1 files changed, 362 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c
new file mode 100644
index 000000000..692fe2bc8
--- /dev/null
+++ b/drivers/irqchip/irq-crossbar.c
@@ -0,0 +1,362 @@
+/*
+ *  drivers/irqchip/irq-crossbar.c
+ *
+ *  Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
+ *  Author: Sricharan R <r.sricharan@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/irqdomain.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+
+#include "irqchip.h"
+
+#define IRQ_FREE	-1
+#define IRQ_RESERVED	-2
+#define IRQ_SKIP	-3
+#define GIC_IRQ_START	32
+
+/**
+ * struct crossbar_device - crossbar device description
+ * @lock: spinlock serializing access to @irq_map
+ * @int_max: maximum number of supported interrupts
+ * @safe_map: safe default value to initialize the crossbar
+ * @max_crossbar_sources: Maximum number of crossbar sources
+ * @irq_map: array of interrupts to crossbar number mapping
+ * @crossbar_base: crossbar base address
+ * @register_offsets: offsets for each irq number
+ * @write: register write function pointer
+ */
+struct crossbar_device {
+	raw_spinlock_t lock;
+	uint int_max;
+	uint safe_map;
+	uint max_crossbar_sources;
+	uint *irq_map;
+	void __iomem *crossbar_base;
+	int *register_offsets;
+	void (*write)(int, int);
+};
+
+static struct crossbar_device *cb;
+
+static void crossbar_writel(int irq_no, int cb_no)
+{
+	writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
+}
+
+static void crossbar_writew(int irq_no, int cb_no)
+{
+	writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
+}
+
+static void crossbar_writeb(int irq_no, int cb_no)
+{
+	writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
+}
+
+static struct irq_chip crossbar_chip = {
+	.name			= "CBAR",
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+	.irq_set_wake		= irq_chip_set_wake_parent,
+#ifdef CONFIG_SMP
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+#endif
+};
+
+static int allocate_gic_irq(struct irq_domain *domain, unsigned virq,
+			    irq_hw_number_t hwirq)
+{
+	struct of_phandle_args args;
+	int i;
+	int err;
+
+	raw_spin_lock(&cb->lock);
+	for (i = cb->int_max - 1; i >= 0; i--) {
+		if (cb->irq_map[i] == IRQ_FREE) {
+			cb->irq_map[i] = hwirq;
+			break;
+		}
+	}
+	raw_spin_unlock(&cb->lock);
+
+	if (i < 0)
+		return -ENODEV;
+
+	args.np = domain->parent->of_node;
+	args.args_count = 3;
+	args.args[0] = 0;	/* SPI */
+	args.args[1] = i;
+	args.args[2] = IRQ_TYPE_LEVEL_HIGH;
+
+	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &args);
+	if (err)
+		cb->irq_map[i] = IRQ_FREE;
+	else
+		cb->write(i, hwirq);
+
+	return err;
+}
+
+static int crossbar_domain_alloc(struct irq_domain *d, unsigned int virq,
+				 unsigned int nr_irqs, void *data)
+{
+	struct of_phandle_args *args = data;
+	irq_hw_number_t hwirq;
+	int i;
+
+	if (args->args_count != 3)
+		return -EINVAL;	/* Not GIC compliant */
+	if (args->args[0] != 0)
+		return -EINVAL;	/* No PPI should point to this domain */
+
+	hwirq = args->args[1];
+	if ((hwirq + nr_irqs) > cb->max_crossbar_sources)
+		return -EINVAL;	/* Can't deal with this */
+
+	for (i = 0; i < nr_irqs; i++) {
+		int err = allocate_gic_irq(d, virq + i, hwirq + i);
+
+		if (err)
+			return err;
+
+		irq_domain_set_hwirq_and_chip(d, virq + i, hwirq + i,
+					      &crossbar_chip, NULL);
+	}
+
+	return 0;
+}
+
+/**
+ * crossbar_domain_free - unmap/free a crossbar<->irq connection
+ * @domain: domain of irq to unmap
+ * @virq: virq number
+ * @nr_irqs: number of irqs to free
+ *
+ * We do not maintain a use count of total number of map/unmap
+ * calls for a particular irq to find out if a irq can be really
+ * unmapped. This is because unmap is called during irq_dispose_mapping(irq),
+ * after which irq is anyways unusable. So an explicit map has to be called
+ * after that.
