drivers/irqchip/qcom-irq-combiner.c

   1 /* Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 /*
  14  * Driver for interrupt combiners in the Top-level Control and Status
  15  * Registers (TCSR) hardware block in Qualcomm Technologies chips.
  16  * An interrupt combiner in this block combines a set of interrupts by
  17  * OR'ing the individual interrupt signals into a summary interrupt
  18  * signal routed to a parent interrupt controller, and provides read-
  19  * only, 32-bit registers to query the status of individual interrupts.
  20  * The status bit for IRQ n is bit (n % 32) within register (n / 32)
  21  * of the given combiner. Thus, each combiner can be described as a set
  22  * of register offsets and the number of IRQs managed.
  23  */
  24
  25 #define pr_fmt(fmt) "QCOM80B1:" fmt
  26
  27 #include <linux/acpi.h>
  28 #include <linux/irqchip/chained_irq.h>
  29 #include <linux/irqdomain.h>
  30 #include <linux/platform_device.h>
  31
  32 #define REG_SIZE 32
  33
  34 struct combiner_reg {
  35         void __iomem *addr;
  36         unsigned long enabled;
  37 };
  38
  39 struct combiner {
  40         struct irq_domain   *domain;
  41         int                 parent_irq;
  42         u32                 nirqs;
  43         u32                 nregs;
  44         struct combiner_reg regs[0];
  45 };
  46
  47 static inline int irq_nr(u32 reg, u32 bit)
  48 {
  49         return reg * REG_SIZE + bit;
  50 }
  51
  52 /*
  53  * Handler for the cascaded IRQ.
  54  */
  55 static void combiner_handle_irq(struct irq_desc *desc)
  56 {
  57         struct combiner *combiner = irq_desc_get_handler_data(desc);
  58         struct irq_chip *chip = irq_desc_get_chip(desc);
  59         u32 reg;
  60
  61         chained_irq_enter(chip, desc);
  62
  63         for (reg = 0; reg < combiner->nregs; reg++) {
  64                 int virq;
  65                 int hwirq;
  66                 u32 bit;
  67                 u32 status;
  68
  69                 bit = readl_relaxed(combiner->regs[reg].addr);
  70                 status = bit & combiner->regs[reg].enabled;
  71                 if (!status)
  72                         pr_warn_ratelimited("Unexpected IRQ on CPU%d: (%08x %08lx %p)\n",
  73                                             smp_processor_id(), bit,
  74                                             combiner->regs[reg].enabled,
  75                                             combiner->regs[reg].addr);
  76
  77                 while (status) {
  78                         bit = __ffs(status);
  79                         status &= ~(1 << bit);
  80                         hwirq = irq_nr(reg, bit);
  81                         virq = irq_find_mapping(combiner->domain, hwirq);
  82                         if (virq > 0)
  83                                 generic_handle_irq(virq);
  84
  85                 }
  86         }
  87
  88         chained_irq_exit(chip, desc);
  89 }
  90
  91 static void combiner_irq_chip_mask_irq(struct irq_data *data)
  92 {
  93         struct combiner *combiner = irq_data_get_irq_chip_data(data);
  94         struct combiner_reg *reg = combiner->regs + data->hwirq / REG_SIZE;
  95
  96         clear_bit(data->hwirq % REG_SIZE, &reg->enabled);
  97 }
  98
  99 static void combiner_irq_chip_unmask_irq(struct irq_data *data)
 100 {
 101         struct combiner *combiner = irq_data_get_irq_chip_data(data);
 102         struct combiner_reg *reg = combiner->regs + data->hwirq / REG_SIZE;
 103
 104         set_bit(data->hwirq % REG_SIZE, &reg->enabled);
 105 }
 106
 107 static struct irq_chip irq_chip = {
 108         .irq_mask = combiner_irq_chip_mask_irq,
 109         .irq_unmask = combiner_irq_chip_unmask_irq,
 110         .name = "qcom-irq-combiner"
 111 };
 112
 113 static int combiner_irq_map(struct irq_domain *domain, unsigned int irq,
 114                                    irq_hw_number_t hwirq)
 115 {
 116         irq_set_chip_and_handler(irq, &irq_chip, handle_level_irq);
 117         irq_set_chip_data(irq, domain->host_data);
 118         irq_set_noprobe(irq);
 119         return 0;
 120 }
 121
 122 static void combiner_irq_unmap(struct irq_domain *domain, unsigned int irq)
 123 {
 124         irq_domain_reset_irq_data(irq_get_irq_data(irq));
 125 }
 126
 127 static int combiner_irq_translate(struct irq_domain *d, struct irq_fwspec *fws,
 128                                   unsigned long *hwirq, unsigned int *type)
 129 {
 130         struct combiner *combiner = d->host_data;
 131
 132         if (is_acpi_node(fws->fwnode)) {
 133                 if (WARN_ON((fws->param_count != 2) ||
 134                             (fws->param[0] >= combiner->nirqs) ||
 135                             (fws->param[1] & IORESOURCE_IRQ_LOWEDGE) ||
 136                             (fws->param[1] & IORESOURCE_IRQ_HIGHEDGE)))
 137                         return -EINVAL;
 138
 139                 *hwirq = fws->param[0];
 140                 *type = fws->param[1];
 141                 return 0;
 142         }
 143
 144         return -EINVAL;
 145 }
 146
 147 static const struct irq_domain_ops domain_ops = {
 148         .map = combiner_irq_map,
