linux/drivers/sh/intc/virq.c
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   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
  20static struct intc_map_entry intc_irq_xlate[INTC_NR_IRQS];
  21
  22struct 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
  35void 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
  45struct intc_map_entry *intc_irq_xlate_get(unsigned int irq)
  46{
  47        return intc_irq_xlate + irq;
  48}
  49
  50int 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}
  82EXPORT_SYMBOL_GPL(intc_irq_lookup);
  83
  84static 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
 112static 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
 137static 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
 147static 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
 192void __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
 203static 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
 212restart:
 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((void **)entries[i],
 258                                        &intc_irq_xlate[irq]);
 259        }
 260
 261        raw_spin_unlock_irqrestore(&d->lock, flags);
 262}
 263
 264void __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