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
 23static void its_mask_msi_irq(struct irq_data *d)
 24{
 25	pci_msi_mask_irq(d);
 26	irq_chip_mask_parent(d);
 27}
 28
 29static void its_unmask_msi_irq(struct irq_data *d)
 30{
 31	pci_msi_unmask_irq(d);
 32	irq_chip_unmask_parent(d);
 33}
 34
 35static 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
 43struct its_pci_alias {
 44	struct pci_dev	*pdev;
 45	u32		count;
 46};
 47
 48static 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
 58static 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
 68static 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
 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(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}
139early_initcall(its_pci_msi_init);