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 | |
14 | static void its_mask_msi_irq(struct irq_data *d) |
15 | { |
16 | pci_msi_mask_irq(data: d); |
17 | irq_chip_mask_parent(data: d); |
18 | } |
19 | |
20 | static void its_unmask_msi_irq(struct irq_data *d) |
21 | { |
22 | pci_msi_unmask_irq(data: d); |
23 | irq_chip_unmask_parent(data: d); |
24 | } |
25 | |
26 | static 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 | |
33 | static 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 | |
44 | static 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 | |
53 | static 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: 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, fn: its_get_pci_alias, data: &alias_dev); |
73 | if (alias_dev != pdev) { |
74 | if (alias_dev->subordinate) |
75 | pci_walk_bus(top: alias_dev->subordinate, |
76 | cb: its_pci_msi_vec_count, userdata: &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 | |
97 | static struct msi_domain_ops its_pci_msi_ops = { |
98 | .msi_prepare = its_pci_msi_prepare, |
99 | }; |
100 | |
101 | static 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 | |
108 | static struct of_device_id its_device_id[] = { |
109 | { .compatible = "arm,gic-v3-its" , }, |
110 | {}, |
111 | }; |
112 | |
113 | static 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(fwnode: handle, bus_token: DOMAIN_BUS_NEXUS); |
119 | if (!parent || !msi_get_domain_info(domain: parent)) { |
120 | pr_err("%s: Unable to locate ITS domain\n" , name); |
121 | return -ENXIO; |
122 | } |
123 | |
124 | if (!pci_msi_create_irq_domain(fwnode: handle, info: &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 | |
133 | static int __init its_pci_of_msi_init(void) |
134 | { |
135 | struct device_node *np; |
136 | |
137 | for (np = of_find_matching_node(NULL, matches: its_device_id); np; |
138 | np = of_find_matching_node(from: np, matches: its_device_id)) { |
139 | if (!of_device_is_available(device: np)) |
140 | continue; |
141 | if (!of_property_read_bool(np, propname: "msi-controller" )) |
142 | continue; |
143 | |
144 | if (its_pci_msi_init_one(handle: of_node_to_fwnode(node: np), name: 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 | |
155 | static int __init |
156 | its_pci_msi_parse_madt(union acpi_subtable_headers *, |
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, fmt: "ITS@0x%lx" , |
166 | (long)its_entry->base_address); |
167 | dom_handle = iort_find_domain_token(trans_id: 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(handle: dom_handle, name: node_name); |
174 | if (!err) |
175 | pr_info("PCI/MSI: %s domain created\n" , node_name); |
176 | |
177 | out: |
178 | kfree(objp: node_name); |
179 | return err; |
180 | } |
181 | |
182 | static int __init its_pci_acpi_msi_init(void) |
183 | { |
184 | acpi_table_parse_madt(id: ACPI_MADT_TYPE_GENERIC_TRANSLATOR, |
185 | handler: its_pci_msi_parse_madt, max_entries: 0); |
186 | return 0; |
187 | } |
188 | #else |
189 | static int __init its_pci_acpi_msi_init(void) |
190 | { |
191 | return 0; |
192 | } |
193 | #endif |
194 | |
195 | static 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 | } |
202 | early_initcall(its_pci_msi_init); |
203 | |