arch/x86/kernel/uv_irq.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * SGI UV IRQ functions
   7  *
   8  * Copyright (C) 2008 Silicon Graphics, Inc. All rights reserved.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/rbtree.h>
  13 #include <linux/slab.h>
  14 #include <linux/irq.h>
  15
  16 #include <asm/apic.h>
  17 #include <asm/uv/uv_irq.h>
  18 #include <asm/uv/uv_hub.h>
  19
  20 /* MMR offset and pnode of hub sourcing interrupts for a given irq */
  21 struct uv_irq_2_mmr_pnode{
  22         struct rb_node          list;
  23         unsigned long           offset;
  24         int                     pnode;
  25         int                     irq;
  26 };
  27
  28 static spinlock_t               uv_irq_lock;
  29 static struct rb_root           uv_irq_root;
  30
  31 static int uv_set_irq_affinity(unsigned int, const struct cpumask *);
  32
  33 static void uv_noop(unsigned int irq)
  34 {
  35 }
  36
  37 static unsigned int uv_noop_ret(unsigned int irq)
  38 {
  39         return 0;
  40 }
  41
  42 static void uv_ack_apic(unsigned int irq)
  43 {
  44         ack_APIC_irq();
  45 }
  46
  47 struct irq_chip uv_irq_chip = {
  48         .name           = "UV-CORE",
  49         .startup        = uv_noop_ret,
  50         .shutdown       = uv_noop,
  51         .enable         = uv_noop,
  52         .disable        = uv_noop,
  53         .ack            = uv_noop,
  54         .mask           = uv_noop,
  55         .unmask         = uv_noop,
  56         .eoi            = uv_ack_apic,
  57         .end            = uv_noop,
  58         .set_affinity   = uv_set_irq_affinity,
  59 };
  60
  61 /*
  62  * Add offset and pnode information of the hub sourcing interrupts to the
  63  * rb tree for a specific irq.
  64  */
  65 static int uv_set_irq_2_mmr_info(int irq, unsigned long offset, unsigned blade)
  66 {
  67         struct rb_node **link = &uv_irq_root.rb_node;
  68         struct rb_node *parent = NULL;
  69         struct uv_irq_2_mmr_pnode *n;
  70         struct uv_irq_2_mmr_pnode *e;
  71         unsigned long irqflags;
  72
  73         n = kmalloc_node(sizeof(struct uv_irq_2_mmr_pnode), GFP_KERNEL,
  74                                 uv_blade_to_memory_nid(blade));
  75         if (!n)
  76                 return -ENOMEM;
  77
  78         n->irq = irq;
  79         n->offset = offset;
  80         n->pnode = uv_blade_to_pnode(blade);
  81         spin_lock_irqsave(&uv_irq_lock, irqflags);
  82         /* Find the right place in the rbtree: */
  83         while (*link) {
  84                 parent = *link;
  85                 e = rb_entry(parent, struct uv_irq_2_mmr_pnode, list);
  86
  87                 if (unlikely(irq == e->irq)) {
  88                         /* irq entry exists */
  89                         e->pnode = uv_blade_to_pnode(blade);
  90                         e->offset = offset;
  91                         spin_unlock_irqrestore(&uv_irq_lock, irqflags);
  92                         kfree(n);
  93                         return 0;
  94                 }
  95
  96                 if (irq < e->irq)
  97                         link = &(*link)->rb_left;
  98                 else
  99                         link = &(*link)->rb_right;
 100         }
 101
 102         /* Insert the node into the rbtree. */
 103         rb_link_node(&n->list, parent, link);
 104         rb_insert_color(&n->list, &uv_irq_root);
 105
 106         spin_unlock_irqrestore(&uv_irq_lock, irqflags);
 107         return 0;
 108 }
 109
 110 /* Retrieve offset and pnode information from the rb tree for a specific irq */
 111 int uv_irq_2_mmr_info(int irq, unsigned long *offset, int *pnode)
 112 {
 113         struct uv_irq_2_mmr_pnode *e;
 114         struct rb_node *n;
 115         unsigned long irqflags;
 116
 117         spin_lock_irqsave(&uv_irq_lock, irqflags);
 118         n = uv_irq_root.rb_node;
 119         while (n) {
 120                 e = rb_entry(n, struct uv_irq_2_mmr_pnode, list);
 121
 122                 if (e->irq == irq) {
 123                         *offset = e->offset;
 124                         *pnode = e->pnode;
 125                         spin_unlock_irqrestore(&uv_irq_lock, irqflags);
 126                         return 0;
 127                 }
 128
 129                 if (irq < e->irq)
 130                         n = n->rb_left;
 131                 else
 132                         n = n->rb_right;
 133         }
 134         spin_unlock_irqrestore(&uv_irq_lock, irqflags);
 135         return -1;
 136 }
 137
 138 /*
 139  * Re-target the irq to the specified CPU and enable the specified MMR located
 140  * on the specified blade to allow the sending of MSIs to the specified CPU.
