linux/drivers/irqchip/qcom-pdc.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
   4 */
   5
   6#include <linux/err.h>
   7#include <linux/init.h>
   8#include <linux/irq.h>
   9#include <linux/irqchip.h>
  10#include <linux/irqdomain.h>
  11#include <linux/io.h>
  12#include <linux/kernel.h>
  13#include <linux/of.h>
  14#include <linux/of_address.h>
  15#include <linux/of_device.h>
  16#include <linux/spinlock.h>
  17#include <linux/platform_device.h>
  18#include <linux/slab.h>
  19#include <linux/types.h>
  20
  21#define PDC_MAX_IRQS            126
  22
  23#define CLEAR_INTR(reg, intr)   (reg & ~(1 << intr))
  24#define ENABLE_INTR(reg, intr)  (reg | (1 << intr))
  25
  26#define IRQ_ENABLE_BANK         0x10
  27#define IRQ_i_CFG               0x110
  28
  29struct pdc_pin_region {
  30        u32 pin_base;
  31        u32 parent_base;
  32        u32 cnt;
  33};
  34
  35static DEFINE_RAW_SPINLOCK(pdc_lock);
  36static void __iomem *pdc_base;
  37static struct pdc_pin_region *pdc_region;
  38static int pdc_region_cnt;
  39
  40static void pdc_reg_write(int reg, u32 i, u32 val)
  41{
  42        writel_relaxed(val, pdc_base + reg + i * sizeof(u32));
  43}
  44
  45static u32 pdc_reg_read(int reg, u32 i)
  46{
  47        return readl_relaxed(pdc_base + reg + i * sizeof(u32));
  48}
  49
  50static void pdc_enable_intr(struct irq_data *d, bool on)
  51{
  52        int pin_out = d->hwirq;
  53        u32 index, mask;
  54        u32 enable;
  55
  56        index = pin_out / 32;
  57        mask = pin_out % 32;
  58
  59        raw_spin_lock(&pdc_lock);
  60        enable = pdc_reg_read(IRQ_ENABLE_BANK, index);
  61        enable = on ? ENABLE_INTR(enable, mask) : CLEAR_INTR(enable, mask);
  62        pdc_reg_write(IRQ_ENABLE_BANK, index, enable);
  63        raw_spin_unlock(&pdc_lock);
  64}
  65
  66static void qcom_pdc_gic_mask(struct irq_data *d)
  67{
  68        pdc_enable_intr(d, false);
  69        irq_chip_mask_parent(d);
  70}
  71
  72static void qcom_pdc_gic_unmask(struct irq_data *d)
  73{
  74        pdc_enable_intr(d, true);
  75        irq_chip_unmask_parent(d);
  76}
  77
  78/*
  79 * GIC does not handle falling edge or active low. To allow falling edge and
  80 * active low interrupts to be handled at GIC, PDC has an inverter that inverts
  81 * falling edge into a rising edge and active low into an active high.
  82 * For the inverter to work, the polarity bit in the IRQ_CONFIG register has to
  83 * set as per the table below.
