1 /*
2 * Support for virtual IRQ subgroups.
3 *
4 * Copyright (C) 2010 Paul Mundt
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10 #define pr_fmt(fmt) "intc: " fmt
11
12 #include <linux/slab.h>
13 #include <linux/irq.h>
14 #include <linux/list.h>
15 #include <linux/radix-tree.h>
16 #include <linux/spinlock.h>
17 #include <linux/export.h>
18 #include "internals.h"
19
20 static struct intc_map_entry intc_irq_xlate[INTC_NR_IRQS];
21
22 struct intc_virq_list {
23 unsigned int irq;
24 struct intc_virq_list *next;
25 };
26
27 #define for_each_virq(entry, head) \
28 for (entry = head; entry; entry = entry->next)
29
30 /*
31 * Tags for the radix tree
32 */
33 #define INTC_TAG_VIRQ_NEEDS_ALLOC 0
34
intc_irq_xlate_set(unsigned int irq,intc_enum id,struct intc_desc_int * d)35 void intc_irq_xlate_set(unsigned int irq, intc_enum id, struct intc_desc_int *d)
36 {
37 unsigned long flags;
38
39 raw_spin_lock_irqsave(&intc_big_lock, flags);
40 intc_irq_xlate[irq].enum_id = id;
41 intc_irq_xlate[irq].desc = d;
42 raw_spin_unlock_irqrestore(&intc_big_lock, flags);
43 }
44
intc_irq_xlate_get(unsigned int irq)45 struct intc_map_entry *intc_irq_xlate_get(unsigned int irq)
46 {
47 return intc_irq_xlate + irq;
48 }
49
intc_irq_lookup(const char * chipname,intc_enum enum_id)50 int intc_irq_lookup(const char *chipname, intc_enum enum_id)
51 {
52 struct intc_map_entry *ptr;
53 struct intc_desc_int *d;
54 int irq = -1;
55
56 list_for_each_entry(d, &intc_list, list) {
57 int tagged;
58
59 if (strcmp(d->chip.name, chipname) != 0)
60 continue;
61
62 /*
63 * Catch early lookups for subgroup VIRQs that have not
64 * yet been allocated an IRQ. This already includes a
65 * fast-path out if the tree is untagged, so there is no
66 * need to explicitly test the root tree.
67 */
68 tagged = radix_tree_tag_get(&d->tree, enum_id,
69 INTC_TAG_VIRQ_NEEDS_ALLOC);
70 if (unlikely(tagged))
71 break;
72
73 ptr = radix_tree_lookup(&d->tree, enum_id);
74 if (ptr) {
75 irq = ptr - intc_irq_xlate;
76 break;
77 }
78 }
79
80 return irq;
81 }
82 EXPORT_SYMBOL_GPL(intc_irq_lookup);
83
add_virq_to_pirq(unsigned int irq,unsigned int virq)84 static int add_virq_to_pirq(unsigned int irq, unsigned int virq)
85 {
86 struct intc_virq_list *entry;
87 struct intc_virq_list **last = NULL;
88
89 /* scan for duplicates */
90 for_each_virq(entry, irq_get_handler_data(irq)) {
91 if (entry->irq == virq)
92 return 0;
93 last = &entry->next;
94 }
95
96 entry = kzalloc(sizeof(struct intc_virq_list), GFP_ATOMIC);
97 if (!entry)
98 return -ENOMEM;
99
100 entry->irq = virq;
101
102 if (last)
103 *last = entry;
104 else
105 irq_set_handler_data(irq, entry);
106
107 return 0;
108 }
109
intc_virq_handler(struct irq_desc * desc)110 static void intc_virq_handler(struct irq_desc *desc)
111 {
112 unsigned int irq = irq_desc_get_irq(desc);
113 struct irq_data *data = irq_desc_get_irq_data(desc);
114 struct irq_chip *chip = irq_data_get_irq_chip(data);
115 struct intc_virq_list *entry, *vlist = irq_data_get_irq_handler_data(data);
116 struct intc_desc_int *d = get_intc_desc(irq);
117
118 chip->irq_mask_ack(data);
119
120 for_each_virq(entry, vlist) {
121 unsigned long addr, handle;
122 struct irq_desc *vdesc = irq_to_desc(entry->irq);
123
124 if (vdesc) {
125 handle = (unsigned long)irq_desc_get_handler_data(vdesc);
126 addr = INTC_REG(d, _INTC_ADDR_E(handle), 0);
127 if (intc_reg_fns[_INTC_FN(handle)](addr, handle, 0))
128 generic_handle_irq_desc(vdesc);
129 }
130 }
131
132 chip->irq_unmask(data);
133 }
134
intc_subgroup_data(struct intc_subgroup * subgroup,struct intc_desc_int * d,unsigned int index)135 static unsigned long __init intc_subgroup_data(struct intc_subgroup *subgroup,
136 struct intc_desc_int *d,
