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/msi.h>
20 #include <linux/of.h>
21 #include <linux/of_irq.h>
22 #include <linux/of_pci.h>
23 
24 static void its_mask_msi_irq(struct irq_data *d)
25 {
26 	pci_msi_mask_irq(d);
27 	irq_chip_mask_parent(d);
28 }
29 
30 static void its_unmask_msi_irq(struct irq_data *d)
31 {
32 	pci_msi_unmask_irq(d);
33 	irq_chip_unmask_parent(d);
34 }
35 
36 static struct irq_chip its_msi_irq_chip = {
37 	.name			= "ITS-MSI",
38 	.irq_unmask		= its_unmask_msi_irq,
39 	.irq_mask		= its_mask_msi_irq,
40 	.irq_eoi		= irq_chip_eoi_parent,
41 	.irq_write_msi_msg	= pci_msi_domain_write_msg,
42 };
43 
44 static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data)
45 {
46 	int msi, msix, *count = data;
47 
48 	msi = max(pci_msi_vec_count(pdev), 0);
49 	msix = max(pci_msix_vec_count(pdev), 0);
50 	*count += max(msi, msix);
51 
52 	return 0;
53 }
54 
55 static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
56 {
57 	struct pci_dev **alias_dev = data;
58 
59 	*alias_dev = pdev;
60 
61 	return 0;
62 }
63 
64 static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
65 			       int nvec, msi_alloc_info_t *info)
66 {
67 	struct pci_dev *pdev, *alias_dev;
68 	struct msi_domain_info *msi_info;
69 	int alias_count = 0;
70 
71 	if (!dev_is_pci(dev))
72 		return -EINVAL;
73 
74 	msi_info = msi_get_domain_info(domain->parent);
75 
76 	pdev = to_pci_dev(dev);
77 	/*
78 	 * If pdev is downstream of any aliasing bridges, take an upper
79 	 * bound of how many other vectors could map to the same DevID.
80 	 */
81 	pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
82 	if (alias_dev != pdev && alias_dev->subordinate)
83 		pci_walk_bus(alias_dev->subordinate, its_pci_msi_vec_count,
84 			     &alias_count);
85 
86 	/* ITS specific DeviceID, as the core ITS ignores dev. */
87 	info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
88 
89 	return msi_info->ops->msi_prepare(domain->parent,
90 					  dev, max(nvec, alias_count), info);
91 }
92 
93 static struct msi_domain_ops its_pci_msi_ops = {
94 	.msi_prepare	= its_pci_msi_prepare,
95 };
96 
97 static struct msi_domain_info its_pci_msi_domain_info = {
98 	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
99 		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
100 	.ops	= &its_pci_msi_ops,
101 	.chip	= &its_msi_irq_chip,
102 };
103 
104 static struct of_device_id its_device_id[] = {
105 	{	.compatible	= "arm,gic-v3-its",	},
106 	{},
107 };
108 
109 static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
110 				       const char *name)
111 {
112 	struct irq_domain *parent;
113 
114 	parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
115 	if (!parent || !msi_get_domain_info(parent)) {
116 		pr_err("%s: Unable to locate ITS domain\n", name);
117 		return -ENXIO;
118 	}
119 
120 	if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
121 				       parent)) {
122 		pr_err("%s: Unable to create PCI domain\n", name);
123 		return -ENOMEM;
124 	}
125 
126 	return 0;
127 }
128 
129 static int __init its_pci_of_msi_init(void)
130 {
131 	struct device_node *np;
132 
133 	for (np = of_find_matching_node(NULL, its_device_id); np;
134 	     np = of_find_matching_node(np, its_device_id)) {
135 		if (!of_device_is_available(np))
136 			continue;
137 		if (!of_property_read_bool(np, "msi-controller"))
138 			continue;
139 
140 		if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
141 			continue;
142 
143 		pr_info("PCI/MSI: %pOF domain created\n", np);
144 	}
145 
146 	return 0;
147 }
148 
149 #ifdef CONFIG_ACPI
150 
151 static int __init
152 its_pci_msi_parse_madt(struct acpi_subtable_header *header,
153 		       const unsigned long end)
154 {
155 	struct acpi_madt_generic_translator *its_entry;
156 	struct fwnode_handle *dom_handle;
157 	const char *node_name;
158 	int err = -ENXIO;
159 
160 	its_entry = (struct acpi_madt_generic_translator *)header;
161 	node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
162 			      (long)its_entry->base_address);
163 	dom_handle = iort_find_domain_token(its_entry->translation_id);
164 	if (!dom_handle) {
165 		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
166 		goto out;
167 	}
168 
169 	err = its_pci_msi_init_one(dom_handle, node_name);
170 	if (!err)
171 		pr_info("PCI/MSI: %s domain created\n", node_name);
172 
173 out:
174 	kfree(node_name);
175 	return err;
176 }
177 
178 static int __init its_pci_acpi_msi_init(void)
179 {
180 	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
181 			      its_pci_msi_parse_madt, 0);
182 	return 0;
183 }
184 #else
185 static int __init its_pci_acpi_msi_init(void)
186 {
187 	return 0;
188 }
189 #endif
190 
191 static int __init its_pci_msi_init(void)
192 {
193 	its_pci_of_msi_init();
194 	its_pci_acpi_msi_init();
195 
196 	return 0;
197 }
198 early_initcall(its_pci_msi_init);
199