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
 24static struct irq_chip its_pmsi_irq_chip = {
 25	.name			= "ITS-pMSI",
 26};
 27
 28static 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
 52int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
 53{
 54	return -1;
 55}
 56
 57static 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	return msi_info->ops->msi_prepare(domain->parent,
 77					  dev, nvec, info);
 78}
 79
 80static struct msi_domain_ops its_pmsi_ops = {
 81	.msi_prepare	= its_pmsi_prepare,
 82};
 83
 84static struct msi_domain_info its_pmsi_domain_info = {
 85	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
 86	.ops	= &its_pmsi_ops,
 87	.chip	= &its_pmsi_irq_chip,
 88};
 89
 90static const struct of_device_id its_device_id[] = {
 91	{	.compatible	= "arm,gic-v3-its",	},
 92	{},
 93};
 94
 95static int __init its_pmsi_init_one(struct fwnode_handle *fwnode,
 96				const char *name)
 97{
 98	struct irq_domain *parent;
 99
100	parent = irq_find_matching_fwnode(fwnode, DOMAIN_BUS_NEXUS);
101	if (!parent || !msi_get_domain_info(parent)) {
102		pr_err("%s: unable to locate ITS domain\n", name);
103		return -ENXIO;
104	}
105
106	if (!platform_msi_create_irq_domain(fwnode, &its_pmsi_domain_info,
107					    parent)) {
108		pr_err("%s: unable to create platform domain\n", name);
109		return -ENXIO;
110	}
111
112	pr_info("Platform MSI: %s domain created\n", name);
113	return 0;
114}
115
116#ifdef CONFIG_ACPI
117static int __init
118its_pmsi_parse_madt(struct acpi_subtable_header *header,
119			const unsigned long end)
120{
121	struct acpi_madt_generic_translator *its_entry;
122	struct fwnode_handle *domain_handle;
123	const char *node_name;
124	int err = -ENXIO;
125
126	its_entry = (struct acpi_madt_generic_translator *)header;
127	node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
128			      (long)its_entry->base_address);
129	domain_handle = iort_find_domain_token(its_entry->translation_id);
130	if (!domain_handle) {
131		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
132		goto out;
133	}
134
135	err = its_pmsi_init_one(domain_handle, node_name);
136
137out:
138	kfree(node_name);
139	return err;
140}
141
142static void __init its_pmsi_acpi_init(void)
143{
144	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
145			      its_pmsi_parse_madt, 0);
146}
147#else
148static inline void its_pmsi_acpi_init(void) { }
149#endif
150
151static void __init its_pmsi_of_init(void)
152{
153	struct device_node *np;
154
155	for (np = of_find_matching_node(NULL, its_device_id); np;
156	     np = of_find_matching_node(np, its_device_id)) {
157		if (!of_device_is_available(np))
158			continue;
159		if (!of_property_read_bool(np, "msi-controller"))
160			continue;
161
162		its_pmsi_init_one(of_node_to_fwnode(np), np->full_name);
163	}
164}
165
166static int __init its_pmsi_init(void)
167{
168	its_pmsi_of_init();
169	its_pmsi_acpi_init();
170	return 0;
171}
172early_initcall(its_pmsi_init);