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