arch/arm/common/gic.c

   1 /*
   2  *  linux/arch/arm/common/gic.c
   3  *
   4  *  Copyright (C) 2002 ARM Limited, All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * Interrupt architecture for the GIC:
  11  *
  12  * o There is one Interrupt Distributor, which receives interrupts
  13  *   from system devices and sends them to the Interrupt Controllers.
  14  *
  15  * o There is one CPU Interface per CPU, which sends interrupts sent
  16  *   by the Distributor, and interrupts generated locally, to the
  17  *   associated CPU. The base address of the CPU interface is usually
  18  *   aliased so that the same address points to different chips depending
  19  *   on the CPU it is accessed from.
  20  *
  21  * Note that IRQs 0-31 are special - they are local to each CPU.
  22  * As such, the enable set/clear, pending set/clear and active bit
  23  * registers are banked per-cpu for these sources.
  24  */
  25 #include <linux/init.h>
  26 #include <linux/kernel.h>
  27 #include <linux/list.h>
  28 #include <linux/smp.h>
  29 #include <linux/cpumask.h>
  30 #include <linux/io.h>
  31
  32 #include <asm/irq.h>
  33 #include <asm/mach/irq.h>
  34 #include <asm/hardware/gic.h>
  35
  36 static DEFINE_SPINLOCK(irq_controller_lock);
  37
  38 struct gic_chip_data {
  39         unsigned int irq_offset;
  40         void __iomem *dist_base;
  41         void __iomem *cpu_base;
  42 };
  43
  44 #ifndef MAX_GIC_NR
  45 #define MAX_GIC_NR      1
  46 #endif
  47
  48 static struct gic_chip_data gic_data[MAX_GIC_NR];
  49
  50 static inline void __iomem *gic_dist_base(unsigned int irq)
  51 {
  52         struct gic_chip_data *gic_data = get_irq_chip_data(irq);
  53         return gic_data->dist_base;
  54 }
  55
  56 static inline void __iomem *gic_cpu_base(unsigned int irq)
  57 {
  58         struct gic_chip_data *gic_data = get_irq_chip_data(irq);
  59         return gic_data->cpu_base;
  60 }
  61
  62 static inline unsigned int gic_irq(unsigned int irq)
  63 {
  64         struct gic_chip_data *gic_data = get_irq_chip_data(irq);
  65         return irq - gic_data->irq_offset;
  66 }
  67
  68 /*
  69  * Routines to acknowledge, disable and enable interrupts
  70  */
  71 static void gic_ack_irq(unsigned int irq)
  72 {
  73
  74         spin_lock(&irq_controller_lock);
  75         writel(gic_irq(irq), gic_cpu_base(irq) + GIC_CPU_EOI);
  76         spin_unlock(&irq_controller_lock);
  77 }
  78
  79 static void gic_mask_irq(unsigned int irq)
  80 {
  81         u32 mask = 1 << (irq % 32);
  82
  83         spin_lock(&irq_controller_lock);
  84         writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_CLEAR + (gic_irq(irq) / 32) * 4);
  85         spin_unlock(&irq_controller_lock);
  86 }
  87
  88 static void gic_unmask_irq(unsigned int irq)
  89 {
  90         u32 mask = 1 << (irq % 32);
  91
  92         spin_lock(&irq_controller_lock);
  93         writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_SET + (gic_irq(irq) / 32) * 4);
  94         spin_unlock(&irq_controller_lock);
  95 }
  96
  97 static int gic_set_type(unsigned int irq, unsigned int type)
  98 {
  99         void __iomem *base = gic_dist_base(irq);
 100         unsigned int gicirq = gic_irq(irq);
 101         u32 enablemask = 1 << (gicirq % 32);
 102         u32 enableoff = (gicirq / 32) * 4;
 103         u32 confmask = 0x2 << ((gicirq % 16) * 2);
 104         u32 confoff = (gicirq / 16) * 4;
 105         bool enabled = false;
 106         u32 val;
 107
 108         /* Interrupt configuration for SGIs can't be changed */
 109         if (gicirq < 16)
 110                 return -EINVAL;
 111
 112         if (type != IRQ_TYPE_LEVEL_HIGH && type != IRQ_TYPE_EDGE_RISING)
 113                 return -EINVAL;
 114
 115         spin_lock(&irq_controller_lock);
