_ior(int reg)
{
DM9000_outb(reg, DM9000_IO);
return DM9000_inb(DM9000_DATA);
}
/*
Write a byte to I/O port
*/
static void DM9000_iow(int reg, u8 value)
{
DM9000_outb(reg, DM9000_IO);
DM9000_outb(value, DM9000_DATA);
}
and the davinci's chipselect space is 16bit. when accessing it as 8bit ,the
last bit(may be A-2 ?) will be effective, but the least significant bit(BA1)
will not be effective, am i wrong? how does it work?
2010/7/19 Stefano Babic <sba...@denx.de>
> yaojin liu wrote:
> > hi:
> > dm9000a works as 16bit bus width. however, i have not seen any init code
> for
> > the dm355's chipselect.
> > and by default ,the cs1 is 8bit bus width at reset. how doew it work?
>
> I think the setup is done by the UBL provided by TI. U-boot is a 3-rd
> stage bootloader for DM355. The RBL (Rom Bootloader) loads the UBL from
> storage, that sets up the required peripherals (RAM / AEMIF), and then
> loads u-boot.
>
> u-boot does not set the a2cr register in the AEMIF interface, but the
> UBL has already configured it for 16-bit access.
>
> Best regards,
> Stefano Babic
>
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