  84 * Level sensitive active low    LOW
  85 * Rising edge sensitive         NOT USED
  86 * Falling edge sensitive        LOW
  87 * Dual Edge sensitive           NOT USED
  88 * Level sensitive active High   HIGH
  89 * Falling Edge sensitive        NOT USED
  90 * Rising edge sensitive         HIGH
  91 * Dual Edge sensitive           HIGH
  92 */
  93enum pdc_irq_config_bits {
  94        PDC_LEVEL_LOW           = 0b000,
  95        PDC_EDGE_FALLING        = 0b010,
  96        PDC_LEVEL_HIGH          = 0b100,
  97        PDC_EDGE_RISING         = 0b110,
  98        PDC_EDGE_DUAL           = 0b111,
  99};
 100
 101/**
 102 * qcom_pdc_gic_set_type: Configure PDC for the interrupt
 103 *
 104 * @d: the interrupt data
 105 * @type: the interrupt type
 106 *
 107 * If @type is edge triggered, forward that as Rising edge as PDC
 108 * takes care of converting falling edge to rising edge signal
 109 * If @type is level, then forward that as level high as PDC
 110 * takes care of converting falling edge to rising edge signal
 111 */
 112static int qcom_pdc_gic_set_type(struct irq_data *d, unsigned int type)
 113{
 114        int pin_out = d->hwirq;
 115        enum pdc_irq_config_bits pdc_type;
 116
 117        switch (type) {
 118        case IRQ_TYPE_EDGE_RISING:
 119                pdc_type = PDC_EDGE_RISING;
 120                break;
 121        case IRQ_TYPE_EDGE_FALLING:
 122                pdc_type = PDC_EDGE_FALLING;
 123                type = IRQ_TYPE_EDGE_RISING;
 124                break;
 125        case IRQ_TYPE_EDGE_BOTH:
 126                pdc_type = PDC_EDGE_DUAL;
 127                type = IRQ_TYPE_EDGE_RISING;
 128                break;
 129        case IRQ_TYPE_LEVEL_HIGH:
 130                pdc_type = PDC_LEVEL_HIGH;
 131                break;
 132        case IRQ_TYPE_LEVEL_LOW:
 133                pdc_type = PDC_LEVEL_LOW;
 134                type = IRQ_TYPE_LEVEL_HIGH;
 135                break;
 136        default:
 137                WARN_ON(1);
 138                return -EINVAL;
 139        }
 140
 141        pdc_reg_write(IRQ_i_CFG, pin_out, pdc_type);
 142
 143        return irq_chip_set_type_parent(d, type);
 144}
 145
 146static struct irq_chip qcom_pdc_gic_chip = {
 147        .name                   = "PDC",
 148        .irq_eoi                = irq_chip_eoi_parent,
 149        .irq_mask               = qcom_pdc_gic_mask,
 150        .irq_unmask             = qcom_pdc_gic_unmask,
 151        .irq_retrigger          = irq_chip_retrigger_hierarchy,
 152        .irq_set_type           = qcom_pdc_gic_set_type,
 153        .flags                  = IRQCHIP_MASK_ON_SUSPEND |
 154                                  IRQCHIP_SET_TYPE_MASKED |
 155                                  IRQCHIP_SKIP_SET_WAKE,
 156        .irq_set_vcpu_affinity  = irq_chip_set_vcpu_affinity_parent,
 157        .irq_set_affinity       = irq_chip_set_affinity_parent,
 158};
 159
 160static irq_hw_number_t get_parent_hwirq(int pin)
 161{
 162        int i;
 163        struct pdc_pin_region *region;
 164
 165        for (i = 0; i < pdc_region_cnt; i++) {
 166                region = &pdc_region[i];
 167                if (pin >= region->pin_base &&
 168                    pin < region->pin_base + region->cnt)
 169                        return (region->parent_base + pin - region->pin_base);
 170        }
 171
 172        WARN_ON(1);
 173        return ~0UL;
 174}
 175
 176static int qcom_pdc_translate(struct irq_domain *d, struct irq_fwspec *fwspec,
 177                              unsigned long *hwirq, unsigned int *type)
 178{
 179        if (is_of_node(fwspec->fwnode)) {
 180                if (fwspec->param_count != 2)
 181                        return -EINVAL;
 182
 183                *hwirq = fwspec->param[0];
 184                *type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
 185                return 0;
 186        }
 187
 188        return -EINVAL;
 189}
 190
 191static int qcom_pdc_alloc(struct irq_domain *domain, unsigned int virq,
 192                          unsigned int nr_irqs, void *data)
 193{
 194        struct irq_fwspec *fwspec = data;
 195        struct irq_fwspec parent_fwspec;
 196        irq_hw_number_t hwirq, parent_hwirq;
