[POWERPC] Add arch/powerpc driver for UIC, PPC4xx interrupt controller

This patch adds a driver to arch/powerpc/sysdev for the UIC, the
on-chip interrupt controller from IBM/AMCC 4xx chips.  It uses the new
irq host mapping infrastructure.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 343 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index 83fbbfc779a1..e96ca9618dbb 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_PM)		+= timer.o
 ifeq ($(CONFIG_PPC_MERGE),y)
 obj-$(CONFIG_PPC_I8259)         += i8259.o
 obj-$(CONFIG_PPC_83xx)          += ipic.o
+obj-$(CONFIG_4xx)               += uic.o
 endif
 
 # Temporary hack until we have migrated to asm-powerpc
diff --git a/arch/powerpc/sysdev/uic.c b/arch/powerpc/sysdev/uic.c
new file mode 100644
index 000000000000..cdbe68437afe
--- /dev/null
+++ b/arch/powerpc/sysdev/uic.c
@@ -0,0 +1,342 @@
+/*
+ * arch/powerpc/sysdev/uic.c
+ *
+ * IBM PowerPC 4xx Universal Interrupt Controller
+ *
+ * Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
+ *
+ * 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/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/stddef.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/sysdev.h>
+#include <linux/device.h>
+#include <linux/bootmem.h>
+#include <linux/spinlock.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <asm/irq.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/dcr.h>
+
+#define NR_UIC_INTS     32
+
+#define UIC_SR          0x0
+#define UIC_ER          0x2
+#define UIC_CR          0x3
+#define UIC_PR          0x4
+#define UIC_TR          0x5
+#define UIC_MSR         0x6
+#define UIC_VR          0x7
+#define UIC_VCR         0x8
+
+#define uic_irq_to_hw(virq)     (irq_map[virq].hwirq)
+
+struct uic *primary_uic;
+
+struct uic {
+        int index;
+        int dcrbase;
+
+        spinlock_t lock;
+
+        /* The remapper for this UIC */
+        struct irq_host *irqhost;
+
+        /* For secondary UICs, the cascade interrupt's irqaction */
+        struct irqaction cascade;
+
+        /* The device node of the interrupt controller */
+        struct device_node *of_node;
+};
+
+static void uic_unmask_irq(unsigned int virq)
+{
+        struct uic *uic = get_irq_chip_data(virq);
+        unsigned int src = uic_irq_to_hw(virq);
+        unsigned long flags;
+        u32 er;
+
+        spin_lock_irqsave(&uic->lock, flags);
+        er = mfdcr(uic->dcrbase + UIC_ER);
+        er |= 1 << (31 - src);
+        mtdcr(uic->dcrbase + UIC_ER, er);
+        spin_unlock_irqrestore(&uic->lock, flags);
+}
+
+static void uic_mask_irq(unsigned int virq)
+{
+        struct uic *uic = get_irq_chip_data(virq);
+        unsigned int src = uic_irq_to_hw(virq);
+        unsigned long flags;
+        u32 er;
+
+        spin_lock_irqsave(&uic->lock, flags);
+        er = mfdcr(uic->dcrbase + UIC_ER);
+        er &= ~(1 << (31 - src));
+        mtdcr(uic->dcrbase + UIC_ER, er);
+        spin_unlock_irqrestore(&uic->lock, flags);
+}
+
+static void uic_ack_irq(unsigned int virq)
+{
+        struct uic *uic = get_irq_chip_data(virq);
+        unsigned int src = uic_irq_to_hw(virq);
+        unsigned long flags;
+
+        spin_lock_irqsave(&uic->lock, flags);
+        mtdcr(uic->dcrbase + UIC_SR, 1 << (31-src));
+        spin_unlock_irqrestore(&uic->lock, flags);
+}
+
+static int uic_set_irq_type(unsigned int virq, unsigned int flow_type)
+{
+        struct uic *uic = get_irq_chip_data(virq);
+        unsigned int src = uic_irq_to_hw(virq);
+        struct irq_desc *desc = get_irq_desc(virq);
+        unsigned long flags;
+        int trigger, polarity;
+        u32 tr, pr, mask;
+
+        switch (flow_type & IRQ_TYPE_SENSE_MASK) {
