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/device.h>
20 #include <linux/msi.h>
21 #include <linux/of.h>
22 #include <linux/of_irq.h>
23
24 static struct irq_chip its_pmsi_irq_chip = {
25 .name = "ITS-pMSI",
26 };
27
of_pmsi_get_dev_id(struct irq_domain * domain,struct device * dev,u32 * dev_id)28 static int of_pmsi_get_dev_id(struct irq_domain *domain, struct device *dev,
29 u32 *dev_id)
30 {
31 int ret, index = 0;
32
33 /* Suck the DeviceID out of the msi-parent property */
34 do {
35 struct of_phandle_args args;
36
37 ret = of_parse_phandle_with_args(dev->of_node,
38 "msi-parent", "#msi-cells",
39 index, &args);
40 if (args.np == irq_domain_get_of_node(domain)) {
41 if (WARN_ON(args.args_count != 1))
42 return -EINVAL;
43 *dev_id = args.args[0];
44 break;
45 }
46 index++;
47 } while (!ret);
48
49 return ret;
50 }
51
iort_pmsi_get_dev_id(struct device * dev,u32 * dev_id)52 int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
53 {
54 return -1;
55 }
56
its_pmsi_prepare(struct irq_domain * domain,struct device * dev,int nvec,msi_alloc_info_t * info)57 static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev,
58 int nvec, msi_alloc_info_t *info)
59 {
60 struct msi_domain_info *msi_info;
61 u32 dev_id;
62 int ret;
63
64 msi_info = msi_get_domain_info(domain->parent);
65
66 if (dev->of_node)
67 ret = of_pmsi_get_dev_id(domain, dev, &dev_id);
68 else
69 ret = iort_pmsi_get_dev_id(dev, &dev_id);
70 if (ret)
71 return ret;
72
73 /* ITS specific DeviceID, as the core ITS ignores dev. */
74 info->scratchpad[0].ul = dev_id;
75
76 /* Allocate at least 32 MSIs, and always as a power of 2 */
77 nvec = max_t(int, 32, roundup_pow_of_two(nvec));
78 return msi_info->ops->msi_prepare(domain->parent,
79 dev, nvec, info);
80 }
81
82 static struct msi_domain_ops its_pmsi_ops = {
83 .msi_prepare = its_pmsi_prepare,
84 };
85
86 static struct msi_domain_info its_pmsi_domain_info = {
87 .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
88 .ops = &its_pmsi_ops,
89 .chip = &its_pmsi_irq_chip,
90 };
91
92 static const struct of_device_id its_device_id[] = {
93 { .compatible = "arm,gic-v3-its", },
94 {},
95 };
96
its_pmsi_init_one(struct fwnode_handle * fwnode,const char * name)97 static int __init its_pmsi_init_one(struct fwnode_handle *fwnode,
98 const char *name)
99 {
100 struct irq_domain *parent;
101
102 parent = irq_find_matching_fwnode(fwnode, DOMAIN_BUS_NEXUS);
103 if (!parent || !msi_get_domain_info(parent)) {
104 pr_err("%s: unable to locate ITS domain\n", name);
105 return -ENXIO;
106 }
107
108 if (!platform_msi_create_irq_domain(fwnode, &its_pmsi_domain_info,
109 parent)) {
110 pr_err("%s: unable to create platform domain\n", name);
111 return -ENXIO;
112 }
113
114 pr_info("Platform MSI: %s domain created\n", name);
115 return 0;
116 }
117
118 #ifdef CONFIG_ACPI
119 static int __init
its_pmsi_parse_madt(struct acpi_subtable_header * header,const unsigned long end)120 its_pmsi_parse_madt(struct acpi_subtable_header *header,
121 const unsigned long end)
122 {
123 struct acpi_madt_generic_translator *its_entry;
124 struct fwnode_handle *domain_handle;
125 const char *node_name;
126 int err = -ENXIO;
127
128 its_entry = (struct acpi_madt_generic_translator *)header;
129 node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
130 (long)its_entry->base_address);
131 domain_handle = iort_find_domain_token(its_entry->translation_id);
132 if (!domain_handle) {
133 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
134 goto out;
135 }
136
137 err = its_pmsi_init_one(domain_handle, node_name);
138
139 out:
140 kfree(node_name);
141 return err;
142 }
143
its_pmsi_acpi_init(void)144 static void __init its_pmsi_acpi_init(void)
145 {
146 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
147 its_pmsi_parse_madt, 0);
148 }
149 #else
its_pmsi_acpi_init(void)150 static inline void its_pmsi_acpi_init(void) { }
151 #endif
152
its_pmsi_of_init(void)153 static void __init its_pmsi_of_init(void)
154 {
155 struct device_node *np;
156
157 for (np = of_find_matching_node(NULL, its_device_id); np;
158 np = of_find_matching_node(np, its_device_id)) {
159 if (!of_device_is_available(np))
160 continue;
161 if (!of_property_read_bool(np, "msi-controller"))
162 continue;
163
164 its_pmsi_init_one(of_node_to_fwnode(np), np->full_name);
165 }
166 }
167
its_pmsi_init(void)168 static int __init its_pmsi_init(void)
169 {
170 its_pmsi_of_init();
171 its_pmsi_acpi_init();
172 return 0;
173 }
174 early_initcall(its_pmsi_init);
175