 116
 117         val = readl(base + GIC_DIST_CONFIG + confoff);
 118         if (type == IRQ_TYPE_LEVEL_HIGH)
 119                 val &= ~confmask;
 120         else if (type == IRQ_TYPE_EDGE_RISING)
 121                 val |= confmask;
 122
 123         /*
 124          * As recommended by the spec, disable the interrupt before changing
 125          * the configuration
 126          */
 127         if (readl(base + GIC_DIST_ENABLE_SET + enableoff) & enablemask) {
 128                 writel(enablemask, base + GIC_DIST_ENABLE_CLEAR + enableoff);
 129                 enabled = true;
 130         }
 131
 132         writel(val, base + GIC_DIST_CONFIG + confoff);
 133
 134         if (enabled)
 135                 writel(enablemask, base + GIC_DIST_ENABLE_SET + enableoff);
 136
 137         spin_unlock(&irq_controller_lock);
 138
 139         return 0;
 140 }
 141
 142 #ifdef CONFIG_SMP
 143 static int gic_set_cpu(unsigned int irq, const struct cpumask *mask_val)
 144 {
 145         void __iomem *reg = gic_dist_base(irq) + GIC_DIST_TARGET + (gic_irq(irq) & ~3);
 146         unsigned int shift = (irq % 4) * 8;
 147         unsigned int cpu = cpumask_first(mask_val);
 148         u32 val;
 149
 150         spin_lock(&irq_controller_lock);
 151         irq_desc[irq].node = cpu;
 152         val = readl(reg) & ~(0xff << shift);
 153         val |= 1 << (cpu + shift);
 154         writel(val, reg);
 155         spin_unlock(&irq_controller_lock);
 156
 157         return 0;
 158 }
 159 #endif
 160
 161 static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
 162 {
 163         struct gic_chip_data *chip_data = get_irq_data(irq);
 164         struct irq_chip *chip = get_irq_chip(irq);
 165         unsigned int cascade_irq, gic_irq;
 166         unsigned long status;
 167
 168         /* primary controller ack'ing */
 169         chip->ack(irq);
 170
 171         spin_lock(&irq_controller_lock);
 172         status = readl(chip_data->cpu_base + GIC_CPU_INTACK);
 173         spin_unlock(&irq_controller_lock);
 174
 175         gic_irq = (status & 0x3ff);
 176         if (gic_irq == 1023)
 177                 goto out;
 178
 179         cascade_irq = gic_irq + chip_data->irq_offset;
 180         if (unlikely(gic_irq < 32 || gic_irq > 1020 || cascade_irq >= NR_IRQS))
 181                 do_bad_IRQ(cascade_irq, desc);
 182         else
 183                 generic_handle_irq(cascade_irq);
 184
 185  out:
 186         /* primary controller unmasking */
 187         chip->unmask(irq);
 188 }
 189
 190 static struct irq_chip gic_chip = {
 191         .name           = "GIC",
 192         .ack            = gic_ack_irq,
 193         .mask           = gic_mask_irq,
 194         .unmask         = gic_unmask_irq,
 195         .set_type       = gic_set_type,
 196 #ifdef CONFIG_SMP
 197         .set_affinity   = gic_set_cpu,
 198 #endif
 199 };
 200
 201 void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
 202 {
 203         if (gic_nr >= MAX_GIC_NR)
 204                 BUG();
 205         if (set_irq_data(irq, &gic_data[gic_nr]) != 0)
 206                 BUG();
 207         set_irq_chained_handler(irq, gic_handle_cascade_irq);
 208 }
 209
 210 void __init gic_dist_init(unsigned int gic_nr, void __iomem *base,
 211                           unsigned int irq_start)
 212 {
 213         unsigned int max_irq, i;
 214         u32 cpumask = 1 << smp_processor_id();
 215
 216         if (gic_nr >= MAX_GIC_NR)
 217                 BUG();
 218
 219         cpumask |= cpumask << 8;
 220         cpumask |= cpumask << 16;
 221
 222         gic_data[gic_nr].dist_base = base;
 223         gic_data[gic_nr].irq_offset = (irq_start - 1) & ~31;
 224
 225         writel(0, base + GIC_DIST_CTRL);
 226
 227         /*
 228          * Find out how many interrupts are supported.
