diff options
Diffstat (limited to 'drivers/irqchip/irq-msi-lib.c')
-rw-r--r-- | drivers/irqchip/irq-msi-lib.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-msi-lib.c b/drivers/irqchip/irq-msi-lib.c new file mode 100644 index 000000000000..b5b90003311a --- /dev/null +++ b/drivers/irqchip/irq-msi-lib.c @@ -0,0 +1,140 @@ +// 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; + 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; + } + + 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; + } + + /* + * 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 |= required_flags; + + /* Chip updates for all child bus types */ + if (!info->chip->irq_eoi) + info->chip->irq_eoi = irq_chip_eoi_parent; + if (!info->chip->irq_ack) + info->chip->irq_ack = irq_chip_ack_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); |