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/of_device.h>
11 #include <linux/of_address.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 
its_fsl_mc_msi_prepare(struct irq_domain * msi_domain,struct device * dev,int nvec,msi_alloc_info_t * info)26 static int its_fsl_mc_msi_prepare(struct irq_domain *msi_domain,
27 				  struct device *dev,
28 				  int nvec, msi_alloc_info_t *info)
29 {
30 	struct fsl_mc_device *mc_bus_dev;
31 	struct msi_domain_info *msi_info;
32 
33 	if (!dev_is_fsl_mc(dev))
34 		return -EINVAL;
35 
36 	mc_bus_dev = to_fsl_mc_device(dev);
37 	if (!(mc_bus_dev->flags & FSL_MC_IS_DPRC))
38 		return -EINVAL;
39 
40 	/*
41 	 * Set the device Id to be passed to the GIC-ITS:
42 	 *
43 	 * NOTE: This device id corresponds to the IOMMU stream ID
44 	 * associated with the DPRC object (ICID).
45 	 */
46 	info->scratchpad[0].ul = mc_bus_dev->icid;
47 	msi_info = msi_get_domain_info(msi_domain->parent);
48 
49 	/* Allocate at least 32 MSIs, and always as a power of 2 */
50 	nvec = max_t(int, 32, roundup_pow_of_two(nvec));
51 	return msi_info->ops->msi_prepare(msi_domain->parent, dev, nvec, info);
52 }
53 
54 static struct msi_domain_ops its_fsl_mc_msi_ops __ro_after_init = {
55 	.msi_prepare = its_fsl_mc_msi_prepare,
56 };
57 
58 static struct msi_domain_info its_fsl_mc_msi_domain_info = {
59 	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
60 	.ops	= &its_fsl_mc_msi_ops,
61 	.chip	= &its_msi_irq_chip,
62 };
63 
64 static const struct of_device_id its_device_id[] = {
65 	{	.compatible	= "arm,gic-v3-its",	},
66 	{},
67 };
68 
its_fsl_mc_msi_init(void)69 static int __init its_fsl_mc_msi_init(void)
70 {
71 	struct device_node *np;
72 	struct irq_domain *parent;
73 	struct irq_domain *mc_msi_domain;
74 
75 	for (np = of_find_matching_node(NULL, its_device_id); np;
76 	     np = of_find_matching_node(np, its_device_id)) {
77 		if (!of_device_is_available(np))
78 			continue;
79 		if (!of_property_read_bool(np, "msi-controller"))
80 			continue;
81 
82 		parent = irq_find_matching_host(np, DOMAIN_BUS_NEXUS);
83 		if (!parent || !msi_get_domain_info(parent)) {
84 			pr_err("%pOF: unable to locate ITS domain\n", np);
85 			continue;
86 		}
87 
88 		mc_msi_domain = fsl_mc_msi_create_irq_domain(
89 						 of_node_to_fwnode(np),
90 						 &its_fsl_mc_msi_domain_info,
91 						 parent);
92 		if (!mc_msi_domain) {
93 			pr_err("%pOF: unable to create fsl-mc domain\n", np);
94 			continue;
95 		}
96 
97 		pr_info("fsl-mc MSI: %pOF domain created\n", np);
98 	}
99 
100 	return 0;
101 }
102 
103 early_initcall(its_fsl_mc_msi_init);
104