linux/drivers/irqchip/irq-gic-v3-its-platform-msi.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2013-2015 ARM Limited, All Rights Reserved.
   4 * Author: Marc Zyngier <marc.zyngier@arm.com>
   5 */
   6
   7#include <linux/acpi_iort.h>
   8#include <linux/device.h>
   9#include <linux/msi.h>
  10#include <linux/of.h>
  11#include <linux/of_irq.h>
  12
  13static struct irq_chip its_pmsi_irq_chip = {
  14        .name                   = "ITS-pMSI",
  15};
  16
  17static int of_pmsi_get_dev_id(struct irq_domain *domain, struct device *dev,
  18                                  u32 *dev_id)
  19{
  20        int ret, index = 0;
  21
  22        /* Suck the DeviceID out of the msi-parent property */
  23        do {
  24                struct of_phandle_args args;
  25
  26                ret = of_parse_phandle_with_args(dev->of_node,
  27                                                 "msi-parent", "#msi-cells",
  28                                                 index, &args);
  29                if (args.np == irq_domain_get_of_node(domain)) {
  30                        if (WARN_ON(args.args_count != 1))
  31                                return -EINVAL;
  32                        *dev_id = args.args[0];
  33                        break;
  34                }
  35                index++;
  36        } while (!ret);
  37
  38        return ret;
  39}
  40
  41int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
  42{
  43        return -1;
  44}
  45
  46static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev,
  47                            int nvec, msi_alloc_info_t *info)
  48{
  49        struct msi_domain_info *msi_info;
  50        u32 dev_id;
  51        int ret;
  52
  53        msi_info = msi_get_domain_info(domain->parent);
  54
  55        if (dev->of_node)
  56                ret = of_pmsi_get_dev_id(domain, dev, &dev_id);
  57        else
  58                ret = iort_pmsi_get_dev_id(dev, &dev_id);
  59        if (ret)
  60                return ret;
  61
  62        /* ITS specific DeviceID, as the core ITS ignores dev. */
  63        info->scratchpad[0].ul = dev_id;
  64
  65        /* Allocate at least 32 MSIs, and always as a power of 2 */
  66        nvec = max_t(int, 32, roundup_pow_of_two(nvec));
  67        return msi_info->ops->msi_prepare(domain->parent,
  68                                          dev, nvec, info);
  69}
  70
  71static struct msi_domain_ops its_pmsi_ops = {
  72        .msi_prepare    = its_pmsi_prepare,
  73};
  74
  75static struct msi_domain_info its_pmsi_domain_info = {
  76        .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
  77        .ops    = &its_pmsi_ops,
  78        .chip   = &its_pmsi_irq_chip,
  79};
  80
  81static const struct of_device_id its_device_id[] = {
  82        {       .compatible     = "arm,gic-v3-its",     },
  83        {},
  84};
  85
  86static int __init its_pmsi_init_one(struct fwnode_handle *fwnode,
  87                                const char *name)
  88{
  89        struct irq_domain *parent;
  90
  91        parent = irq_find_matching_fwnode(fwnode, DOMAIN_BUS_NEXUS);
  92        if (!parent || !msi_get_domain_info(parent)) {
  93                pr_err("%s: unable to locate ITS domain\n", name);
  94                return -ENXIO;
  95        }
  96
  97        if (!platform_msi_create_irq_domain(fwnode, &its_pmsi_domain_info,
  98                                            parent)) {
  99                pr_err("%s: unable to create platform domain\n", name);
 100                return -ENXIO;
 101        }
 102
 103        pr_info("Platform MSI: %s domain created\n", name);
 104        return 0;
 105}
 106
 107#ifdef CONFIG_ACPI
 108static int __init
 109its_pmsi_parse_madt(union acpi_subtable_headers *header,
 110                        const unsigned long end)
 111{
 112        struct acpi_madt_generic_translator *its_entry;
 113        struct fwnode_handle *domain_handle;
 114        const char *node_name;
 115        int err = -ENXIO;
 116
 117        its_entry = (struct acpi_madt_generic_translator *)header;
 118        node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
 119                              (long)its_entry->base_address);
 120        domain_handle = iort_find_domain_token(its_entry->translation_id);
 121        if (!domain_handle) {
 122                pr_err("%s: Unable to locate ITS domain handle\n", node_name);
 123                goto out;
 124        }
 125
 126        err = its_pmsi_init_one(domain_handle, node_name);
 127
 128out:
 129        kfree(node_name);
 130        return err;
 131}
 132
 133static void __init its_pmsi_acpi_init(void)
 134{
 135        acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
 136                              its_pmsi_parse_madt, 0);
 137}
 138#else
 139static inline void its_pmsi_acpi_init(void) { }
 140#endif
 141
 142static void __init its_pmsi_of_init(void)
 143{
 144        struct device_node *np;
 145
 146        for (np = of_find_matching_node(NULL, its_device_id); np;
 147             np = of_find_matching_node(np, its_device_id)) {
 148                if (!of_device_is_available(np))
 149                        continue;
 150                if (!of_property_read_bool(np, "msi-controller"))
 151                        continue;
 152
 153                its_pmsi_init_one(of_node_to_fwnode(np), np->full_name);
 154        }
 155}
 156
 157static int __init its_pmsi_init(void)
 158{
 159        its_pmsi_of_init();
 160        its_pmsi_acpi_init();
 161        return 0;
 162}
 163early_initcall(its_pmsi_init);
 164