1// SPDX-License-Identifier: GPL-2.0-only
  2// Copyright (C) 2022 Linutronix GmbH
  3// Copyright (C) 2022 Intel
  4
  5#include <linux/export.h>
  6
  7#include "irq-msi-lib.h"
  8
  9/**
 10 * msi_lib_init_dev_msi_info - Domain info setup for MSI domains
 11 * @dev:		The device for which the domain is created for
 12 * @domain:		The domain providing this callback
 13 * @real_parent:	The real parent domain of the domain to be initialized
 14 *			which might be a domain built on top of @domain or
 15 *			@domain itself
 16 * @info:		The domain info for the domain to be initialize
 17 *
 18 * This function is to be used for all types of MSI domains above the root
 19 * parent domain and any intermediates. The topmost parent domain specific
 20 * functionality is determined via @real_parent.
 21 *
 22 * All intermediate domains between the root and the device domain must
 23 * have either msi_parent_ops.init_dev_msi_info = msi_parent_init_dev_msi_info
 24 * or invoke it down the line.
 25 */
 26bool msi_lib_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
 27			       struct irq_domain *real_parent,
 28			       struct msi_domain_info *info)
 29{
 30	const struct msi_parent_ops *pops = real_parent->msi_parent_ops;
 31	u32 required_flags;
 32
 33	/* Parent ops available? */
 34	if (WARN_ON_ONCE(!pops))
 35		return false;
 36
 37	/*
 38	 * MSI parent domain specific settings. For now there is only the
 39	 * root parent domain, e.g. NEXUS, acting as a MSI parent, but it is
 40	 * possible to stack MSI parents. See x86 vector -> irq remapping
 41	 */
 42	if (domain->bus_token == pops->bus_select_token) {
 43		if (WARN_ON_ONCE(domain != real_parent))
 44			return false;
 45	} else {
 46		WARN_ON_ONCE(1);
 47		return false;
 48	}
 49
 50	required_flags = pops->required_flags;
 51
 52	/* Is the target domain bus token supported? */
 53	switch(info->bus_token) {
 54	case DOMAIN_BUS_PCI_DEVICE_MSI:
 55	case DOMAIN_BUS_PCI_DEVICE_MSIX:
 56		if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_PCI_MSI)))
 57			return false;
 58
 59		break;
 60	case DOMAIN_BUS_DEVICE_MSI:
 61		/*
 62		 * Per device MSI should never have any MSI feature bits
 63		 * set. It's sole purpose is to create a dumb interrupt
 64		 * chip which has a device specific irq_write_msi_msg()
 65		 * callback.
 66		 */
 67		if (WARN_ON_ONCE(info->flags))
 68			return false;
 69
 70		/* Core managed MSI descriptors */
 71		info->flags = MSI_FLAG_ALLOC_SIMPLE_MSI_DESCS | MSI_FLAG_FREE_MSI_DESCS;
 72		fallthrough;
 73	case DOMAIN_BUS_WIRED_TO_MSI:
 74		/* Remove PCI specific flags */
 75		required_flags &= ~MSI_FLAG_PCI_MSI_MASK_PARENT;
 76		break;
 77	default:
 78		/*
 79		 * This should never be reached. See
 80		 * msi_lib_irq_domain_select()
 81		 */
 82		WARN_ON_ONCE(1);
 83		return false;
 84	}
 85
 86	/*
 87	 * Mask out the domain specific MSI feature flags which are not
 88	 * supported by the real parent.
 89	 */
 90	info->flags			&= pops->supported_flags;
 91	/* Enforce the required flags */
 92	info->flags			|= required_flags;
 93
 94	/* Chip updates for all child bus types */
 95	if (!info->chip->irq_eoi)
 96		info->chip->irq_eoi	= irq_chip_eoi_parent;
 97	if (!info->chip->irq_ack)
 98		info->chip->irq_ack	= irq_chip_ack_parent;
 99
100	/*
101	 * The device MSI domain can never have a set affinity callback. It
102	 * always has to rely on the parent domain to handle affinity
103	 * settings. The device MSI domain just has to write the resulting
104	 * MSI message into the hardware which is the whole purpose of the
105	 * device MSI domain aside of mask/unmask which is provided e.g. by
106	 * PCI/MSI device domains.
107	 */
108	info->chip->irq_set_affinity	= msi_domain_set_affinity;
109	return true;
110}
111EXPORT_SYMBOL_GPL(msi_lib_init_dev_msi_info);
112
113/**
114 * msi_lib_irq_domain_select - Shared select function for NEXUS domains
115 * @d:		Pointer to the irq domain on which select is invoked
116 * @fwspec:	Firmware spec describing what is searched
117 * @bus_token:	The bus token for which a matching irq domain is looked up
118 *
119 * Returns:	%0 if @d is not what is being looked for
120 *
121 *		%1 if @d is either the domain which is directly searched for or
122 *		   if @d is providing the parent MSI domain for the functionality
123 *			 requested with @bus_token.
124 */
125int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,
126			      enum irq_domain_bus_token bus_token)
127{
128	const struct msi_parent_ops *ops = d->msi_parent_ops;
129	u32 busmask = BIT(bus_token);
130
131	if (!ops)
132		return 0;
133
134	if (fwspec->fwnode != d->fwnode || fwspec->param_count != 0)
135		return 0;
136
137	/* Handle pure domain searches */
138	if (bus_token == ops->bus_select_token)
139		return 1;
140
141	return !!(ops->bus_select_mask & busmask);
142}
143EXPORT_SYMBOL_GPL(msi_lib_irq_domain_select);