Thread (6 messages) 6 messages, 3 authors, 2010-01-20

Re: [PATCH] powerpc/4xx: Add support for type 1 pci transactions on 4xx boards

From: Felix Radensky <hidden>
Date: 2010-01-19 22:52:19

Benjamin Herrenschmidt wrote:
On Wed, 2010-01-13 at 10:18 +1100, Benjamin Herrenschmidt wrote:
  
quoted
On Tue, 2010-01-12 at 15:09 +0100, Stef van Os wrote:
    
quoted
This patch adds type 1 PCI transactions to 4xx PCI code, enabling the
discovery of
devices behind a PCI bridge.
      
Your patch appears word wrapped and whitespace damaged...

I'll fix it up manually this time around but please check your mailer
setup :-)
    
Allright, it's not quite that.

I've looked at my docs, and it looks like older parts such as the 440EP
do -not- take the config type in the low bit.

More interestingly, they only generate config 0 cycles if you pass a bus
number of 0 :-)

So we'll need do do something a little bit different here. We probably
need to indicate in the device-tree what kind of SoC we have (whether
it supports the explicit bit to choose between type 0 and type 1 or
not).

If not, we should then set the "self_busno" field of the bridge to 0,
causing indirect_pci to always use bus number 0 when trying to talk
to the bus segment behind the bridge, whatever the linux bus number
for it actually is.

Now, we need to make a precise list here of what SoC uses what. 460xx
seem to all support the explicit bit. 440EP doesn't. What else ?

Somebody from AMCC can dbl check that ?
  
I've checked what platforms take configuration type in the lower bit:

405XX - no
440EP - no
440GR - no
440EPx/440GRx - no

440GP - yes
440GX - yes
440SP - yes
440SPe - yes
460XX - yes

The distinction between these groups is pretty clear in the device trees.
The members of the first group all have "ibm,plb-pci" property, and all
members of second group have "ibm,plb-pcix" property.

So only ppc4xx_probe_pcix_bridge() routine should be fixed.

Felix.
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