diff options
Diffstat (limited to 'arch/powerpc/sysdev/i8259.c')
-rw-r--r-- | arch/powerpc/sysdev/i8259.c | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c new file mode 100644 index 000000000..06e391485 --- /dev/null +++ b/arch/powerpc/sysdev/i8259.c @@ -0,0 +1,283 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * i8259 interrupt controller driver. + */ +#undef DEBUG + +#include <linux/ioport.h> +#include <linux/interrupt.h> +#include <linux/irqdomain.h> +#include <linux/kernel.h> +#include <linux/delay.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_RAW_SPINLOCK(i8259_lock); + +static struct irq_domain *i8259_host; + +/* + * 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. + */ +unsigned int i8259_irq(void) +{ + int irq; + int lock = 0; + + /* Either int-ack or poll for the IRQ */ + if (pci_intack) + irq = readb(pci_intack); + else { + raw_spin_lock(&i8259_lock); + lock = 1; + + /* 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 = 0; + } else if (irq == 0xff) + irq = 0; + + if (lock) + raw_spin_unlock(&i8259_lock); + return irq; +} + +static void i8259_mask_and_ack_irq(struct irq_data *d) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&i8259_lock, flags); + if (d->irq > 7) { + cached_A1 |= 1 << (d->irq-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 << d->irq; + inb(0x21); /* DUMMY */ + outb(cached_21, 0x21); + outb(0x20, 0x20); /* Non-specific EOI */ + } + raw_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(struct irq_data *d) +{ + unsigned long flags; + + pr_debug("i8259_mask_irq(%d)\n", d->irq); + + raw_spin_lock_irqsave(&i8259_lock, flags); + if (d->irq < 8) + cached_21 |= 1 << d->irq; + else + cached_A1 |= 1 << (d->irq-8); + i8259_set_irq_mask(d->irq); + raw_spin_unlock_irqrestore(&i8259_lock, flags); +} + +static void i8259_unmask_irq(struct irq_data *d) +{ + unsigned long flags; + + pr_debug("i8259_unmask_irq(%d)\n", d->irq); + + raw_spin_lock_irqsave(&i8259_lock, flags); + if (d->irq < 8) + cached_21 &= ~(1 << d->irq); + else + cached_A1 &= ~(1 << (d->irq-8)); + i8259_set_irq_mask(d->irq); + raw_spin_unlock_irqrestore(&i8259_lock, flags); +} + +static struct irq_chip i8259_pic = { + .name = "i8259", + .irq_mask = i8259_mask_irq, + .irq_disable = i8259_mask_irq, + .irq_unmask = i8259_unmask_irq, + .irq_mask_ack = i8259_mask_and_ack_irq, +}; + +static struct resource pic1_iores = { + .name = "8259 (master)", + .start = 0x20, + .end = 0x21, + .flags = IORESOURCE_IO | IORESOURCE_BUSY, +}; + +static struct resource pic2_iores = { + .name = "8259 (slave)", + .start = 0xa0, + .end = 0xa1, + .flags = IORESOURCE_IO | IORESOURCE_BUSY, +}; + +static struct resource pic_edgectrl_iores = { + .name = "8259 edge control", + .start = 0x4d0, + .end = 0x4d1, + .flags = IORESOURCE_IO | IORESOURCE_BUSY, +}; + +static int i8259_host_match(struct irq_domain *h, struct device_node *node, + enum irq_domain_bus_token bus_token) +{ + struct device_node *of_node = irq_domain_get_of_node(h); + return of_node == NULL || of_node == node; +} + +static int i8259_host_map(struct irq_domain *h, unsigned int virq, + irq_hw_number_t hw) +{ + pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw); + + /* We block the internal cascade */ + if (hw == 2) + irq_set_status_flags(virq, IRQ_NOREQUEST); + + /* We use the level handler only for now, we might want to + * be more cautious here but that works for now + */ + irq_set_status_flags(virq, IRQ_LEVEL); + irq_set_chip_and_handler(virq, &i8259_pic, handle_level_irq); + return 0; +} + +static int i8259_host_xlate(struct irq_domain *h, struct device_node *ct, + const u32 *intspec, unsigned int intsize, + irq_hw_number_t *out_hwirq, unsigned int *out_flags) +{ + static unsigned char map_isa_senses[4] = { + IRQ_TYPE_LEVEL_LOW, + IRQ_TYPE_LEVEL_HIGH, + IRQ_TYPE_EDGE_FALLING, + IRQ_TYPE_EDGE_RISING, + }; + + *out_hwirq = intspec[0]; + if (intsize > 1 && intspec[1] < 4) + *out_flags = map_isa_senses[intspec[1]]; + else + *out_flags = IRQ_TYPE_NONE; + + return 0; +} + +static const struct irq_domain_ops i8259_host_ops = { + .match = i8259_host_match, + .map = i8259_host_map, + .xlate = i8259_host_xlate, +}; + +struct irq_domain *__init i8259_get_host(void) +{ + return i8259_host; +} + +/** + * i8259_init - Initialize the legacy controller + * @node: device node of the legacy PIC (can be NULL, but then, it will match + * all interrupts, so beware) + * @intack_addr: PCI interrupt acknowledge (real) address which will return + * the active irq from the 8259 + */ +void i8259_init(struct device_node *node, unsigned long intack_addr) +{ + unsigned long flags; + + /* initialize the controller */ + raw_spin_lock_irqsave(&i8259_lock, flags); + + /* Mask all first */ + outb(0xff, 0xA1); + outb(0xff, 0x21); + + /* init master interrupt controller */ + outb(0x11, 0x20); /* Start init sequence */ + outb(0x00, 0x21); /* Vector base */ + outb(0x04, 0x21); /* edge triggered, 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 */ + + /* That thing is slow */ + udelay(100); + + /* always read ISR */ + outb(0x0B, 0x20); + outb(0x0B, 0xA0); + + /* Unmask the internal cascade */ + cached_21 &= ~(1 << 2); + + /* Set interrupt masks */ + outb(cached_A1, 0xA1); + outb(cached_21, 0x21); + + raw_spin_unlock_irqrestore(&i8259_lock, flags); + + /* create a legacy host */ + i8259_host = irq_domain_add_legacy(node, NR_IRQS_LEGACY, 0, 0, + &i8259_host_ops, NULL); + if (i8259_host == NULL) { + printk(KERN_ERR "i8259: failed to allocate irq host !\n"); + return; + } + + /* reserve our resources */ + /* XXX should we continue doing that ? it seems to cause problems + * with further requesting of PCI IO resources for that range... + * need to look into it. + */ + 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); + + printk(KERN_INFO "i8259 legacy interrupt controller initialized\n"); +} |