1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * MSI framework for platform devices
 4 *
 5 * Copyright (C) 2015 ARM Limited, All Rights Reserved.
 6 * Author: Marc Zyngier <marc.zyngier@arm.com>
 7 * Copyright (C) 2022 Linutronix GmbH
 8 */
 9
10#include <linux/device.h>
11#include <linux/irqdomain.h>
12#include <linux/msi.h>
13
14/*
15 * This indirection can go when platform_device_msi_init_and_alloc_irqs()
16 * is switched to a proper irq_chip::irq_write_msi_msg() callback. Keep it
17 * simple for now.
18 */
19static void platform_msi_write_msi_msg(struct irq_data *d, struct msi_msg *msg)
20{
21	irq_write_msi_msg_t cb = d->chip_data;
22
23	cb(irq_data_get_msi_desc(d), msg);
24}
25
26static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
27{
28	arg->desc = desc;
29	arg->hwirq = desc->msi_index;
30}
31
32static const struct msi_domain_template platform_msi_template = {
33	.chip = {
34		.name			= "pMSI",
35		.irq_mask		= irq_chip_mask_parent,
36		.irq_unmask		= irq_chip_unmask_parent,
37		.irq_write_msi_msg	= platform_msi_write_msi_msg,
38		/* The rest is filled in by the platform MSI parent */
39	},
40
41	.ops = {
42		.set_desc		= platform_msi_set_desc,
43	},
44
45	.info = {
46		.bus_token		= DOMAIN_BUS_DEVICE_MSI,
47	},
48};
49
50/**
51 * platform_device_msi_init_and_alloc_irqs - Initialize platform device MSI
52 *					     and allocate interrupts for @dev
53 * @dev:		The device for which to allocate interrupts
54 * @nvec:		The number of interrupts to allocate
55 * @write_msi_msg:	Callback to write an interrupt message for @dev
56 *
57 * Returns:
58 * Zero for success, or an error code in case of failure
59 *
60 * This creates a MSI domain on @dev which has @dev->msi.domain as
61 * parent. The parent domain sets up the new domain. The domain has
62 * a fixed size of @nvec. The domain is managed by devres and will
63 * be removed when the device is removed.
64 *
65 * Note: For migration purposes this falls back to the original platform_msi code
66 *	 up to the point where all platforms have been converted to the MSI
67 *	 parent model.
68 */
69int platform_device_msi_init_and_alloc_irqs(struct device *dev, unsigned int nvec,
70					    irq_write_msi_msg_t write_msi_msg)
71{
72	struct irq_domain *domain = dev->msi.domain;
73
74	if (!domain || !write_msi_msg)
75		return -EINVAL;
76
77	/*
78	 * @write_msi_msg is stored in the resulting msi_domain_info::data.
79	 * The underlying domain creation mechanism will assign that
80	 * callback to the resulting irq chip.
81	 */
82	if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN,
83					  &platform_msi_template,
84					  nvec, NULL, write_msi_msg))
85		return -ENODEV;
86
87	return msi_domain_alloc_irqs_range(dev, MSI_DEFAULT_DOMAIN, 0, nvec - 1);
88}
89EXPORT_SYMBOL_GPL(platform_device_msi_init_and_alloc_irqs);
90
91/**
92 * platform_device_msi_free_irqs_all - Free all interrupts for @dev
93 * @dev:	The device for which to free interrupts
94 */
95void platform_device_msi_free_irqs_all(struct device *dev)
96{
97	msi_domain_free_irqs_all(dev, MSI_DEFAULT_DOMAIN);
98}
99EXPORT_SYMBOL_GPL(platform_device_msi_free_irqs_all);