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Sricharan R96ca8482013-12-03 15:57:23 +05301/*
2 * drivers/irqchip/irq-crossbar.c
3 *
4 * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
5 * Author: Sricharan R <r.sricharan@ti.com>
6 *
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.
10 *
11 */
12#include <linux/err.h>
13#include <linux/io.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>
Nishanth Menon4dbf45e2014-06-26 12:40:25 +053018#include <linux/irqchip/irq-crossbar.h>
Sricharan R96ca8482013-12-03 15:57:23 +053019
20#define IRQ_FREE -1
Nishanth Menon1d50d2c2014-06-26 12:40:19 +053021#define IRQ_RESERVED -2
Nishanth Menon64e0f8b2014-06-26 12:40:21 +053022#define IRQ_SKIP -3
Sricharan R96ca8482013-12-03 15:57:23 +053023#define GIC_IRQ_START 32
24
Nishanth Menone30ef8a2014-06-26 12:40:26 +053025/**
26 * struct crossbar_device - crossbar device description
Sricharan R96ca8482013-12-03 15:57:23 +053027 * @int_max: maximum number of supported interrupts
Nishanth Menona35057d2014-06-26 12:40:22 +053028 * @safe_map: safe default value to initialize the crossbar
Nishanth Menon2f7d2fb2014-06-26 12:40:31 +053029 * @max_crossbar_sources: Maximum number of crossbar sources
Sricharan R96ca8482013-12-03 15:57:23 +053030 * @irq_map: array of interrupts to crossbar number mapping
31 * @crossbar_base: crossbar base address
32 * @register_offsets: offsets for each irq number
Nishanth Menone30ef8a2014-06-26 12:40:26 +053033 * @write: register write function pointer
Sricharan R96ca8482013-12-03 15:57:23 +053034 */
35struct crossbar_device {
36 uint int_max;
Nishanth Menona35057d2014-06-26 12:40:22 +053037 uint safe_map;
Nishanth Menon2f7d2fb2014-06-26 12:40:31 +053038 uint max_crossbar_sources;
Sricharan R96ca8482013-12-03 15:57:23 +053039 uint *irq_map;
40 void __iomem *crossbar_base;
41 int *register_offsets;
Nishanth Menona35057d2014-06-26 12:40:22 +053042 void (*write)(int, int);
Sricharan R96ca8482013-12-03 15:57:23 +053043};
44
45static struct crossbar_device *cb;
46
47static inline void crossbar_writel(int irq_no, int cb_no)
48{
49 writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
50}
51
52static inline void crossbar_writew(int irq_no, int cb_no)
53{
54 writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
55}
56
57static inline void crossbar_writeb(int irq_no, int cb_no)
58{
59 writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
60}
61
Nishanth Menon6f16fc82014-06-26 12:40:20 +053062static inline int get_prev_map_irq(int cb_no)
63{
64 int i;
65
Nishanth Menonddee0fb2014-06-26 12:40:23 +053066 for (i = cb->int_max - 1; i >= 0; i--)
Nishanth Menon6f16fc82014-06-26 12:40:20 +053067 if (cb->irq_map[i] == cb_no)
68 return i;
69
70 return -ENODEV;
71}
72
Sricharan R96ca8482013-12-03 15:57:23 +053073static inline int allocate_free_irq(int cb_no)
74{
75 int i;
76
Nishanth Menonddee0fb2014-06-26 12:40:23 +053077 for (i = cb->int_max - 1; i >= 0; i--) {
Sricharan R96ca8482013-12-03 15:57:23 +053078 if (cb->irq_map[i] == IRQ_FREE) {
79 cb->irq_map[i] = cb_no;
80 return i;
81 }
82 }
83
84 return -ENODEV;
85}
86
Nishanth Menon29918b62014-06-26 12:40:32 +053087static inline bool needs_crossbar_write(irq_hw_number_t hw)
88{
Nishanth Menond3608922014-06-26 12:40:34 +053089 int cb_no;
90
91 if (hw > GIC_IRQ_START) {
92 cb_no = cb->irq_map[hw - GIC_IRQ_START];
93 if (cb_no != IRQ_RESERVED && cb_no != IRQ_SKIP)
94 return true;
95 }
Nishanth Menon29918b62014-06-26 12:40:32 +053096
97 return false;
98}
99
Sricharan R96ca8482013-12-03 15:57:23 +0530100static int crossbar_domain_map(struct irq_domain *d, unsigned int irq,
101 irq_hw_number_t hw)
102{
Nishanth Menon29918b62014-06-26 12:40:32 +0530103 if (needs_crossbar_write(hw))
104 cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
105
Sricharan R96ca8482013-12-03 15:57:23 +0530106 return 0;
107}
108
Sricharan R8b09a452014-06-26 12:40:30 +0530109/**
110 * crossbar_domain_unmap - unmap a crossbar<->irq connection
111 * @d: domain of irq to unmap
112 * @irq: virq number
113 *
114 * We do not maintain a use count of total number of map/unmap
115 * calls for a particular irq to find out if a irq can be really
116 * unmapped. This is because unmap is called during irq_dispose_mapping(irq),
117 * after which irq is anyways unusable. So an explicit map has to be called
118 * after that.
