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 }; 32 33 static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data) 34 { 35 int msi, msix, *count = data; 36 37 msi = max(pci_msi_vec_count(pdev), 0); 38 msix = max(pci_msix_vec_count(pdev), 0); 39 *count += max(msi, msix); 40 41 return 0; 42 } 43 44 static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data) 45 { 46 struct pci_dev **alias_dev = data; 47 48 *alias_dev = pdev; 49 50 return 0; 51 } 52 53 static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev, 54 int nvec, msi_alloc_info_t *info) 55 { 56 struct pci_dev *pdev, *alias_dev; 57 struct msi_domain_info *msi_info; 58 int alias_count = 0, minnvec = 1; 59 60 if (!dev_is_pci(dev)) 61 return -EINVAL; 62 63 msi_info = msi_get_domain_info(domain->parent); 64 65 pdev = to_pci_dev(dev); 66 /* 67 * If pdev is downstream of any aliasing bridges, take an upper 68 * bound of how many other vectors could map to the same DevID. 69 * Also tell the ITS that the signalling will come from a proxy 70 * device, and that special allocation rules apply. 71 */ 72 pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev); 73 if (alias_dev != pdev) { 74 if (alias_dev->subordinate) 75 pci_walk_bus(alias_dev->subordinate, 76 its_pci_msi_vec_count, &alias_count); 77 info->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE; 78 } 79 80 /* ITS specific DeviceID, as the core ITS ignores dev. */ 81 info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev); 82 83 /* 84 * Always allocate a power of 2, and special case device 0 for 85 * broken systems where the DevID is not wired (and all devices 86 * appear as DevID 0). For that reason, we generously allocate a 87 * minimum of 32 MSIs for DevID 0. If you want more because all 88 * your devices are aliasing to DevID 0, consider fixing your HW. 89 */ 90 nvec = max(nvec, alias_count); 91 if (!info->scratchpad[0].ul) 92 minnvec = 32; 93 nvec = max_t(int, minnvec, roundup_pow_of_two(nvec)); 94 return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info); 95 } 96 97 static struct msi_domain_ops its_pci_msi_ops = { 98 .msi_prepare = its_pci_msi_prepare, 99 }; 100 101 static struct msi_domain_info its_pci_msi_domain_info = { 102 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | 103 MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX), 104 .ops = &its_pci_msi_ops, 105 .chip = &its_msi_irq_chip, 106 }; 107 108 static struct of_device_id its_device_id[] = { 109 { .compatible = "arm,gic-v3-its", }, 110 {}, 111 }; 112 113 static int __init its_pci_msi_init_one(struct fwnode_handle *handle, 114 const char *name) 115 { 116 struct irq_domain *parent; 117 118 parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS); 119 if (!parent || !msi_get_domain_info(parent)) { 120 pr_err("%s: Unable to locate ITS domain\n", name); 121 return -ENXIO; 122 } 123 124 if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info, 125 parent)) { 126 pr_err("%s: Unable to create PCI domain\n", name); 127 return -ENOMEM; 128 } 129 130 return 0; 131 } 132 133 static int __init its_pci_of_msi_init(void) 134 { 135 struct device_node *np; 136 137 for (np = of_find_matching_node(NULL, its_device_id); np; 138 np = of_find_matching_node(np, its_device_id)) { 139 if (!of_device_is_available(np)) 140 continue; 141 if (!of_property_read_bool(np, "msi-controller")) 142 continue; 143 144 if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name)) 145 continue; 146 147 pr_info("PCI/MSI: %pOF domain created\n", np); 148 } 149 150 return 0; 151 } 152 153 #ifdef CONFIG_ACPI 154 155 static int __init 156 its_pci_msi_parse_madt(union acpi_subtable_headers *header, 157 const unsigned long end) 158 { 159 struct acpi_madt_generic_translator *its_entry; 160 struct fwnode_handle *dom_handle; 161 const char *node_name; 162 int err = -ENXIO; 163 164 its_entry = (struct acpi_madt_generic_translator *)header; 165 node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx", 166 (long)its_entry->base_address); 167 dom_handle = iort_find_domain_token(its_entry->translation_id); 168 if (!dom_handle) { 169 pr_err("%s: Unable to locate ITS domain handle\n", node_name); 170 goto out; 171 } 172 173 err = its_pci_msi_init_one(dom_handle, node_name); 174 if (!err) 175 pr_info("PCI/MSI: %s domain created\n", node_name); 176 177 out: 178 kfree(node_name); 179 return err; 180 } 181 182 static int __init its_pci_acpi_msi_init(void) 183 { 184 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR, 185 its_pci_msi_parse_madt, 0); 186 return 0; 187 } 188 #else 189 static int __init its_pci_acpi_msi_init(void) 190 { 191 return 0; 192 } 193 #endif 194 195 static int __init its_pci_msi_init(void) 196 { 197 its_pci_of_msi_init(); 198 its_pci_acpi_msi_init(); 199 200 return 0; 201 } 202 early_initcall(its_pci_msi_init); 203