1 files changed, 266 insertions, 0 deletions

diff --git a/arch/mips/sgi-ip27/ip27-irq-pci.c b/arch/mips/sgi-ip27/ip27-irq-pci.c
new file mode 100644
index 000000000000..ec22ec5600f3
--- /dev/null
+++ b/arch/mips/sgi-ip27/ip27-irq-pci.c
@@ -0,0 +1,266 @@
+/*
+ * ip27-irq.c: Highlevel interrupt handling for IP27 architecture.
+ *
+ * Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
+ * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
+ * Copyright (C) 1999 - 2001 Kanoj Sarcar
+ */
+
+#undef DEBUG
+
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/errno.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/timex.h>
+#include <linux/smp.h>
+#include <linux/random.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/delay.h>
+#include <linux/bitops.h>
+
+#include <asm/bootinfo.h>
+#include <asm/io.h>
+#include <asm/mipsregs.h>
+
+#include <asm/processor.h>
+#include <asm/pci/bridge.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/agent.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/hub.h>
+#include <asm/sn/intr.h>
+
+/*
+ * Linux has a controller-independent x86 interrupt architecture.
+ * every controller has a 'controller-template', that is used
+ * by the main code to do the right thing. Each driver-visible
+ * interrupt source is transparently wired to the appropriate
+ * controller. Thus drivers need not be aware of the
+ * interrupt-controller.
+ *
+ * Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
+ * PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
+ * (IO-APICs assumed to be messaging to Pentium local-APICs)
+ *
+ * the code is designed to be easily extended with new/different
+ * interrupt controllers, without having to do assembly magic.
+ */
+
+extern struct bridge_controller *irq_to_bridge[];
+extern int irq_to_slot[];
+
+/*
+ * use these macros to get the encoded nasid and widget id
+ * from the irq value
+ */
+#define IRQ_TO_BRIDGE(i)                irq_to_bridge[(i)]
+#define SLOT_FROM_PCI_IRQ(i)            irq_to_slot[i]
+
+static inline int alloc_level(int cpu, int irq)
+{
+        struct hub_data *hub = hub_data(cpu_to_node(cpu));
+        struct slice_data *si = cpu_data[cpu].data;
+        int level;
+
+        level = find_first_zero_bit(hub->irq_alloc_mask, LEVELS_PER_SLICE);
+        if (level >= LEVELS_PER_SLICE)
+                panic("Cpu %d flooded with devices", cpu);
+
+        __set_bit(level, hub->irq_alloc_mask);
+        si->level_to_irq[level] = irq;
+
+        return level;
+}
+
+static inline int find_level(cpuid_t *cpunum, int irq)
+{
+        int cpu, i;
+
+        for_each_online_cpu(cpu) {
+                struct slice_data *si = cpu_data[cpu].data;
+
+                for (i = BASE_PCI_IRQ; i < LEVELS_PER_SLICE; i++)
+                        if (si->level_to_irq[i] == irq) {
+                                *cpunum = cpu;
+
+                                return i;
+                        }
+        }
+
+        panic("Could not identify cpu/level for irq %d", irq);
+}
+
+static int intr_connect_level(int cpu, int bit)
+{
+        nasid_t nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
+        struct slice_data *si = cpu_data[cpu].data;
+
+        set_bit(bit, si->irq_enable_mask);
+
+        if (!cputoslice(cpu)) {
+                REMOTE_HUB_S(nasid, PI_INT_MASK0_A, si->irq_enable_mask[0]);
+                REMOTE_HUB_S(nasid, PI_INT_MASK1_A, si->irq_enable_mask[1]);
+        } else {
+                REMOTE_HUB_S(nasid, PI_INT_MASK0_B, si->irq_enable_mask[0]);
+                REMOTE_HUB_S(nasid, PI_INT_MASK1_B, si->irq_enable_mask[1]);
+        }
+
+        return 0;
+}
+
+static int intr_disconnect_level(int cpu, int bit)
+{
+        nasid_t nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
+        struct slice_data *si = cpu_data[cpu].data;
+
+        clear_bit(bit, si->irq_enable_mask);
+
+        if (!cputoslice(cpu)) {
+                REMOTE_HUB_S(nasid, PI_INT_MASK0_A, si->irq_enable_mask[0]);
+                REMOTE_HUB_S(nasid, PI_INT_MASK1_A, si->irq_enable_mask[1]);
+        } else {
+                REMOTE_HUB_S(nasid, PI_INT_MASK0_B, si->irq_enable_mask[0]);
+                REMOTE_HUB_S(nasid, PI_INT_MASK1_B, si->irq_enable_mask[1]);
+        }
+
+        return 0;
+}
+
+/* Startup one of the (PCI ...) IRQs routes over a bridge.  */
+static unsigned int startup_bridge_irq(struct irq_data *d)
+{
+        struct bridge_controller *bc;
+        bridgereg_t device;
+        bridge_t *bridge;
+        int pin, swlevel;
+        cpuid_t cpu;
+
+        pin = SLOT_FROM_PCI_IRQ(d->irq);
+        bc = IRQ_TO_BRIDGE(d->irq);
+        bridge = bc->base;
+
+        pr_debug("bridge_startup(): irq= 0x%x  pin=%d\n", d->irq, pin);
+        /*
+         * "map" irq to a swlevel greater than 6 since the first 6 bits
+         * of INT_PEND0 are taken
+         */
+        swlevel = find_level(&cpu, d->irq);
+        bridge->b_int_addr[pin].addr = (0x20000 | swlevel | (bc->nasid << 8));
+        bridge->b_int_enable |= (1 << pin);
+        bridge->b_int_enable |= 0x7ffffe00;     /* more stuff in int_enable */
+
+        /*
+         * Enable sending of an interrupt clear packt to the hub on a high to
+         * low transition of the interrupt pin.
