[coreboot] AMDk8 - HT routing

[Marc Jones]

Viswesh S wrote:
> Hi,
> 
>  
> 
> But when you read the registers of Node7, as the device is not there, 
> what value will it return, if we try to read any register, say 0x6c for 
> getting the default link.
> 
>  
> 
> val = pci_read_config32(NODE_HT(7), 0x6c);   // What value does get 
> return, as node7 is not there.
>  byte = (val>>2) & 0x3; /*get default link on node7 to node0*/
> 
>  
> 
> Viswesh
> 
> 

Viswesh,

All AP nodes are node7 until re-numbered in the initialization process. 
Your node1 is node7 until it is told to be node1. A device that isn't 
attached (no ht link) should never be written to.

Marc





> 
> ----- Original Message ----
> From: Marc Jones <marc.jones at amd.com>
> To: Viswesh S <viswesh_vichu at yahoo.com>
> Cc: coreboot at coreboot.org
> Sent: Wednesday, 7 May, 2008 9:38:13 PM
> Subject: Re: [coreboot] AMDk8 - HT routing
> 
> Viswesh S wrote:
>  > Hi,
>  > 
>  > I am looking into the Linux bios code for AMD 64 boards.
>  > 
>  > In the setup_coherent_ht_domain function, we have functions
>  > setup_smp() and setup_smp2().
>  > 
>  > In the setup_smp2(), say the link1 is coherent and connected, we write
>  > the routing table for it, but then we veriify the connection for Node7
>  > and then try to set the routing table registers for the link between 7
>  > and 1.
>  > 
>  > //*
>  > print_linkn("(0,1) link=", byte);
>  >  setup_row_direct(0,1, byte); //
>  >  setup_temp_row(0, 1);
>  > 
>  >  verify_connection(7);
>  >  /* We found 2 nodes so far */
>  >  val = pci_read_config32(NODE_HT(7), 0x6c);
>  >  byte = (val>>2) & 0x3; /*get default link on node7 to node0*/
>  >  print_linkn("(1,0) link=", byte);
>  >  setup_row_local(7,1);
>  >  setup_remote_row_direct(1, 0, byte);
>  > *//
>  > 
>  > What is the logic reason behind checking the node7 here.
>  > 
>  > In the case of my board, there is no Node7 itself and will the
>  > pci_write(outb instruction) cause any unknown behaviour, as the node
>  > is not present.
>  > 
>  > Thanks,
>  > 
>  > Viswesh
>  >
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> 
> Hi Viswesh,
> 
> All AP nodes are node7 until they have been found and initialized by the
> BSP. The BSP looks at each active link and then sets the nodeids.
> 
> Marc
> 
> 
> -- 
> Marc Jones
> Senior Firmware Engineer
> (970) 226-9684 Office
> mailto:Marc.Jones at amd.com <mailto:Marc.Jones at amd.com>
> http://www.amd.com/embeddedprocessors
> 
> 
> 
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-- 
Marc Jones
Senior Firmware Engineer
(970) 226-9684 Office
mailto:Marc.Jones at amd.com
http://www.amd.com/embeddedprocessors