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 */ 26 bool 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 } 111 EXPORT_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 */ 125 int 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 (fwspec->fwnode != d->fwnode || fwspec->param_count != 0) 132 return 0; 133 134 /* Handle pure domain searches */ 135 if (bus_token == ops->bus_select_token) 136 return 1; 137 138 return ops && !!(ops->bus_select_mask & busmask); 139 } 140 EXPORT_SYMBOL_GPL(msi_lib_irq_domain_select); 141