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
 24static void its_mask_msi_irq(struct irq_data *d)
 25{
 26	pci_msi_mask_irq(d);
 27	irq_chip_mask_parent(d);
 28}
 29
 30static void its_unmask_msi_irq(struct irq_data *d)
 31{
 32	pci_msi_unmask_irq(d);
 33	irq_chip_unmask_parent(d);
 34}
 35
 36static 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
 44static 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
 55static 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
 64static 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
 93static struct msi_domain_ops its_pci_msi_ops = {
 94	.msi_prepare	= its_pci_msi_prepare,
 95};
 96
 97static 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
104static struct of_device_id its_device_id[] = {
105	{	.compatible	= "arm,gic-v3-its",	},
106	{},
107};
108
109static 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
129static 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
151static int __init
152its_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
173out:
174	kfree(node_name);
175	return err;
176}
177
178static 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
185static int __init its_pci_acpi_msi_init(void)
186{
187	return 0;
188}
189#endif
190
191static 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}
198early_initcall(its_pci_msi_init);