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/device.h>
19 #include <linux/msi.h>
20 #include <linux/of.h>
21 #include <linux/of_irq.h>
22 
23 static struct irq_chip its_pmsi_irq_chip = {
24 	.name			= "ITS-pMSI",
25 };
26 
27 static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev,
28 			    int nvec, msi_alloc_info_t *info)
29 {
30 	struct msi_domain_info *msi_info;
31 	u32 dev_id;
32 	int ret, index = 0;
33 
34 	msi_info = msi_get_domain_info(domain->parent);
35 
36 	/* Suck the DeviceID out of the msi-parent property */
37 	do {
38 		struct of_phandle_args args;
39 
40 		ret = of_parse_phandle_with_args(dev->of_node,
41 						 "msi-parent", "#msi-cells",
42 						 index, &args);
43 		if (args.np == irq_domain_get_of_node(domain)) {
44 			if (WARN_ON(args.args_count != 1))
45 				return -EINVAL;
46 			dev_id = args.args[0];
47 			break;
48 		}
49 	} while (!ret);
50 
51 	if (ret)
52 		return ret;
53 
54 	/* ITS specific DeviceID, as the core ITS ignores dev. */
55 	info->scratchpad[0].ul = dev_id;
56 
57 	return msi_info->ops->msi_prepare(domain->parent,
58 					  dev, nvec, info);
59 }
60 
61 static struct msi_domain_ops its_pmsi_ops = {
62 	.msi_prepare	= its_pmsi_prepare,
63 };
64 
65 static struct msi_domain_info its_pmsi_domain_info = {
66 	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
67 	.ops	= &its_pmsi_ops,
68 	.chip	= &its_pmsi_irq_chip,
69 };
70 
71 static struct of_device_id its_device_id[] = {
72 	{	.compatible	= "arm,gic-v3-its",	},
73 	{},
74 };
75 
76 static int __init its_pmsi_init(void)
77 {
78 	struct device_node *np;
79 	struct irq_domain *parent;
80 
81 	for (np = of_find_matching_node(NULL, its_device_id); np;
82 	     np = of_find_matching_node(np, its_device_id)) {
83 		if (!of_property_read_bool(np, "msi-controller"))
84 			continue;
85 
86 		parent = irq_find_matching_host(np, DOMAIN_BUS_NEXUS);
87 		if (!parent || !msi_get_domain_info(parent)) {
88 			pr_err("%s: unable to locate ITS domain\n",
89 			       np->full_name);
90 			continue;
91 		}
92 
93 		if (!platform_msi_create_irq_domain(of_node_to_fwnode(np),
94 						    &its_pmsi_domain_info,
95 						    parent)) {
96 			pr_err("%s: unable to create platform domain\n",
97 			       np->full_name);
98 			continue;
99 		}
100 
101 		pr_info("Platform MSI: %s domain created\n", np->full_name);
102 	}
103 
104 	return 0;
105 }
106 early_initcall(its_pmsi_init);
107