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
13static struct irq_chip its_pmsi_irq_chip = {
14	.name			= "ITS-pMSI",
15};
16
17static 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
41int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
42{
43	return -1;
44}
45
46static 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
71static struct msi_domain_ops its_pmsi_ops = {
72	.msi_prepare	= its_pmsi_prepare,
73};
74
75static 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
81static const struct of_device_id its_device_id[] = {
82	{	.compatible	= "arm,gic-v3-its",	},
83	{},
84};
85
86static 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
108static int __init
109its_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
128out:
129	kfree(node_name);
130	return err;
131}
132
133static 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
139static inline void its_pmsi_acpi_init(void) { }
140#endif
141
142static 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
157static int __init its_pmsi_init(void)
158{
159	its_pmsi_of_init();
160	its_pmsi_acpi_init();
161	return 0;
162}
163early_initcall(its_pmsi_init);
164