xref: /openbmc/linux/drivers/sh/intc/virq.c (revision 711aab1d)
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 
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 
45 struct intc_map_entry *intc_irq_xlate_get(unsigned int irq)
46 {
47 	return intc_irq_xlate + irq;
48 }
49 
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 
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 
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 
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 
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 
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 
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 
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