On 14/06/2019 12:59, Alexey Kardashevskiy wrote:
> The pseries platform uses the PCI_PROBE_DEVTREE method of PCI probing
> which is basically reading "assigned-addresses" of every PCI device.
> However if the property is missing or zero sized, then there is
> no fallback of any kind and the PCI resources remain undiscovered, i.e.
> pdev->resource[] array is empty.
>
> This adds a fallback which parses the "reg" property in pretty much same
> way except it marks resources as "unset" which later makes Linux assign
> those resources with proper addresses.
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> ---
>
> This is an attempts to boot linux directly under QEMU without slof/rtas;
> the aim is to use petitboot instead and let the guest kernel configure
> devices.
>
> QEMU does not allocate resources, it creates correct "reg" and zero length
> "assigned-addresses" (which is probably a bug on its own) which is
> normally populated by SLOF later but not during this exercise.
>
> ---
> arch/powerpc/kernel/pci_of_scan.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/arch/powerpc/kernel/pci_of_scan.c
> b/arch/powerpc/kernel/pci_of_scan.c
> index 64ad92016b63..cfe6ec3c6aaf 100644
> --- a/arch/powerpc/kernel/pci_of_scan.c
> +++ b/arch/powerpc/kernel/pci_of_scan.c
> @@ -82,10 +82,18 @@ static void of_pci_parse_addrs(struct device_node *node,
> struct pci_dev *dev)
> const __be32 *addrs;
> u32 i;
> int proplen;
> + bool unset = false;
>
> addrs = of_get_property(node, "assigned-addresses", &proplen);
> if (!addrs)
> return;
Ah. Of course, these 2 lines above should go, my bad. I'll repost if
there are no other (and bigger) problems with this.
> + if (!addrs || !proplen) {
> + addrs = of_get_property(node, "reg", &proplen);
> + if (!addrs || !proplen)
> + return;
> + unset = true;
> + }
> +
> pr_debug(" parse addresses (%d bytes) @ %p\n", proplen, addrs);
> for (; proplen >= 20; proplen -= 20, addrs += 5) {
> flags = pci_parse_of_flags(of_read_number(addrs, 1), 0);
> @@ -110,6 +118,8 @@ static void of_pci_parse_addrs(struct device_node *node,
> struct pci_dev *dev)
> continue;
> }
> res->flags = flags;
> + if (unset)
> + res->flags |= IORESOURCE_UNSET;
> res->name = pci_name(dev);
> region.start = base;
> region.end = base + size - 1;
>
--
Alexey
