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/pci.h>
  9#include <linux/msi.h>
 10#include <linux/of.h>
 11#include <linux/of_irq.h>
 12#include <linux/of_pci.h>
 13
 14static void its_mask_msi_irq(struct irq_data *d)
 15{
 16	pci_msi_mask_irq(d);
 17	irq_chip_mask_parent(d);
 18}
 19
 20static void its_unmask_msi_irq(struct irq_data *d)
 21{
 22	pci_msi_unmask_irq(d);
 23	irq_chip_unmask_parent(d);
 24}
 25
 26static struct irq_chip its_msi_irq_chip = {
 27	.name			= "ITS-MSI",
 28	.irq_unmask		= its_unmask_msi_irq,
 29	.irq_mask		= its_mask_msi_irq,
 30	.irq_eoi		= irq_chip_eoi_parent,
 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	 * Also tell the ITS that the signalling will come from a proxy
 70	 * device, and that special allocation rules apply.
 71	 */
 72	pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev);
 73	if (alias_dev != pdev) {
 74		if (alias_dev->subordinate)
 75			pci_walk_bus(alias_dev->subordinate,
 76				     its_pci_msi_vec_count, &alias_count);
 77		info->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE;
 78	}
 79
 80	/* ITS specific DeviceID, as the core ITS ignores dev. */
 81	info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain, pdev);
 82
 83	/*
 84	 * Always allocate a power of 2, and special case device 0 for
 85	 * broken systems where the DevID is not wired (and all devices
 86	 * appear as DevID 0). For that reason, we generously allocate a
 87	 * minimum of 32 MSIs for DevID 0. If you want more because all
 88	 * your devices are aliasing to DevID 0, consider fixing your HW.
 89	 */
 90	nvec = max(nvec, alias_count);
 91	if (!info->scratchpad[0].ul)
 92		minnvec = 32;
 93	nvec = max_t(int, minnvec, roundup_pow_of_two(nvec));
 94	return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info);
 95}
 96
 97static struct msi_domain_ops its_pci_msi_ops = {
 98	.msi_prepare	= its_pci_msi_prepare,
 99};
100
101static struct msi_domain_info its_pci_msi_domain_info = {
102	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
103		   MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
104	.ops	= &its_pci_msi_ops,
105	.chip	= &its_msi_irq_chip,
106};
107
108static struct of_device_id its_device_id[] = {
109	{	.compatible	= "arm,gic-v3-its",	},
110	{},
111};
112
113static int __init its_pci_msi_init_one(struct fwnode_handle *handle,
114				       const char *name)
115{
116	struct irq_domain *parent;
117
118	parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
119	if (!parent || !msi_get_domain_info(parent)) {
120		pr_err("%s: Unable to locate ITS domain\n", name);
121		return -ENXIO;
122	}
123
124	if (!pci_msi_create_irq_domain(handle, &its_pci_msi_domain_info,
125				       parent)) {
126		pr_err("%s: Unable to create PCI domain\n", name);
127		return -ENOMEM;
128	}
129
130	return 0;
131}
132
133static int __init its_pci_of_msi_init(void)
134{
135	struct device_node *np;
136
137	for (np = of_find_matching_node(NULL, its_device_id); np;
138	     np = of_find_matching_node(np, its_device_id)) {
139		if (!of_device_is_available(np))
140			continue;
141		if (!of_property_read_bool(np, "msi-controller"))
142			continue;
143
144		if (its_pci_msi_init_one(of_node_to_fwnode(np), np->full_name))
145			continue;
146
147		pr_info("PCI/MSI: %pOF domain created\n", np);
148	}
149
150	return 0;
151}
152
153#ifdef CONFIG_ACPI
154
155static int __init
156its_pci_msi_parse_madt(union acpi_subtable_headers *header,
157		       const unsigned long end)
158{
159	struct acpi_madt_generic_translator *its_entry;
160	struct fwnode_handle *dom_handle;
161	const char *node_name;
162	int err = -ENXIO;
163
164	its_entry = (struct acpi_madt_generic_translator *)header;
165	node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
166			      (long)its_entry->base_address);
167	dom_handle = iort_find_domain_token(its_entry->translation_id);
168	if (!dom_handle) {
169		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
170		goto out;
171	}
172
173	err = its_pci_msi_init_one(dom_handle, node_name);
174	if (!err)
175		pr_info("PCI/MSI: %s domain created\n", node_name);
176
177out:
178	kfree(node_name);
179	return err;
180}
181
182static int __init its_pci_acpi_msi_init(void)
183{
184	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
185			      its_pci_msi_parse_madt, 0);
186	return 0;
187}
188#else
189static int __init its_pci_acpi_msi_init(void)
190{
191	return 0;
192}
193#endif
194
195static int __init its_pci_msi_init(void)
196{
197	its_pci_of_msi_init();
198	its_pci_acpi_msi_init();
199
200	return 0;
201}
202early_initcall(its_pci_msi_init);