 149         .unmap = combiner_irq_unmap,
 150         .translate = combiner_irq_translate
 151 };
 152
 153 static acpi_status count_registers_cb(struct acpi_resource *ares, void *context)
 154 {
 155         int *count = context;
 156
 157         if (ares->type == ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
 158                 ++(*count);
 159         return AE_OK;
 160 }
 161
 162 static int count_registers(struct platform_device *pdev)
 163 {
 164         acpi_handle ahandle = ACPI_HANDLE(&pdev->dev);
 165         acpi_status status;
 166         int count = 0;
 167
 168         if (!acpi_has_method(ahandle, METHOD_NAME__CRS))
 169                 return -EINVAL;
 170
 171         status = acpi_walk_resources(ahandle, METHOD_NAME__CRS,
 172                                      count_registers_cb, &count);
 173         if (ACPI_FAILURE(status))
 174                 return -EINVAL;
 175         return count;
 176 }
 177
 178 struct get_registers_context {
 179         struct device *dev;
 180         struct combiner *combiner;
 181         int err;
 182 };
 183
 184 static acpi_status get_registers_cb(struct acpi_resource *ares, void *context)
 185 {
 186         struct get_registers_context *ctx = context;
 187         struct acpi_resource_generic_register *reg;
 188         phys_addr_t paddr;
 189         void __iomem *vaddr;
 190
 191         if (ares->type != ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
 192                 return AE_OK;
 193
 194         reg = &ares->data.generic_reg;
 195         paddr = reg->address;
 196         if ((reg->space_id != ACPI_SPACE_MEM) ||
 197             (reg->bit_offset != 0) ||
 198             (reg->bit_width > REG_SIZE)) {
 199                 dev_err(ctx->dev, "Bad register resource @%pa\n", &paddr);
 200                 ctx->err = -EINVAL;
 201                 return AE_ERROR;
 202         }
 203
 204         vaddr = devm_ioremap(ctx->dev, reg->address, REG_SIZE);
 205         if (!vaddr) {
 206                 dev_err(ctx->dev, "Can't map register @%pa\n", &paddr);
 207                 ctx->err = -ENOMEM;
 208                 return AE_ERROR;
 209         }
 210
 211         ctx->combiner->regs[ctx->combiner->nregs].addr = vaddr;
 212         ctx->combiner->nirqs += reg->bit_width;
 213         ctx->combiner->nregs++;
 214         return AE_OK;
 215 }
 216
 217 static int get_registers(struct platform_device *pdev, struct combiner *comb)
 218 {
 219         acpi_handle ahandle = ACPI_HANDLE(&pdev->dev);
 220         acpi_status status;
 221         struct get_registers_context ctx;
 222
 223         if (!acpi_has_method(ahandle, METHOD_NAME__CRS))
 224                 return -EINVAL;
 225
 226         ctx.dev = &pdev->dev;
 227         ctx.combiner = comb;
 228         ctx.err = 0;
 229
 230         status = acpi_walk_resources(ahandle, METHOD_NAME__CRS,
 231                                      get_registers_cb, &ctx);
 232         if (ACPI_FAILURE(status))
 233                 return ctx.err;
 234         return 0;
 235 }
 236
 237 static int __init combiner_probe(struct platform_device *pdev)
 238 {
 239         struct combiner *combiner;
 240         size_t alloc_sz;
 241         u32 nregs;
 242         int err;
 243
 244         nregs = count_registers(pdev);
 245         if (nregs <= 0) {
 246                 dev_err(&pdev->dev, "Error reading register resources\n");
 247                 return -EINVAL;
 248         }
 249
 250         alloc_sz = sizeof(*combiner) + sizeof(struct combiner_reg) * nregs;
 251         combiner = devm_kzalloc(&pdev->dev, alloc_sz, GFP_KERNEL);
 252         if (!combiner)
 253                 return -ENOMEM;
 254
 255         err = get_registers(pdev, combiner);
 256         if (err < 0)
 257                 return err;
 258
 259         combiner->parent_irq = platform_get_irq(pdev, 0);
 260         if (combiner->parent_irq <= 0) {
 261                 dev_err(&pdev->dev, "Error getting IRQ resource\n");
 262                 return -EPROBE_DEFER;
 263         }
 264
 265         combiner->domain = irq_domain_create_linear(pdev->dev.fwnode, combiner->nirqs,
 266                                                     &domain_ops, combiner);
 267         if (!combiner->domain)
 268                 /* Errors printed by irq_domain_create_linear */
 269                 return -ENODEV;
 270
 271         irq_set_chained_handler_and_data(combiner->parent_irq,
 272                                          combiner_handle_irq, combiner);
 273
 274         dev_info(&pdev->dev, "Initialized with [p=%d,n=%d,r=%p]\n",
 275                  combiner->parent_irq, combiner->nirqs, combiner->regs[0].addr);
 276         return 0;
 277 }
 278
 279 static const struct acpi_device_id qcom_irq_combiner_ids[] = {
 280         { "QCOM80B1", },
 281         { }
 282 };
 283
 284 static struct platform_driver qcom_irq_combiner_probe = {
 285         .driver = {
 286                 .name = "qcom-irq-combiner",
 287                 .acpi_match_table = ACPI_PTR(qcom_irq_combiner_ids),
 288         },
 289         .probe = combiner_probe,
 290 };
 291 builtin_platform_driver(qcom_irq_combiner_probe);