Hi Robert,
On Mon, Sep 19, 2016 at 11:15:39AM -0700, Robert Jones wrote:
> Greetings,
>
> I'm looking into a PCI resource limitation issue on an IMX6 based
> board and I find that in the 3.14 kernel I am able to use 6 Ath10k
> devices with the following resources:
>
> 03:00.0 Network controller: Qualcomm Atheros QCA986x/988x 802.11ac
> Wireless Network Adapter
> Flags: fast devsel, IRQ 155
> Memory at 01200000 (64-bit, non-prefetchable) [disabled] [size=2M]
> [virtual] Expansion ROM at 01100000 [disabled] [size=64K]
> Capabilities: [40] Power Management version 2
> Capabilities: [50] MSI: Enable- Count=1/8 Maskable+ 64bit-
> Capabilities: [70] Express Endpoint, MSI 00
> Capabilities: [100] Advanced Error Reporting
> Capabilities: [140] Virtual Channel
> Capabilities: [160] Device Serial Number 00-00-00-00-00-00-00-00
>
> In the 3.15 kernel following commit
> (5b28541552ef5eeffc41d6936105f38c2508e566), allocation has changed in
> such a way that results in none of the 6 radios nor the pci based
> ethernet interface being mapped.
> I am very new to PCI but after fiddling with some of the changes in
> the aforementioned commit I was able to come up with a 1 line patch
> that allows all 6 radios to once again become mapped and usable on the
> IMX6. The patch contents being:
>
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -807,6 +807,7 @@ static struct resource
> *find_free_bus_resource(struct pci_bus *bus,
> {
> int i;
> struct resource *r;
> + type_mask = IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH;
>
> pci_bus_for_each_resource(bus, r, i) {
> if (r == &ioport_resource || r == &iomem_resource)
>
>
> I understand that this blatantly ignores the type mask parameter and
> would greatly appreciate any insight that you can provide as far as
> the proper way to proceed.
>
> 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
Can you test this with a current kernel? v3.15 is over two years old,
and there have been several fixes related to 5b28541552ef.
If a current kernel, e.g., v4.7, still fails, can you post the
complete dmesg log and contents of /proc/iomem?
Bjorn
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