arch/mn10300/kernel/irq.c

   1 /* MN10300 Arch-specific interrupt handling
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public Licence
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the Licence, or (at your option) any later version.
  10  */
  11 #include <linux/module.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/kernel_stat.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/cpumask.h>
  16 #include <asm/setup.h>
  17 #include <asm/serial-regs.h>
  18
  19 unsigned long __mn10300_irq_enabled_epsw[NR_CPUS] __cacheline_aligned_in_smp = {
  20         [0 ... NR_CPUS - 1] = EPSW_IE | EPSW_IM_7
  21 };
  22 EXPORT_SYMBOL(__mn10300_irq_enabled_epsw);
  23
  24 #ifdef CONFIG_SMP
  25 static char irq_affinity_online[NR_IRQS] = {
  26         [0 ... NR_IRQS - 1] = 0
  27 };
  28
  29 #define NR_IRQ_WORDS    ((NR_IRQS + 31) / 32)
  30 static unsigned long irq_affinity_request[NR_IRQ_WORDS] = {
  31         [0 ... NR_IRQ_WORDS - 1] = 0
  32 };
  33 #endif  /* CONFIG_SMP */
  34
  35 atomic_t irq_err_count;
  36
  37 /*
  38  * MN10300 interrupt controller operations
  39  */
  40 static void mn10300_cpupic_ack(struct irq_data *d)
  41 {
  42         unsigned int irq = d->irq;
  43         unsigned long flags;
  44         u16 tmp;
  45
  46         flags = arch_local_cli_save();
  47         GxICR_u8(irq) = GxICR_DETECT;
  48         tmp = GxICR(irq);
  49         arch_local_irq_restore(flags);
  50 }
  51
  52 static void __mask_and_set_icr(unsigned int irq,
  53                                unsigned int mask, unsigned int set)
  54 {
  55         unsigned long flags;
  56         u16 tmp;
  57
  58         flags = arch_local_cli_save();
  59         tmp = GxICR(irq);
  60         GxICR(irq) = (tmp & mask) | set;
  61         tmp = GxICR(irq);
  62         arch_local_irq_restore(flags);
  63 }
  64
  65 static void mn10300_cpupic_mask(struct irq_data *d)
  66 {
  67         __mask_and_set_icr(d->irq, GxICR_LEVEL, 0);
  68 }
  69
  70 static void mn10300_cpupic_mask_ack(struct irq_data *d)
  71 {
  72         unsigned int irq = d->irq;
  73 #ifdef CONFIG_SMP
  74         unsigned long flags;
  75         u16 tmp;
  76
  77         flags = arch_local_cli_save();
  78
  79         if (!test_and_clear_bit(irq, irq_affinity_request)) {
  80                 tmp = GxICR(irq);
  81                 GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_DETECT;
  82                 tmp = GxICR(irq);
  83         } else {
  84                 u16 tmp2;
  85                 tmp = GxICR(irq);
  86                 GxICR(irq) = (tmp & GxICR_LEVEL);
  87                 tmp2 = GxICR(irq);
  88
  89                 irq_affinity_online[irq] =
  90                         cpumask_any_and(d->affinity, cpu_online_mask);
  91                 CROSS_GxICR(irq, irq_affinity_online[irq]) =
  92                         (tmp & (GxICR_LEVEL | GxICR_ENABLE)) | GxICR_DETECT;
  93                 tmp = CROSS_GxICR(irq, irq_affinity_online[irq]);
  94         }
  95
  96         arch_local_irq_restore(flags);
  97 #else  /* CONFIG_SMP */
  98         __mask_and_set_icr(irq, GxICR_LEVEL, GxICR_DETECT);
  99 #endif /* CONFIG_SMP */
 100 }
 101
 102 static void mn10300_cpupic_unmask(struct irq_data *d)
 103 {
 104         __mask_and_set_icr(d->irq, GxICR_LEVEL, GxICR_ENABLE);
 105 }
 106
 107 static void mn10300_cpupic_unmask_clear(struct irq_data *d)
 108 {
 109         unsigned int irq = d->irq;
 110         /* the MN10300 PIC latches its interrupt request bit, even after the
 111          * device has ceased to assert its interrupt line and the interrupt
 112          * channel has been disabled in the PIC, so for level-triggered
 113          * interrupts we need to clear the request bit when we re-enable */
 114 #ifdef CONFIG_SMP
 115         unsigned long flags;
 116         u16 tmp;
 117
 118         flags = arch_local_cli_save();
 119
 120         if (!test_and_clear_bit(irq, irq_affinity_request)) {
 121                 tmp = GxICR(irq);
 122                 GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT;
 123                 tmp = GxICR(irq);
 124         } else {
 125                 tmp = GxICR(irq);
 126
 127                 irq_affinity_online[irq] = cpumask_any_and(d->affinity,
 128                                                            cpu_online_mask);
 129                 CROSS_GxICR(irq, irq_affinity_online[irq]) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT;
 130                 tmp = CROSS_GxICR(irq, irq_affinity_online[irq]);
 131         }
 132
 133         arch_local_irq_restore(flags);
 134 #else  /* CONFIG_SMP */
 135         __mask_and_set_icr(irq, GxICR_LEVEL, GxICR_ENABLE | GxICR_DETECT);
 136 #endif /* CONFIG_SMP */
 137 }
 138
 139 #ifdef CONFIG_SMP
 140 static int
 141 mn10300_cpupic_setaffinity(struct irq_data *d, const struct cpumask *mask,
 142                            bool force)
 143 {
 144         unsigned long flags;
 145
 146         flags = arch_local_cli_save();
 147         set_bit(d->irq, irq_affinity_request);
 148         arch_local_irq_restore(flags);
 149         return 0;
 150 }
 151 #endif /* CONFIG_SMP */
 152
 153 /*
 154  * MN10300 PIC level-triggered IRQ handling.