137 unsigned int index)
138 {
139 unsigned int fn = REG_FN_TEST_BASE + (subgroup->reg_width >> 3) - 1;
140
141 return _INTC_MK(fn, MODE_ENABLE_REG, intc_get_reg(d, subgroup->reg),
142 0, 1, (subgroup->reg_width - 1) - index);
143 }
144
intc_subgroup_init_one(struct intc_desc * desc,struct intc_desc_int * d,struct intc_subgroup * subgroup)145 static void __init intc_subgroup_init_one(struct intc_desc *desc,
146 struct intc_desc_int *d,
147 struct intc_subgroup *subgroup)
148 {
149 struct intc_map_entry *mapped;
150 unsigned int pirq;
151 unsigned long flags;
152 int i;
153
154 mapped = radix_tree_lookup(&d->tree, subgroup->parent_id);
155 if (!mapped) {
156 WARN_ON(1);
157 return;
158 }
159
160 pirq = mapped - intc_irq_xlate;
161
162 raw_spin_lock_irqsave(&d->lock, flags);
163
164 for (i = 0; i < ARRAY_SIZE(subgroup->enum_ids); i++) {
165 struct intc_subgroup_entry *entry;
166 int err;
167
168 if (!subgroup->enum_ids[i])
169 continue;
170
171 entry = kmalloc(sizeof(*entry), GFP_NOWAIT);
172 if (!entry)
173 break;
174
175 entry->pirq = pirq;
176 entry->enum_id = subgroup->enum_ids[i];
177 entry->handle = intc_subgroup_data(subgroup, d, i);
178
179 err = radix_tree_insert(&d->tree, entry->enum_id, entry);
180 if (unlikely(err < 0))
181 break;
182
183 radix_tree_tag_set(&d->tree, entry->enum_id,
184 INTC_TAG_VIRQ_NEEDS_ALLOC);
185 }
186
187 raw_spin_unlock_irqrestore(&d->lock, flags);
188 }
189
intc_subgroup_init(struct intc_desc * desc,struct intc_desc_int * d)190 void __init intc_subgroup_init(struct intc_desc *desc, struct intc_desc_int *d)
191 {
192 int i;
193
194 if (!desc->hw.subgroups)
195 return;
196
197 for (i = 0; i < desc->hw.nr_subgroups; i++)
198 intc_subgroup_init_one(desc, d, desc->hw.subgroups + i);
199 }
200
intc_subgroup_map(struct intc_desc_int * d)201 static void __init intc_subgroup_map(struct intc_desc_int *d)
202 {
203 struct intc_subgroup_entry *entries[32];
204 unsigned long flags;
205 unsigned int nr_found;
206 int i;
207
208 raw_spin_lock_irqsave(&d->lock, flags);
209
210 restart:
211 nr_found = radix_tree_gang_lookup_tag_slot(&d->tree,
212 (void ***)entries, 0, ARRAY_SIZE(entries),
213 INTC_TAG_VIRQ_NEEDS_ALLOC);
214
215 for (i = 0; i < nr_found; i++) {
216 struct intc_subgroup_entry *entry;
217 int irq;
218
219 entry = radix_tree_deref_slot((void **)entries[i]);
220 if (unlikely(!entry))
221 continue;
222 if (radix_tree_deref_retry(entry))
223 goto restart;
224
225 irq = irq_alloc_desc(numa_node_id());
226 if (unlikely(irq < 0)) {
227 pr_err("no more free IRQs, bailing..\n");
228 break;
229 }
230
231 activate_irq(irq);
232
233 pr_info("Setting up a chained VIRQ from %d -> %d\n",
234 irq, entry->pirq);
235
236 intc_irq_xlate_set(irq, entry->enum_id, d);
237
238 irq_set_chip_and_handler_name(irq, irq_get_chip(entry->pirq),
239 handle_simple_irq, "virq");
240 irq_set_chip_data(irq, irq_get_chip_data(entry->pirq));
241
242 irq_set_handler_data(irq, (void *)entry->handle);
243
244 /*
245 * Set the virtual IRQ as non-threadable.
246 */
247 irq_set_nothread(irq);
248
249 /* Set handler data before installing the handler */
250 add_virq_to_pirq(entry->pirq, irq);
251 irq_set_chained_handler(entry->pirq, intc_virq_handler);
252
253 radix_tree_tag_clear(&d->tree, entry->enum_id,
254 INTC_TAG_VIRQ_NEEDS_ALLOC);
255 radix_tree_replace_slot(&d->tree, (void **)entries[i],
256 &intc_irq_xlate[irq]);
257 }
258
259 raw_spin_unlock_irqrestore(&d->lock, flags);
260 }
261
intc_finalize(void)262 void __init intc_finalize(void)
263 {
264 struct intc_desc_int *d;
265
266 list_for_each_entry(d, &intc_list, list)
267 if (radix_tree_tagged(&d->tree, INTC_TAG_VIRQ_NEEDS_ALLOC))
268 intc_subgroup_map(d);
269 }
270