+         *
+         * IRIX sets additional bits in the address which are documented as
+         * reserved in the bridge docs.
+         */
+        bridge->b_int_mode |= (1UL << pin);
+
+        /*
+         * We assume the bridge to have a 1:1 mapping between devices
+         * (slots) and intr pins.
+         */
+        device = bridge->b_int_device;
+        device &= ~(7 << (pin*3));
+        device |= (pin << (pin*3));
+        bridge->b_int_device = device;
+
+        bridge->b_wid_tflush;
+
+        intr_connect_level(cpu, swlevel);
+
+        return 0;       /* Never anything pending.  */
+}
+
+/* Shutdown one of the (PCI ...) IRQs routes over a bridge.  */
+static void shutdown_bridge_irq(struct irq_data *d)
+{
+        struct bridge_controller *bc = IRQ_TO_BRIDGE(d->irq);
+        bridge_t *bridge = bc->base;
+        int pin, swlevel;
+        cpuid_t cpu;
+
+        pr_debug("bridge_shutdown: irq 0x%x\n", d->irq);
+        pin = SLOT_FROM_PCI_IRQ(d->irq);
+
+        /*
+         * map irq to a swlevel greater than 6 since the first 6 bits
+         * of INT_PEND0 are taken
+         */
+        swlevel = find_level(&cpu, d->irq);
+        intr_disconnect_level(cpu, swlevel);
+
+        bridge->b_int_enable &= ~(1 << pin);
+        bridge->b_wid_tflush;
+}
+
+static inline void enable_bridge_irq(struct irq_data *d)
+{
+        cpuid_t cpu;
+        int swlevel;
+
+        swlevel = find_level(&cpu, d->irq);     /* Criminal offence */
+        intr_connect_level(cpu, swlevel);
+}
+
+static inline void disable_bridge_irq(struct irq_data *d)
+{
+        cpuid_t cpu;
+        int swlevel;
+
+        swlevel = find_level(&cpu, d->irq);     /* Criminal offence */
+        intr_disconnect_level(cpu, swlevel);
+}
+
+static struct irq_chip bridge_irq_type = {
+        .name           = "bridge",
+        .irq_startup    = startup_bridge_irq,
+        .irq_shutdown   = shutdown_bridge_irq,
+        .irq_mask       = disable_bridge_irq,
+        .irq_unmask     = enable_bridge_irq,
+};
+
+void register_bridge_irq(unsigned int irq)
+{
+        irq_set_chip_and_handler(irq, &bridge_irq_type, handle_level_irq);
+}
+
+int request_bridge_irq(struct bridge_controller *bc)
+{
+        int irq = allocate_irqno();
+        int swlevel, cpu;
+        nasid_t nasid;
+
+        if (irq < 0)
+                return irq;
+
+        /*
+         * "map" irq to a swlevel greater than 6 since the first 6 bits
+         * of INT_PEND0 are taken
+         */
+        cpu = bc->irq_cpu;
+        swlevel = alloc_level(cpu, irq);
+        if (unlikely(swlevel < 0)) {
+                free_irqno(irq);
+
+                return -EAGAIN;
+        }
+
+        /* Make sure it's not already pending when we connect it. */
+        nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
+        REMOTE_HUB_CLR_INTR(nasid, swlevel);
+
+        intr_connect_level(cpu, swlevel);
+
+        register_bridge_irq(irq);
+
+        return irq;
+}