+        case IRQ_TYPE_NONE:
+                uic_mask_irq(virq);
+                return 0;
+
+        case IRQ_TYPE_EDGE_RISING:
+                trigger = 1; polarity = 1;
+                break;
+        case IRQ_TYPE_EDGE_FALLING:
+                trigger = 1; polarity = 0;
+                break;
+        case IRQ_TYPE_LEVEL_HIGH:
+                trigger = 0; polarity = 1;
+                break;
+        case IRQ_TYPE_LEVEL_LOW:
+                trigger = 0; polarity = 0;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        mask = ~(1 << (31 - src));
+
+        spin_lock_irqsave(&uic->lock, flags);
+        tr = mfdcr(uic->dcrbase + UIC_TR);
+        pr = mfdcr(uic->dcrbase + UIC_PR);
+        tr = (tr & mask) | (trigger << (31-src));
+        pr = (pr & mask) | (polarity << (31-src));
+
+        mtdcr(uic->dcrbase + UIC_PR, pr);
+        mtdcr(uic->dcrbase + UIC_TR, tr);
+
+        desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
+        desc->status |= flow_type & IRQ_TYPE_SENSE_MASK;
+        if (trigger)
+                desc->status |= IRQ_LEVEL;
+
+        spin_unlock_irqrestore(&uic->lock, flags);
+
+        return 0;
+}
+
+static struct irq_chip uic_irq_chip = {
+        .typename       = " UIC  ",
+        .unmask         = uic_unmask_irq,
+        .mask           = uic_mask_irq,
+/*      .mask_ack       = uic_mask_irq_and_ack, */
+        .ack            = uic_ack_irq,
+        .set_type       = uic_set_irq_type,
+};
+
+static int uic_host_match(struct irq_host *h, struct device_node *node)
+{
+        struct uic *uic = h->host_data;
+        return uic->of_node == node;
+}
+
+static int uic_host_map(struct irq_host *h, unsigned int virq,
+                        irq_hw_number_t hw)
+{
+        struct uic *uic = h->host_data;
+
+        set_irq_chip_data(virq, uic);
+        /* Despite the name, handle_level_irq() works for both level
+         * and edge irqs on UIC.  FIXME: check this is correct */
+        set_irq_chip_and_handler(virq, &uic_irq_chip, handle_level_irq);
+
+        /* Set default irq type */
+        set_irq_type(virq, IRQ_TYPE_NONE);
+
+        return 0;
+}
+
+static int uic_host_xlate(struct irq_host *h, struct device_node *ct,
+                          u32 *intspec, unsigned int intsize,
+                          irq_hw_number_t *out_hwirq, unsigned int *out_type)
+
+{
+        /* UIC intspecs must have 2 cells */
+        BUG_ON(intsize != 2);
+        *out_hwirq = intspec[0];
+        *out_type = intspec[1];
+        return 0;
+}
+
+static struct irq_host_ops uic_host_ops = {
+        .match  = uic_host_match,
+        .map    = uic_host_map,
+        .xlate  = uic_host_xlate,
+};
+
+irqreturn_t uic_cascade(int virq, void *data)
+{
+        struct uic *uic = data;
+        u32 msr;
+        int src;
+        int subvirq;
+
+        msr = mfdcr(uic->dcrbase + UIC_MSR);
+        src = 32 - ffs(msr);
+
+        subvirq = irq_linear_revmap(uic->irqhost, src);
+        generic_handle_irq(subvirq);
+
+        return IRQ_HANDLED;
+}
+
+static struct uic * __init uic_init_one(struct device_node *node)
+{
+        struct uic *uic;
+        const u32 *indexp, *dcrreg;
+        int len;
+
+        BUG_ON(! device_is_compatible(node, "ibm,uic"));
+
+        uic = alloc_bootmem(sizeof(*uic));
+        if (! uic)
+                return NULL; /* FIXME: panic? */
+
+        memset(uic, 0, sizeof(*uic));
+        spin_lock_init(&uic->lock);
+        uic->of_node = of_node_get(node);
+        indexp = get_property(node, "cell-index", &len);
+        if (!indexp || (len != sizeof(u32))) {
+                printk(KERN_ERR "uic: Device node %s has missing or invalid "
+                       "cell-index property\n", node->full_name);
