drivers/irqchip/irq-bcm7038-l1.c

   1 /*
   2  * Broadcom BCM7038 style Level 1 interrupt controller driver
   3  *
   4  * Copyright (C) 2014 Broadcom Corporation
   5  * Author: Kevin Cernekee
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #define pr_fmt(fmt)     KBUILD_MODNAME  ": " fmt
  13
  14 #include <linux/bitops.h>
  15 #include <linux/kconfig.h>
  16 #include <linux/kernel.h>
  17 #include <linux/init.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/io.h>
  20 #include <linux/ioport.h>
  21 #include <linux/irq.h>
  22 #include <linux/irqdomain.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/of_irq.h>
  26 #include <linux/of_address.h>
  27 #include <linux/of_platform.h>
  28 #include <linux/platform_device.h>
  29 #include <linux/slab.h>
  30 #include <linux/smp.h>
  31 #include <linux/types.h>
  32 #include <linux/irqchip.h>
  33 #include <linux/irqchip/chained_irq.h>
  34
  35 #define IRQS_PER_WORD           32
  36 #define REG_BYTES_PER_IRQ_WORD  (sizeof(u32) * 4)
  37 #define MAX_WORDS               8
  38
  39 struct bcm7038_l1_cpu;
  40
  41 struct bcm7038_l1_chip {
  42         raw_spinlock_t          lock;
  43         unsigned int            n_words;
  44         struct irq_domain       *domain;
  45         struct bcm7038_l1_cpu   *cpus[NR_CPUS];
  46         u8                      affinity[MAX_WORDS * IRQS_PER_WORD];
  47 };
  48
  49 struct bcm7038_l1_cpu {
  50         void __iomem            *map_base;
  51         u32                     mask_cache[0];
  52 };
  53
  54 /*
  55  * STATUS/MASK_STATUS/MASK_SET/MASK_CLEAR are packed one right after another:
  56  *
  57  * 7038:
  58  *   0x1000_1400: W0_STATUS
  59  *   0x1000_1404: W1_STATUS
  60  *   0x1000_1408: W0_MASK_STATUS
  61  *   0x1000_140c: W1_MASK_STATUS
  62  *   0x1000_1410: W0_MASK_SET
  63  *   0x1000_1414: W1_MASK_SET
  64  *   0x1000_1418: W0_MASK_CLEAR
  65  *   0x1000_141c: W1_MASK_CLEAR
  66  *
  67  * 7445:
  68  *   0xf03e_1500: W0_STATUS
  69  *   0xf03e_1504: W1_STATUS
  70  *   0xf03e_1508: W2_STATUS
  71  *   0xf03e_150c: W3_STATUS
  72  *   0xf03e_1510: W4_STATUS
  73  *   0xf03e_1514: W0_MASK_STATUS
  74  *   0xf03e_1518: W1_MASK_STATUS
  75  *   [...]
  76  */
  77
  78 static inline unsigned int reg_status(struct bcm7038_l1_chip *intc,
  79                                       unsigned int word)
  80 {
  81         return (0 * intc->n_words + word) * sizeof(u32);
  82 }
  83
  84 static inline unsigned int reg_mask_status(struct bcm7038_l1_chip *intc,
  85                                            unsigned int word)
  86 {
  87         return (1 * intc->n_words + word) * sizeof(u32);
  88 }
  89
  90 static inline unsigned int reg_mask_set(struct bcm7038_l1_chip *intc,
  91                                         unsigned int word)
  92 {
  93         return (2 * intc->n_words + word) * sizeof(u32);
  94 }
  95
  96 static inline unsigned int reg_mask_clr(struct bcm7038_l1_chip *intc,
  97                                         unsigned int word)
  98 {
  99         return (3 * intc->n_words + word) * sizeof(u32);
 100 }
 101
 102 static inline u32 l1_readl(void __iomem *reg)
 103 {
 104         if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
 105                 return ioread32be(reg);
 106         else
 107                 return readl(reg);
 108 }
 109
 110 static inline void l1_writel(u32 val, void __iomem *reg)
 111 {
 112         if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
 113                 iowrite32be(val, reg);
 114         else
 115                 writel(val, reg);
 116 }
 117
 118 static void bcm7038_l1_irq_handle(struct irq_desc *desc)
 119 {
 120         struct bcm7038_l1_chip *intc = irq_desc_get_handler_data(desc);
 121         struct bcm7038_l1_cpu *cpu;
 122         struct irq_chip *chip = irq_desc_get_chip(desc);
 123         unsigned int idx;
 124
 125 #ifdef CONFIG_SMP
 126         cpu = intc->cpus[cpu_logical_map(smp_processor_id())];
 127 #else
 128         cpu = intc->cpus[0];
 129 #endif
 130
 131         chained_irq_enter(chip, desc);
 132
 133         for (idx = 0; idx < intc->n_words; idx++) {
 134                 int base = idx * IRQS_PER_WORD;
 135                 unsigned long pending, flags;
 136                 int hwirq;
 137
