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

   1 /*
   2  * Copyright (C) 2013-2015 ARM Limited, All Rights Reserved.
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <linux/acpi_iort.h>
  19 #include <linux/msi.h>
  20 #include <linux/of.h>
  21 #include <linux/of_irq.h>
  22 #include <linux/of_pci.h>
  23
  24 static void its_mask_msi_irq(struct irq_data *d)
  25 {
  26         pci_msi_mask_irq(d);
  27         irq_chip_mask_parent(d);
  28 }
  29
  30 static void its_unmask_msi_irq(struct irq_data *d)
  31 {
  32         pci_msi_unmask_irq(d);
  33         irq_chip_unmask_parent(d);
  34 }
  35
  36 static struct irq_chip its_msi_irq_chip = {
  37         .name                   = "ITS-MSI",
  38         .irq_unmask             = its_unmask_msi_irq,
  39         .irq_mask               = its_mask_msi_irq,
  40         .irq_eoi                = irq_chip_eoi_parent,
  41         .irq_write_msi_msg      = pci_msi_domain_write_msg,
  42 };
  43
  44 static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data)
  45 {
  46         int msi, msix, *count = data;
  47
  48         msi = max(pci_msi_vec_count(pdev), 0);
  49         msix = max(pci_msix_vec_count(pdev), 0);
  50         *count += max(msi, msix);
  51
  52         return 0;
  53 }
  54
  55 static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
  56 {
  57         struct pci_dev **alias_dev = data;
  58
  59         *alias_dev = pdev;
  60
  61         return 0;
  62 }
  63
  64 static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
  65                                int nvec, msi_alloc_info_t *info)
  66 {
  67         struct pci_dev *pdev, *alias_dev;
  68         struct msi_domain_info *msi_info;
  69         int alias_count = 0;
  70
  71         if (!dev_is_pci(dev))
  72                 return -EINVAL;
  73
  74         msi_info = msi_get_domain_info(domain->parent);
  75
  76         pdev = to_pci_dev(dev);
  77         /*
  78          * If pdev is downstream of any aliasing bridges, take an upper
  79          * bound of how many other vectors could map to the same DevID.
  80          */
  81         pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
  82         if (alias_dev != pdev && alias_dev->subordinate)
  83                 pci_walk_bus(alias_dev->subordinate, its_pci_msi_vec_count,
  84                              &alias_count);
  85
  86         /* ITS specific DeviceID, as the core ITS ignores dev. */
  87         info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
  88
  89         return msi_info->ops->msi_prepare(domain->parent,
  90                                           dev, max(nvec, alias_count), 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_property_read_bool(np, "msi-controller"))
 136                         continue;
 137
 138                 if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
 139                         continue;
 140
 141                 pr_info("PCI/MSI: %s domain created\n", np->full_name);
 142         }
 143
 144         return 0;
 145 }
 146
 147 #ifdef CONFIG_ACPI
 148
 149 static int __init
 150 its_pci_msi_parse_madt(struct acpi_subtable_header *header,
 151                        const unsigned long end)
 152 {
 153         struct acpi_madt_generic_translator *its_entry;
 154         struct fwnode_handle *dom_handle;
 155         const char *node_name;
 156         int err = -ENXIO;
 157
 158         its_entry = (struct acpi_madt_generic_translator *)header;
 159         node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
 160                               (long)its_entry->base_address);
 161         dom_handle = iort_find_domain_token(its_entry->translation_id);
 162         if (!dom_handle) {
 163                 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
 164                 goto out;
 165         }
 166
 167         err = its_pci_msi_init_one(dom_handle, node_name);
 168         if (!err)
 169                 pr_info("PCI/MSI: %s domain created\n", node_name);
 170
 171 out:
 172         kfree(node_name);
 173         return err;
 174 }
 175
 176 static int __init its_pci_acpi_msi_init(void)
 177 {
 178         acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
 179                               its_pci_msi_parse_madt, 0);
 180         return 0;
 181 }
 182 #else
 183 static int __init its_pci_acpi_msi_init(void)
 184 {
 185         return 0;
 186 }
 187 #endif
 188
 189 static int __init its_pci_msi_init(void)
 190 {
 191         its_pci_of_msi_init();
 192         its_pci_acpi_msi_init();
 193
 194         return 0;
 195 }
 196 early_initcall(its_pci_msi_init);