[PATCH v2 07/10] ARM: tegra: pcie: Add device tree support

[Thierry Reding]

On Tue, Jun 12, 2012 at 10:05:35PM -1000, Mitch Bradley wrote:
> On 6/12/2012 9:52 PM, Thierry Reding wrote:
> >I think the configuration spaces and downstream I/O ranges need to be in the
> >pcie-controller's reg property because they are remapped and used by the
> >controller driver, not by the individual ports.
> >
> >That's probably not really necessary but rather a result of how the driver
> >was written. Perhaps the driver should handle them differently instead,
> >listing the regions in the ranges property of the parent and listing the
> >corresponding partitions in the ranges properties of the pci child nodes.
> >
> >Like in the following, where the ranges property of the ports partition the
> >ranges passed from the parent evenly:
> >
> >	pcie-controller {
> >		compatible = "nvidia,tegra20-pcie";
> >		reg =<0x80003000 0x00000800   /* PADS registers */
> >		       0x80003800 0x00000200>; /* AFI registers */
> >		interrupts =<0 98 0x04   /* controller interrupt */
> >			      0 99 0x04>; /* MSI interrupt */
> >		status = "disabled";
> >
> >		ranges =<0x80000000 0x80000000 0x00002000   /* 2 root ports */
> >			  0x80004000 0x80004000 0x00100000   /* configuration space */
> >			  0x80104000 0x80100000 0x00100000   /* extended configuration space */
> >			  0x80400000 0x80400000 0x00010000   /* downstream I/O */
> >			  0x90000000 0x90000000 0x10000000   /* non-prefetchable memory */
> >			  0xa0000000 0xa0000000 0x10000000>; /* prefetchable memory */
> >
> >		#address-cells =<1>;
> >		#size-cells =<1>;
> >
> >		pci at 80000000 {
> >			reg =<0x80000000 0x00001000>;
> >			status = "disabled";
> >
> >			#address-cells =<3>;
> >			#size-cells =<2>;
> >
> >			ranges =<0x80400000 0x80400000 0x00008000   /* I/O */
> >				  0x90000000 0x90000000 0x08000000   /* non-prefetchable memory */
> >				  0xa0000000 0xa0000000 0x08000000>; /* prefetchable memory */
> 
> You are on the right track here, but the format of the child-address
> portion of the above ranges property is incorrect.  Since the child
> address space is the PCI address space, the child-address portion
> needs to be 3 cells.  It's not a linear address but rather a triple.
> The first cell identifies the address type (config, I/O, memory..)
> and the second and third cells are offsets within that subspace.
> The second and third cells will typically be 0.  The PCI binding has
> details.

Okay, I'll need to read up some more.

Thanks,
Thierry
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