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); 209