119 */
Sricharan R96ca8482013-12-03 15:57:23 +0530120static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq)
121{
122 irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq;
123
Nishanth Menon29918b62014-06-26 12:40:32 +0530124 if (needs_crossbar_write(hw)) {
Sricharan R96ca8482013-12-03 15:57:23 +0530125 cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE;
Nishanth Menona35057d2014-06-26 12:40:22 +0530126 cb->write(hw - GIC_IRQ_START, cb->safe_map);
127 }
Sricharan R96ca8482013-12-03 15:57:23 +0530128}
129
130static int crossbar_domain_xlate(struct irq_domain *d,
131 struct device_node *controller,
132 const u32 *intspec, unsigned int intsize,
133 unsigned long *out_hwirq,
134 unsigned int *out_type)
135{
Nishanth Menond4922a92014-06-26 12:40:24 +0530136 int ret;
Nishanth Menon2f7d2fb2014-06-26 12:40:31 +0530137 int req_num = intspec[1];
Nishanth Menond3608922014-06-26 12:40:34 +0530138 int direct_map_num;
Sricharan R96ca8482013-12-03 15:57:23 +0530139
Nishanth Menon2f7d2fb2014-06-26 12:40:31 +0530140 if (req_num >= cb->max_crossbar_sources) {
Nishanth Menond3608922014-06-26 12:40:34 +0530141 direct_map_num = req_num - cb->max_crossbar_sources;
142 if (direct_map_num < cb->int_max) {
143 ret = cb->irq_map[direct_map_num];
144 if (ret == IRQ_RESERVED || ret == IRQ_SKIP) {
145 /* We use the interrupt num as h/w irq num */
146 ret = direct_map_num;
147 goto found;
148 }
149 }
150
Nishanth Menon2f7d2fb2014-06-26 12:40:31 +0530151 pr_err("%s: requested crossbar number %d > max %d\n",
152 __func__, req_num, cb->max_crossbar_sources);
153 return -EINVAL;
154 }
155
156 ret = get_prev_map_irq(req_num);
Nishanth Menond4922a92014-06-26 12:40:24 +0530157 if (ret >= 0)
Nishanth Menon6f16fc82014-06-26 12:40:20 +0530158 goto found;
159
Nishanth Menon2f7d2fb2014-06-26 12:40:31 +0530160 ret = allocate_free_irq(req_num);
Sricharan R96ca8482013-12-03 15:57:23 +0530161
Nishanth Menond4922a92014-06-26 12:40:24 +0530162 if (ret < 0)
Sricharan R96ca8482013-12-03 15:57:23 +0530163 return ret;
164
Nishanth Menon6f16fc82014-06-26 12:40:20 +0530165found:
Sricharan R96ca8482013-12-03 15:57:23 +0530166 *out_hwirq = ret + GIC_IRQ_START;
167 return 0;
168}
169
Nishanth Menon4dbf45e2014-06-26 12:40:25 +0530170static const struct irq_domain_ops routable_irq_domain_ops = {
Sricharan R96ca8482013-12-03 15:57:23 +0530171 .map = crossbar_domain_map,
172 .unmap = crossbar_domain_unmap,
173 .xlate = crossbar_domain_xlate
174};
175
176static int __init crossbar_of_init(struct device_node *node)
177{
Nishanth Menonedb442d2014-06-26 12:40:27 +0530178 int i, size, max = 0, reserved = 0, entry;
Sricharan R96ca8482013-12-03 15:57:23 +0530179 const __be32 *irqsr;
Nishanth Menonedb442d2014-06-26 12:40:27 +0530180 int ret = -ENOMEM;
Sricharan R96ca8482013-12-03 15:57:23 +0530181
