x86: Move pci init function to x86_init

The PCI initialization in pci_subsys_init() is a mess. pci_numaq_init,
pci_acpi_init, pci_visws_init and pci_legacy_init are called and each
implementation checks and eventually modifies the global variable
pcibios_scanned.

x86_init functions allow us to do this more elegant. The pci.init
function pointer is preset to pci_legacy_init. numaq, acpi and visws
can modify the pointer in their early setup functions. The functions
return 0 when they did the full initialization including bus scan. A
non zero return value indicates that pci_legacy_init needs to be
called either because the selected function failed or wants the
generic bus scan in pci_legacy_init to happen (e.g. visws).

Signed-off-by: Thomas Gleixner <[e-mail]>
LKML-Reference: <[e-mail]>
Acked-by: Jesse Barnes <[e-mail]>
Signed-off-by: Jacob Pan <[e-mail]>
Signed-off-by: H. Peter Anvin <[e-mail]>

arch/x86/include/asm/numaq.h

···
 
 extern int found_numaq;
 extern int get_memcfg_numaq(void);
+extern int pci_numaq_init(void);
 
 extern void *xquad_portio;
 

arch/x86/include/asm/pci.h

···
 
 #ifdef CONFIG_PCI
 extern unsigned int pcibios_assign_all_busses(void);
+extern int pci_legacy_init(void);
+# ifdef CONFIG_ACPI
+#  define x86_default_pci_init pci_acpi_init
+# else
+#  define x86_default_pci_init pci_legacy_init
+# endif
 #else
-#define pcibios_assign_all_busses()	0
+# define pcibios_assign_all_busses()	0
+# define x86_default_pci_init		NULL
 #endif
 
 extern unsigned long pci_mem_start;

arch/x86/include/asm/pci_x86.h

···
 
 extern unsigned int pcibios_irq_mask;
 
-extern int pcibios_scanned;
 extern spinlock_t pci_config_lock;
 
 extern int (*pcibios_enable_irq)(struct pci_dev *dev);
···
 /* some common used subsys_initcalls */
 extern int __init pci_acpi_init(void);
 extern int __init pcibios_irq_init(void);
-extern int __init pci_visws_init(void);
-extern int __init pci_numaq_init(void);
 extern int __init pcibios_init(void);
+extern int pci_legacy_init(void);
 
 /* pci-mmconfig.c */
 
···
 {
 	asm volatile("movl %%eax,(%1)" : : "a" (val), "r" (pos) : "memory");
 }
+
+#ifdef CONFIG_PCI
+# ifdef CONFIG_ACPI
+#  define x86_default_pci_init		pci_acpi_init
+# else
+#  define x86_default_pci_init		pci_legacy_init
+# endif
+#else
+# define x86_default_pci_init		NULL
+#endif

arch/x86/include/asm/setup.h

···
 
 #ifdef CONFIG_X86_VISWS
 extern void visws_early_detect(void);
-extern int is_visws_box(void);
 #else
 static inline void visws_early_detect(void) { }
-static inline int is_visws_box(void) { return 0; }
 #endif
 
 extern unsigned long saved_video_mode;

arch/x86/include/asm/visws/cobalt.h

···
 
 extern char visws_board_rev;
 
+extern int pci_visws_init(void);
+
 #endif /* _ASM_X86_VISWS_COBALT_H */

arch/x86/include/asm/x86_init.h

···
 	int (*iommu_init)(void);
 };
 
+ /*
+  * struct x86_init_pci - platform specific pci init functions
+ * @init:			platform specific pci init
+ */
+struct x86_init_pci {
+	int (*init)(void);
+};
+
 /**
  * struct x86_init_ops - functions for platform specific setup
  *
···
 	struct x86_init_paging		paging;
 	struct x86_init_timers		timers;
 	struct x86_init_iommu		iommu;
+	struct x86_init_pci		pci;
 };
 
