powerpc/pci: Prefer PCI domain assignment via DT 'linux,pci-domain' and alias

Other Linux architectures use DT property 'linux,pci-domain' for
specifying fixed PCI domain of PCI controller specified in Device-Tree.

And lot of Freescale powerpc boards have defined numbered pci alias in
Device-Tree for every PCIe controller which number specify preferred PCI
domain.

So prefer usage of DT property 'linux,pci-domain' (via function
of_get_pci_domain_nr()) and DT pci alias (via function
of_alias_get_id()) on powerpc architecture for assigning PCI domain to
PCI controller.

Fixes: dd27a8d8aa3c ("powerpc/pci: Assign fixed PHB number based on device-tree properties")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220706102148.5060-2-pali@kernel.org

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index cbb912ee92fadf8d17d1b2d0c19bc4267cf8e1aa..8ce36aba42da0b15c7a1cd01e297c65bc464d538 100644 (file)
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -75,16 +75,30 @@ void __init set_pci_dma_ops(const struct dma_map_ops *dma_ops)
 static int get_phb_number(struct device_node *dn)
 {
        int ret, phb_id = -1;
-       u32 prop_32;
        u64 prop;
 
        /*
         * Try fixed PHB numbering first, by checking archs and reading
-        * the respective device-tree properties. Firstly, try powernv by
-        * reading "ibm,opal-phbid", only present in OPAL environment.
+        * the respective device-tree properties. Firstly, try reading
+        * standard "linux,pci-domain", then try reading "ibm,opal-phbid"
+        * (only present in powernv OPAL environment), then try device-tree
+        * alias and as the last try to use lower bits of "reg" property.
         */
-       ret = of_property_read_u64(dn, "ibm,opal-phbid", &prop);
+       ret = of_get_pci_domain_nr(dn);
+       if (ret >= 0) {
+               prop = ret;
+               ret = 0;
+       }
+       if (ret)
+               ret = of_property_read_u64(dn, "ibm,opal-phbid", &prop);
+       if (ret)
+               ret = of_alias_get_id(dn, "pci");
+       if (ret >= 0) {
+               prop = ret;
+               ret = 0;
+       }
        if (ret) {
+               u32 prop_32;
                ret = of_property_read_u32_index(dn, "reg", 1, &prop_32);
                prop = prop_32;
        }
@@ -96,10 +110,7 @@ static int get_phb_number(struct device_node *dn)
        if ((phb_id >= 0) && !test_and_set_bit(phb_id, phb_bitmap))
                return phb_id;
 
-       /*
-        * If not pseries nor powernv, or if fixed PHB numbering tried to add
-        * the same PHB number twice, then fallback to dynamic PHB numbering.
-        */
+       /* If everything fails then fallback to dynamic PHB numbering. */
        phb_id = find_first_zero_bit(phb_bitmap, MAX_PHBS);
        BUG_ON(phb_id >= MAX_PHBS);
        set_bit(phb_id, phb_bitmap);