Dan Carpenter3894e9e2014-04-03 10:21:34 +0300182 cb = kzalloc(sizeof(*cb), GFP_KERNEL);
Sricharan R96ca8482013-12-03 15:57:23 +0530183
184 if (!cb)
Nishanth Menonedb442d2014-06-26 12:40:27 +0530185 return ret;
Sricharan R96ca8482013-12-03 15:57:23 +0530186
187 cb->crossbar_base = of_iomap(node, 0);
188 if (!cb->crossbar_base)
Nishanth Menon3c44d512014-06-26 12:40:28 +0530189 goto err_cb;
Sricharan R96ca8482013-12-03 15:57:23 +0530190
Nishanth Menon2f7d2fb2014-06-26 12:40:31 +0530191 of_property_read_u32(node, "ti,max-crossbar-sources",
192 &cb->max_crossbar_sources);
193 if (!cb->max_crossbar_sources) {
194 pr_err("missing 'ti,max-crossbar-sources' property\n");
195 ret = -EINVAL;
196 goto err_base;
197 }
198
Sricharan R96ca8482013-12-03 15:57:23 +0530199 of_property_read_u32(node, "ti,max-irqs", &max);
Nishanth Menonedb442d2014-06-26 12:40:27 +0530200 if (!max) {
201 pr_err("missing 'ti,max-irqs' property\n");
202 ret = -EINVAL;
Nishanth Menon3c44d512014-06-26 12:40:28 +0530203 goto err_base;
Nishanth Menonedb442d2014-06-26 12:40:27 +0530204 }
Nishanth Menon4dbf45e2014-06-26 12:40:25 +0530205 cb->irq_map = kcalloc(max, sizeof(int), GFP_KERNEL);
Sricharan R96ca8482013-12-03 15:57:23 +0530206 if (!cb->irq_map)
Nishanth Menon3c44d512014-06-26 12:40:28 +0530207 goto err_base;
Sricharan R96ca8482013-12-03 15:57:23 +0530208
209 cb->int_max = max;
210
211 for (i = 0; i < max; i++)
212 cb->irq_map[i] = IRQ_FREE;
213
214 /* Get and mark reserved irqs */
215 irqsr = of_get_property(node, "ti,irqs-reserved", &size);
216 if (irqsr) {
217 size /= sizeof(__be32);
218
219 for (i = 0; i < size; i++) {
220 of_property_read_u32_index(node,
221 "ti,irqs-reserved",
222 i, &entry);
Dan Carpenter702f7e32014-08-07 18:28:21 +0300223 if (entry >= max) {
Sricharan R96ca8482013-12-03 15:57:23 +0530224 pr_err("Invalid reserved entry\n");
Nishanth Menonedb442d2014-06-26 12:40:27 +0530225 ret = -EINVAL;
Nishanth Menon3c44d512014-06-26 12:40:28 +0530226 goto err_irq_map;
Sricharan R96ca8482013-12-03 15:57:23 +0530227 }
Nishanth Menon1d50d2c2014-06-26 12:40:19 +0530228 cb->irq_map[entry] = IRQ_RESERVED;
Sricharan R96ca8482013-12-03 15:57:23 +0530229 }
230 }
231
Nishanth Menon64e0f8b2014-06-26 12:40:21 +0530232 /* Skip irqs hardwired to bypass the crossbar */
233 irqsr = of_get_property(node, "ti,irqs-skip", &size);
234 if (irqsr) {
235 size /= sizeof(__be32);
236
237 for (i = 0; i < size; i++) {
238 of_property_read_u32_index(node,
239 "ti,irqs-skip",
240 i, &entry);
Dan Carpenter702f7e32014-08-07 18:28:21 +0300241 if (entry >= max) {
Nishanth Menon64e0f8b2014-06-26 12:40:21 +0530242 pr_err("Invalid skip entry\n");
243 ret = -EINVAL;
Nishanth Menon3c44d512014-06-26 12:40:28 +0530244 goto err_irq_map;
Nishanth Menon64e0f8b2014-06-26 12:40:21 +0530245 }
