1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Freescale Management Complex (MC) bus driver MSI support
4  *
5  * Copyright (C) 2015-2016 Freescale Semiconductor, Inc.
6  * Author: German Rivera <German.Rivera@freescale.com>
7  *
8  */
9 
10 #include <linux/acpi.h>
11 #include <linux/acpi_iort.h>
12 #include <linux/irq.h>
13 #include <linux/msi.h>
14 #include <linux/of.h>
15 #include <linux/of_irq.h>
16 #include <linux/fsl/mc.h>
17 
18 static struct irq_chip its_msi_irq_chip = {
19 	.name = "ITS-fMSI",
20 	.irq_mask = irq_chip_mask_parent,
21 	.irq_unmask = irq_chip_unmask_parent,
22 	.irq_eoi = irq_chip_eoi_parent,
23 	.irq_set_affinity = msi_domain_set_affinity
24 };
25 
fsl_mc_msi_domain_get_msi_id(struct irq_domain * domain,struct fsl_mc_device * mc_dev)26 static u32 fsl_mc_msi_domain_get_msi_id(struct irq_domain *domain,
27 					struct fsl_mc_device *mc_dev)
28 {
29 	struct device_node *of_node;
30 	u32 out_id;
31 
32 	of_node = irq_domain_get_of_node(domain);
33 	out_id = of_node ? of_msi_map_id(&mc_dev->dev, of_node, mc_dev->icid) :
34 			iort_msi_map_id(&mc_dev->dev, mc_dev->icid);
35 
36 	return out_id;
37 }
38 
its_fsl_mc_msi_prepare(struct irq_domain * msi_domain,struct device * dev,int nvec,msi_alloc_info_t * info)39 static int its_fsl_mc_msi_prepare(struct irq_domain *msi_domain,
40 				  struct device *dev,
41 				  int nvec, msi_alloc_info_t *info)
42 {
43 	struct fsl_mc_device *mc_bus_dev;
44 	struct msi_domain_info *msi_info;
45 
46 	if (!dev_is_fsl_mc(dev))
47 		return -EINVAL;
48 
49 	mc_bus_dev = to_fsl_mc_device(dev);
50 	if (!(mc_bus_dev->flags & FSL_MC_IS_DPRC))
51 		return -EINVAL;
52 
53 	/*
54 	 * Set the device Id to be passed to the GIC-ITS:
55 	 *
56 	 * NOTE: This device id corresponds to the IOMMU stream ID
57 	 * associated with the DPRC object (ICID).
58 	 */
59 	info->scratchpad[0].ul = fsl_mc_msi_domain_get_msi_id(msi_domain,
60 							      mc_bus_dev);
61 	msi_info = msi_get_domain_info(msi_domain->parent);
62 
63 	/* Allocate at least 32 MSIs, and always as a power of 2 */
64 	nvec = max_t(int, 32, roundup_pow_of_two(nvec));
65 	return msi_info->ops->msi_prepare(msi_domain->parent, dev, nvec, info);
66 }
67 
68 static struct msi_domain_ops its_fsl_mc_msi_ops __ro_after_init = {
69 	.msi_prepare = its_fsl_mc_msi_prepare,
70 };
71 
72 static struct msi_domain_info its_fsl_mc_msi_domain_info = {
73 	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
74 	.ops	= &its_fsl_mc_msi_ops,
75 	.chip	= &its_msi_irq_chip,
76 };
77 
78 static const struct of_device_id its_device_id[] = {
79 	{	.compatible	= "arm,gic-v3-its",	},
80 	{},
81 };
82 
its_fsl_mc_msi_init_one(struct fwnode_handle * handle,const char * name)83 static void __init its_fsl_mc_msi_init_one(struct fwnode_handle *handle,
84 					  const char *name)
85 {
86 	struct irq_domain *parent;
87 	struct irq_domain *mc_msi_domain;
88 
89 	parent = irq_find_matching_fwnode(handle, DOMAIN_BUS_NEXUS);
90 	if (!parent || !msi_get_domain_info(parent)) {
91 		pr_err("%s: unable to locate ITS domain\n", name);
92 		return;
93 	}
94 
95 	mc_msi_domain = fsl_mc_msi_create_irq_domain(handle,
96 						&its_fsl_mc_msi_domain_info,
97 						parent);
98 	if (!mc_msi_domain) {
99 		pr_err("%s: unable to create fsl-mc domain\n", name);
100 		return;
101 	}
102 
103 	pr_info("fsl-mc MSI: %s domain created\n", name);
104 }
105 
106 #ifdef CONFIG_ACPI
107 static int __init
its_fsl_mc_msi_parse_madt(union acpi_subtable_headers * header,const unsigned long end)108 its_fsl_mc_msi_parse_madt(union acpi_subtable_headers *header,
109 			  const unsigned long end)
110 {
111 	struct acpi_madt_generic_translator *its_entry;
112 	struct fwnode_handle *dom_handle;
113 	const char *node_name;
114 	int err = 0;
115 
116 	its_entry = (struct acpi_madt_generic_translator *)header;
117 	node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
118 			      (long)its_entry->base_address);
119 
120 	dom_handle = iort_find_domain_token(its_entry->translation_id);
121 	if (!dom_handle) {
122 		pr_err("%s: Unable to locate ITS domain handle\n", node_name);
123 		err = -ENXIO;
124 		goto out;
125 	}
126 
127 	its_fsl_mc_msi_init_one(dom_handle, node_name);
128 
129 out:
130 	kfree(node_name);
131 	return err;
132 }
133 
134 
its_fsl_mc_acpi_msi_init(void)135 static void __init its_fsl_mc_acpi_msi_init(void)
136 {
137 	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
138 			      its_fsl_mc_msi_parse_madt, 0);
139 }
140 #else
its_fsl_mc_acpi_msi_init(void)141 static inline void its_fsl_mc_acpi_msi_init(void) { }
142 #endif
143 
its_fsl_mc_of_msi_init(void)144 static void __init its_fsl_mc_of_msi_init(void)
145 {
146 	struct device_node *np;
147 
148 	for (np = of_find_matching_node(NULL, its_device_id); np;
149 	     np = of_find_matching_node(np, its_device_id)) {
150 		if (!of_device_is_available(np))
151 			continue;
152 		if (!of_property_read_bool(np, "msi-controller"))
153 			continue;
154 
155 		its_fsl_mc_msi_init_one(of_node_to_fwnode(np),
156 					np->full_name);
157 	}
158 }
159 
its_fsl_mc_msi_init(void)160 static int __init its_fsl_mc_msi_init(void)
161 {
162 	its_fsl_mc_of_msi_init();
163 	its_fsl_mc_acpi_msi_init();
164 
165 	return 0;
166 }
167 
168 early_initcall(its_fsl_mc_msi_init);
169