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
its_mask_msi_irq(struct irq_data * d)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
its_unmask_msi_irq(struct irq_data * d)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 .irq_write_msi_msg = pci_msi_domain_write_msg,
32 };
33
its_pci_msi_vec_count(struct pci_dev * pdev,void * data)34 static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data)
35 {
36 int msi, msix, *count = data;
37
38 msi = max(pci_msi_vec_count(pdev), 0);
39 msix = max(pci_msix_vec_count(pdev), 0);
40 *count += max(msi, msix);
41
42 return 0;
43 }
44
its_get_pci_alias(struct pci_dev * pdev,u16 alias,void * data)45 static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
46 {
47 struct pci_dev **alias_dev = data;
48
49 *alias_dev = pdev;
50
51 return 0;
52 }
53
its_pci_msi_prepare(struct irq_domain * domain,struct device * dev,int nvec,msi_alloc_info_t * info)54 static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
55 int nvec, msi_alloc_info_t *info)
56 {
57 struct pci_dev *pdev, *alias_dev;
58 struct msi_domain_info *msi_info;
59 int alias_count = 0, minnvec = 1;
60
61 if (!dev_is_pci(dev))
62 return -EINVAL;
63
64 msi_info = msi_get_domain_info(domain->parent);
65
66 pdev = to_pci_dev(dev);
67 /*
68 * If pdev is downstream of any aliasing bridges, take an upper
69 * bound of how many other vectors could map to the same DevID.
70 * Also tell the ITS that the signalling will come from a proxy
71 * device, and that special allocation rules apply.
72 */
73 pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
74 if (alias_dev != pdev) {
75 if (alias_dev->subordinate)
76 pci_walk_bus(alias_dev->subordinate,
77 its_pci_msi_vec_count, &alias_count);
78 info->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
79 }
80
81 /* ITS specific DeviceID, as the core ITS ignores dev. */
82 info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
83
84 /*
85 * Always allocate a power of 2, and special case device 0 for
86 * broken systems where the DevID is not wired (and all devices
87 * appear as DevID 0). For that reason, we generously allocate a
88 * minimum of 32 MSIs for DevID 0. If you want more because all
89 * your devices are aliasing to DevID 0, consider fixing your HW.
90 */
91 nvec = max(nvec, alias_count);
92 if (!info->scratchpad[0].ul)
93 minnvec = 32;
94 nvec = max_t(int, minnvec, roundup_pow_of_two(nvec));
95 return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info);
96 }
97
98 static struct msi_domain_ops its_pci_msi_ops = {
99 .msi_prepare = its_pci_msi_prepare,
100 };
101
102 static struct msi_domain_info its_pci_msi_domain_info = {
103 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
104 MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
105 .ops = &its_pci_msi_ops,
106 .chip = &its_msi_irq_chip,
107 };
108
109 static struct of_device_id its_device_id[] = {
110 { .compatible = "arm,gic-v3-its", },
111 {},
112 };
113
its_pci_msi_init_one(struct fwnode_handle * handle,const char * name)114 static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
115 const char *name)
116 {
117 struct irq_domain *parent;
118
119 parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
120 if (!parent || !msi_get_domain_info(parent)) {
121 pr_err("%s: Unable to locate ITS domain\n", name);
122 return -ENXIO;
123 }
124
125 if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
126 parent)) {
127 pr_err("%s: Unable to create PCI domain\n", name);
128 return -ENOMEM;
129 }
130
131 return 0;
132 }
133
its_pci_of_msi_init(void)134 static int __init its_pci_of_msi_init(void)
135 {
136 struct device_node *np;
137
138 for (np = of_find_matching_node(NULL, its_device_id); np;
139 np = of_find_matching_node(np, its_device_id)) {
140 if (!of_device_is_available(np))
141 continue;
142 if (!of_property_read_bool(np, "msi-controller"))
143 continue;
144
145 if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
146 continue;
147
148 pr_info("PCI/MSI: %pOF domain created\n", np);
149 }
150
151 return 0;
152 }
153
154 #ifdef CONFIG_ACPI
155
156 static int __init
its_pci_msi_parse_madt(union acpi_subtable_headers * header,const unsigned long end)157 its_pci_msi_parse_madt(union acpi_subtable_headers *header,
158 const unsigned long end)
159 {
160 struct acpi_madt_generic_translator *its_entry;
161 struct fwnode_handle *dom_handle;
162 const char *node_name;
163 int err = -ENXIO;
164
165 its_entry = (struct acpi_madt_generic_translator *)header;
166 node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
167 (long)its_entry->base_address);
168 dom_handle = iort_find_domain_token(its_entry->translation_id);
169 if (!dom_handle) {
170 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
171 goto out;
172 }
173
174 err = its_pci_msi_init_one(dom_handle, node_name);
175 if (!err)
176 pr_info("PCI/MSI: %s domain created\n", node_name);
177
178 out:
179 kfree(node_name);
180 return err;
181 }
182
its_pci_acpi_msi_init(void)183 static int __init its_pci_acpi_msi_init(void)
184 {
185 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
186 its_pci_msi_parse_madt, 0);
187 return 0;
188 }
189 #else
its_pci_acpi_msi_init(void)190 static int __init its_pci_acpi_msi_init(void)
191 {
192 return 0;
193 }
194 #endif
195
its_pci_msi_init(void)196 static int __init its_pci_msi_init(void)
197 {
198 its_pci_of_msi_init();
199 its_pci_acpi_msi_init();
200
201 return 0;
202 }
203 early_initcall(its_pci_msi_init);
204