 155  *
 156  * The PIC has no 'ACK' function per se.  It is possible to clear individual
 157  * channel latches, but each latch relatches whether or not the channel is
 158  * masked, so we need to clear the latch when we unmask the channel.
 159  *
 160  * Also for this reason, we don't supply an ack() op (it's unused anyway if
 161  * mask_ack() is provided), and mask_ack() just masks.
 162  */
 163 static struct irq_chip mn10300_cpu_pic_level = {
 164         .name                   = "cpu_l",
 165         .irq_disable            = mn10300_cpupic_mask,
 166         .irq_enable             = mn10300_cpupic_unmask_clear,
 167         .irq_ack                = NULL,
 168         .irq_mask               = mn10300_cpupic_mask,
 169         .irq_mask_ack           = mn10300_cpupic_mask,
 170         .irq_unmask             = mn10300_cpupic_unmask_clear,
 171 #ifdef CONFIG_SMP
 172         .irq_set_affinity       = mn10300_cpupic_setaffinity,
 173 #endif
 174 };
 175
 176 /*
 177  * MN10300 PIC edge-triggered IRQ handling.
 178  *
 179  * We use the latch clearing function of the PIC as the 'ACK' function.
 180  */
 181 static struct irq_chip mn10300_cpu_pic_edge = {
 182         .name                   = "cpu_e",
 183         .irq_disable            = mn10300_cpupic_mask,
 184         .irq_enable             = mn10300_cpupic_unmask,
 185         .irq_ack                = mn10300_cpupic_ack,
 186         .irq_mask               = mn10300_cpupic_mask,
 187         .irq_mask_ack           = mn10300_cpupic_mask_ack,
 188         .irq_unmask             = mn10300_cpupic_unmask,
 189 #ifdef CONFIG_SMP
 190         .irq_set_affinity       = mn10300_cpupic_setaffinity,
 191 #endif
 192 };
 193
 194 /*
 195  * 'what should we do if we get a hw irq event on an illegal vector'.
 196  * each architecture has to answer this themselves.
 197  */
 198 void ack_bad_irq(int irq)
 199 {
 200         printk(KERN_WARNING "unexpected IRQ trap at vector %02x\n", irq);
 201 }
 202
 203 /*
 204  * change the level at which an IRQ executes
 205  * - must not be called whilst interrupts are being processed!
