drivers/sh/intc/virq.c

   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 }