Commit 72e257c6 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

irqchip: Provide irq-msi-lib 



All irqdomains which provide MSI parent domain functionality for per device
MSI domains need to provide a select() callback for the irqdomain and a
function to initialize the child domain.

Most of these functions would just be copy&paste with minimal
modifications, so provide a library function which implements the required
functionality and is customizable via parent_domain::msi_parent_ops. The
check for the supported bus tokens in msi_lib_init_dev_msi_info() is
expanded step by step within the next patches.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAnna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: default avatarShivamurthy Shastri <shivamurthy.shastri@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240623142234.840975799@linutronix.de
parent 7d189c77

drivers/irqchip/Kconfig

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@@ -74,6 +74,9 @@ config ARM_VIC_NR 
	  The maximum number of VICs available in the system, for

	  power management.



config IRQ_MSI_LIB

	bool



config ARMADA_370_XP_IRQ

	bool

	select GENERIC_IRQ_CHIP

drivers/irqchip/Makefile

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@@ -29,6 +29,7 @@ obj-$(CONFIG_ARCH_SPEAR3XX) += spear-shirq.o 
obj-$(CONFIG_ARM_GIC)			+= irq-gic.o irq-gic-common.o

obj-$(CONFIG_ARM_GIC_PM)		+= irq-gic-pm.o

obj-$(CONFIG_ARCH_REALVIEW)		+= irq-gic-realview.o

obj-$(CONFIG_IRQ_MSI_LIB)		+= irq-msi-lib.o

obj-$(CONFIG_ARM_GIC_V2M)		+= irq-gic-v2m.o

obj-$(CONFIG_ARM_GIC_V3)		+= irq-gic-v3.o irq-gic-v3-mbi.o irq-gic-common.o

obj-$(CONFIG_ARM_GIC_V3_ITS)		+= irq-gic-v3-its.o irq-gic-v3-its-platform-msi.o irq-gic-v4.o

drivers/irqchip/irq-msi-lib.c

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// SPDX-License-Identifier: GPL-2.0-only

// Copyright (C) 2022 Linutronix GmbH

// Copyright (C) 2022 Intel



#include <linux/export.h>



#include "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;



	/* 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;

	}



	/* Is the target domain bus token supported? */

	switch(info->bus_token) {

	default:

		/*

		 * This should never be reached. See

		 * msi_lib_irq_domain_select()

		 */

		WARN_ON_ONCE(1);

		return false;

	}



	/*

	 * Mask out the domain specific MSI feature flags which are not

	 * supported by the real parent.

	 */

	info->flags			&= pops->supported_flags;

	/* Enforce the required flags */

	info->flags			|= pops->required_flags;



	/* Chip updates for all child bus types */

	if (!info->chip->irq_eoi)

		info->chip->irq_eoi	= irq_chip_eoi_parent;



	/*

	 * The device MSI domain can never have a set affinity callback. It

	 * always has to rely on the parent domain to handle affinity

	 * settings. The device MSI domain just has to write the resulting

	 * MSI message into the hardware which is the whole purpose of the

	 * device MSI domain aside of mask/unmask which is provided e.g. by

	 * PCI/MSI device domains.

	 */

	info->chip->irq_set_affinity	= msi_domain_set_affinity;

	return true;

}

EXPORT_SYMBOL_GPL(msi_lib_init_dev_msi_info);



/**

 * msi_lib_irq_domain_select - Shared select function for NEXUS domains

 * @d:		Pointer to the irq domain on which select is invoked

 * @fwspec:	Firmware spec describing what is searched

 * @bus_token:	The bus token for which a matching irq domain is looked up

 *

 * Returns:	%0 if @d is not what is being looked for

 *

 *		%1 if @d is either the domain which is directly searched for or

 *		   if @d is providing the parent MSI domain for the functionality

 *			 requested with @bus_token.

 */

int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,

			      enum irq_domain_bus_token bus_token)

{

	const struct msi_parent_ops *ops = d->msi_parent_ops;

	u32 busmask = BIT(bus_token);



	if (fwspec->fwnode != d->fwnode || fwspec->param_count != 0)

		return 0;



	/* Handle pure domain searches */

	if (bus_token == ops->bus_select_token)

		return 1;



	return ops && !!(ops->bus_select_mask & busmask);

}

EXPORT_SYMBOL_GPL(msi_lib_irq_domain_select);

drivers/irqchip/irq-msi-lib.h

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// SPDX-License-Identifier: GPL-2.0-only

// Copyright (C) 2022 Linutronix GmbH

// Copyright (C) 2022 Intel



#ifndef _DRIVERS_IRQCHIP_IRQ_MSI_LIB_H

#define _DRIVERS_IRQCHIP_IRQ_MSI_LIB_H



#include <linux/bits.h>

#include <linux/irqdomain.h>

#include <linux/msi.h>



int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,

			      enum irq_domain_bus_token bus_token);



bool msi_lib_init_dev_msi_info(struct device *dev, struct irq_domain *domain,

			       struct irq_domain *real_parent,

			       struct msi_domain_info *info);



#endif /* _DRIVERS_IRQCHIP_IRQ_MSI_LIB_H */