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/msi.h>
  19 #include <linux/of.h>
  20 #include <linux/of_irq.h>
  21 #include <linux/of_pci.h>
  22
  23 static void its_mask_msi_irq(struct irq_data *d)
  24 {
  25         pci_msi_mask_irq(d);
  26         irq_chip_mask_parent(d);
  27 }
  28
  29 static void its_unmask_msi_irq(struct irq_data *d)
  30 {
  31         pci_msi_unmask_irq(d);
  32         irq_chip_unmask_parent(d);
  33 }
  34
  35 static struct irq_chip its_msi_irq_chip = {
  36         .name                   = "ITS-MSI",
  37         .irq_unmask             = its_unmask_msi_irq,
  38         .irq_mask               = its_mask_msi_irq,
  39         .irq_eoi                = irq_chip_eoi_parent,
  40         .irq_write_msi_msg      = pci_msi_domain_write_msg,
  41 };
  42
  43 struct its_pci_alias {
  44         struct pci_dev  *pdev;
  45         u32             count;
  46 };
  47
  48 static int its_pci_msi_vec_count(struct pci_dev *pdev)
  49 {
  50         int msi, msix;
  51
  52         msi = max(pci_msi_vec_count(pdev), 0);
  53         msix = max(pci_msix_vec_count(pdev), 0);
  54
  55         return max(msi, msix);
  56 }
  57
  58 static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
  59 {
  60         struct its_pci_alias *dev_alias = data;
  61
  62         if (pdev != dev_alias->pdev)
  63                 dev_alias->count += its_pci_msi_vec_count(pdev);
  64
  65         return 0;
  66 }
  67
  68 static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
  69                                int nvec, msi_alloc_info_t *info)
  70 {
  71         struct pci_dev *pdev;
  72         struct its_pci_alias dev_alias;
  73         struct msi_domain_info *msi_info;
  74
  75         if (!dev_is_pci(dev))
  76                 return -EINVAL;
  77
  78         msi_info = msi_get_domain_info(domain->parent);
  79
  80         pdev = to_pci_dev(dev);
  81         dev_alias.pdev = pdev;
  82         dev_alias.count = nvec;
  83
  84         pci_for_each_dma_alias(pdev, its_get_pci_alias, &dev_alias);
  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, dev_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(void)
 110 {
 111         struct device_node *np;
 112         struct irq_domain *parent;
 113
 114         for (np = of_find_matching_node(NULL, its_device_id); np;
 115              np = of_find_matching_node(np, its_device_id)) {
 116                 if (!of_property_read_bool(np, "msi-controller"))
 117                         continue;
 118
 119                 parent = irq_find_matching_host(np, DOMAIN_BUS_NEXUS);
 120                 if (!parent || !msi_get_domain_info(parent)) {
 121                         pr_err("%s: unable to locate ITS domain\n",
 122                                np->full_name);
 123                         continue;
 124                 }
 125
 126                 if (!pci_msi_create_irq_domain(of_node_to_fwnode(np),
 127                                                &its_pci_msi_domain_info,
 128                                                parent)) {
 129                         pr_err("%s: unable to create PCI domain\n",
 130                                np->full_name);
 131                         continue;
 132                 }
 133
 134                 pr_info("PCI/MSI: %s domain created\n", np->full_name);
 135         }
 136
 137         return 0;
 138 }
 139 early_initcall(its_pci_msi_init);