* Questions on PCI & Linux Kernel
@ 2001-01-30 18:17 Jan Rovins
2001-01-30 18:48 ` Dan Malek
0 siblings, 1 reply; 2+ messages in thread
From: Jan Rovins @ 2001-01-30 18:17 UTC (permalink / raw)
To: Linux PPC Embeded (E-mail); +Cc: 'Adrian Cox'
We are working on a Linux port to 860 cards that have a PLX 9060 & PLX 9054
PCI Bus master chips.
My Co-worker Steve has gotten some advice & example code for a PLX9080
implementation from Adrian Cox, (Thanks loads!).
I have some general basic questions here that I am posting to the list in
general so that others in a similar situation can benefit.
I need a better understanding of the stuff in io.h, & how it needs to be set
up for our PCI chip to work.
Our boards memory map is as follows
PCI chip interface registers: 0xC100,0000 - 0xC101,0000
PCI I/O Space: 0x6000,0000 - 0x8000,0000
PCI Mem Space: 0x4000,0000 - 0x5FFF,FFFF
I am looking for some clear explanations of the following io.h conventions:
PCI_ISA_IO_ADDR: 0x60000000
is it ok to have a physical address here?
I do a ioremap of the this physical into isa_io_base is that
correct?
PCI_ISA_IO_SIZE:0x20000000
PCI_ISA_MEM_ADDR: 0x40000000
PCI_ISA_MEM_SIZE: 0x20000000
PCI_CSR_ADDR: 0xc1000000
I take this to be the beginning of local access to our PCI chip,
or should it be the beginning of a specific register of the chip?
Physical address Ok? or do we need to ioremap again?
PCI_CSR_SIZE: 0x10000
_IO_BASE: 0x60000000
Should this be a Physical or virtual address?
should it correspond to isa_io_base?
isa_io_base: 0xc4011000
an ioremap of PCI_ISA_IO_ADDR
isa_mem_base: 0xc4017000
an ioremap of PCI_ISA_MEM_ADDR
pci_dram_offset: 0x8000000
PCI_DRAM_OFFSET: 0x80000000
This is being Hard set somewhere in the CONFIG_8XX code path, and I
need to grab control of it. (TBD)
Any explanations will be helpful
Thanks,
Jan Rovins
Member Technical Staff
S-Link Corp.
jrovins@ss7-link•com
856-642-9229 X-228
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* Re: Questions on PCI & Linux Kernel
2001-01-30 18:17 Questions on PCI & Linux Kernel Jan Rovins
@ 2001-01-30 18:48 ` Dan Malek
0 siblings, 0 replies; 2+ messages in thread
From: Dan Malek @ 2001-01-30 18:48 UTC (permalink / raw)
To: Jan Rovins; +Cc: Linux PPC Embeded (E-mail), 'Adrian Cox'
Jan Rovins wrote:
> Our boards memory map is as follows
> PCI chip interface registers: 0xC100,0000 - 0xC101,0000
> PCI I/O Space: 0x6000,0000 - 0x8000,0000
> PCI Mem Space: 0x4000,0000 - 0x5FFF,FFFF
OK.
>
> I am looking for some clear explanations of the following io.h conventions:
For 8xx, these definitions should go into your board specific file,
see mbx.h for example. On MPC8xx boards, these addresses are all over
the place, and it is not appropriate to hack up io.h for this.
> PCI_ISA_IO_ADDR: 0x60000000
> is it ok to have a physical address here?
Yes, that is what it is supposed to be (and should match the BARs
in your PCI devices....well must match :-).
> I do a ioremap of the this physical into isa_io_base is that
> correct?
Yes, but.......
> PCI_ISA_IO_SIZE:0x20000000
> PCI_ISA_MEM_ADDR: 0x40000000
> PCI_ISA_MEM_SIZE: 0x20000000
OK, but......
> PCI_CSR_ADDR: 0xc1000000
> I take this to be the beginning of local access to our PCI chip,
> or should it be the beginning of a specific register of the chip?
Depends how you want to access it. It has to be properly aligned.
> Physical address Ok? or do we need to ioremap again?
You MUST ioremap to access it.
> PCI_CSR_SIZE: 0x10000
> _IO_BASE: 0x60000000
> Should this be a Physical or virtual address?
> should it correspond to isa_io_base?
It should be #define _IO_BASE isa_io_base
> isa_io_base: 0xc4011000
> an ioremap of PCI_ISA_IO_ADDR
> isa_mem_base: 0xc4017000
> an ioremap of PCI_ISA_MEM_ADDR
> pci_dram_offset: 0x8000000
> PCI_DRAM_OFFSET: 0x80000000
Which is it? This is the address of the physical memory as seen from
a PCI master viewpoint.
> This is being Hard set somewhere in the CONFIG_8XX code path, and I
> need to grab control of it. (TBD)
OK, here is the 'but' part.......You can only ioremap the CSR address
in the MMU_init code. The others must wait until the kernel VM is
initialized (mem_init_done is set, like later in 'm8xx_setup'). You
can only access your PCI memory and I/O space through VM windows in
the kernel space. If you map these too early, you get a 1:1 mapping
virt:phys which will break everything because those virtual addresses
belong to user application space.
-- Dan
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