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, minnvec = 1;
  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         /*
  90          * Always allocate a power of 2, and special case device 0 for
  91          * broken systems where the DevID is not wired (and all devices
  92          * appear as DevID 0). For that reason, we generously allocate a
  93          * minimum of 32 MSIs for DevID 0. If you want more because all
  94          * your devices are aliasing to DevID 0, consider fixing your HW.
  95          */
  96         nvec = max(nvec, alias_count);
  97         if (!info->scratchpad[0].ul)
  98                 minnvec = 32;
  99         nvec = max_t(int, minnvec, roundup_pow_of_two(nvec));
 100         return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info);
 101 }
 102
 103 static struct msi_domain_ops its_pci_msi_ops = {
 104         .msi_prepare    = its_pci_msi_prepare,
 105 };
 106
 107 static struct msi_domain_info its_pci_msi_domain_info = {
 108         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
 109                    MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
 110         .ops    = &its_pci_msi_ops,
 111         .chip   = &its_msi_irq_chip,
 112 };
 113
 114 static struct of_device_id its_device_id[] = {
 115         {       .compatible     = "arm,gic-v3-its",     },
 116         {},
 117 };
 118
 119 static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
 120                                        const char *name)
 121 {
 122         struct irq_domain *parent;
 123
 124         parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
 125         if (!parent || !msi_get_domain_info(parent)) {
 126                 pr_err("%s: Unable to locate ITS domain\n", name);
 127                 return -ENXIO;
 128         }
 129
 130         if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
 131                                        parent)) {
 132                 pr_err("%s: Unable to create PCI domain\n", name);
 133                 return -ENOMEM;
 134         }
 135
 136         return 0;
 137 }
 138
 139 static int __init its_pci_of_msi_init(void)
 140 {
 141         struct device_node *np;
 142
 143         for (np = of_find_matching_node(NULL, its_device_id); np;
 144              np = of_find_matching_node(np, its_device_id)) {
 145                 if (!of_device_is_available(np))
 146                         continue;
 147                 if (!of_property_read_bool(np, "msi-controller"))
 148                         continue;
 149
 150                 if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
 151                         continue;
 152
 153                 pr_info("PCI/MSI: %pOF domain created\n", np);
 154         }
 155
 156         return 0;
 157 }
 158
 159 #ifdef CONFIG_ACPI
 160
 161 static int __init
 162 its_pci_msi_parse_madt(struct acpi_subtable_header *header,
 163                        const unsigned long end)
 164 {
 165         struct acpi_madt_generic_translator *its_entry;
 166         struct fwnode_handle *dom_handle;
 167         const char *node_name;
 168         int err = -ENXIO;
 169
 170         its_entry = (struct acpi_madt_generic_translator *)header;
 171         node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
 172                               (long)its_entry->base_address);
 173         dom_handle = iort_find_domain_token(its_entry->translation_id);
 174         if (!dom_handle) {
 175                 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
 176                 goto out;
 177         }
 178
 179         err = its_pci_msi_init_one(dom_handle, node_name);
 180         if (!err)
 181                 pr_info("PCI/MSI: %s domain created\n", node_name);
 182
 183 out:
 184         kfree(node_name);
 185         return err;
 186 }
 187
 188 static int __init its_pci_acpi_msi_init(void)
 189 {
 190         acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
 191                               its_pci_msi_parse_madt, 0);
 192         return 0;
 193 }
 194 #else
 195 static int __init its_pci_acpi_msi_init(void)
 196 {
 197         return 0;
 198 }
 199 #endif
 200
 201 static int __init its_pci_msi_init(void)
 202 {
 203         its_pci_of_msi_init();
 204         its_pci_acpi_msi_init();
 205
 206         return 0;
 207 }
 208 early_initcall(its_pci_msi_init);