diff options
Diffstat (limited to 'arch/i386/kernel/io_apic.c')
| -rw-r--r-- | arch/i386/kernel/io_apic.c | 66 |
1 files changed, 63 insertions, 3 deletions
diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c index 350192d6ab986f..507983c513c34b 100644 --- a/arch/i386/kernel/io_apic.c +++ b/arch/i386/kernel/io_apic.c @@ -91,6 +91,46 @@ static struct irq_pin_list { int apic, pin, next; } irq_2_pin[PIN_MAP_SIZE]; +struct io_apic { + unsigned int index; + unsigned int unused[3]; + unsigned int data; +}; + +static __attribute_const__ struct io_apic __iomem *io_apic_base(int idx) +{ + return (void __iomem *) __fix_to_virt(FIX_IO_APIC_BASE_0 + idx) + + (mp_ioapics[idx].mpc_apicaddr & ~PAGE_MASK); +} + +static inline unsigned int io_apic_read(unsigned int apic, unsigned int reg) +{ + struct io_apic __iomem *io_apic = io_apic_base(apic); + writel(reg, &io_apic->index); + return readl(&io_apic->data); +} + +static inline void io_apic_write(unsigned int apic, unsigned int reg, unsigned int value) +{ + struct io_apic __iomem *io_apic = io_apic_base(apic); + writel(reg, &io_apic->index); + writel(value, &io_apic->data); +} + +/* + * Re-write a value: to be used for read-modify-write + * cycles where the read already set up the index register. + * + * Older SiS APIC requires we rewrite the index register + */ +static inline void io_apic_modify(unsigned int apic, unsigned int reg, unsigned int value) +{ + volatile struct io_apic *io_apic = io_apic_base(apic); + if (sis_apic_bug) + writel(reg, &io_apic->index); + writel(value, &io_apic->data); +} + union entry_union { struct { u32 w1, w2; }; struct IO_APIC_route_entry entry; @@ -107,12 +147,34 @@ static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin) return eu.entry; } +/* + * When we write a new IO APIC routing entry, we need to write the high + * word first! If the mask bit in the low word is clear, we will enable + * the interrupt, and we need to make sure the entry is fully populated + * before that happens. + */ static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e) { unsigned long flags; union entry_union eu; eu.entry = e; spin_lock_irqsave(&ioapic_lock, flags); + io_apic_write(apic, 0x11 + 2*pin, eu.w2); + io_apic_write(apic, 0x10 + 2*pin, eu.w1); + spin_unlock_irqrestore(&ioapic_lock, flags); +} + +/* + * When we mask an IO APIC routing entry, we need to write the low + * word first, in order to set the mask bit before we change the + * high bits! + */ +static void ioapic_mask_entry(int apic, int pin) +{ + unsigned long flags; + union entry_union eu = { .entry.mask = 1 }; + + spin_lock_irqsave(&ioapic_lock, flags); io_apic_write(apic, 0x10 + 2*pin, eu.w1); io_apic_write(apic, 0x11 + 2*pin, eu.w2); spin_unlock_irqrestore(&ioapic_lock, flags); @@ -234,9 +296,7 @@ static void clear_IO_APIC_pin(unsigned int apic, unsigned int pin) /* * Disable it in the IO-APIC irq-routing table: */ - memset(&entry, 0, sizeof(entry)); - entry.mask = 1; - ioapic_write_entry(apic, pin, entry); + ioapic_mask_entry(apic, pin); } static void clear_IO_APIC (void) |