1 // SPDX-License-Identifier: GPL-2.0-only
2 // Copyright (C) 2022 Linutronix GmbH
3 // Copyright (C) 2022 Intel
4
5 #include <linux/export.h>
6
7 #include "irq-msi-lib.h"
8
9 /**
10 * msi_lib_init_dev_msi_info - Domain info setup for MSI domains
11 * @dev: The device for which the domain is created for
12 * @domain: The domain providing this callback
13 * @real_parent: The real parent domain of the domain to be initialized
14 * which might be a domain built on top of @domain or
15 * @domain itself
16 * @info: The domain info for the domain to be initialize
17 *
18 * This function is to be used for all types of MSI domains above the root
19 * parent domain and any intermediates. The topmost parent domain specific
20 * functionality is determined via @real_parent.
21 *
22 * All intermediate domains between the root and the device domain must
23 * have either msi_parent_ops.init_dev_msi_info = msi_parent_init_dev_msi_info
24 * or invoke it down the line.
25 */
msi_lib_init_dev_msi_info(struct device * dev,struct irq_domain * domain,struct irq_domain * real_parent,struct msi_domain_info * info)26 bool msi_lib_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
27 struct irq_domain *real_parent,
28 struct msi_domain_info *info)
29 {
30 const struct msi_parent_ops *pops = real_parent->msi_parent_ops;
31 u32 required_flags;
32
33 /* Parent ops available? */
34 if (WARN_ON_ONCE(!pops))
35 return false;
36
37 /*
38 * MSI parent domain specific settings. For now there is only the
39 * root parent domain, e.g. NEXUS, acting as a MSI parent, but it is
40 * possible to stack MSI parents. See x86 vector -> irq remapping
41 */
42 if (domain->bus_token == pops->bus_select_token) {
43 if (WARN_ON_ONCE(domain != real_parent))
44 return false;
45 } else {
46 WARN_ON_ONCE(1);
47 return false;
48 }
49
50 required_flags = pops->required_flags;
51
52 /* Is the target domain bus token supported? */
53 switch(info->bus_token) {
54 case DOMAIN_BUS_PCI_DEVICE_MSI:
55 case DOMAIN_BUS_PCI_DEVICE_MSIX:
56 if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PCI_MSI)))
57 return false;
58
59 break;
60 case DOMAIN_BUS_DEVICE_MSI:
61 /*
62 * Per device MSI should never have any MSI feature bits
63 * set. It's sole purpose is to create a dumb interrupt
64 * chip which has a device specific irq_write_msi_msg()
65 * callback.
66 */
67 if (WARN_ON_ONCE(info->flags))
68 return false;
69
70 /* Core managed MSI descriptors */
71 info->flags = MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS | MSI_FLAG_FREE_MSI_DESCS;
72 fallthrough;
73 case DOMAIN_BUS_WIRED_TO_MSI:
74 /* Remove PCI specific flags */
75 required_flags &= ~MSI_FLAG_PCI_MSI_MASK_PARENT;
76 break;
77 default:
78 /*
79 * This should never be reached. See
80 * msi_lib_irq_domain_select()
81 */
82 WARN_ON_ONCE(1);
83 return false;
84 }
85
86 /*
87 * Mask out the domain specific MSI feature flags which are not
88 * supported by the real parent.
89 */
90 info->flags &= pops->supported_flags;
91 /* Enforce the required flags */
92 info->flags |= required_flags;
93
94 /* Chip updates for all child bus types */
95 if (!info->chip->irq_eoi)
96 info->chip->irq_eoi = irq_chip_eoi_parent;
97 if (!info->chip->irq_ack)
98 info->chip->irq_ack = irq_chip_ack_parent;
99
100 /*
101 * The device MSI domain can never have a set affinity callback. It
102 * always has to rely on the parent domain to handle affinity
103 * settings. The device MSI domain just has to write the resulting
104 * MSI message into the hardware which is the whole purpose of the
105 * device MSI domain aside of mask/unmask which is provided e.g. by
106 * PCI/MSI device domains.
107 */
108 info->chip->irq_set_affinity = msi_domain_set_affinity;
109 return true;
110 }
111 EXPORT_SYMBOL_GPL(msi_lib_init_dev_msi_info);
112
113 /**
114 * msi_lib_irq_domain_select - Shared select function for NEXUS domains
115 * @d: Pointer to the irq domain on which select is invoked
116 * @fwspec: Firmware spec describing what is searched
117 * @bus_token: The bus token for which a matching irq domain is looked up
118 *
119 * Returns: %0 if @d is not what is being looked for
120 *
121 * %1 if @d is either the domain which is directly searched for or
122 * if @d is providing the parent MSI domain for the functionality
123 * requested with @bus_token.
124 */
msi_lib_irq_domain_select(struct irq_domain * d,struct irq_fwspec * fwspec,enum irq_domain_bus_token bus_token)125 int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,
126 enum irq_domain_bus_token bus_token)
127 {
128 const struct msi_parent_ops *ops = d->msi_parent_ops;
129 u32 busmask = BIT(bus_token);
130
131 if (!ops)
132 return 0;
133
134 if (fwspec->fwnode != d->fwnode || fwspec->param_count != 0)
135 return 0;
136
137 /* Handle pure domain searches */
138 if (bus_token == ops->bus_select_token)
139 return 1;
140
141 return !!(ops->bus_select_mask & busmask);
142 }
143 EXPORT_SYMBOL_GPL(msi_lib_irq_domain_select);
144