--- /dev/null
+/*
+ * 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);
Code Review / kvmfornfv.git / blobdiff