MIPS: PCI: Support for CONFIG_PCI_DOMAINS_GENERIC

Introduce support for CONFIG_PCI_DOMAINS_GENERIC, allowing for platforms
to make use of generic PCI domains instead of the MIPS-specific
implementation. The set_pci_need_domain_info function is introduced to
abstract away the removed need_domain_info field in struct
pci_controller, and pcibios_scanbus is adjusted to use the pci_domain_nr
accessor instead of directly accessing the index field.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14341/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -2995,6 +2995,9 @@ config HT_PCI
 config PCI_DOMAINS
 	bool
 
+config PCI_DOMAINS_GENERIC
+	bool
+
 source "drivers/pci/Kconfig"
 
 #

arch/mips/include/asm/pci.h

@@ -39,10 +39,12 @@ struct pci_controller {
 	struct resource *busn_resource;
 	unsigned long busn_offset;
 
+#ifndef CONFIG_PCI_DOMAINS_GENERIC
 	unsigned int index;
 	/* For compatibility with current (as of July 2003) pciutils
 	   and XFree86. Eventually will be removed. */
 	unsigned int need_domain_info;
+#endif
 
 	/* Optional access methods for reading/writing the bus number
 	   of the PCI controller */
@@ -101,14 +103,31 @@ struct pci_dev;
  */
 #define PCI_DMA_BUS_IS_PHYS     (1)
 
-#ifdef CONFIG_PCI_DOMAINS
+#ifdef CONFIG_PCI_DOMAINS_GENERIC
+static inline int pci_proc_domain(struct pci_bus *bus)
+{
+	return pci_domain_nr(bus);
+}
+
+static inline void set_pci_need_domain_info(struct pci_controller *hose,
+					    int need_domain_info)
+{
+	/* nothing to do */
+}
+#elif defined(CONFIG_PCI_DOMAINS)
 #define pci_domain_nr(bus) ((struct pci_controller *)(bus)->sysdata)->index
 
 static inline int pci_proc_domain(struct pci_bus *bus)
 {
 	struct pci_controller *hose = bus->sysdata;
 	return hose->need_domain_info;
 }
+
+static inline void set_pci_need_domain_info(struct pci_controller *hose,
+					    int need_domain_info)
+{
+	hose->need_domain_info = need_domain_info;
+}
 #endif /* CONFIG_PCI_DOMAINS */
 
 #endif /* __KERNEL__ */

arch/mips/pci/pci.c

@@ -95,8 +95,8 @@ static void pcibios_scanbus(struct pci_controller *hose)
 				&resources);
 	hose->bus = bus;
 
-	need_domain_info = need_domain_info || hose->index;
-	hose->need_domain_info = need_domain_info;
+	need_domain_info = need_domain_info || pci_domain_nr(bus);
+	set_pci_need_domain_info(hose, need_domain_info);
 
 	if (!bus) {
 		pci_free_resource_list(&resources);