1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2013-2015 ARM Limited, All Rights Reserved.
  4 * Author: Marc Zyngier <marc.zyngier@arm.com>
  5 */
  6
  7#include <linux/acpi_iort.h>
  8#include <linux/msi.h>
  9#include <linux/of.h>
 10#include <linux/of_irq.h>
 11#include <linux/of_pci.h>
 12
 13static void its_mask_msi_irq(struct irq_data *d)
 14{
 15	pci_msi_mask_irq(d);
 16	irq_chip_mask_parent(d);
 17}
 18
 19static void its_unmask_msi_irq(struct irq_data *d)
 20{
 21	pci_msi_unmask_irq(d);
 22	irq_chip_unmask_parent(d);
 23}
 24
 25static struct irq_chip its_msi_irq_chip = {
 26	.name			= "ITS-MSI",
 27	.irq_unmask		= its_unmask_msi_irq,
 28	.irq_mask		= its_mask_msi_irq,
 29	.irq_eoi		= irq_chip_eoi_parent,
 30	.irq_write_msi_msg	= pci_msi_domain_write_msg,
 31};
 32
 33static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data)
 34{
 35	int msi, msix, *count = data;
 36
 37	msi = max(pci_msi_vec_count(pdev), 0);
 38	msix = max(pci_msix_vec_count(pdev), 0);
 39	*count += max(msi, msix);
 40
 41	return 0;
 42}
 43
 44static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data)
 45{
 46	struct pci_dev **alias_dev = data;
 47
 48	*alias_dev = pdev;
 49
 50	return 0;
 51}
 52
 53static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev,
 54			       int nvec, msi_alloc_info_t *info)
 55{
 56	struct pci_dev *pdev, *alias_dev;
 57	struct msi_domain_info *msi_info;
 58	int alias_count = 0, minnvec = 1;
 59
 60	if (!dev_is_pci(dev))
 61		return -EINVAL;
 62
 63	msi_info = msi_get_domain_info(domain->parent);
 64
 65	pdev = to_pci_dev(dev);
 66	/*
 67	 * If pdev is downstream of any aliasing bridges, take an upper
 68	 * bound of how many other vectors could map to the same DevID.
 69	 */
 70	pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
 71	if (alias_dev != pdev && alias_dev->subordinate)
 72		pci_walk_bus(alias_dev->subordinate, its_pci_msi_vec_count,
 73			     &alias_count);
 74
 75	/* ITS specific DeviceID, as the core ITS ignores dev. */
 76	info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
 77
 78	/*
 79	 * Always allocate a power of 2, and special case device 0 for
 80	 * broken systems where the DevID is not wired (and all devices
 81	 * appear as DevID 0). For that reason, we generously allocate a
 82	 * minimum of 32 MSIs for DevID 0. If you want more because all
 83	 * your devices are aliasing to DevID 0, consider fixing your HW.
 84	 */
 85	nvec = max(nvec, alias_count);
 86	if (!info->scratchpad[0].ul)
 87		minnvec = 32;
 88	nvec = max_t(int, minnvec, roundup_pow_of_two(nvec));
 89	return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info);
 90}
 91
 92static struct msi_domain_ops its_pci_msi_ops = {
 93	.msi_prepare	= its_pci_msi_prepare,
 94};
 95
 96static struct msi_domain_info its_pci_msi_domain_info = {
 97	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
 98		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
 99	.ops	= &its_pci_msi_ops,
100	.chip	= &its_msi_irq_chip,
101};
102
103static struct of_device_id its_device_id[] = {
104	{	.compatible	= "arm,gic-v3-its",	},
105	{},
106};
107
108static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
109				       const char *name)
110{
111	struct irq_domain *parent;
112
113	parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
114	if (!parent || !msi_get_domain_info(parent)) {
115		pr_err("%s: Unable to locate ITS domain\n", name);
116		return -ENXIO;
117	}
118
119	if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
120				       parent)) {
121		pr_err("%s: Unable to create PCI domain\n", name);
122		return -ENOMEM;
123	}
124
125	return 0;
126}
127
128static int __init its_pci_of_msi_init(void)
129{
130	struct device_node *np;
131
132	for (np = of_find_matching_node(NULL, its_device_id); np;
133	     np = of_find_matching_node(np, its_device_id)) {
134		if (!of_device_is_available(np))
135			continue;
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: %pOF domain created\n", np);
143	}
144
145	return 0;
146}
147
148#ifdef CONFIG_ACPI
149
150static int __init
151its_pci_msi_parse_madt(union acpi_subtable_headers *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);