diff options
Diffstat (limited to 'arch/powerpc/sysdev/i8259.c')
| -rw-r--r-- | arch/powerpc/sysdev/i8259.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c new file mode 100644 index 0000000..90bce6e --- /dev/null +++ b/arch/powerpc/sysdev/i8259.c @@ -0,0 +1,221 @@ +/* + * i8259 interrupt controller driver. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ +#include <linux/init.h> +#include <linux/ioport.h> +#include <linux/interrupt.h> +#include <asm/io.h> +#include <asm/i8259.h> + +static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */ + +static unsigned char cached_8259[2] = { 0xff, 0xff }; +#define cached_A1 (cached_8259[0]) +#define cached_21 (cached_8259[1]) + +static DEFINE_SPINLOCK(i8259_lock); + +static int i8259_pic_irq_offset; + +/* + * Acknowledge the IRQ using either the PCI host bridge's interrupt + * acknowledge feature or poll. How i8259_init() is called determines + * which is called. It should be noted that polling is broken on some + * IBM and Motorola PReP boxes so we must use the int-ack feature on them. + */ +int i8259_irq(struct pt_regs *regs) +{ + int irq; + + spin_lock(&i8259_lock); + + /* Either int-ack or poll for the IRQ */ + if (pci_intack) + irq = readb(pci_intack); + else { + /* Perform an interrupt acknowledge cycle on controller 1. */ + outb(0x0C, 0x20); /* prepare for poll */ + irq = inb(0x20) & 7; + if (irq == 2 ) { + /* + * Interrupt is cascaded so perform interrupt + * acknowledge on controller 2. + */ + outb(0x0C, 0xA0); /* prepare for poll */ + irq = (inb(0xA0) & 7) + 8; + } + } + + if (irq == 7) { + /* + * This may be a spurious interrupt. + * + * Read the interrupt status register (ISR). If the most + * significant bit is not set then there is no valid + * interrupt. + */ + if (!pci_intack) + outb(0x0B, 0x20); /* ISR register */ + if(~inb(0x20) & 0x80) + irq = -1; + } + + spin_unlock(&i8259_lock); + return irq + i8259_pic_irq_offset; +} + +int i8259_irq_cascade(struct pt_regs *regs, void *unused) +{ + return i8259_irq(regs); +} + +static void i8259_mask_and_ack_irq(unsigned int irq_nr) +{ + unsigned long flags; + + spin_lock_irqsave(&i8259_lock, flags); + irq_nr -= i8259_pic_irq_offset; + if (irq_nr > 7) { + cached_A1 |= 1 << (irq_nr-8); + inb(0xA1); /* DUMMY */ + outb(cached_A1, 0xA1); + outb(0x20, 0xA0); /* Non-specific EOI */ + outb(0x20, 0x20); /* Non-specific EOI to cascade */ + } else { + cached_21 |= 1 << irq_nr; + inb(0x21); /* DUMMY */ + outb(cached_21, 0x21); + outb(0x20, 0x20); /* Non-specific EOI */ + } + spin_unlock_irqrestore(&i8259_lock, flags); +} + +static void i8259_set_irq_mask(int irq_nr) +{ + outb(cached_A1,0xA1); + outb(cached_21,0x21); +} + +static void i8259_mask_irq(unsigned int irq_nr) +{ + unsigned long flags; + + spin_lock_irqsave(&i8259_lock, flags); + irq_nr -= i8259_pic_irq_offset; + if (irq_nr < 8) + cached_21 |= 1 << irq_nr; + else + cached_A1 |= 1 << (irq_nr-8); + i8259_set_irq_mask(irq_nr); + spin_unlock_irqrestore(&i8259_lock, flags); +} + +static void i8259_unmask_irq(unsigned int irq_nr) +{ + unsigned long flags; + + spin_lock_irqsave(&i8259_lock, flags); + irq_nr -= i8259_pic_irq_offset; + if (irq_nr < 8) + cached_21 &= ~(1 << irq_nr); + else + cached_A1 &= ~(1 << (irq_nr-8)); + i8259_set_irq_mask(irq_nr); + spin_unlock_irqrestore(&i8259_lock, flags); +} + +static void i8259_end_irq(unsigned int irq) +{ + if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)) + && irq_desc[irq].action) + i8259_unmask_irq(irq); +} + +struct hw_interrupt_type i8259_pic = { + .typename = " i8259 ", + .enable = i8259_unmask_irq, + .disable = i8259_mask_irq, + .ack = i8259_mask_and_ack_irq, + .end = i8259_end_irq, +}; + +static struct resource pic1_iores = { + .name = "8259 (master)", + .start = 0x20, + .end = 0x21, + .flags = IORESOURCE_BUSY, +}; + +static struct resource pic2_iores = { + .name = "8259 (slave)", + .start = 0xa0, + .end = 0xa1, + .flags = IORESOURCE_BUSY, +}; + +static struct resource pic_edgectrl_iores = { + .name = "8259 edge control", + .start = 0x4d0, + .end = 0x4d1, + .flags = IORESOURCE_BUSY, +}; + +static struct irqaction i8259_irqaction = { + .handler = no_action, + .flags = SA_INTERRUPT, + .mask = CPU_MASK_NONE, + .name = "82c59 secondary cascade", +}; + +/* + * i8259_init() + * intack_addr - PCI interrupt acknowledge (real) address which will return + * the active irq from the 8259 + */ +void __init i8259_init(unsigned long intack_addr, int offset) +{ + unsigned long flags; + int i; + + spin_lock_irqsave(&i8259_lock, flags); + i8259_pic_irq_offset = offset; + + /* init master interrupt controller */ + outb(0x11, 0x20); /* Start init sequence */ + outb(0x00, 0x21); /* Vector base */ + outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */ + outb(0x01, 0x21); /* Select 8086 mode */ + + /* init slave interrupt controller */ + outb(0x11, 0xA0); /* Start init sequence */ + outb(0x08, 0xA1); /* Vector base */ + outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */ + outb(0x01, 0xA1); /* Select 8086 mode */ + + /* always read ISR */ + outb(0x0B, 0x20); + outb(0x0B, 0xA0); + + /* Mask all interrupts */ + outb(cached_A1, 0xA1); + outb(cached_21, 0x21); + + spin_unlock_irqrestore(&i8259_lock, flags); + + /* reserve our resources */ + setup_irq(offset + 2, &i8259_irqaction); + request_resource(&ioport_resource, &pic1_iores); + request_resource(&ioport_resource, &pic2_iores); + request_resource(&ioport_resource, &pic_edgectrl_iores); + + if (intack_addr != 0) + pci_intack = ioremap(intack_addr, 1); + + for (i = 0; i < NUM_ISA_INTERRUPTS; ++i) + irq_desc[offset + i].handler = &i8259_pic; +} |
