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 pr_err("can't allocate VIRQ mapping for %d\n", virq); 99 return -ENOMEM; 100 } 101 102 entry->irq = virq; 103 104 if (last) 105 *last = entry; 106 else 107 irq_set_handler_data(irq, entry); 108 109 return 0; 110 } 111 112 static void intc_virq_handler(struct irq_desc *desc) 113 { 114 unsigned int irq = irq_desc_get_irq(desc); 115 struct irq_data *data = irq_desc_get_irq_data(desc); 116 struct irq_chip *chip = irq_data_get_irq_chip(data); 117 struct intc_virq_list *entry, *vlist = irq_data_get_irq_handler_data(data); 118 struct intc_desc_int *d = get_intc_desc(irq); 119 120 chip->irq_mask_ack(data); 121 122 for_each_virq(entry, vlist) { 123 unsigned long addr, handle; 124 struct irq_desc *vdesc = irq_to_desc(entry->irq); 125 126 if (vdesc) { 127 handle = (unsigned long)irq_desc_get_handler_data(vdesc); 128 addr = INTC_REG(d, _INTC_ADDR_E(handle), 0); 129 if (intc_reg_fns[_INTC_FN(handle)](addr, handle, 0)) 130 generic_handle_irq_desc(vdesc); 131 } 132 } 133 134 chip->irq_unmask(data); 135 } 136 137 static unsigned long __init intc_subgroup_data(struct intc_subgroup *subgroup, 138 struct intc_desc_int *d, 139 unsigned int index) 140 { 141 unsigned int fn = REG_FN_TEST_BASE + (subgroup->reg_width >> 3) - 1; 142 143 return _INTC_MK(fn, MODE_ENABLE_REG, intc_get_reg(d, subgroup->reg), 144 0, 1, (subgroup->reg_width - 1) - index); 145 } 146 147 static void __init intc_subgroup_init_one(struct intc_desc *desc, 148 struct intc_desc_int *d, 149 struct intc_subgroup *subgroup) 150 { 151 struct intc_map_entry *mapped; 152 unsigned int pirq; 153 unsigned long flags; 154 int i; 155 156 mapped = radix_tree_lookup(&d->tree, subgroup->parent_id); 157 if (!mapped) { 158 WARN_ON(1); 159 return; 160 } 161 162 pirq = mapped - intc_irq_xlate; 163 164 raw_spin_lock_irqsave(&d->lock, flags); 165 166 for (i = 0; i < ARRAY_SIZE(subgroup->enum_ids); i++) { 167 struct intc_subgroup_entry *entry; 168 int err; 169 170 if (!subgroup->enum_ids[i]) 171 continue; 172 173 entry = kmalloc(sizeof(*entry), GFP_NOWAIT); 174 if (!entry) 175 break; 176 177 entry->pirq = pirq; 178 entry->enum_id = subgroup->enum_ids[i]; 179 entry->handle = intc_subgroup_data(subgroup, d, i); 180 181 err = radix_tree_insert(&d->tree, entry->enum_id, entry); 182 if (unlikely(err < 0)) 183 break; 184 185 radix_tree_tag_set(&d->tree, entry->enum_id, 186 INTC_TAG_VIRQ_NEEDS_ALLOC); 187 } 188 189 raw_spin_unlock_irqrestore(&d->lock, flags); 190 } 191 192 void __init intc_subgroup_init(struct intc_desc *desc, struct intc_desc_int *d) 193 { 194 int i; 195 196 if (!desc->hw.subgroups) 197 return; 198 199 for (i = 0; i < desc->hw.nr_subgroups; i++) 200 intc_subgroup_init_one(desc, d, desc->hw.subgroups + i); 201 } 202 203 static void __init intc_subgroup_map(struct intc_desc_int *d) 204 { 205 struct intc_subgroup_entry *entries[32]; 206 unsigned long flags; 207 unsigned int nr_found; 208 int i; 209 210 raw_spin_lock_irqsave(&d->lock, flags); 211 212 restart: 213 nr_found = radix_tree_gang_lookup_tag_slot(&d->tree, 214 (void ***)entries, 0, ARRAY_SIZE(entries), 215 INTC_TAG_VIRQ_NEEDS_ALLOC); 216 217 for (i = 0; i < nr_found; i++) { 218 struct intc_subgroup_entry *entry; 219 int irq; 220 221 entry = radix_tree_deref_slot((void **)entries[i]); 222 if (unlikely(!entry)) 223 continue; 224 if (radix_tree_deref_retry(entry)) 225 goto restart; 226 227 irq = irq_alloc_desc(numa_node_id()); 228 if (unlikely(irq < 0)) { 229 pr_err("no more free IRQs, bailing..\n"); 230 break; 231 } 232 233 activate_irq(irq); 234 235 pr_info("Setting up a chained VIRQ from %d -> %d\n", 236 irq, entry->pirq); 237 238 intc_irq_xlate_set(irq, entry->enum_id, d); 239 240 irq_set_chip_and_handler_name(irq, irq_get_chip(entry->pirq), 241 handle_simple_irq, "virq"); 242 irq_set_chip_data(irq, irq_get_chip_data(entry->pirq)); 243 244 irq_set_handler_data(irq, (void *)entry->handle); 245 246 /* 247 * Set the virtual IRQ as non-threadable. 248 */ 249 irq_set_nothread(irq); 250 251 /* Set handler data before installing the handler */ 252 add_virq_to_pirq(entry->pirq, irq); 253 irq_set_chained_handler(entry->pirq, intc_virq_handler); 254 255 radix_tree_tag_clear(&d->tree, entry->enum_id, 256 INTC_TAG_VIRQ_NEEDS_ALLOC); 257 radix_tree_replace_slot(&d->tree, (void **)entries[i], 258 &intc_irq_xlate[irq]); 259 } 260 261 raw_spin_unlock_irqrestore(&d->lock, flags); 262 } 263 264 void __init intc_finalize(void) 265 { 266 struct intc_desc_int *d; 267 268 list_for_each_entry(d, &intc_list, list) 269 if (radix_tree_tagged(&d->tree, INTC_TAG_VIRQ_NEEDS_ALLOC)) 270 intc_subgroup_map(d); 271 } 272