+                return NULL;
+        }
+        uic->index = *indexp;
+
+        dcrreg = get_property(node, "dcr-reg", &len);
+        if (!dcrreg || (len != 2*sizeof(u32))) {
+                printk(KERN_ERR "uic: Device node %s has missing or invalid "
+                       "dcr-reg property\n", node->full_name);
+                return NULL;
+        }
+        uic->dcrbase = *dcrreg;
+
+        uic->irqhost = irq_alloc_host(IRQ_HOST_MAP_LINEAR, NR_UIC_INTS,
+                                      &uic_host_ops, -1);
+        if (! uic->irqhost) {
+                of_node_put(node);
+                return NULL; /* FIXME: panic? */
+        }
+
+        uic->irqhost->host_data = uic;
+
+        /* Start with all interrupts disabled, level and non-critical */
+        mtdcr(uic->dcrbase + UIC_ER, 0);
+        mtdcr(uic->dcrbase + UIC_CR, 0);
+        mtdcr(uic->dcrbase + UIC_TR, 0);
+        /* Clear any pending interrupts, in case the firmware left some */
+        mtdcr(uic->dcrbase + UIC_SR, 0xffffffff);
+
+        printk ("UIC%d (%d IRQ sources) at DCR 0x%x\n", uic->index,
+                NR_UIC_INTS, uic->dcrbase);
+
+        return uic;
+}
+
+void __init uic_init_tree(void)
+{
+        struct device_node *np;
+        struct uic *uic;
+        const u32 *interrupts;
+
+        /* First locate and initialize the top-level UIC */
+
+        np = of_find_compatible_node(NULL, NULL, "ibm,uic");
+        while (np) {
+                interrupts = get_property(np, "interrupts", NULL);
+                if (! interrupts)
+                        break;
+
+                np = of_find_compatible_node(np, NULL, "ibm,uic");
+        }
+
+        BUG_ON(!np); /* uic_init_tree() assumes there's a UIC as the
+                      * top-level interrupt controller */
+        primary_uic = uic_init_one(np);
+        if (! primary_uic)
+                panic("Unable to initialize primary UIC %s\n", np->full_name);
+
+        irq_set_default_host(primary_uic->irqhost);
+        of_node_put(np);
+
+        /* The scan again for cascaded UICs */
+        np = of_find_compatible_node(NULL, NULL, "ibm,uic");
+        while (np) {
+                interrupts = get_property(np, "interrupts", NULL);
+                if (interrupts) {
+                        /* Secondary UIC */
+                        int cascade_virq;
+                        int ret;
+
+                        uic = uic_init_one(np);
+                        if (! uic)
+                                panic("Unable to initialize a secondary UIC %s\n",
+                                      np->full_name);
+
+                        cascade_virq = irq_of_parse_and_map(np, 0);
+
+                        uic->cascade.handler = uic_cascade;
+                        uic->cascade.name = "UIC cascade";
+                        uic->cascade.dev_id = uic;
+
+                        ret = setup_irq(cascade_virq, &uic->cascade);
+                        if (ret)
+                                printk(KERN_ERR "Failed to setup_irq(%d) for "
+                                       "UIC%d cascade\n", cascade_virq,
+                                       uic->index);
+
+                        /* FIXME: setup critical cascade?? */
+                }
+
+                np = of_find_compatible_node(np, NULL, "ibm,uic");
+        }
+}
+
+/* Return an interrupt vector or NO_IRQ if no interrupt is pending. */
+unsigned int uic_get_irq(void)
+{
+        u32 msr;
+        int src;
+
+        BUG_ON(! primary_uic);
+
+        msr = mfdcr(primary_uic->dcrbase + UIC_MSR);
+        src = 32 - ffs(msr);
+
+        return irq_linear_revmap(primary_uic->irqhost, src);
+}