diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/mips/kernel/i8259.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/mips/kernel/i8259.c')
-rw-r--r-- | arch/mips/kernel/i8259.c | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/arch/mips/kernel/i8259.c b/arch/mips/kernel/i8259.c new file mode 100644 index 00000000000..7eec7568bfe --- /dev/null +++ b/arch/mips/kernel/i8259.c @@ -0,0 +1,331 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Code to handle x86 style IRQs plus some generic interrupt stuff. + * + * Copyright (C) 1992 Linus Torvalds + * Copyright (C) 1994 - 2000 Ralf Baechle + */ +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/ioport.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/spinlock.h> +#include <linux/sysdev.h> + +#include <asm/i8259.h> +#include <asm/io.h> + +void enable_8259A_irq(unsigned int irq); +void disable_8259A_irq(unsigned int irq); + +/* + * This is the 'legacy' 8259A Programmable Interrupt Controller, + * present in the majority of PC/AT boxes. + * plus some generic x86 specific things if generic specifics makes + * any sense at all. + * this file should become arch/i386/kernel/irq.c when the old irq.c + * moves to arch independent land + */ + +spinlock_t i8259A_lock = SPIN_LOCK_UNLOCKED; + +static void end_8259A_irq (unsigned int irq) +{ + if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)) && + irq_desc[irq].action) + enable_8259A_irq(irq); +} + +#define shutdown_8259A_irq disable_8259A_irq + +void mask_and_ack_8259A(unsigned int); + +static unsigned int startup_8259A_irq(unsigned int irq) +{ + enable_8259A_irq(irq); + + return 0; /* never anything pending */ +} + +static struct hw_interrupt_type i8259A_irq_type = { + "XT-PIC", + startup_8259A_irq, + shutdown_8259A_irq, + enable_8259A_irq, + disable_8259A_irq, + mask_and_ack_8259A, + end_8259A_irq, + NULL +}; + +/* + * 8259A PIC functions to handle ISA devices: + */ + +/* + * This contains the irq mask for both 8259A irq controllers, + */ +static unsigned int cached_irq_mask = 0xffff; + +#define cached_21 (cached_irq_mask) +#define cached_A1 (cached_irq_mask >> 8) + +void disable_8259A_irq(unsigned int irq) +{ + unsigned int mask = 1 << irq; + unsigned long flags; + + spin_lock_irqsave(&i8259A_lock, flags); + cached_irq_mask |= mask; + if (irq & 8) + outb(cached_A1,0xA1); + else + outb(cached_21,0x21); + spin_unlock_irqrestore(&i8259A_lock, flags); +} + +void enable_8259A_irq(unsigned int irq) +{ + unsigned int mask = ~(1 << irq); + unsigned long flags; + + spin_lock_irqsave(&i8259A_lock, flags); + cached_irq_mask &= mask; + if (irq & 8) + outb(cached_A1,0xA1); + else + outb(cached_21,0x21); + spin_unlock_irqrestore(&i8259A_lock, flags); +} + +int i8259A_irq_pending(unsigned int irq) +{ + unsigned int mask = 1 << irq; + unsigned long flags; + int ret; + + spin_lock_irqsave(&i8259A_lock, flags); + if (irq < 8) + ret = inb(0x20) & mask; + else + ret = inb(0xA0) & (mask >> 8); + spin_unlock_irqrestore(&i8259A_lock, flags); + + return ret; +} + +void make_8259A_irq(unsigned int irq) +{ + disable_irq_nosync(irq); + irq_desc[irq].handler = &i8259A_irq_type; + enable_irq(irq); +} + +/* + * This function assumes to be called rarely. Switching between + * 8259A registers is slow. + * This has to be protected by the irq controller spinlock + * before being called. + */ +static inline int i8259A_irq_real(unsigned int irq) +{ + int value; + int irqmask = 1 << irq; + + if (irq < 8) { + outb(0x0B,0x20); /* ISR register */ + value = inb(0x20) & irqmask; + outb(0x0A,0x20); /* back to the IRR register */ + return value; + } + outb(0x0B,0xA0); /* ISR register */ + value = inb(0xA0) & (irqmask >> 8); + outb(0x0A,0xA0); /* back to the IRR register */ + return value; +} + +/* + * Careful! The 8259A is a fragile beast, it pretty + * much _has_ to be done exactly like this (mask it + * first, _then_ send the EOI, and the order of EOI + * to the two 8259s is important! + */ +void mask_and_ack_8259A(unsigned int irq) +{ + unsigned int irqmask = 1 << irq; + unsigned long flags; + + spin_lock_irqsave(&i8259A_lock, flags); + /* + * Lightweight spurious IRQ detection. We do not want to overdo + * spurious IRQ handling - it's usually a sign of hardware problems, so + * we only do the checks we can do without slowing down good hardware + * nnecesserily. + * + * Note that