MPC8548 PCIe / PCI support with BSP MPC8548CDS 02/24/2006

Zhang Wei-r63237 Wei.Zhang at
Mon Jul 3 17:54:30 EST 2006


> -----Original Message-----
> From: 
> at 
> [ at ozla
>] On Behalf Of Florian Boelstler
> Sent: Monday, July 03, 2006 2:38 PM
> To: linuxppc-embedded at
> Subject: Re: MPC8548 PCIe / PCI support with BSP MPC8548CDS 02/24/2006
> Hi,
> Zhang Wei-r63237 schrieb:
> > Yes, I think so. You can plug a PCIe ethernet card to test it. 
> A single device always works.
> > :-), Maybe it's need more study. Could you enable the DEBUG 
> and post the kernel verbose message?
> We added lots of debug output and made some modifications 
> (mostly delays between calls to early_read_config_dword() and
> early_write_config_dword() in pci_auto.c) and came to the 
> conclusion that generic bridge devices (PCIe-to-PCI), even in 
> a cascaded setup of three bridges, work fine.

Yea, that's a good news.

> However a PCIe switch (PLX8516/8532) doesn't work. The 
> MPC8548 only detects a single device (i.e. primary side of 
> the switch).
> We are going to analyze the problem more deeply soon. It 
> seems that the configuration space of that devices isn't 
> properly set up.

Just a suggestion.
Do you see below codes in mpc85xx_pex_errata.c(in read and write functions)?
	if (devfn != 0x0) 
Change them to:
	if (devfn != 0x0 && bus->number ==0) 
And try again. :-)
(If you apply my patch, please use "if (devfn != 0x0 && bus->number ==0xff)" )

> The provided patch doesn't make any difference, besides that 
> it is moved to a location where the PPC itself is not detected.
This patch fix an issue of MPC8641 PCI-Ex controller. It seems MPC8548 has no that issue. Well then fotget it.

Zhang Wei

> Please keep us informed if there is any progress besides 
> Freescale, as I will do.
> Cheers,
>    Florian
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