 141  */
 142 static int
 143 arch_enable_uv_irq(char *irq_name, unsigned int irq, int cpu, int mmr_blade,
 144                        unsigned long mmr_offset, int restrict)
 145 {
 146         const struct cpumask *eligible_cpu = cpumask_of(cpu);
 147         struct irq_desc *desc = irq_to_desc(irq);
 148         struct irq_cfg *cfg;
 149         int mmr_pnode;
 150         unsigned long mmr_value;
 151         struct uv_IO_APIC_route_entry *entry;
 152         int err;
 153
 154         BUILD_BUG_ON(sizeof(struct uv_IO_APIC_route_entry) !=
 155                         sizeof(unsigned long));
 156
 157         cfg = irq_cfg(irq);
 158
 159         err = assign_irq_vector(irq, cfg, eligible_cpu);
 160         if (err != 0)
 161                 return err;
 162
 163         if (restrict == UV_AFFINITY_CPU)
 164                 desc->status |= IRQ_NO_BALANCING;
 165         else
 166                 desc->status |= IRQ_MOVE_PCNTXT;
 167
 168         set_irq_chip_and_handler_name(irq, &uv_irq_chip, handle_percpu_irq,
 169                                       irq_name);
 170
 171         mmr_value = 0;
 172         entry = (struct uv_IO_APIC_route_entry *)&mmr_value;
 173         entry->vector           = cfg->vector;
 174         entry->delivery_mode    = apic->irq_delivery_mode;
 175         entry->dest_mode        = apic->irq_dest_mode;
 176         entry->polarity         = 0;
 177         entry->trigger          = 0;
 178         entry->mask             = 0;
 179         entry->dest             = apic->cpu_mask_to_apicid(eligible_cpu);
 180
 181         mmr_pnode = uv_blade_to_pnode(mmr_blade);
 182         uv_write_global_mmr64(mmr_pnode, mmr_offset, mmr_value);
 183
 184         if (cfg->move_in_progress)
 185                 send_cleanup_vector(cfg);
 186
 187         return irq;
 188 }
 189
 190 /*
 191  * Disable the specified MMR located on the specified blade so that MSIs are
 192  * longer allowed to be sent.
