platform-msi.c

  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	msi_remove_device_irq_domain(dev, MSI_DEFAULT_DOMAIN);
 99}
100EXPORT_SYMBOL_GPL(platform_device_msi_free_irqs_all);