 197        unsigned int type;
 198        int ret;
 199
 200        ret = qcom_pdc_translate(domain, fwspec, &hwirq, &type);
 201        if (ret)
 202                return -EINVAL;
 203
 204        parent_hwirq = get_parent_hwirq(hwirq);
 205        if (parent_hwirq == ~0UL)
 206                return -EINVAL;
 207
 208        ret  = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
 209                                             &qcom_pdc_gic_chip, NULL);
 210        if (ret)
 211                return ret;
 212
 213        if (type & IRQ_TYPE_EDGE_BOTH)
 214                type = IRQ_TYPE_EDGE_RISING;
 215
 216        if (type & IRQ_TYPE_LEVEL_MASK)
 217                type = IRQ_TYPE_LEVEL_HIGH;
 218
 219        parent_fwspec.fwnode      = domain->parent->fwnode;
 220        parent_fwspec.param_count = 3;
 221        parent_fwspec.param[0]    = 0;
 222        parent_fwspec.param[1]    = parent_hwirq;
 223        parent_fwspec.param[2]    = type;
 224
 225        return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
 226                                            &parent_fwspec);
 227}
 228
 229static const struct irq_domain_ops qcom_pdc_ops = {
 230        .translate      = qcom_pdc_translate,
 231        .alloc          = qcom_pdc_alloc,
 232        .free           = irq_domain_free_irqs_common,
 233};
 234
 235static int pdc_setup_pin_mapping(struct device_node *np)
 236{
 237        int ret, n;
 238
 239        n = of_property_count_elems_of_size(np, "qcom,pdc-ranges", sizeof(u32));
 240        if (n <= 0 || n % 3)
 241                return -EINVAL;
 242
 243        pdc_region_cnt = n / 3;
 244        pdc_region = kcalloc(pdc_region_cnt, sizeof(*pdc_region), GFP_KERNEL);
 245        if (!pdc_region) {
 246                pdc_region_cnt = 0;
 247                return -ENOMEM;
 248        }
 249
 250        for (n = 0; n < pdc_region_cnt; n++) {
 251                ret = of_property_read_u32_index(np, "qcom,pdc-ranges",
 252                                                 n * 3 + 0,
 253                                                 &pdc_region[n].pin_base);
 254                if (ret)
 255                        return ret;
 256                ret = of_property_read_u32_index(np, "qcom,pdc-ranges",
 257                                                 n * 3 + 1,
 258                                                 &pdc_region[n].parent_base);
 259                if (ret)
 260                        return ret;
 261                ret = of_property_read_u32_index(np, "qcom,pdc-ranges",
 262                                                 n * 3 + 2,
 263                                                 &pdc_region[n].cnt);
 264                if (ret)
 265                        return ret;
 266        }
 267
 268        return 0;
 269}
 270
 271static int qcom_pdc_init(struct device_node *node, struct device_node *parent)
 272{
 273        struct irq_domain *parent_domain, *pdc_domain;
 274        int ret;
 275
 276        pdc_base = of_iomap(node, 0);
 277        if (!pdc_base) {
 278                pr_err("%pOF: unable to map PDC registers\n", node);
 279                return -ENXIO;
 280        }
 281
 282        parent_domain = irq_find_host(parent);
 283        if (!parent_domain) {
 284                pr_err("%pOF: unable to find PDC's parent domain\n", node);
 285                ret = -ENXIO;
 286                goto fail;
 287        }
 288
 289        ret = pdc_setup_pin_mapping(node);
 290        if (ret) {
 291                pr_err("%pOF: failed to init PDC pin-hwirq mapping\n", node);
 292                goto fail;
 293        }
 294
 295        pdc_domain = irq_domain_create_hierarchy(parent_domain, 0, PDC_MAX_IRQS,
 296                                                 of_fwnode_handle(node),
 297                                                 &qcom_pdc_ops, NULL);
 298        if (!pdc_domain) {
 299                pr_err("%pOF: GIC domain add failed\n", node);
 300                ret = -ENOMEM;
 301                goto fail;
 302        }
 303
 304        return 0;
 305
 306fail:
 307        kfree(pdc_region);
 308        iounmap(pdc_base);
 309        return ret;
 310}
 311
 312IRQCHIP_DECLARE(pdc_sdm845, "qcom,sdm845-pdc", qcom_pdc_init);
 313