drivers/irqchip/irq-msi-lib.c

Source file repositories/reference/linux-study-clean/drivers/irqchip/irq-msi-lib.c

File Facts

System
Linux kernel
Corpus path
drivers/irqchip/irq-msi-lib.c
Extension
.c
Size
5564 bytes
Lines
170
Domain
Driver Families
Bucket
drivers/irqchip
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2022 Linutronix GmbH
// Copyright (C) 2022 Intel

#include <linux/export.h>

#include <linux/irqchip/irq-msi-lib.h>

/**
 * msi_lib_init_dev_msi_info - Domain info setup for MSI domains
 * @dev:		The device for which the domain is created for
 * @domain:		The domain providing this callback
 * @real_parent:	The real parent domain of the domain to be initialized
 *			which might be a domain built on top of @domain or
 *			@domain itself
 * @info:		The domain info for the domain to be initialize
 *
 * This function is to be used for all types of MSI domains above the root
 * parent domain and any intermediates. The topmost parent domain specific
 * functionality is determined via @real_parent.
 *
 * All intermediate domains between the root and the device domain must
 * have either msi_parent_ops.init_dev_msi_info = msi_parent_init_dev_msi_info
 * or invoke it down the line.
 */
bool msi_lib_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
			       struct irq_domain *real_parent,
			       struct msi_domain_info *info)
{
	const struct msi_parent_ops *pops = real_parent->msi_parent_ops;
	struct irq_chip *chip = info->chip;
	u32 required_flags;

	/* Parent ops available? */
	if (WARN_ON_ONCE(!pops))
		return false;

	/*
	 * MSI parent domain specific settings. For now there is only the
	 * root parent domain, e.g. NEXUS, acting as a MSI parent, but it is
	 * possible to stack MSI parents. See x86 vector -> irq remapping
	 */
	if (domain->bus_token == pops->bus_select_token) {
		if (WARN_ON_ONCE(domain != real_parent))
			return false;
	} else {
		WARN_ON_ONCE(1);
		return false;
	}

	if (WARN_ON_ONCE(!chip->irq_write_msi_msg))
		return false;

	required_flags = pops->required_flags;

	/* Is the target domain bus token supported? */
	switch(info->bus_token) {
	case DOMAIN_BUS_PCI_DEVICE_MSI:
	case DOMAIN_BUS_PCI_DEVICE_MSIX:
		if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PCI_MSI)))
			return false;

		break;
	case DOMAIN_BUS_DEVICE_MSI:
		/*
		 * Per device MSI should never have any MSI feature bits
		 * set. It's sole purpose is to create a dumb interrupt
		 * chip which has a device specific irq_write_msi_msg()
		 * callback.
		 */
		if (WARN_ON_ONCE(info->flags))
			return false;

		/* Core managed MSI descriptors */
		info->flags = MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS | MSI_FLAG_FREE_MSI_DESCS;
		fallthrough;
	case DOMAIN_BUS_WIRED_TO_MSI:
		/* Remove PCI specific flags */
		required_flags &= ~MSI_FLAG_PCI_MSI_MASK_PARENT;
		break;
	default:
		/*
		 * This should never be reached. See
		 * msi_lib_irq_domain_select()
		 */
		WARN_ON_ONCE(1);
		return false;
	}

	/*

Annotation

Implementation Notes