2 * drivers/irqchip/irq-crossbar.c
4 * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
5 * Author: Sricharan R <r.sricharan@ti.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/err.h>
14 #include <linux/of_address.h>
15 #include <linux/of_irq.h>
16 #include <linux/slab.h>
17 #include <linux/irqchip/arm-gic.h>
18 #include <linux/irqchip/irq-crossbar.h>
21 #define IRQ_RESERVED -2
23 #define GIC_IRQ_START 32
26 * struct crossbar_device - crossbar device description
27 * @int_max: maximum number of supported interrupts
28 * @safe_map: safe default value to initialize the crossbar
29 * @max_crossbar_sources: Maximum number of crossbar sources
30 * @irq_map: array of interrupts to crossbar number mapping
31 * @crossbar_base: crossbar base address
32 * @register_offsets: offsets for each irq number
33 * @write: register write function pointer
35 struct crossbar_device {
38 uint max_crossbar_sources;
40 void __iomem *crossbar_base;
41 int *register_offsets;
42 void (*write)(int, int);
45 static struct crossbar_device *cb;
47 static inline void crossbar_writel(int irq_no, int cb_no)
49 writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
52 static inline void crossbar_writew(int irq_no, int cb_no)
54 writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
57 static inline void crossbar_writeb(int irq_no, int cb_no)
59 writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
62 static inline int get_prev_map_irq(int cb_no)
66 for (i = cb->int_max - 1; i >= 0; i--)
67 if (cb->irq_map[i] == cb_no)
73 static inline int allocate_free_irq(int cb_no)
77 for (i = cb->int_max - 1; i >= 0; i--) {
78 if (cb->irq_map[i] == IRQ_FREE) {
79 cb->irq_map[i] = cb_no;
87 static int crossbar_domain_map(struct irq_domain *d, unsigned int irq,
90 cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
95 * crossbar_domain_unmap - unmap a crossbar<->irq connection
96 * @d: domain of irq to unmap
99 * We do not maintain a use count of total number of map/unmap
100 * calls for a particular irq to find out if a irq can be really
101 * unmapped. This is because unmap is called during irq_dispose_mapping(irq),
102 * after which irq is anyways unusable. So an explicit map has to be called
105 static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq)
107 irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq;
109 if (hw > GIC_IRQ_START) {
110 cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE;
111 cb->write(hw - GIC_IRQ_START, cb->safe_map);
115 static int crossbar_domain_xlate(struct irq_domain *d,
116 struct device_node *controller,
117 const u32 *intspec, unsigned int intsize,
118 unsigned long *out_hwirq,
119 unsigned int *out_type)
122 int req_num = intspec[1];
124 if (req_num >= cb->max_crossbar_sources) {
125 pr_err("%s: requested crossbar number %d > max %d\n",
126 __func__, req_num, cb->max_crossbar_sources);
130 ret = get_prev_map_irq(req_num);
134 ret = allocate_free_irq(req_num);
140 *out_hwirq = ret + GIC_IRQ_START;
144 static const struct irq_domain_ops routable_irq_domain_ops = {
145 .map = crossbar_domain_map,
146 .unmap = crossbar_domain_unmap,
147 .xlate = crossbar_domain_xlate
150 static int __init crossbar_of_init(struct device_node *node)
152 int i, size, max = 0, reserved = 0, entry;
156 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
161 cb->crossbar_base = of_iomap(node, 0);
162 if (!cb->crossbar_base)
165 of_property_read_u32(node, "ti,max-crossbar-sources",
166 &cb->max_crossbar_sources);
167 if (!cb->max_crossbar_sources) {
168 pr_err("missing 'ti,max-crossbar-sources' property\n");
173 of_property_read_u32(node, "ti,max-irqs", &max);
175 pr_err("missing 'ti,max-irqs' property\n");
179 cb->irq_map = kcalloc(max, sizeof(int), GFP_KERNEL);
185 for (i = 0; i < max; i++)
186 cb->irq_map[i] = IRQ_FREE;
188 /* Get and mark reserved irqs */
189 irqsr = of_get_property(node, "ti,irqs-reserved", &size);
191 size /= sizeof(__be32);
193 for (i = 0; i < size; i++) {
194 of_property_read_u32_index(node,
198 pr_err("Invalid reserved entry\n");
202 cb->irq_map[entry] = IRQ_RESERVED;
206 /* Skip irqs hardwired to bypass the crossbar */
207 irqsr = of_get_property(node, "ti,irqs-skip", &size);
209 size /= sizeof(__be32);
211 for (i = 0; i < size; i++) {
212 of_property_read_u32_index(node,
216 pr_err("Invalid skip entry\n");
220 cb->irq_map[entry] = IRQ_SKIP;
225 cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
226 if (!cb->register_offsets)
229 of_property_read_u32(node, "ti,reg-size", &size);
233 cb->write = crossbar_writeb;
236 cb->write = crossbar_writew;
239 cb->write = crossbar_writel;
242 pr_err("Invalid reg-size property\n");
249 * Register offsets are not linear because of the
250 * reserved irqs. so find and store the offsets once.
252 for (i = 0; i < max; i++) {
253 if (cb->irq_map[i] == IRQ_RESERVED)
256 cb->register_offsets[i] = reserved;
260 of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map);
261 /* Initialize the crossbar with safe map to start with */
262 for (i = 0; i < max; i++) {
263 if (cb->irq_map[i] == IRQ_RESERVED ||
264 cb->irq_map[i] == IRQ_SKIP)
267 cb->write(i, cb->safe_map);
270 register_routable_domain_ops(&routable_irq_domain_ops);
274 kfree(cb->register_offsets);
278 iounmap(cb->crossbar_base);
286 static const struct of_device_id crossbar_match[] __initconst = {
287 { .compatible = "ti,irq-crossbar" },
291 int __init irqcrossbar_init(void)
293 struct device_node *np;
294 np = of_find_matching_node(NULL, crossbar_match);
298 crossbar_of_init(np);