PCIE device tree bindings - Could you help me to understand?

[Murali Karicheri]

Hello All,

I am working to develop a PCIE driver that requires DT bindings. Could 
someone point me to a documentation or code or explain how to interpret 
the following device tree bindings. I understand the reg property only. 
There is outbound PCIE memory and inbound PCIE memory. But can't 
understand the below bindings for the same. Also how the interrupt 
mapping works? Below dts bindings is copied from 
powerpc/boot/dts/ep405.dts. Surprisingly I am not seeing any example 
pcie bindings on ARM architecture even though there PCI or PCIE drivers 
available on ARM. Your help is appreciated.

                 PCI0: pci at ec000000 {
                         device_type = "pci";
                         #interrupt-cells = <1>;
                         #size-cells = <2>;
                         #address-cells = <3>;
                         compatible = "ibm,plb405gp-pci", "ibm,plb-pci";
                         primary;
                         reg = <0xeec00000 0x00000008    /* Config space 
access */
                                0xeed80000 0x00000004    /* IACK */
                                0xeed80000 0x00000004    /* Special cycle */
                                0xef480000 0x00000040>;  /* Internal 
registers */

                         /* Outbound ranges, one memory and one IO,
                          * later cannot be changed. Chip supports a second
                          * IO range but we don't use it for now
                          */
                         ranges = <0x02000000 0x00000000 0x80000000 
0x80000000 0x00000000 0x20000000
                                   0x01000000 0x00000000 0x00000000 
0xe8000000 0x00000000 0x00010000>;

                         /* Inbound 2GB range starting at 0 */
                         dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 
0x80000000>;

                         /* That's all I know about IRQs on that thing 
... */
                         interrupt-map-mask = <0xf800 0x0 0x0 0x0>;
                         interrupt-map = <
                                 /* USB */
                                 0x7000 0x0 0x0 0x0 &UIC0 0x1e 0x8 /* 
IRQ5 */
                         >;
                 };