246 cb->irq_map[entry] = IRQ_SKIP;
247 }
248 }
249
250
Nishanth Menon4dbf45e2014-06-26 12:40:25 +0530251 cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
Sricharan R96ca8482013-12-03 15:57:23 +0530252 if (!cb->register_offsets)
Nishanth Menon3c44d512014-06-26 12:40:28 +0530253 goto err_irq_map;
Sricharan R96ca8482013-12-03 15:57:23 +0530254
255 of_property_read_u32(node, "ti,reg-size", &size);
256
257 switch (size) {
258 case 1:
259 cb->write = crossbar_writeb;
260 break;
261 case 2:
262 cb->write = crossbar_writew;
263 break;
264 case 4:
265 cb->write = crossbar_writel;
266 break;
267 default:
268 pr_err("Invalid reg-size property\n");
Nishanth Menonedb442d2014-06-26 12:40:27 +0530269 ret = -EINVAL;
Nishanth Menon3c44d512014-06-26 12:40:28 +0530270 goto err_reg_offset;
Sricharan R96ca8482013-12-03 15:57:23 +0530271 break;
272 }
273
274 /*
275 * Register offsets are not linear because of the
276 * reserved irqs. so find and store the offsets once.
277 */
278 for (i = 0; i < max; i++) {
Nishanth Menon1d50d2c2014-06-26 12:40:19 +0530279 if (cb->irq_map[i] == IRQ_RESERVED)
Sricharan R96ca8482013-12-03 15:57:23 +0530280 continue;
281
282 cb->register_offsets[i] = reserved;
283 reserved += size;
284 }
285
Nishanth Menona35057d2014-06-26 12:40:22 +0530286 of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map);
Nishanth Menona35057d2014-06-26 12:40:22 +0530287 /* Initialize the crossbar with safe map to start with */
288 for (i = 0; i < max; i++) {
289 if (cb->irq_map[i] == IRQ_RESERVED ||
290 cb->irq_map[i] == IRQ_SKIP)
291 continue;
292
293 cb->write(i, cb->safe_map);
294 }
295
Sricharan R96ca8482013-12-03 15:57:23 +0530296 register_routable_domain_ops(&routable_irq_domain_ops);
297 return 0;
298
Nishanth Menon3c44d512014-06-26 12:40:28 +0530299err_reg_offset:
Sricharan R96ca8482013-12-03 15:57:23 +0530300 kfree(cb->register_offsets);
Nishanth Menon3c44d512014-06-26 12:40:28 +0530301err_irq_map:
Sricharan R96ca8482013-12-03 15:57:23 +0530302 kfree(cb->irq_map);
Nishanth Menon3c44d512014-06-26 12:40:28 +0530303err_base:
Sricharan R96ca8482013-12-03 15:57:23 +0530304 iounmap(cb->crossbar_base);
Nishanth Menon3c44d512014-06-26 12:40:28 +0530305err_cb:
Sricharan R96ca8482013-12-03 15:57:23 +0530306 kfree(cb);
Sricharan R99e37d0e2014-06-26 12:40:29 +0530307
308 cb = NULL;
Nishanth Menonedb442d2014-06-26 12:40:27 +0530309 return ret;
Sricharan R96ca8482013-12-03 15:57:23 +0530310}
311
312static const struct of_device_id crossbar_match[] __initconst = {
313 { .compatible = "ti,irq-crossbar" },
314 {}
315};
316
317int __init irqcrossbar_init(void)
318{
319 struct device_node *np;
320 np = of_find_matching_node(NULL, crossbar_match);
321 if (!np)
322 return -ENODEV;
323
324 crossbar_of_init(np);
325 return 0;
326}