On 23/07/20 10:11 am, Chris Packham wrote:

On 22/07/20 4:19 pm, Chris Packham wrote:

quoted

Hi,

I've just fired up linux kernel v5.7 on a p2040 based system and I'm 
getting the following new warning

OF: Can't handle multiple dma-ranges with different offsets on 
node(/pcie@ffe202000)
OF: Can't handle multiple dma-ranges with different offsets on 
node(/pcie@ffe202000)

The warning itself was added in commit 9d55bebd9816 ("of/address: 
Support multiple 'dma-ranges' entries") but I gather it's pointing 
out something about the dts. My boards dts is based heavily on 
p2041rdb.dts and the relevant pci2 section is identical (reproduced 
below for reference).

    pci2: pcie@ffe202000 {
        reg = <0xf 0xfe202000 0 0x1000>;
        ranges = <0x02000000 0 0xe0000000 0xc 0x40000000 0 0x20000000
              0x01000000 0 0x00000000 0xf 0xf8020000 0 0x00010000>;
        pcie@0 {
            ranges = <0x02000000 0 0xe0000000
                  0x02000000 0 0xe0000000
                  0 0x20000000

                  0x01000000 0 0x00000000
                  0x01000000 0 0x00000000
                  0 0x00010000>;
        };
    };

I haven't noticed any ill effect (aside from the scary message). I'm 
not sure if there's something missing in the dts or in the code that 
checks the ranges. Any guidance would be appreciated.

I've also just checked the T2080RDB on v5.7.9 which shows a similar issue

OF: Can't handle multiple dma-ranges with different offsets on 
node(/pcie@ffe250000)
OF: Can't handle multiple dma-ranges with different offsets on 
node(/pcie@ffe250000)
pcieport 0000:00:00.0: Invalid size 0xfffff9 for dma-range
pcieport 0000:00:00.0: AER: enabled with IRQ 21
OF: Can't handle multiple dma-ranges with different offsets on 
node(/pcie@ffe270000)
OF: Can't handle multiple dma-ranges with different offsets on 
node(/pcie@ffe270000)
pcieport 0001:00:00.0: Invalid size 0xfffff9 for dma-range
pcieport 0001:00:00.0: AER: enabled with IRQ 23

I've been doing a bit more digging. The dma-ranges property is not in 
the dts/dtb. It's actually inserted by u-boot via ft_fsl_pci_setup().

Here's some output from my T2080RDB

root@linuxbox ~]# xxd -g4 
/sys/firmware/devicetree/base/pcie@ffe240000/dma-ranges
0000000: 02000000 00000000 df000007 0000000f  ................
0000010: fe000000 00000000 00fffff9 42000000  ............B...
0000020: 00000000 00000000 00000000 00000000  ................
0000030: 00000000 df000007 43000000 00000010  ........C.......
0000040: 00000000 00000000 00000000 00000001  ................
0000050: 00000000                             ....

I'm still wondering how best to deal with this. Hopefully without 
needing to deploy a u-boot update.