 229          */
 230         max_irq = readl(base + GIC_DIST_CTR) & 0x1f;
 231         max_irq = (max_irq + 1) * 32;
 232
 233         /*
 234          * The GIC only supports up to 1020 interrupt sources.
 235          * Limit this to either the architected maximum, or the
 236          * platform maximum.
 237          */
 238         if (max_irq > max(1020, NR_IRQS))
 239                 max_irq = max(1020, NR_IRQS);
 240
 241         /*
 242          * Set all global interrupts to be level triggered, active low.
 243          */
 244         for (i = 32; i < max_irq; i += 16)
 245                 writel(0, base + GIC_DIST_CONFIG + i * 4 / 16);
 246
 247         /*
 248          * Set all global interrupts to this CPU only.
 249          */
 250         for (i = 32; i < max_irq; i += 4)
 251                 writel(cpumask, base + GIC_DIST_TARGET + i * 4 / 4);
 252
 253         /*
 254          * Set priority on all global interrupts.
 255          */
 256         for (i = 32; i < max_irq; i += 4)
 257                 writel(0xa0a0a0a0, base + GIC_DIST_PRI + i * 4 / 4);
 258
 259         /*
 260          * Disable all interrupts.  Leave the PPI and SGIs alone
 261          * as these enables are banked registers.
 262          */
 263         for (i = 32; i < max_irq; i += 32)
 264                 writel(0xffffffff, base + GIC_DIST_ENABLE_CLEAR + i * 4 / 32);
 265
 266         /*
 267          * Setup the Linux IRQ subsystem.
 268          */
 269         for (i = irq_start; i < gic_data[gic_nr].irq_offset + max_irq; i++) {
 270                 set_irq_chip(i, &gic_chip);
 271                 set_irq_chip_data(i, &gic_data[gic_nr]);
 272                 set_irq_handler(i, handle_level_irq);
 273                 set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
 274         }
 275
 276         writel(1, base + GIC_DIST_CTRL);
 277 }
 278
 279 void __cpuinit gic_cpu_init(unsigned int gic_nr, void __iomem *base)
 280 {
 281         void __iomem *dist_base;
 282         int i;
 283
 284         if (gic_nr >= MAX_GIC_NR)
 285                 BUG();
 286
 287         dist_base = gic_data[gic_nr].dist_base;
 288         BUG_ON(!dist_base);
 289
 290         gic_data[gic_nr].cpu_base = base;
 291
 292         /*
 293          * Deal with the banked PPI and SGI interrupts - disable all
 294          * PPI interrupts, ensure all SGI interrupts are enabled.
 295          */
 296         writel(0xffff0000, dist_base + GIC_DIST_ENABLE_CLEAR);
 297         writel(0x0000ffff, dist_base + GIC_DIST_ENABLE_SET);
 298
 299         /*
 300          * Set priority on PPI and SGI interrupts
 301          */
 302         for (i = 0; i < 32; i += 4)
 303                 writel(0xa0a0a0a0, dist_base + GIC_DIST_PRI + i * 4 / 4);
 304
 305         writel(0xf0, base + GIC_CPU_PRIMASK);
 306         writel(1, base + GIC_CPU_CTRL);
 307 }
 308
 309 #ifdef CONFIG_SMP
 310 void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
 311 {
 312         unsigned long map = *cpus_addr(*mask);
 313
 314         /* this always happens on GIC0 */
 315         writel(map << 16 | irq, gic_data[0].dist_base + GIC_DIST_SOFTINT);
 316 }
 317 #endif