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/msi.h>
19 #include <linux/of.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_pci.h>
22 
23 static void its_mask_msi_irq(struct irq_data *d)
24 {
25 	pci_msi_mask_irq(d);
26 	irq_chip_mask_parent(d);
27 }
28 
29 static void its_unmask_msi_irq(struct irq_data *d)
30 {
31 	pci_msi_unmask_irq(d);
32 	irq_chip_unmask_parent(d);
33 }
34 
35 static struct irq_chip its_msi_irq_chip = {
36 	.name			= "ITS-MSI",
37 	.irq_unmask		= its_unmask_msi_irq,
38 	.irq_mask		= its_mask_msi_irq,
39 	.irq_eoi		= irq_chip_eoi_parent,
40 	.irq_write_msi_msg	= pci_msi_domain_write_msg,
41 };
42 
43 struct its_pci_alias {
44 	struct pci_dev	*pdev;
45 	u32		count;
46 };
47 
48 static int its_pci_msi_vec_count(struct pci_dev *pdev)
49 {
50 	int msi, msix;
51 
52 	msi = max(pci_msi_vec_count(pdev), 0);
53 	msix = max(pci_msix_vec_count(pdev), 0);
54 
55 	return max(msi, msix);
56 }
57 
58 static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
59 {
60 	struct its_pci_alias *dev_alias = data;
61 
62 	if (pdev != dev_alias->pdev)
63 		dev_alias->count += its_pci_msi_vec_count(pdev);
64 
65 	return 0;
66 }
67 
68 static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
69 			       int nvec, msi_alloc_info_t *info)
70 {
71 	struct pci_dev *pdev;
72 	struct its_pci_alias dev_alias;
73 	struct msi_domain_info *msi_info;
74 
75 	if (!dev_is_pci(dev))
76 		return -EINVAL;
77 
78 	msi_info = msi_get_domain_info(domain->parent);
79 
80 	pdev = to_pci_dev(dev);
81 	dev_alias.pdev = pdev;
82 	dev_alias.count = nvec;
83 
84 	pci_for_each_dma_alias(pdev, its_get_pci_alias, &dev_alias);
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, dev_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(void)
110 {
111 	struct device_node *np;
112 	struct irq_domain *parent;
113 
114 	for (np = of_find_matching_node(NULL, its_device_id); np;
115 	     np = of_find_matching_node(np, its_device_id)) {
116 		if (!of_property_read_bool(np, "msi-controller"))
117 			continue;
118 
119 		parent = irq_find_matching_host(np, DOMAIN_BUS_NEXUS);
120 		if (!parent || !msi_get_domain_info(parent)) {
121 			pr_err("%s: unable to locate ITS domain\n",
122 			       np->full_name);
123 			continue;
124 		}
125 
126 		if (!pci_msi_create_irq_domain(of_node_to_fwnode(np),
127 					       &its_pci_msi_domain_info,
128 					       parent)) {
129 			pr_err("%s: unable to create PCI domain\n",
130 			       np->full_name);
131 			continue;
132 		}
133 
134 		pr_info("PCI/MSI: %s domain created\n", np->full_name);
135 	}
136 
137 	return 0;
138 }
139 early_initcall(its_pci_msi_init);
140