linux/drivers/irqchip/qcom-irq-combiner.c
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   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
  34struct combiner_reg {
  35        void __iomem *addr;
  36        unsigned long enabled;
  37};
  38
  39struct combiner {
  40        struct irq_domain   *domain;
  41        int                 parent_irq;
  42        u32                 nirqs;
  43        u32                 nregs;
  44        struct combiner_reg regs[0];
  45};
  46
  47static 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 */
  55static 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
  91static 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
  99static 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
 107static 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
 113static 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
 122static 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
 127static 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
 147static const struct irq_domain_ops domain_ops = {
 148        .map = combiner_irq_map,
 149        .unmap = combiner_irq_unmap,
 150        .translate = combiner_irq_translate
 151};
 152
 153static 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
 162static 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
 178struct get_registers_context {
 179        struct device *dev;
 180        struct combiner *combiner;
 181        int err;
 182};
 183
 184static 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
 217static 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
 237static 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
 279static const struct acpi_device_id qcom_irq_combiner_ids[] = {
 280        { "QCOM80B1", },
 281        { }
 282};
 283
 284static 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};
 291builtin_platform_driver(qcom_irq_combiner_probe);
 292