 /**

arch/x86/kernel/acpi/boot.c

···
 #include <linux/ioport.h>
 #include <linux/pci.h>
 
+#include <asm/pci_x86.h>
 #include <asm/pgtable.h>
 #include <asm/io_apic.h>
 #include <asm/apic.h>
···
 	acpi_process_madt();
 
 	acpi_table_parse(ACPI_SIG_HPET, acpi_parse_hpet);
+
+	if (!acpi_noirq)
+		x86_init.pci.init = pci_acpi_init;
 
 	return 0;
 }

arch/x86/kernel/apic/numaq_32.c

···
 		x86_init.mpparse.mpc_oem_pci_bus = mpc_oem_pci_bus;
 		x86_init.mpparse.mpc_oem_bus_info = mpc_oem_bus_info;
 		x86_init.timers.tsc_pre_init = numaq_tsc_init;
+		x86_init.pci.init = pci_numaq_init;
 	}
 }
 

arch/x86/kernel/visws_quirks.c

···
 char visws_board_type	= -1;
 char visws_board_rev	= -1;
 
-int is_visws_box(void)
-{
-	return visws_board_type >= 0;
-}
-
 static void __init visws_time_init(void)
 {
 	printk(KERN_INFO "Starting Cobalt Timer system clock\n");
···
 	x86_init.irqs.pre_vector_init = visws_pre_intr_init;
 	x86_init.irqs.trap_init = visws_trap_init;
 	x86_init.timers.timer_init = visws_time_init;
+	x86_init.pci.init = pci_visws_init;
 
 	/*
 	 * Install reboot quirks:

arch/x86/kernel/x86_init.c

···
 
 #include <asm/bios_ebda.h>
 #include <asm/paravirt.h>
+#include <asm/pci_x86.h>
 #include <asm/mpspec.h>
 #include <asm/setup.h>
 #include <asm/apic.h>
···
 
 	.iommu = {
 		.iommu_init		= iommu_init_noop,
+	},
+
+	.pci = {
+		.init			= x86_default_pci_init,
 	},
 };
 

arch/x86/pci/acpi.c

···
 {
 	struct pci_dev *dev = NULL;
 
-	if (pcibios_scanned)
-		return 0;
-
 	if (acpi_noirq)
-		return 0;
+		return -ENODEV;
 
 	printk(KERN_INFO "PCI: Using ACPI for IRQ routing\n");
 	acpi_irq_penalty_init();
-	pcibios_scanned++;
 	pcibios_enable_irq = acpi_pci_irq_enable;
 	pcibios_disable_irq = acpi_pci_irq_disable;
 

arch/x86/pci/common.c

···
 };
 
 /*
- * legacy, numa, and acpi all want to call pcibios_scan_root
- * from their initcalls. This flag prevents that.
- */
-int pcibios_scanned;
-
-/*
  * This interrupt-safe spinlock protects all accesses to PCI
  * configuration space.
  */

arch/x86/pci/legacy.c

···
 	}
 }
 
-static int __init pci_legacy_init(void)
+int __init pci_legacy_init(void)
 {
 	if (!raw_pci_ops) {
 		printk("PCI: System does not support PCI\n");
 		return 0;
 	}
-
-	if (pcibios_scanned++)
-		return 0;
 
 	printk("PCI: Probing PCI hardware\n");
 	pci_root_bus = pcibios_scan_root(0);
···
 
 int __init pci_subsys_init(void)
 {
-#ifdef CONFIG_X86_NUMAQ
-	pci_numaq_init();
-#endif
-#ifdef CONFIG_ACPI
-	pci_acpi_init();
-#endif
-#ifdef CONFIG_X86_VISWS
-	pci_visws_init();
-#endif
-	pci_legacy_init();
+	/*
+	 * The init function returns an non zero value when
+	 * pci_legacy_init should be invoked.
+	 */
+	if (x86_init.pci.init())
+		pci_legacy_init();
+
 	pcibios_fixup_peer_bridges();
 	pcibios_irq_init();
 	pcibios_init();

arch/x86/pci/numaq_32.c

···
 {
 	int quad;
 
-	if (!found_numaq)
-		return 0;
-
 	raw_pci_ops = &pci_direct_conf1_mq;
-
-	if (pcibios_scanned++)
-		return 0;
 
 	pci_root_bus = pcibios_scan_root(0);
 	if (pci_root_bus)

arch/x86/pci/visws.c

···
 
 int __init pci_visws_init(void)
 {
-	if (!is_visws_box())
-		return -1;
-
 	pcibios_enable_irq = &pci_visws_enable_irq;
 	pcibios_disable_irq = &pci_visws_disable_irq;
 
···
 	pci_scan_bus_with_sysdata(pci_bus1);
 	pci_fixup_irqs(pci_common_swizzle, visws_map_irq);
 	pcibios_resource_survey();
-	return 0;
+	/* Request bus scan */
+	return 1;
 }