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 };
32
its_pci_msi_vec_count(struct pci_dev * pdev,void * data)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
its_get_pci_alias(struct pci_dev * pdev,u16 alias,void * data)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
its_pci_msi_prepare(struct irq_domain * domain,struct device * dev,int nvec,msi_alloc_info_t * info)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
its_pci_msi_init_one(struct fwnode_handle * handle,const char * name)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
its_pci_of_msi_init(void)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
its_pci_msi_parse_madt(union acpi_subtable_headers * header,const unsigned long end)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
its_pci_acpi_msi_init(void)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
its_pci_acpi_msi_init(void)189 static int __init its_pci_acpi_msi_init(void)
190 {
191 return 0;
192 }
193 #endif
194
its_pci_msi_init(void)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