 193  */
 194 static void arch_disable_uv_irq(int mmr_pnode, unsigned long mmr_offset)
 195 {
 196         unsigned long mmr_value;
 197         struct uv_IO_APIC_route_entry *entry;
 198
 199         BUILD_BUG_ON(sizeof(struct uv_IO_APIC_route_entry) !=
 200                         sizeof(unsigned long));
 201
 202         mmr_value = 0;
 203         entry = (struct uv_IO_APIC_route_entry *)&mmr_value;
 204         entry->mask = 1;
 205
 206         uv_write_global_mmr64(mmr_pnode, mmr_offset, mmr_value);
 207 }
 208
 209 static int uv_set_irq_affinity(unsigned int irq, const struct cpumask *mask)
 210 {
 211         struct irq_desc *desc = irq_to_desc(irq);
 212         struct irq_cfg *cfg = desc->chip_data;
 213         unsigned int dest;
 214         unsigned long mmr_value;
 215         struct uv_IO_APIC_route_entry *entry;
 216         unsigned long mmr_offset;
 217         unsigned mmr_pnode;
 218
 219         if (set_desc_affinity(desc, mask, &dest))
 220                 return -1;
 221
 222         mmr_value = 0;
 223         entry = (struct uv_IO_APIC_route_entry *)&mmr_value;
 224
 225         entry->vector           = cfg->vector;
 226         entry->delivery_mode    = apic->irq_delivery_mode;
 227         entry->dest_mode        = apic->irq_dest_mode;
 228         entry->polarity         = 0;
 229         entry->trigger          = 0;
 230         entry->mask             = 0;
 231         entry->dest             = dest;
 232
 233         /* Get previously stored MMR and pnode of hub sourcing interrupts */
 234         if (uv_irq_2_mmr_info(irq, &mmr_offset, &mmr_pnode))
 235                 return -1;
 236
 237         uv_write_global_mmr64(mmr_pnode, mmr_offset, mmr_value);
 238
 239         if (cfg->move_in_progress)
 240                 send_cleanup_vector(cfg);
 241
 242         return 0;
 243 }
 244
 245 /*
 246  * Set up a mapping of an available irq and vector, and enable the specified
 247  * MMR that defines the MSI that is to be sent to the specified CPU when an
 248  * interrupt is raised.
 249  */
 250 int uv_setup_irq(char *irq_name, int cpu, int mmr_blade,
 251                  unsigned long mmr_offset, int restrict)
 252 {
 253         int irq, ret;
 254
 255         irq = create_irq_nr(NR_IRQS_LEGACY, uv_blade_to_memory_nid(mmr_blade));
 256
 257         if (irq <= 0)
 258                 return -EBUSY;
 259
 260         ret = arch_enable_uv_irq(irq_name, irq, cpu, mmr_blade, mmr_offset,
 261                 restrict);
 262         if (ret == irq)
 263                 uv_set_irq_2_mmr_info(irq, mmr_offset, mmr_blade);
 264         else
 265                 destroy_irq(irq);
 266
 267         return ret;
 268 }
 269 EXPORT_SYMBOL_GPL(uv_setup_irq);
 270
 271 /*
 272  * Tear down a mapping of an irq and vector, and disable the specified MMR that
 273  * defined the MSI that was to be sent to the specified CPU when an interrupt
 274  * was raised.
 275  *
 276  * Set mmr_blade and mmr_offset to what was passed in on uv_setup_irq().
 277  */
 278 void uv_teardown_irq(unsigned int irq)
 279 {
 280         struct uv_irq_2_mmr_pnode *e;
 281         struct rb_node *n;
 282         unsigned long irqflags;
 283
 284         spin_lock_irqsave(&uv_irq_lock, irqflags);
 285         n = uv_irq_root.rb_node;
 286         while (n) {
 287                 e = rb_entry(n, struct uv_irq_2_mmr_pnode, list);
 288                 if (e->irq == irq) {
 289                         arch_disable_uv_irq(e->pnode, e->offset);
 290                         rb_erase(n, &uv_irq_root);
 291                         kfree(e);
 292                         break;
 293                 }
 294                 if (irq < e->irq)
 295                         n = n->rb_left;
 296                 else
 297                         n = n->rb_right;
 298         }
 299         spin_unlock_irqrestore(&uv_irq_lock, irqflags);
 300         destroy_irq(irq);
 301 }
 302 EXPORT_SYMBOL_GPL(uv_teardown_irq);