+ */
+static void crossbar_domain_free(struct irq_domain *domain, unsigned int virq,
+				 unsigned int nr_irqs)
+{
+	int i;
+
+	raw_spin_lock(&cb->lock);
+	for (i = 0; i < nr_irqs; i++) {
+		struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
+
+		irq_domain_reset_irq_data(d);
+		cb->irq_map[d->hwirq] = IRQ_FREE;
+		cb->write(d->hwirq, cb->safe_map);
+	}
+	raw_spin_unlock(&cb->lock);
+}
+
+static int crossbar_domain_xlate(struct irq_domain *d,
+				 struct device_node *controller,
+				 const u32 *intspec, unsigned int intsize,
+				 unsigned long *out_hwirq,
+				 unsigned int *out_type)
+{
+	if (d->of_node != controller)
+		return -EINVAL;	/* Shouldn't happen, really... */
+	if (intsize != 3)
+		return -EINVAL;	/* Not GIC compliant */
+	if (intspec[0] != 0)
+		return -EINVAL;	/* No PPI should point to this domain */
+
+	*out_hwirq = intspec[1];
+	*out_type = intspec[2];
+	return 0;
+}
+
+static const struct irq_domain_ops crossbar_domain_ops = {
+	.alloc	= crossbar_domain_alloc,
+	.free	= crossbar_domain_free,
+	.xlate	= crossbar_domain_xlate,
+};
+
+static int __init crossbar_of_init(struct device_node *node)
+{
+	int i, size, max = 0, reserved = 0, entry;
+	const __be32 *irqsr;
+	int ret = -ENOMEM;
+
+	cb = kzalloc(sizeof(*cb), GFP_KERNEL);
+
+	if (!cb)
+		return ret;
+
+	cb->crossbar_base = of_iomap(node, 0);
+	if (!cb->crossbar_base)
+		goto err_cb;
+
+	of_property_read_u32(node, "ti,max-crossbar-sources",
+			     &cb->max_crossbar_sources);
+	if (!cb->max_crossbar_sources) {
+		pr_err("missing 'ti,max-crossbar-sources' property\n");
+		ret = -EINVAL;
+		goto err_base;
+	}
+
+	of_property_read_u32(node, "ti,max-irqs", &max);
+	if (!max) {
+		pr_err("missing 'ti,max-irqs' property\n");
+		ret = -EINVAL;
+		goto err_base;
+	}
+	cb->irq_map = kcalloc(max, sizeof(int), GFP_KERNEL);
+	if (!cb->irq_map)
+		goto err_base;
+
+	cb->int_max = max;
+
+	for (i = 0; i < max; i++)
+		cb->irq_map[i] = IRQ_FREE;
+
+	/* Get and mark reserved irqs */
+	irqsr = of_get_property(node, "ti,irqs-reserved", &size);
+	if (irqsr) {
+		size /= sizeof(__be32);
+
+		for (i = 0; i < size; i++) {
+			of_property_read_u32_index(node,
+						   "ti,irqs-reserved",
+						   i, &entry);
+			if (entry >= max) {
+				pr_err("Invalid reserved entry\n");
+				ret = -EINVAL;
+				goto err_irq_map;
+			}
+			cb->irq_map[entry] = IRQ_RESERVED;
+		}
+	}
+
+	/* Skip irqs hardwired to bypass the crossbar */
+	irqsr = of_get_property(node, "ti,irqs-skip", &size);
+	if (irqsr) {
+		size /= sizeof(__be32);
+
+		for (i = 0; i < size; i++) {
+			of_property_read_u32_index(node,
+						   "ti,irqs-skip",
+						   i, &entry);
+			if (entry >= max) {
+				pr_err("Invalid skip entry\n");
+				ret = -EINVAL;
+				goto err_irq_map;
+			}
+			cb->irq_map[entry] = IRQ_SKIP;
+		}
+	}
+
+
+	cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
+	if (!cb->register_offsets)
+		goto err_irq_map;
+
+	of_property_read_u32(node, "ti,reg-size", &size);
+
+	switch (size) {
+	case 1:
+		cb->write = crossbar_writeb;
+		break;
+	case 2:
+		cb->write = crossbar_writew;
+		break;
+	case 4:
+		cb->write = crossbar_writel;
+		break;
+	default:
+		pr_err("Invalid reg-size property\n");
+		ret = -EINVAL;
+		goto err_reg_offset;
+		break;
+	}
+
+	/*
+	 * Register offsets are not linear because of the
+	 * reserved irqs. so find and store the offsets once.
+	 */
+	for (i = 0; i < max; i++) {
+		if (cb->irq_map[i] == IRQ_RESERVED)
+			continue;
+
+		cb->register_offsets[i] = reserved;
+		reserved += size;
+	}
+
+	of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map);
+	/* Initialize the crossbar with safe map to start with */
+	for (i = 0; i < max; i++) {
+		if (cb->irq_map[i] == IRQ_RESERVED ||
+		    cb->irq_map[i] == IRQ_SKIP)
+			continue;
+
+		cb->write(i, cb->safe_map);
+	}
+
+	raw_spin_lock_init(&cb->lock);
+
+	return 0;
+
+err_reg_offset:
+	kfree(cb->register_offsets);
+err_irq_map:
+	kfree(cb->irq_map);
+err_base:
+	iounmap(cb->crossbar_base);
+err_cb:
+	kfree(cb);
+
+	cb = NULL;
+	return ret;
+}
+
+static int __init irqcrossbar_init(struct device_node *node,
+				   struct device_node *parent)
+{
+	struct irq_domain *parent_domain, *domain;
+	int err;
+
+	if (!parent) {
+		pr_err("%s: no parent, giving up\n", node->full_name);
+		return -ENODEV;
+	}
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		pr_err("%s: unable to obtain parent domain\n", node->full_name);
+		return -ENXIO;
+	}
+
+	err = crossbar_of_init(node);
+	if (err)
+		return err;
+
+	domain = irq_domain_add_hierarchy(parent_domain, 0,
+					  cb->max_crossbar_sources,
+					  node, &crossbar_domain_ops,
+					  NULL);
+	if (!domain) {
+		pr_err("%s: failed to allocated domain\n", node->full_name);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(ti_irqcrossbar, "ti,irq-crossbar", irqcrossbar_init);