I have P2020 RDB to which i have connected a miniPCIe board on which 2 ICs are there.
I am able to access the mini pCie device in uboot log as shown-
PCIe1: Root Complex of mini PCIe SLOT, x1, regs @ 0xffe0a000
01:00.0 - 104c:8240 - Bridge device
02:00.0 - 4ddc:1a00 - Simple comm. controller
02:01.0 - 4ddc:1a00 - Simple comm. controller
And further command show in the log as follows-
pci header 02.00.0
vendor ID = 0x4ddc
device ID = 0x1a00
command register = 0x0006
status register = 0x02a0
revision ID = 0x10
class code = 0x07 (Simple comm. controller)
sub class code = 0x80
programming interface = 0x00
cache line = 0x08
latency time = 0x80
header type = 0x00
BIST = 0x00
base address 0 = 0x80000000
base address 1 = 0x80040000
base address 2 = 0x00000000
base address 3 = 0x00000000
base address 4 = 0x00000000
base address 5 = 0x00000000
cardBus CIS pointer = 0x00000000
I want to access the registers inside the device at "2.00.0". Seeing the BAR0, I gave the following command-
md 0x80000000 10. 

Is it correct way to access the registers inside the pCIe device? How do i know whether i am accessing correct memory address. Can anyone tell.