IMX6SX PCI mem space failed to assign BAR0

[mattiasbarthel]

Hi!

I am trying assign the BAR0 of a FPGA PCIe interface. I get:

pci 0000:01:00.0: BAR 0: no space for [mem size 0x10000000 64bit pref]
pci 0000:01:00.0: BAR 0: failed to assign [mem size 0x10000000 64bit pref]

So the FPGA wants 268435456 Bytes of PCIe memory space. 

Is the IMX6SX PCI allocatable size a maximum of 16MB or even less?

Found this:

Note that the IMX6 has a limited memory window (16M) between the PCI
core and the memory controller. This is mapped as:

512KB config space
64KB io space
15MB mem space available for devices

Is the same for IMX6SX?

[igorpadykov]

Hi Mattias

yes it is the same for IMX6SX, as it has similar to i.MX6DQ PCIe module.

Best regards
igor
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[mattiasbarthel]

So does this mean that 16MB (or 15Mb) will work out of the box or does the kernel need to be patched?

We use 4.1.39.

[igorpadykov]

please check

https://community.freescale.com/message/334959#334959

~igor

[mattiasbarthel]

Ok, thanks. That patch is for an older kernel 3.* something.

I cant seem to match that code to anywhere.

I suspect that in this version a change to the DT is the correct way.

Something here maybe?:

pcie: pcie@0x08000000 {

........

ranges = <0x81000000 0 0 0x08f80000 0 0x00010000 /* downstream I/O */
0x82000000 0 0x08000000 0x08000000 0 0x00f00000>; /* non-prefetchable memory */

.......

Im not sure though.