1 files changed, 331 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/4xx/uic.c b/arch/powerpc/platforms/4xx/uic.c
new file mode 100644
index 000000000..36fb66ce5
--- /dev/null
+++ b/arch/powerpc/platforms/4xx/uic.c
@@ -0,0 +1,331 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * arch/powerpc/sysdev/uic.c
+ *
+ * IBM PowerPC 4xx Universal Interrupt Controller
+ *
+ * Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
+ */
+#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/device.h>
+#include <linux/spinlock.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.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
+
+struct uic *primary_uic;
+
+struct uic {
+	int index;
+	int dcrbase;
+
+	raw_spinlock_t lock;
+
+	/* The remapper for this UIC */
+	struct irq_domain	*irqhost;
+};
+
+static void uic_unmask_irq(struct irq_data *d)
+{
+	struct uic *uic = irq_data_get_irq_chip_data(d);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 er, sr;
+
+	sr = 1 << (31-src);
+	raw_spin_lock_irqsave(&uic->lock, flags);
+	/* ack level-triggered interrupts here */
+	if (irqd_is_level_type(d))
+		mtdcr(uic->dcrbase + UIC_SR, sr);
+	er = mfdcr(uic->dcrbase + UIC_ER);
+	er |= sr;
+	mtdcr(uic->dcrbase + UIC_ER, er);
+	raw_spin_unlock_irqrestore(&uic->lock, flags);
+}
+
+static void uic_mask_irq(struct irq_data *d)
+{
+	struct uic *uic = irq_data_get_irq_chip_data(d);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 er;
+
+	raw_spin_lock_irqsave(&uic->lock, flags);
+	er = mfdcr(uic->dcrbase + UIC_ER);
+	er &= ~(1 << (31 - src));
+	mtdcr(uic->dcrbase + UIC_ER, er);
+	raw_spin_unlock_irqrestore(&uic->lock, flags);
+}
+
+static void uic_ack_irq(struct irq_data *d)
+{
+	struct uic *uic = irq_data_get_irq_chip_data(d);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&uic->lock, flags);
+	mtdcr(uic->dcrbase + UIC_SR, 1 << (31-src));
+	raw_spin_unlock_irqrestore(&uic->lock, flags);
+}
+
+static void uic_mask_ack_irq(struct irq_data *d)
+{
+	struct uic *uic = irq_data_get_irq_chip_data(d);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	u32 er, sr;
+
+	sr = 1 << (31-src);
+	raw_spin_lock_irqsave(&uic->lock, flags);
+	er = mfdcr(uic->dcrbase + UIC_ER);
+	er &= ~sr;
+	mtdcr(uic->dcrbase + UIC_ER, er);
+ 	/* On the UIC, acking (i.e. clearing the SR bit)
+	 * a level irq will have no effect if the interrupt
+	 * is still asserted by the device, even if
+	 * the interrupt is already masked. Therefore
+	 * we only ack the egde interrupts here, while
+	 * level interrupts are ack'ed after the actual
+	 * isr call in the uic_unmask_irq()
+	 */
+	if (!irqd_is_level_type(d))
+		mtdcr(uic->dcrbase + UIC_SR, sr);
+	raw_spin_unlock_irqrestore(&uic->lock, flags);
+}
+
+static int uic_set_irq_type(struct irq_data *d, unsigned int flow_type)
+{
+	struct uic *uic = irq_data_get_irq_chip_data(d);
+	unsigned int src = irqd_to_hwirq(d);
+	unsigned long flags;
+	int trigger, polarity;
+	u32 tr, pr, mask;
+
+	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_NONE:
+		uic_mask_irq(d);
+		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));
+
+	raw_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);
+	mtdcr(uic->dcrbase + UIC_SR, ~mask);
+
+	raw_spin_unlock_irqrestore(&uic->lock, flags);
+
+	return 0;
+}
+
+static struct irq_chip uic_irq_chip = {
+	.name		= "UIC",
+	.irq_unmask	= uic_unmask_irq,
+	.irq_mask	= uic_mask_irq,
+	.irq_mask_ack	= uic_mask_ack_irq,
