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          * Also tell the ITS that the signalling will come from a proxy
  71          * device, and that special allocation rules apply.
  72          */
  73         pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
  74         if (alias_dev != pdev) {
  75                 if (alias_dev->subordinate)
  76                         pci_walk_bus(alias_dev->subordinate,
  77                                      its_pci_msi_vec_count, &alias_count);
  78                 info->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
  79         }
  80
  81         /* ITS specific DeviceID, as the core ITS ignores dev. */
  82         info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
  83
  84         /*
  85          * Always allocate a power of 2, and special case device 0 for
  86          * broken systems where the DevID is not wired (and all devices
  87          * appear as DevID 0). For that reason, we generously allocate a
  88          * minimum of 32 MSIs for DevID 0. If you want more because all
  89          * your devices are aliasing to DevID 0, consider fixing your HW.
  90          */
  91         nvec = max(nvec, alias_count);
  92         if (!info->scratchpad[0].ul)
  93                 minnvec = 32;
  94         nvec = max_t(int, minnvec, roundup_pow_of_two(nvec));
  95         return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info);
  96 }
  97
  98 static struct msi_domain_ops its_pci_msi_ops = {
  99         .msi_prepare    = its_pci_msi_prepare,
 100 };
 101
 102 static struct msi_domain_info its_pci_msi_domain_info = {
 103         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
 104                    MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
 105         .ops    = &its_pci_msi_ops,
 106         .chip   = &its_msi_irq_chip,
 107 };
 108
 109 static struct of_device_id its_device_id[] = {
 110         {       .compatible     = "arm,gic-v3-its",     },
 111         {},
 112 };
 113
 114 static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
 115                                        const char *name)
 116 {
 117         struct irq_domain *parent;
 118
 119         parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
 120         if (!parent || !msi_get_domain_info(parent)) {
 121                 pr_err("%s: Unable to locate ITS domain\n", name);
 122                 return -ENXIO;
 123         }
 124
 125         if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
 126                                        parent)) {
 127                 pr_err("%s: Unable to create PCI domain\n", name);
 128                 return -ENOMEM;
 129         }
 130
 131         return 0;
 132 }
 133
 134 static int __init its_pci_of_msi_init(void)
 135 {
 136         struct device_node *np;
 137
 138         for (np = of_find_matching_node(NULL, its_device_id); np;
 139              np = of_find_matching_node(np, its_device_id)) {
 140                 if (!of_device_is_available(np))
 141                         continue;
 142                 if (!of_property_read_bool(np, "msi-controller"))
 143                         continue;
 144
 145                 if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
 146                         continue;
 147
 148                 pr_info("PCI/MSI: %pOF domain created\n", np);
 149         }
 150
 151         return 0;
 152 }
 153
 154 #ifdef CONFIG_ACPI
 155
 156 static int __init
 157 its_pci_msi_parse_madt(union acpi_subtable_headers *header,
 158                        const unsigned long end)
 159 {
 160         struct acpi_madt_generic_translator *its_entry;
 161         struct fwnode_handle *dom_handle;
 162         const char *node_name;
 163         int err = -ENXIO;
 164
 165         its_entry = (struct acpi_madt_generic_translator *)header;
 166         node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
 167                               (long)its_entry->base_address);
 168         dom_handle = iort_find_domain_token(its_entry->translation_id);
 169         if (!dom_handle) {
 170                 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
 171                 goto out;
 172         }
 173
 174         err = its_pci_msi_init_one(dom_handle, node_name);
 175         if (!err)
 176                 pr_info("PCI/MSI: %s domain created\n", node_name);
 177
 178 out:
 179         kfree(node_name);
 180         return err;
 181 }
 182
 183 static int __init its_pci_acpi_msi_init(void)
 184 {
 185         acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
 186                               its_pci_msi_parse_madt, 0);
 187         return 0;
 188 }
 189 #else
 190 static int __init its_pci_acpi_msi_init(void)
 191 {
 192         return 0;
 193 }
 194 #endif
 195
 196 static int __init its_pci_msi_init(void)
 197 {
 198         its_pci_of_msi_init();
 199         its_pci_acpi_msi_init();
 200
 201         return 0;
 202 }
 203 early_initcall(its_pci_msi_init);