[U-Boot-Users] initialize non-transparent PCI-to-PCI bridge

Stephen Williams steve at icarus.com
Fri Jul 15 17:03:24 CEST 2005

Hash: SHA1

CuiYW wrote:
| hi, all
|     I am porting U-boot to custom cpci board (MPC8540 based). On the
| board, we use Intel non-transparent PCI-to-PCI bridge 21555 to isolate
| MPC8540 from system, and MPC8540 is connected to secondary pci bus of 21555.

We use that chip on our JSE board.

|     Because no srom is connected to 21555, we configure 21555 using
| mpc8540 (implemented in U-boot).

That's how we do it. Check out the board support files for the
JSE board in the U-Boot CVS head.

After system starts up,  mpc8540 can
| find and access 21555, but system card can not find and configure
| it(such as BAR0, BAR1). If we delay booting of system card(boot mpc8540
| firstly),  system card can find and configure 21555 successfully.
|     How to fixthe problem? Could you please give me a hand?

The bridge should initially come up configured so that the host
side configuration cycles are retried. Configure the 21555 to your
liking, then clear the PCI-Lockout bit. The chip should boot up with
the PCI-Lockout bit set. Otherwise, you are stuck.

- --
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
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