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