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/device.h>
9 #include <linux/msi.h>
10 #include <linux/of.h>
11 #include <linux/of_irq.h>
12
13 static struct irq_chip its_pmsi_irq_chip = {
14 .name = "ITS-pMSI",
15 };
16
of_pmsi_get_dev_id(struct irq_domain * domain,struct device * dev,u32 * dev_id)17 static int of_pmsi_get_dev_id(struct irq_domain *domain, struct device *dev,
18 u32 *dev_id)
19 {
20 int ret, index = 0;
21
22 /* Suck the DeviceID out of the msi-parent property */
23 do {
24 struct of_phandle_args args;
25
26 ret = of_parse_phandle_with_args(dev->of_node,
27 "msi-parent", "#msi-cells",
28 index, &args);
29 if (args.np == irq_domain_get_of_node(domain)) {
30 if (WARN_ON(args.args_count != 1))
31 return -EINVAL;
32 *dev_id = args.args[0];
33 break;
34 }
35 index++;
36 } while (!ret);
37
38 return ret;
39 }
40
iort_pmsi_get_dev_id(struct device * dev,u32 * dev_id)41 int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
42 {
43 return -1;
44 }
45
its_pmsi_prepare(struct irq_domain * domain,struct device * dev,int nvec,msi_alloc_info_t * info)46 static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev,
47 int nvec, msi_alloc_info_t *info)
48 {
49 struct msi_domain_info *msi_info;
50 u32 dev_id;
51 int ret;
52
53 msi_info = msi_get_domain_info(domain->parent);
54
55 if (dev->of_node)
56 ret = of_pmsi_get_dev_id(domain, dev, &dev_id);
57 else
58 ret = iort_pmsi_get_dev_id(dev, &dev_id);
59 if (ret)
60 return ret;
61
62 /* ITS specific DeviceID, as the core ITS ignores dev. */
63 info->scratchpad[0].ul = dev_id;
64
65 /* Allocate at least 32 MSIs, and always as a power of 2 */
66 nvec = max_t(int, 32, roundup_pow_of_two(nvec));
67 return msi_info->ops->msi_prepare(domain->parent,
68 dev, nvec, info);
69 }
70
71 static struct msi_domain_ops its_pmsi_ops = {
72 .msi_prepare = its_pmsi_prepare,
73 };
74
75 static struct msi_domain_info its_pmsi_domain_info = {
76 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
77 .ops = &its_pmsi_ops,
78 .chip = &its_pmsi_irq_chip,
79 };
80
81 static const struct of_device_id its_device_id[] = {
82 { .compatible = "arm,gic-v3-its", },
83 {},
84 };
85
its_pmsi_init_one(struct fwnode_handle * fwnode,const char * name)86 static int __init its_pmsi_init_one(struct fwnode_handle *fwnode,
87 const char *name)
88 {
89 struct irq_domain *parent;
90
91 parent = irq_find_matching_fwnode(fwnode, DOMAIN_BUS_NEXUS);
92 if (!parent || !msi_get_domain_info(parent)) {
93 pr_err("%s: unable to locate ITS domain\n", name);
94 return -ENXIO;
95 }
96
97 if (!platform_msi_create_irq_domain(fwnode, &its_pmsi_domain_info,
98 parent)) {
99 pr_err("%s: unable to create platform domain\n", name);
100 return -ENXIO;
101 }
102
103 pr_info("Platform MSI: %s domain created\n", name);
104 return 0;
105 }
106
107 #ifdef CONFIG_ACPI
108 static int __init
its_pmsi_parse_madt(union acpi_subtable_headers * header,const unsigned long end)109 its_pmsi_parse_madt(union acpi_subtable_headers *header,
110 const unsigned long end)
111 {
112 struct acpi_madt_generic_translator *its_entry;
113 struct fwnode_handle *domain_handle;
114 const char *node_name;
115 int err = -ENXIO;
116
117 its_entry = (struct acpi_madt_generic_translator *)header;
118 node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
119 (long)its_entry->base_address);
120 domain_handle = iort_find_domain_token(its_entry->translation_id);
121 if (!domain_handle) {
122 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
123 goto out;
124 }
125
126 err = its_pmsi_init_one(domain_handle, node_name);
127
128 out:
129 kfree(node_name);
130 return err;
131 }
132
its_pmsi_acpi_init(void)133 static void __init its_pmsi_acpi_init(void)
134 {
135 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
136 its_pmsi_parse_madt, 0);
137 }
138 #else
its_pmsi_acpi_init(void)139 static inline void its_pmsi_acpi_init(void) { }
140 #endif
141
its_pmsi_of_init(void)142 static void __init its_pmsi_of_init(void)
143 {
144 struct device_node *np;
145
146 for (np = of_find_matching_node(NULL, its_device_id); np;
147 np = of_find_matching_node(np, its_device_id)) {
148 if (!of_device_is_available(np))
149 continue;
150 if (!of_property_read_bool(np, "msi-controller"))
151 continue;
152
153 its_pmsi_init_one(of_node_to_fwnode(np), np->full_name);
154 }
155 }
156
its_pmsi_init(void)157 static int __init its_pmsi_init(void)
158 {
159 its_pmsi_of_init();
160 its_pmsi_acpi_init();
161 return 0;
162 }
163 early_initcall(its_pmsi_init);
164