RE: Purpose of pci_remap_iospace

[Bharat Kumar Gogada]

> Subject: Re: Purpose of pci_remap_iospace
>
> On Wed, Jul 13, 2016 at 12:30:44PM +0000, Bharat Kumar Gogada wrote:
>
> [...]
>
> > err = of_pci_get_host_bridge_resources(node, 0, 0xff, &res, &iobase);
> >         if (err) {
> >                 pr_err("Getting bridge resources failed\n");
> >                 return err;
> >         }
> > resource_list_for_each_entry(window, &res) {            //code for io resource
> >                 struct resource *res = window->res;
> >                 u64 restype = resource_type(res);
> >
> >                 switch (restype) {
> >                 case IORESOURCE_IO:
> >                         err = pci_remap_iospace(res, iobase);
> >                         if(err)
> >                                 pr_info("FAILED TO IPREMAP RESOURCE\n");
> >                         break;
> >                 default:
> >                         dev_err(pcie->dev, "invalid resource %pR\n",
> > res);
> >
> >                 }
> >         }
> >
> > Other than above code I haven't done any change in driver.
> >
> Here is your PCI bridge mem space window assignment. I do not see an IO
> window assignment which makes me think that IO cycles and relative IO
> window is not enabled through the bridge, that's the reason you can't assign
> IO space to the endpoint, because it has no parent IO window enabled IIUC.
>

We sorted this out, enabled the IO base limit / upper 16bit registers in the bridge for 32 bit decode.
However my IO address being assigned to EP is different than what I provide in device tree.

Device tree property:
ranges = <0x01000000 0x00000000 0x00000000 0x00000000 0xe0000000 0 0x00010000   //io
                      0x02000000 0x00000000 0xe0100000 0x00000000 0xe0100000 0 0x0ef00000>; //non prefetchabe memory

Here is the boot log:
[    2.312504] nwl-pcie fd0e0000.pcie: Link is UP
[    2.312548] PCI host bridge /amba/pcie@fd0e0000 ranges:
[    2.312565]   No bus range found for /amba/pcie@fd0e0000, using [bus 00-ff]
[    2.312591]    IO 0xe0000000..0xe000ffff -> 0x00000000
[    2.312610]   MEM 0xe0100000..0xeeffffff -> 0xe0100000
[    2.312711] nwl-pcie fd0e0000.pcie: PCI host bridge to bus 0000:00
[    2.312729] pci_bus 0000:00: root bus resource [bus 00-ff]
[    2.312745] pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
[    2.312761] pci_bus 0000:00: root bus resource [mem 0xe0100000-0xeeffffff]
[    2.312993] pci 0000:00:00.0: cannot attach to SMMU, is it on the same bus?
[    2.313009] iommu: Adding device 0000:00:00.0 to group 1
[    2.313363] pci 0000:01:00.0: cannot attach to SMMU, is it on the same bus?
[    2.313379] iommu: Adding device 0000:01:00.0 to group 1
[    2.313434] pci 0000:00:00.0: BAR 8: assigned [mem 0xe0100000-0xe02fffff]
[    2.313452] pci 0000:00:00.0: BAR 7: assigned [io  0x1000-0x1fff]
[    2.313469] pci 0000:00:00.0: BAR 6: assigned [mem 0xe0300000-0xe03007ff pref]
[    2.313495] pci 0000:01:00.0: BAR 0: assigned [mem 0xe0100000-0xe01fffff 64bit]
[    2.313529] pci 0000:01:00.0: BAR 2: assigned [mem 0xe0200000-0xe02fffff 64bit]
[    2.313561] pci 0000:01:00.0: BAR 4: assigned [io  0x1000-0x103f]
[    2.313581] pci 0000:00:00.0: PCI bridge to [bus 01-0c]
[    2.313597] pci 0000:00:00.0:   bridge window [io  0x1000-0x1fff]
[    2.313614] pci 0000:00:00.0:   bridge window [mem 0xe0100000-0xe02fffff]

If we are mapping our IO space to 0xe0000000 and 64k size, why kernel is showing 0x1000-0x1fff which is 4k ?

Lspci of bridge :
00:00.0 PCI bridge: Xilinx Corporation Device a024 (prog-if 00 [Normal decode])
        Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Interrupt: pin A routed to IRQ 224
        Bus: primary=00, secondary=01, subordinate=0c, sec-latency=0
        I/O behind bridge: 00001000-00001fff
        Memory behind bridge: e0100000-e02fffff

Lspci ofEP:
01:00.0 Memory controller: Xilinx Corporation Device d024
        Subsystem: Xilinx Corporation Device 0007
        Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Interrupt: pin A routed to IRQ 224
        Region 0: Memory at e0100000 (64-bit, non-prefetchable) [disabled] [size=1M]
        Region 2: Memory at e0200000 (64-bit, non-prefetchable) [disabled] [size=1M]
        Region 4: I/O ports at 1000 [disabled] [size=64]

I'm yet to try with the other API's you have pointed out (devm_request_resource()).

Thanks & Regards,
Bharat


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