drivers/irqchip/irq-gic-v3-its-pci-msi.c

   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/msi.h>
   9 #include <linux/of.h>
  10 #include <linux/of_irq.h>
  11 #include <linux/of_pci.h>
  12
  13 static void its_mask_msi_irq(struct irq_data *d)
  14 {
  15         pci_msi_mask_irq(d);
  16         irq_chip_mask_parent(d);
  17 }
  18
  19 static void its_unmask_msi_irq(struct irq_data *d)
  20 {
  21         pci_msi_unmask_irq(d);
  22         irq_chip_unmask_parent(d);
  23 }
  24
  25 static struct irq_chip its_msi_irq_chip = {
  26         .name                   = "ITS-MSI",
  27         .irq_unmask             = its_unmask_msi_irq,
  28         .irq_mask               = its_mask_msi_irq,
  29         .irq_eoi                = irq_chip_eoi_parent,
  30         .irq_write_msi_msg      = pci_msi_domain_write_msg,
  31 };
  32
  33 static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data)
  34 {
  35         int msi, msix, *count = data;
  36
  37         msi = max(pci_msi_vec_count(pdev), 0);
  38         msix = max(pci_msix_vec_count(pdev), 0);
  39         *count += max(msi, msix);
  40
  41         return 0;
  42 }
  43
  44 static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
  45 {
  46         struct pci_dev **alias_dev = data;
  47
  48         *alias_dev = pdev;
  49
  50         return 0;
  51 }
  52
  53 static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
  54                                int nvec, msi_alloc_info_t *info)
  55 {
  56         struct pci_dev *pdev, *alias_dev;
  57         struct msi_domain_info *msi_info;
  58         int alias_count = 0, minnvec = 1;
  59
  60         if (!dev_is_pci(dev))
  61                 return -EINVAL;
  62
  63         msi_info = msi_get_domain_info(domain->parent);
  64
  65         pdev = to_pci_dev(dev);
  66         /*
  67          * If pdev is downstream of any aliasing bridges, take an upper
  68          * bound of how many other vectors could map to the same DevID.
  69          */
  70         pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
  71         if (alias_dev != pdev && alias_dev->subordinate)
  72                 pci_walk_bus(alias_dev->subordinate, its_pci_msi_vec_count,
  73                              &alias_count);
  74
  75         /* ITS specific DeviceID, as the core ITS ignores dev. */
  76         info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
  77
  78         /*
  79          * Always allocate a power of 2, and special case device 0 for
  80          * broken systems where the DevID is not wired (and all devices
  81          * appear as DevID 0). For that reason, we generously allocate a
  82          * minimum of 32 MSIs for DevID 0. If you want more because all
  83          * your devices are aliasing to DevID 0, consider fixing your HW.
  84          */
  85         nvec = max(nvec, alias_count);
  86         if (!info->scratchpad[0].ul)
  87                 minnvec = 32;
  88         nvec = max_t(int, minnvec, roundup_pow_of_two(nvec));
  89         return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info);
  90 }
  91
  92 static struct msi_domain_ops its_pci_msi_ops = {
  93         .msi_prepare    = its_pci_msi_prepare,
  94 };
  95
  96 static struct msi_domain_info its_pci_msi_domain_info = {
  97         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
  98                    MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
  99         .ops    = &its_pci_msi_ops,
 100         .chip   = &its_msi_irq_chip,
 101 };
 102
 103 static struct of_device_id its_device_id[] = {
 104         {       .compatible     = "arm,gic-v3-its",     },
 105         {},
 106 };
 107
 108 static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
 109                                        const char *name)
 110 {
 111         struct irq_domain *parent;
 112
 113         parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
 114         if (!parent || !msi_get_domain_info(parent)) {
 115                 pr_err("%s: Unable to locate ITS domain\n", name);
 116                 return -ENXIO;
 117         }
 118
 119         if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
 120                                        parent)) {
 121                 pr_err("%s: Unable to create PCI domain\n", name);
 122                 return -ENOMEM;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static int __init its_pci_of_msi_init(void)
 129 {
 130         struct device_node *np;
 131
 132         for (np = of_find_matching_node(NULL, its_device_id); np;
 133              np = of_find_matching_node(np, its_device_id)) {
 134                 if (!of_device_is_available(np))
 135                         continue;
 136                 if (!of_property_read_bool(np, "msi-controller"))
 137                         continue;
 138
 139                 if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
 140                         continue;
 141
 142                 pr_info("PCI/MSI: %pOF domain created\n", np);
 143         }
 144
 145         return 0;
 146 }
 147
 148 #ifdef CONFIG_ACPI
 149
 150 static int __init
 151 its_pci_msi_parse_madt(union acpi_subtable_headers *header,
 152                        const unsigned long end)
 153 {
 154         struct acpi_madt_generic_translator *its_entry;
 155         struct fwnode_handle *dom_handle;
 156         const char *node_name;
 157         int err = -ENXIO;
 158
 159         its_entry = (struct acpi_madt_generic_translator *)header;
 160         node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
 161                               (long)its_entry->base_address);
 162         dom_handle = iort_find_domain_token(its_entry->translation_id);
 163         if (!dom_handle) {
 164                 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
 165                 goto out;
 166         }
 167
 168         err = its_pci_msi_init_one(dom_handle, node_name);
 169         if (!err)
 170                 pr_info("PCI/MSI: %s domain created\n", node_name);
 171
 172 out:
 173         kfree(node_name);
 174         return err;
 175 }
 176
 177 static int __init its_pci_acpi_msi_init(void)
 178 {
 179         acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
 180                               its_pci_msi_parse_madt, 0);
 181         return 0;
 182 }
 183 #else
 184 static int __init its_pci_acpi_msi_init(void)
 185 {
 186         return 0;
 187 }
 188 #endif
 189
 190 static int __init its_pci_msi_init(void)
 191 {
 192         its_pci_of_msi_init();
 193         its_pci_acpi_msi_init();
 194
 195         return 0;
 196 }
 197 early_initcall(its_pci_msi_init);