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[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 **last, *entry; 87 struct irq_data *data = irq_get_irq_data(irq); 88 89 /* scan for duplicates */ 90 last = (struct intc_virq_list **)&data->handler_data; 91 for_each_virq(entry, data->handler_data) { 92 if (entry->irq == virq) 93 return 0; 94 last = &entry->next; 95 } 96 97 entry = kzalloc(sizeof(struct intc_virq_list), GFP_ATOMIC); 98 if (!entry) { 99 pr_err("can't allocate VIRQ mapping for %d\n", virq); 100 return -ENOMEM; 101 } 102 103 entry->irq = virq; 104 105 *last = entry; 106 107 return 0; 108 } 109 110 static void intc_virq_handler(unsigned int irq, struct irq_desc *desc) 111 { 112 struct irq_data *data = irq_get_irq_data(irq); 113 struct irq_chip *chip = irq_data_get_irq_chip(data); 114 struct intc_virq_list *entry, *vlist = irq_data_get_irq_handler_data(data); 115 struct intc_desc_int *d = get_intc_desc(irq); 116 117 chip->irq_mask_ack(data); 118 119 for_each_virq(entry, vlist) { 120 unsigned long addr, handle; 121 122 handle = (unsigned long)irq_get_handler_data(entry->irq); 123 addr = INTC_REG(d, _INTC_ADDR_E(handle), 0); 124 125 if (intc_reg_fns[_INTC_FN(handle)](addr, handle, 0)) 126 generic_handle_irq(entry->irq); 127 } 128 129 chip->irq_unmask(data); 130 } 131 132 static unsigned long __init intc_subgroup_data(struct intc_subgroup *subgroup, 133 struct intc_desc_int *d, 134 unsigned int index) 135 { 136 unsigned int fn = REG_FN_TEST_BASE + (subgroup->reg_width >> 3) - 1; 137 138 return _INTC_MK(fn, MODE_ENABLE_REG, intc_get_reg(d, subgroup->reg), 139 0, 1, (subgroup->reg_width - 1) - index); 140 } 141 142 static void __init intc_subgroup_init_one(struct intc_desc *desc, 143 struct intc_desc_int *d, 144 struct intc_subgroup *subgroup) 145 { 146 struct intc_map_entry *mapped; 147 unsigned int pirq; 148 unsigned long flags; 149 int i; 150 151 mapped = radix_tree_lookup(&d->tree, subgroup->parent_id); 152 if (!mapped) { 153 WARN_ON(1); 154 return; 155 } 156 157 pirq = mapped - intc_irq_xlate; 158 159 raw_spin_lock_irqsave(&d->lock, flags); 160 161 for (i = 0; i < ARRAY_SIZE(subgroup->enum_ids); i++) { 162 struct intc_subgroup_entry *entry; 163 int err; 164 165 if (!subgroup->enum_ids[i]) 166 continue; 167 168 entry = kmalloc(sizeof(*entry), GFP_NOWAIT); 169 if (!entry) 170 break; 171 172 entry->pirq = pirq; 173 entry->enum_id = subgroup->enum_ids[i]; 174 entry->handle = intc_subgroup_data(subgroup, d, i); 175 176 err = radix_tree_insert(&d->tree, entry->enum_id, entry); 177 if (unlikely(err < 0)) 178 break; 179 180 radix_tree_tag_set(&d->tree, entry->enum_id, 181 INTC_TAG_VIRQ_NEEDS_ALLOC); 182 } 183 184 raw_spin_unlock_irqrestore(&d->lock, flags); 185 } 186 187 void __init intc_subgroup_init(struct intc_desc *desc, struct intc_desc_int *d) 188 { 189 int i; 190 191 if (!desc->hw.subgroups) 192 return; 193 194 for (i = 0; i < desc->hw.nr_subgroups; i++) 195 intc_subgroup_init_one(desc, d, desc->hw.subgroups + i); 196 } 197 198 static void __init intc_subgroup_map(struct intc_desc_int *d) 199 { 200 struct intc_subgroup_entry *entries[32]; 201 unsigned long flags; 202 unsigned int nr_found; 203 int i; 204 205 raw_spin_lock_irqsave(&d->lock, flags); 206 207 restart: 208 nr_found = radix_tree_gang_lookup_tag_slot(&d->tree, 209 (void ***)entries, 0, ARRAY_SIZE(entries), 210 INTC_TAG_VIRQ_NEEDS_ALLOC); 211 212 for (i = 0; i < nr_found; i++) { 213 struct intc_subgroup_entry *entry; 214 int irq; 215 216 entry = radix_tree_deref_slot((void **)entries[i]); 217 if (unlikely(!entry)) 218 continue; 219 if (radix_tree_deref_retry(entry)) 220 goto restart; 221 222 irq = create_irq(); 223 if (unlikely(irq < 0)) { 224 pr_err("no more free IRQs, bailing..\n"); 225 break; 226 } 227 228 pr_info("Setting up a chained VIRQ from %d -> %d\n", 229 irq, entry->pirq); 230 231 intc_irq_xlate_set(irq, entry->enum_id, d); 232 233 irq_set_chip_and_handler_name(irq, irq_get_chip(entry->pirq), 234 handle_simple_irq, "virq"); 235 irq_set_chip_data(irq, irq_get_chip_data(entry->pirq)); 236 237 irq_set_handler_data(irq, (void *)entry->handle); 238 239 /* 240 * Set the virtual IRQ as non-threadable. 241 */ 242 irq_set_nothread(irq); 243 244 irq_set_chained_handler(entry->pirq, intc_virq_handler); 245 add_virq_to_pirq(entry->pirq, irq); 246 247 radix_tree_tag_clear(&d->tree, entry->enum_id, 248 INTC_TAG_VIRQ_NEEDS_ALLOC); 249 radix_tree_replace_slot((void **)entries[i], 250 &intc_irq_xlate[irq]); 251 } 252 253 raw_spin_unlock_irqrestore(&d->lock, flags); 254 } 255 256 void __init intc_finalize(void) 257 { 258 struct intc_desc_int *d; 259 260 list_for_each_entry(d, &intc_list, list) 261 if (radix_tree_tagged(&d->tree, INTC_TAG_VIRQ_NEEDS_ALLOC)) 262 intc_subgroup_map(d); 263 } 264