 206  */
 207 void set_intr_level(int irq, u16 level)
 208 {
 209         BUG_ON(in_interrupt());
 210
 211         __mask_and_set_icr(irq, GxICR_ENABLE, level);
 212 }
 213
 214 /*
 215  * mark an interrupt to be ACK'd after interrupt handlers have been run rather
 216  * than before
 217  */
 218 void mn10300_set_lateack_irq_type(int irq)
 219 {
 220         irq_set_chip_and_handler(irq, &mn10300_cpu_pic_level,
 221                                  handle_level_irq);
 222 }
 223
 224 /*
 225  * initialise the interrupt system
 226  */
 227 void __init init_IRQ(void)
 228 {
 229         int irq;
 230
 231         for (irq = 0; irq < NR_IRQS; irq++)
 232                 if (irq_get_chip(irq) == &no_irq_chip)
 233                         /* due to the PIC latching interrupt requests, even
 234                          * when the IRQ is disabled, IRQ_PENDING is superfluous
 235                          * and we can use handle_level_irq() for edge-triggered
 236                          * interrupts */
 237                         irq_set_chip_and_handler(irq, &mn10300_cpu_pic_edge,
 238                                                  handle_level_irq);
 239
 240         unit_init_IRQ();
 241 }
 242
 243 /*
 244  * handle normal device IRQs
 245  */
 246 asmlinkage void do_IRQ(void)
 247 {
 248         unsigned long sp, epsw, irq_disabled_epsw, old_irq_enabled_epsw;
 249         unsigned int cpu_id = smp_processor_id();
 250         int irq;
 251
 252         sp = current_stack_pointer();
 253         BUG_ON(sp - (sp & ~(THREAD_SIZE - 1)) < STACK_WARN);
 254
 255         /* make sure local_irq_enable() doesn't muck up the interrupt priority
 256          * setting in EPSW */
 257         old_irq_enabled_epsw = __mn10300_irq_enabled_epsw[cpu_id];
 258         local_save_flags(epsw);
 259         __mn10300_irq_enabled_epsw[cpu_id] = EPSW_IE | (EPSW_IM & epsw);
 260         irq_disabled_epsw = EPSW_IE | MN10300_CLI_LEVEL;
 261
 262 #ifdef CONFIG_MN10300_WD_TIMER
 263         __IRQ_STAT(cpu_id, __irq_count)++;
 264 #endif
 265
 266         irq_enter();
 267
 268         for (;;) {
 269                 /* ask the interrupt controller for the next IRQ to process
 270                  * - the result we get depends on EPSW.IM
 271                  */
 272                 irq = IAGR & IAGR_GN;
 273                 if (!irq)
 274                         break;
 275
 276                 local_irq_restore(irq_disabled_epsw);
 277
 278                 generic_handle_irq(irq >> 2);
 279
 280                 /* restore IRQ controls for IAGR access */
 281                 local_irq_restore(epsw);
 282         }
 283
 284         __mn10300_irq_enabled_epsw[cpu_id] = old_irq_enabled_epsw;
 285
 286         irq_exit();
 287 }
 288
 289 /*
 290  * Display interrupt management information through /proc/interrupts
 291  */
 292 int arch_show_interrupts(struct seq_file *p, int prec)
 293 {
 294 #ifdef CONFIG_MN10300_WD_TIMER
 295         int j;
 296
 297         seq_printf(p, "%*s: ", prec, "NMI");
 298         for (j = 0; j < NR_CPUS; j++)
 299                 if (cpu_online(j))
 300                         seq_printf(p, "%10u ", nmi_count(j));
 301         seq_putc(p, '\n');
 302 #endif
 303
 304         seq_printf(p, "%*s: ", prec, "ERR");
 305         seq_printf(p, "%10u\n", atomic_read(&irq_err_count));
 306         return 0;
 307 }
 308
 309 #ifdef CONFIG_HOTPLUG_CPU
 310 void migrate_irqs(void)
 311 {
 312         int irq;
 313         unsigned int self, new;
 314         unsigned long flags;
 315
 316         self = smp_processor_id();
 317         for (irq = 0; irq < NR_IRQS; irq++) {
 318                 struct irq_data *data = irq_get_irq_data(irq);
 319
 320                 if (irqd_is_per_cpu(data))
 321                         continue;
 322
 323                 if (cpumask_test_cpu(self, &data->affinity) &&
 324                     !cpumask_intersects(&irq_affinity[irq], cpu_online_mask)) {
 325                         int cpu_id;
 326                         cpu_id = cpumask_first(cpu_online_mask);
 327                         cpumask_set_cpu(cpu_id, &data->affinity);
 328                 }
 329                 /* We need to operate irq_affinity_online atomically. */
 330                 arch_local_cli_save(flags);
 331                 if (irq_affinity_online[irq] == self) {
 332                         u16 x, tmp;
 333
 334                         x = GxICR(irq);
 335                         GxICR(irq) = x & GxICR_LEVEL;
 336                         tmp = GxICR(irq);
 337
 338                         new = cpumask_any_and(&data->affinity,
 339                                               cpu_online_mask);
 340                         irq_affinity_online[irq] = new;
 341
 342                         CROSS_GxICR(irq, new) =
 343                                 (x & GxICR_LEVEL) | GxICR_DETECT;
 344                         tmp = CROSS_GxICR(irq, new);
 345
 346                         x &= GxICR_LEVEL | GxICR_ENABLE;
 347                         if (GxICR(irq) & GxICR_REQUEST)
 348                                 x |= GxICR_REQUEST | GxICR_DETECT;
 349                         CROSS_GxICR(irq, new) = x;
 350                         tmp = CROSS_GxICR(irq, new);
 351                 }
 352                 arch_local_irq_restore(flags);
 353         }
 354 }
 355 #endif /* CONFIG_HOTPLUG_CPU */