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 
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 
41 int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
42 {
43 	return -1;
44 }
45 
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 
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
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 
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
139 static inline void its_pmsi_acpi_init(void) { }
140 #endif
141 
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 
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