IRQ7 and IRQ15 (the two spurious IRQs usually resulting + * rom the 8259A-1|2 PICs) occur even if the IRQ is masked in the 8259A. + * Thus we can check spurious 8259A IRQs without doing the quite slow + * i8259A_irq_real() call for every IRQ. This does not cover 100% of + * spurious interrupts, but should be enough to warn the user that + * there is something bad going on ... + */ + if (cached_irq_mask & irqmask) + goto spurious_8259A_irq; + cached_irq_mask |= irqmask; + +handle_real_irq: + if (irq & 8) { + inb(0xA1); /* DUMMY - (do we need this?) */ + outb(cached_A1,0xA1); + outb(0x60+(irq&7),0xA0);/* 'Specific EOI' to slave */ + outb(0x62,0x20); /* 'Specific EOI' to master-IRQ2 */ + } else { + inb(0x21); /* DUMMY - (do we need this?) */ + outb(cached_21,0x21); + outb(0x60+irq,0x20); /* 'Specific EOI' to master */ + } + spin_unlock_irqrestore(&i8259A_lock, flags); + return; + +spurious_8259A_irq: + /* + * this is the slow path - should happen rarely. + */ + if (i8259A_irq_real(irq)) + /* + * oops, the IRQ _is_ in service according to the + * 8259A - not spurious, go handle it. + */ + goto handle_real_irq; + + { + static int spurious_irq_mask = 0; + /* + * At this point we can be sure the IRQ is spurious, + * lets ACK and report it. [once per IRQ] + */ + if (!(spurious_irq_mask & irqmask)) { + printk(KERN_DEBUG "spurious 8259A interrupt: IRQ%d.\n", irq); + spurious_irq_mask |= irqmask; + } + atomic_inc(&irq_err_count); + /* + * Theoretically we do not have to handle this IRQ, + * but in Linux this does not cause problems and is + * simpler for us. + */ + goto handle_real_irq; + } +} + +static int i8259A_resume(struct sys_device *dev) +{ + init_8259A(0); + return 0; +} + +static struct sysdev_class i8259_sysdev_class = { + set_kset_name("i8259"), + .resume = i8259A_resume, +}; + +static struct sys_device device_i8259A = { + .id = 0, + .cls = &i8259_sysdev_class, +}; + +static int __init i8259A_init_sysfs(void) +{ + int error = sysdev_class_register(&i8259_sysdev_class); + if (!error) + error = sysdev_register(&device_i8259A); + return error; +} + +device_initcall(i8259A_init_sysfs); + +void __init init_8259A(int auto_eoi) +{ + unsigned long flags; + + spin_lock_irqsave(&i8259A_lock, flags); + + outb(0xff, 0x21); /* mask all of 8259A-1 */ + outb(0xff, 0xA1); /* mask all of 8259A-2 */ + + /* + * outb_p - this has to work on a wide range of PC hardware. + */ + outb_p(0x11, 0x20); /* ICW1: select 8259A-1 init */ + outb_p(0x00, 0x21); /* ICW2: 8259A-1 IR0-7 mapped to 0x00-0x07 */ + outb_p(0x04, 0x21); /* 8259A-1 (the master) has a slave on IR2 */ + if (auto_eoi) + outb_p(0x03, 0x21); /* master does Auto EOI */ + else + outb_p(0x01, 0x21); /* master expects normal EOI */ + + outb_p(0x11, 0xA0); /* ICW1: select 8259A-2 init */ + outb_p(0x08, 0xA1); /* ICW2: 8259A-2 IR0-7 mapped to 0x08-0x0f */ + outb_p(0x02, 0xA1); /* 8259A-2 is a slave on master's IR2 */ + outb_p(0x01, 0xA1); /* (slave's support for AEOI in flat mode + is to be investigated) */ + + if (auto_eoi) + /* + * in AEOI mode we just have to mask the interrupt + * when acking. + */ + i8259A_irq_type.ack = disable_8259A_irq; + else + i8259A_irq_type.ack = mask_and_ack_8259A; + + udelay(100); /* wait for 8259A to initialize */ + + outb(cached_21, 0x21); /* restore master IRQ mask */ + outb(cached_A1, 0xA1); /* restore slave IRQ mask */ + + spin_unlock_irqrestore(&i8259A_lock, flags); +} + +/* + * IRQ2 is cascade interrupt to second interrupt controller + */ +static struct irqaction irq2 = { + no_action, 0, CPU_MASK_NONE, "cascade", NULL, NULL +}; + +static struct resource pic1_io_resource = { + "pic1", 0x20, 0x3f, IORESOURCE_BUSY +}; + +static struct resource pic2_io_resource = { + "pic2", 0xa0, 0xbf, IORESOURCE_BUSY +}; + +/* + * On systems with i8259-style interrupt controllers we assume for + * driver compatibility reasons interrupts 0 - 15 to be the i8295 + * interrupts even if the hardware uses a different interrupt numbering. + */ +void __init init_i8259_irqs (void) +{ + int i; + + request_resource(&ioport_resource, &pic1_io_resource); + request_resource(&ioport_resource, &pic2_io_resource); + + init_8259A(0); + + for (i = 0; i < 16; i++) { + irq_desc[i].status = IRQ_DISABLED; + irq_desc[i].action = 0; + irq_desc[i].depth = 1; + irq_desc[i].handler = &i8259A_irq_type; + } + + setup_irq(2, &irq2); +} |