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
 44struct its_pci_alias {
 45	struct pci_dev	*pdev;
 46	u32		count;
 47};
 48
 49static int its_pci_msi_vec_count(struct pci_dev *pdev)
 50{
 51	int msi, msix;
 52
 53	msi = max(pci_msi_vec_count(pdev), 0);
 54	msix = max(pci_msix_vec_count(pdev), 0);
 55
 56	return max(msi, msix);
 57}
 58
 59static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
 60{
 61	struct its_pci_alias *dev_alias = data;
 62
 63	if (pdev != dev_alias->pdev)
 64		dev_alias->count += its_pci_msi_vec_count(pdev);
 65
 66	return 0;
 67}
 68
 69static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
 70			       int nvec, msi_alloc_info_t *info)
 71{
 72	struct pci_dev *pdev;
 73	struct its_pci_alias dev_alias;
 74	struct msi_domain_info *msi_info;
 75
 76	if (!dev_is_pci(dev))
 77		return -EINVAL;
 78
 79	msi_info = msi_get_domain_info(domain->parent);
 80
 81	pdev = to_pci_dev(dev);
 82	dev_alias.pdev = pdev;
 83	dev_alias.count = nvec;
 84
 85	pci_for_each_dma_alias(pdev, its_get_pci_alias, &dev_alias);
 86
 87	/* ITS specific DeviceID, as the core ITS ignores dev. */
 88	info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
 89
 90	return msi_info->ops->msi_prepare(domain->parent,
 91					  dev, dev_alias.count, info);
 92}
 93
 94static struct msi_domain_ops its_pci_msi_ops = {
 95	.msi_prepare	= its_pci_msi_prepare,
 96};
 97
 98static struct msi_domain_info its_pci_msi_domain_info = {
 99	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
100		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
101	.ops	= &its_pci_msi_ops,
102	.chip	= &its_msi_irq_chip,
103};
104
105static struct of_device_id its_device_id[] = {
106	{	.compatible	= "arm,gic-v3-its",	},
107	{},
108};
109
110static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
111				       const char *name)
112{
113	struct irq_domain *parent;
114
115	parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
116	if (!parent || !msi_get_domain_info(parent)) {
117		pr_err("%s: Unable to locate ITS domain\n", name);
118		return -ENXIO;
119	}
120
121	if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
122				       parent)) {
123		pr_err("%s: Unable to create PCI domain\n", name);
124		return -ENOMEM;
125	}
126
127	return 0;
128}
129
130static int __init its_pci_of_msi_init(void)
131{
132	struct device_node *np;
133
134	for (np = of_find_matching_node(NULL, its_device_id); np;
135	     np = of_find_matching_node(np, its_device_id)) {
136		if (!of_property_read_bool(np, "msi-controller"))
137			continue;
138
139		if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
140			continue;
141
142		pr_info("PCI/MSI: %s domain created\n", np->full_name);
143	}
144
145	return 0;
146}
147
148#ifdef CONFIG_ACPI
149
150static int __init
151its_pci_msi_parse_madt(struct acpi_subtable_header *header,
152		       const unsigned long end)
153{
154	struct acpi_madt_generic_translator *its_entry;
155	struct fwnode_handle *dom_handle;
156	const char *node_name;
157	int err = -ENXIO;
158
159	its_entry = (struct acpi_madt_generic_translator *)header;
160	node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
161			      (long)its_entry->base_address);
162	dom_handle = iort_find_domain_token(its_entry->translation_id);
163	if (!dom_handle) {
164		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
165		goto out;
166	}
167
168	err = its_pci_msi_init_one(dom_handle, node_name);
169	if (!err)
170		pr_info("PCI/MSI: %s domain created\n", node_name);
171
172out:
173	kfree(node_name);
174	return err;
175}
176
177static int __init its_pci_acpi_msi_init(void)
178{
179	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
180			      its_pci_msi_parse_madt, 0);
181	return 0;
182}
183#else
184static int __init its_pci_acpi_msi_init(void)
185{
186	return 0;
187}
188#endif
189
190static int __init its_pci_msi_init(void)
191{
192	its_pci_of_msi_init();
193	its_pci_acpi_msi_init();
194
195	return 0;
196}
197early_initcall(its_pci_msi_init);