On Friday 16 May 2014 14:30:56 Kishon Vijay Abraham I wrote:
> On Wednesday 14 May 2014 06:15 PM, Arnd Bergmann wrote:
> > On Wednesday 14 May 2014 11:14:45 Kishon Vijay Abraham I wrote:
> > / {
> >       #address-cells = <1>; // or <2> if you support > 4GB address space
> >       #size-cells = <1>;
> > 
> >       soc {
> >               #address-cells <1>;
> >               #size-cells = <1>;
> >               ranges;
> >               dma-ranges;
> > 
> >               ... // all normal devices
> > 
> >               axi@20000000 {
> >                       #size-cells = <1>;
> >                       #address-cells = <1>;
> >                       dma-ranges; // can access all 4GB outbound
> >                       ranges = <0 0x20000000 0x10000000>; // 28-bit bus
> > 
> >                       pci@0 {
> >                               reg = <0x0    0x1000>, // internal regs
> >                                     <0x1000 0x2000>; // config space
> 
> The internal reg address space starts at 0x51000000. By Using this <0
> 0x20000000 0x10000000>; as ranges, we are not able to get the memory resource
> properly. Can we use multiple ranges? how do we specify which ranges the *reg*
> property to use?

Yes, multiple ranges will work fine. You can make up a representation
yourself if you don't know what the hardware really does.

Two possible ways of doing this would be

a)

        /* two separate physical connections represented as one logical bus */
        axi@20000000 {
                #address-cells = <2>;
                #size-cells = <1>;
                ranges = <0 0 0x20000000 0x10000000>, /* configurable registers 
*/
                         <1 0 0x51000000 0x01000000>; /* PCI host registers */

                [email protected] {
                        reg = <1 0 0x01000000>, /* host registers */
                                <0 0x1000 0x2000>; /* config space */
                }

        };

b) 

        /* one physical bus, with some address munging */
        axi@20000000 {
                #address-cells = <1>;
                #size-cells = <1>;
                ranges = <0 0x20000000 0x10000000>, /* configurable registers */
                         <0x51000000 0x51000000 0x01000000>; /* PCI host 
registers */

                [email protected] {
                        reg = <0x51000000 0x01000000>, /* host registers */
                                <0x1000 0x2000>; /* config space */
                }

        };


> Btw I was using *simple-bus* as compatible to *axi*. Or should I create a new
> *axi* driver to create the pcie memory resources myself?

simple-bus is best here, since you don't have a complex bus that needs to
be set up using register accesses or that generates interrupts.

        Arnd
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