 138                 raw_spin_lock_irqsave(&intc->lock, flags);
 139                 pending = l1_readl(cpu->map_base + reg_status(intc, idx)) &
 140                           ~cpu->mask_cache[idx];
 141                 raw_spin_unlock_irqrestore(&intc->lock, flags);
 142
 143                 for_each_set_bit(hwirq, &pending, IRQS_PER_WORD) {
 144                         generic_handle_irq(irq_find_mapping(intc->domain,
 145                                                             base + hwirq));
 146                 }
 147         }
 148
 149         chained_irq_exit(chip, desc);
 150 }
 151
 152 static void __bcm7038_l1_unmask(struct irq_data *d, unsigned int cpu_idx)
 153 {
 154         struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
 155         u32 word = d->hwirq / IRQS_PER_WORD;
 156         u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
 157
 158         intc->cpus[cpu_idx]->mask_cache[word] &= ~mask;
 159         l1_writel(mask, intc->cpus[cpu_idx]->map_base +
 160                         reg_mask_clr(intc, word));
 161 }
 162
 163 static void __bcm7038_l1_mask(struct irq_data *d, unsigned int cpu_idx)
 164 {
 165         struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
 166         u32 word = d->hwirq / IRQS_PER_WORD;
 167         u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
 168
 169         intc->cpus[cpu_idx]->mask_cache[word] |= mask;
 170         l1_writel(mask, intc->cpus[cpu_idx]->map_base +
 171                         reg_mask_set(intc, word));
 172 }
 173
 174 static void bcm7038_l1_unmask(struct irq_data *d)
 175 {
 176         struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
 177         unsigned long flags;
 178
 179         raw_spin_lock_irqsave(&intc->lock, flags);
 180         __bcm7038_l1_unmask(d, intc->affinity[d->hwirq]);
 181         raw_spin_unlock_irqrestore(&intc->lock, flags);
 182 }
 183
 184 static void bcm7038_l1_mask(struct irq_data *d)
 185 {
 186         struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
 187         unsigned long flags;
 188
 189         raw_spin_lock_irqsave(&intc->lock, flags);
 190         __bcm7038_l1_mask(d, intc->affinity[d->hwirq]);
 191         raw_spin_unlock_irqrestore(&intc->lock, flags);
 192 }
 193
 194 static int bcm7038_l1_set_affinity(struct irq_data *d,
 195                                    const struct cpumask *dest,
 196                                    bool force)
 197 {
 198         struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
 199         unsigned long flags;
 200         irq_hw_number_t hw = d->hwirq;
 201         u32 word = hw / IRQS_PER_WORD;
 202         u32 mask = BIT(hw % IRQS_PER_WORD);
 203         unsigned int first_cpu = cpumask_any_and(dest, cpu_online_mask);
 204         bool was_disabled;
 205
 206         raw_spin_lock_irqsave(&intc->lock, flags);
 207
 208         was_disabled = !!(intc->cpus[intc->affinity[hw]]->mask_cache[word] &
 209                           mask);
 210         __bcm7038_l1_mask(d, intc->affinity[hw]);
 211         intc->affinity[hw] = first_cpu;
 212         if (!was_disabled)
 213                 __bcm7038_l1_unmask(d, first_cpu);
 214
 215         raw_spin_unlock_irqrestore(&intc->lock, flags);
 216         return 0;
 217 }
 218
 219 static void bcm7038_l1_cpu_offline(struct irq_data *d)
 220 {
 221         struct cpumask *mask = irq_data_get_affinity_mask(d);
 222         int cpu = smp_processor_id();
 223         cpumask_t new_affinity;
 224
 225         /* This CPU was not on the affinity mask */
 226         if (!cpumask_test_cpu(cpu, mask))
 227                 return;
 228
 229         if (cpumask_weight(mask) > 1) {
 230                 /*
 231                  * Multiple CPU affinity, remove this CPU from the affinity
 232                  * mask
 233                  */
 234                 cpumask_copy(&new_affinity, mask);
 235                 cpumask_clear_cpu(cpu, &new_affinity);
 236         } else {
 237                 /* Only CPU, put on the lowest online CPU */
 238                 cpumask_clear(&new_affinity);
 239                 cpumask_set_cpu(cpumask_first(cpu_online_mask), &new_affinity);
 240         }
 241         irq_set_affinity_locked(d, &new_affinity, false);
 242 }
 243
 244 static int __init bcm7038_l1_init_one(struct device_node *dn,
