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-rw-r--r--arch/powerpc/sysdev/i8259.c283
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");
+}