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