 245                                       unsigned int idx,
 246                                       struct bcm7038_l1_chip *intc)
 247 {
 248         struct resource res;
 249         resource_size_t sz;
 250         struct bcm7038_l1_cpu *cpu;
 251         unsigned int i, n_words, parent_irq;
 252
 253         if (of_address_to_resource(dn, idx, &res))
 254                 return -EINVAL;
 255         sz = resource_size(&res);
 256         n_words = sz / REG_BYTES_PER_IRQ_WORD;
 257
 258         if (n_words > MAX_WORDS)
 259                 return -EINVAL;
 260         else if (!intc->n_words)
 261                 intc->n_words = n_words;
 262         else if (intc->n_words != n_words)
 263                 return -EINVAL;
 264
 265         cpu = intc->cpus[idx] = kzalloc(sizeof(*cpu) + n_words * sizeof(u32),
 266                                         GFP_KERNEL);
 267         if (!cpu)
 268                 return -ENOMEM;
 269
 270         cpu->map_base = ioremap(res.start, sz);
 271         if (!cpu->map_base)
 272                 return -ENOMEM;
 273
 274         for (i = 0; i < n_words; i++) {
 275                 l1_writel(0xffffffff, cpu->map_base + reg_mask_set(intc, i));
 276                 cpu->mask_cache[i] = 0xffffffff;
 277         }
 278
 279         parent_irq = irq_of_parse_and_map(dn, idx);
 280         if (!parent_irq) {
 281                 pr_err("failed to map parent interrupt %d\n", parent_irq);
 282                 return -EINVAL;
 283         }
 284         irq_set_chained_handler_and_data(parent_irq, bcm7038_l1_irq_handle,
 285                                          intc);
 286
 287         return 0;
 288 }
 289
 290 static struct irq_chip bcm7038_l1_irq_chip = {
 291         .name                   = "bcm7038-l1",
 292         .irq_mask               = bcm7038_l1_mask,
 293         .irq_unmask             = bcm7038_l1_unmask,
 294         .irq_set_affinity       = bcm7038_l1_set_affinity,
 295         .irq_cpu_offline        = bcm7038_l1_cpu_offline,
 296 };
 297
 298 static int bcm7038_l1_map(struct irq_domain *d, unsigned int virq,
 299                           irq_hw_number_t hw_irq)
 300 {
 301         irq_set_chip_and_handler(virq, &bcm7038_l1_irq_chip, handle_level_irq);
 302         irq_set_chip_data(virq, d->host_data);
 303         return 0;
 304 }
 305
 306 static const struct irq_domain_ops bcm7038_l1_domain_ops = {
 307         .xlate                  = irq_domain_xlate_onecell,
 308         .map                    = bcm7038_l1_map,
 309 };
 310
 311 int __init bcm7038_l1_of_init(struct device_node *dn,
 312                               struct device_node *parent)
 313 {
 314         struct bcm7038_l1_chip *intc;
 315         int idx, ret;
 316
 317         intc = kzalloc(sizeof(*intc), GFP_KERNEL);
 318         if (!intc)
 319                 return -ENOMEM;
 320
 321         raw_spin_lock_init(&intc->lock);
 322         for_each_possible_cpu(idx) {
 323                 ret = bcm7038_l1_init_one(dn, idx, intc);
 324                 if (ret < 0) {
 325                         if (idx)
 326                                 break;
 327                         pr_err("failed to remap intc L1 registers\n");
 328                         goto out_free;
 329                 }
 330         }
 331
 332         intc->domain = irq_domain_add_linear(dn, IRQS_PER_WORD * intc->n_words,
 333                                              &bcm7038_l1_domain_ops,
 334                                              intc);
 335         if (!intc->domain) {
 336                 ret = -ENOMEM;
 337                 goto out_unmap;
 338         }
 339
 340         pr_info("registered BCM7038 L1 intc (mem: 0x%p, IRQs: %d)\n",
 341                 intc->cpus[0]->map_base, IRQS_PER_WORD * intc->n_words);
 342
 343         return 0;
 344
 345 out_unmap:
 346         for_each_possible_cpu(idx) {
 347                 struct bcm7038_l1_cpu *cpu = intc->cpus[idx];
 348
 349                 if (cpu) {
 350                         if (cpu->map_base)
 351                                 iounmap(cpu->map_base);
 352                         kfree(cpu);
 353                 }
 354         }
 355 out_free:
 356         kfree(intc);
 357         return ret;
 358 }
 359
 360 IRQCHIP_DECLARE(bcm7038_l1, "brcm,bcm7038-l1-intc", bcm7038_l1_of_init);