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