x86: dt: Cleanup local apic setup

Up to now we force enable the local apic in the devicetree setup
uncoditionally and set smp_found_config unconditionally to 1 when a
devicetree blob is available. This breaks, when local apic is disabled
in the Kconfig.

Make it consistent by initializing device tree explicitely before
smp_get_config() so a non lapic configuration could be used as well.
To be functional that would require to implement PIT as an interrupt
host, but the only user of this code until now is ce4100 which
requires apics to be available. So we leave this up to those who need
it.

Tested-by: Sebastian Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/apic.h

@@ -240,7 +240,7 @@ extern void setup_boot_APIC_clock(void);
 extern void setup_secondary_APIC_clock(void);
 extern int APIC_init_uniprocessor(void);
 extern void enable_NMI_through_LVT0(void);
-extern int apic_force_enable(void);
+extern int apic_force_enable(unsigned long addr);
 
 /*
  * On 32bit this is mach-xxx local

arch/x86/include/asm/prom.h

@@ -28,9 +28,8 @@ extern int of_ioapic;
 extern u64 initial_dtb;
 extern void add_dtb(u64 data);
 extern void x86_add_irq_domains(void);
-void x86_dtb_find_config(void);
-void x86_dtb_get_config(unsigned int unused);
 void __cpuinit x86_of_pci_init(void);
+void x86_dtb_init(void);
 
 static inline struct device_node *pci_device_to_OF_node(struct pci_dev *pdev)
 {
@@ -46,8 +45,7 @@ static inline struct device_node *pci_bus_to_OF_node(struct pci_bus *bus)
 static inline void add_dtb(u64 data) { }
 static inline void x86_add_irq_domains(void) { }
 static inline void x86_of_pci_init(void) { }
-#define x86_dtb_find_config x86_init_noop
-#define x86_dtb_get_config x86_init_uint_noop
+static inline void x86_dtb_init(void) { }
 #define of_ioapic 0
 #endif
 

arch/x86/kernel/apic/apic.c

@@ -1563,7 +1563,7 @@ static int apic_verify(void)
 	return 0;
 }
 
-int apic_force_enable(void)
+int apic_force_enable(unsigned long addr)
 {
 	u32 h, l;
 
@@ -1579,7 +1579,7 @@ int apic_force_enable(void)
 	if (!(l & MSR_IA32_APICBASE_ENABLE)) {
 		pr_info("Local APIC disabled by BIOS -- reenabling.\n");
 		l &= ~MSR_IA32_APICBASE_BASE;
-		l |= MSR_IA32_APICBASE_ENABLE | APIC_DEFAULT_PHYS_BASE;
+		l |= MSR_IA32_APICBASE_ENABLE | addr;
 		wrmsr(MSR_IA32_APICBASE, l, h);
 		enabled_via_apicbase = 1;
 	}
@@ -1620,7 +1620,7 @@ static int __init detect_init_APIC(void)
 				"you can enable it with \"lapic\"\n");
 			return -1;
 		}
-		if (apic_force_enable())
+		if (apic_force_enable(APIC_DEFAULT_PHYS_BASE))
 			return -1;
 	} else {
 		if (apic_verify())

arch/x86/kernel/devicetree.c

@@ -26,6 +26,7 @@ static DEFINE_RAW_SPINLOCK(big_irq_lock);
 
 int __initdata of_ioapic;
 
+#ifdef CONFIG_X86_IO_APIC
 static void add_interrupt_host(struct irq_domain *ih)
 {
 	unsigned long flags;
@@ -34,6 +35,7 @@ static void add_interrupt_host(struct irq_domain *ih)
 	list_add(&ih->l, &irq_domains);
 	raw_spin_unlock_irqrestore(&big_irq_lock, flags);
 }
+#endif
 
 static struct irq_domain *get_ih_from_node(struct device_node *controller)
 {
@@ -223,18 +225,28 @@ static void __init dtb_setup_hpet(void)
 static void __init dtb_lapic_setup(void)
 {
 #ifdef CONFIG_X86_LOCAL_APIC
-	if (apic_force_enable())
+	struct device_node *dn;
+	struct resource r;
+	int ret;
+
+	dn = of_find_compatible_node(NULL, NULL, "intel,ce4100-lapic");
+	if (!dn)
+		return;
+
+	ret = of_address_to_resource(dn, 0, &r);
+	if (WARN_ON(ret))
 		return;
 
+	/* Did the boot loader setup the local APIC ? */
+	if (!cpu_has_apic) {
+		if (apic_force_enable(r.start))
+			return;
+	}
 	smp_found_config = 1;
 	pic_mode = 1;
-	/* Required for ioapic registration */
-	set_fixmap_nocache(FIX_APIC_BASE, mp_lapic_addr);
-	if (boot_cpu_physical_apicid == -1U)
-		boot_cpu_physical_apicid = read_apic_id();
-
+	register_lapic_address(r.start);
 	generic_processor_info(boot_cpu_physical_apicid,
-			GET_APIC_VERSION(apic_read(APIC_LVR)));
+			       GET_APIC_VERSION(apic_read(APIC_LVR)));
 #endif
 }
 
@@ -259,9 +271,6 @@ static void __init dtb_ioapic_setup(void)
 {
 	struct device_node *dn;
 
-	if (!smp_found_config)
-		return;
-
 	for_each_compatible_node(dn, NULL, "intel,ce4100-ioapic")
 		dtb_add_ioapic(dn);
 
@@ -270,7 +279,6 @@ static void __init dtb_ioapic_setup(void)
 		return;
 	}
 	printk(KERN_ERR "Error: No information about IO-APIC in OF.\n");
-	smp_found_config = 0;
 }
 #else
 static void __init dtb_ioapic_setup(void) {}
@@ -282,14 +290,6 @@ static void __init dtb_apic_setup(void)
 	dtb_ioapic_setup();
 }
 
-void __init x86_dtb_find_config(void)
-{
-	if (initial_dtb)
-		smp_found_config = 1;
-	else
-		printk(KERN_ERR "Missing device tree!.\n");
-}
-
 #ifdef CONFIG_OF_FLATTREE
 static void __init x86_flattree_get_config(void)
 {
@@ -325,7 +325,7 @@ static void __init x86_flattree_get_config(void)
 static inline void x86_flattree_get_config(void) { }
 #endif
 
-void __init x86_dtb_get_config(unsigned int unused)
+void __init x86_dtb_init(void)
 {
 	x86_flattree_get_config();
 

arch/x86/kernel/setup.c

@@ -1044,8 +1044,8 @@ void __init setup_arch(char **cmdline_p)
 	 * Read APIC and some other early information from ACPI tables.
 	 */
 	acpi_boot_init();
-
 	sfi_init();
+	x86_dtb_init();
 
 	/*
 	 * get boot-time SMP configuration:

arch/x86/platform/ce4100/ce4100.c

@@ -134,8 +134,8 @@ void __init x86_ce4100_early_setup(void)
 	x86_init.oem.arch_setup = sdv_arch_setup;
 	x86_platform.i8042_detect = ce4100_i8042_detect;
 	x86_init.resources.probe_roms = x86_init_noop;
-	x86_init.mpparse.get_smp_config = x86_dtb_get_config;
-	x86_init.mpparse.find_smp_config = x86_dtb_find_config;
+	x86_init.mpparse.get_smp_config = x86_init_uint_noop;
+	x86_init.mpparse.find_smp_config = x86_init_noop;
 
 #ifdef CONFIG_X86_IO_APIC
 	x86_init.pci.init_irq = sdv_pci_init;