+	.irq_ack	= uic_ack_irq,
+	.irq_set_type	= uic_set_irq_type,
+};
+
+static int uic_host_map(struct irq_domain *h, unsigned int virq,
+			irq_hw_number_t hw)
+{
+	struct uic *uic = h->host_data;
+
+	irq_set_chip_data(virq, uic);
+	/* Despite the name, handle_level_irq() works for both level
+	 * and edge irqs on UIC.  FIXME: check this is correct */
+	irq_set_chip_and_handler(virq, &uic_irq_chip, handle_level_irq);
+
+	/* Set default irq type */
+	irq_set_irq_type(virq, IRQ_TYPE_NONE);
+
+	return 0;
+}
+
+static const struct irq_domain_ops uic_host_ops = {
+	.map	= uic_host_map,
+	.xlate	= irq_domain_xlate_twocell,
+};
+
+static void uic_irq_cascade(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irq_data *idata = irq_desc_get_irq_data(desc);
+	struct uic *uic = irq_desc_get_handler_data(desc);
+	u32 msr;
+	int src;
+	int subvirq;
+
+	raw_spin_lock(&desc->lock);
+	if (irqd_is_level_type(idata))
+		chip->irq_mask(idata);
+	else
+		chip->irq_mask_ack(idata);
+	raw_spin_unlock(&desc->lock);
+
+	msr = mfdcr(uic->dcrbase + UIC_MSR);
+	if (!msr) /* spurious interrupt */
+		goto uic_irq_ret;
+
+	src = 32 - ffs(msr);
+
+	subvirq = irq_linear_revmap(uic->irqhost, src);
+	generic_handle_irq(subvirq);
+
+uic_irq_ret:
+	raw_spin_lock(&desc->lock);
+	if (irqd_is_level_type(idata))
+		chip->irq_ack(idata);
+	if (!irqd_irq_disabled(idata) && chip->irq_unmask)
+		chip->irq_unmask(idata);
+	raw_spin_unlock(&desc->lock);
+}
+
+static struct uic * __init uic_init_one(struct device_node *node)
+{
+	struct uic *uic;
+	const u32 *indexp, *dcrreg;
+	int len;
+
+	BUG_ON(! of_device_is_compatible(node, "ibm,uic"));
+
+	uic = kzalloc(sizeof(*uic), GFP_KERNEL);
+	if (! uic)
+		return NULL; /* FIXME: panic? */
+
+	raw_spin_lock_init(&uic->lock);
+	indexp = of_get_property(node, "cell-index", &len);
+	if (!indexp || (len != sizeof(u32))) {
+		printk(KERN_ERR "uic: Device node %pOF has missing or invalid "
+		       "cell-index property\n", node);
+		return NULL;
+	}
+	uic->index = *indexp;
+
+	dcrreg = of_get_property(node, "dcr-reg", &len);
+	if (!dcrreg || (len != 2*sizeof(u32))) {
+		printk(KERN_ERR "uic: Device node %pOF has missing or invalid "
+		       "dcr-reg property\n", node);
+		return NULL;
+	}
+	uic->dcrbase = *dcrreg;
+
+	uic->irqhost = irq_domain_add_linear(node, NR_UIC_INTS, &uic_host_ops,
+					     uic);
+	if (! uic->irqhost)
+		return NULL; /* FIXME: panic? */
+
+	/* 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 */
+	for_each_compatible_node(np, NULL, "ibm,uic") {
+		interrupts = of_get_property(np, "interrupts", NULL);
+		if (!interrupts)
+			break;
+	}
+
+	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 %pOF\n", np);
+
+	irq_set_default_host(primary_uic->irqhost);
+	of_node_put(np);
+
+	/* The scan again for cascaded UICs */
+	for_each_compatible_node(np, NULL, "ibm,uic") {
+		interrupts = of_get_property(np, "interrupts", NULL);
+		if (interrupts) {
+			/* Secondary UIC */
+			int cascade_virq;
+
+			uic = uic_init_one(np);
+			if (! uic)
+				panic("Unable to initialize a secondary UIC %pOF\n",
+				      np);
+
+			cascade_virq = irq_of_parse_and_map(np, 0);
+
+			irq_set_handler_data(cascade_virq, uic);
+			irq_set_chained_handler(cascade_virq, uic_irq_cascade);
+
+			/* FIXME: setup critical cascade?? */
+		}
+	}
+}
+
+/* Return an interrupt vector or 0 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);
+}