diff options
Diffstat (limited to 'drivers/pci/msi/api.c')
| -rw-r--r-- | drivers/pci/msi/api.c | 458 |
1 files changed, 458 insertions, 0 deletions
diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c new file mode 100644 index 000000000..be679aa5d --- /dev/null +++ b/drivers/pci/msi/api.c @@ -0,0 +1,458 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI MSI/MSI-X — Exported APIs for device drivers + * + * Copyright (C) 2003-2004 Intel + * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com) + * Copyright (C) 2016 Christoph Hellwig. + * Copyright (C) 2022 Linutronix GmbH + */ + +#include <linux/export.h> +#include <linux/irq.h> + +#include "msi.h" + +/** + * pci_enable_msi() - Enable MSI interrupt mode on device + * @dev: the PCI device to operate on + * + * Legacy device driver API to enable MSI interrupts mode on device and + * allocate a single interrupt vector. On success, the allocated vector + * Linux IRQ will be saved at @dev->irq. The driver must invoke + * pci_disable_msi() on cleanup. + * + * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API + * pair should, in general, be used instead. + * + * Return: 0 on success, errno otherwise + */ +int pci_enable_msi(struct pci_dev *dev) +{ + int rc = __pci_enable_msi_range(dev, 1, 1, NULL); + if (rc < 0) + return rc; + return 0; +} +EXPORT_SYMBOL(pci_enable_msi); + +/** + * pci_disable_msi() - Disable MSI interrupt mode on device + * @dev: the PCI device to operate on + * + * Legacy device driver API to disable MSI interrupt mode on device, + * free earlier allocated interrupt vectors, and restore INTx emulation. + * The PCI device Linux IRQ (@dev->irq) is restored to its default + * pin-assertion IRQ. This is the cleanup pair of pci_enable_msi(). + * + * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API + * pair should, in general, be used instead. + */ +void pci_disable_msi(struct pci_dev *dev) +{ + if (!pci_msi_enabled() || !dev || !dev->msi_enabled) + return; + + msi_lock_descs(&dev->dev); + pci_msi_shutdown(dev); + pci_free_msi_irqs(dev); + msi_unlock_descs(&dev->dev); +} +EXPORT_SYMBOL(pci_disable_msi); + +/** + * pci_msix_vec_count() - Get number of MSI-X interrupt vectors on device + * @dev: the PCI device to operate on + * + * Return: number of MSI-X interrupt vectors available on this device + * (i.e., the device's MSI-X capability structure "table size"), -EINVAL + * if the device is not MSI-X capable, other errnos otherwise. + */ +int pci_msix_vec_count(struct pci_dev *dev) +{ + u16 control; + + if (!dev->msix_cap) + return -EINVAL; + + pci_read_config_word(dev, dev->msix_cap + PCI_MSIX_FLAGS, &control); + return msix_table_size(control); +} +EXPORT_SYMBOL(pci_msix_vec_count); + +/** + * pci_enable_msix_range() - Enable MSI-X interrupt mode on device + * @dev: the PCI device to operate on + * @entries: input/output parameter, array of MSI-X configuration entries + * @minvec: minimum required number of MSI-X vectors + * @maxvec: maximum desired number of MSI-X vectors + * + * Legacy device driver API to enable MSI-X interrupt mode on device and + * configure its MSI-X capability structure as appropriate. The passed + * @entries array must have each of its members "entry" field set to a + * desired (valid) MSI-X vector number, where the range of valid MSI-X + * vector numbers can be queried through pci_msix_vec_count(). If + * successful, the driver must invoke pci_disable_msix() on cleanup. + * + * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API + * pair should, in general, be used instead. + * + * Return: number of MSI-X vectors allocated (which might be smaller + * than @maxvecs), where Linux IRQ numbers for such allocated vectors + * are saved back in the @entries array elements' "vector" field. Return + * -ENOSPC if less than @minvecs interrupt vectors are available. + * Return -EINVAL if one of the passed @entries members "entry" field + * was invalid or a duplicate, or if plain MSI interrupts mode was + * earlier enabled on device. Return other errnos otherwise. + */ +int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, + int minvec, int maxvec) +{ + return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL, 0); +} +EXPORT_SYMBOL(pci_enable_msix_range); + +/** + * pci_msix_can_alloc_dyn - Query whether dynamic allocation after enabling + * MSI-X is supported + * + * @dev: PCI device to operate on + * + * Return: True if supported, false otherwise + */ +bool pci_msix_can_alloc_dyn(struct pci_dev *dev) +{ + if (!dev->msix_cap) + return false; + + return pci_msi_domain_supports(dev, MSI_FLAG_PCI_MSIX_ALLOC_DYN, DENY_LEGACY); +} +EXPORT_SYMBOL_GPL(pci_msix_can_alloc_dyn); + +/** + * pci_msix_alloc_irq_at - Allocate an MSI-X interrupt after enabling MSI-X + * at a given MSI-X vector index or any free vector index + * + * @dev: PCI device to operate on + * @index: Index to allocate. If @index == MSI_ANY_INDEX this allocates + * the next free index in the MSI-X table + * @affdesc: Optional pointer to an affinity descriptor structure. NULL otherwise + * + * Return: A struct msi_map + * + * On success msi_map::index contains the allocated index (>= 0) and + * msi_map::virq contains the allocated Linux interrupt number (> 0). + * + * On fail msi_map::index contains the error code and msi_map::virq + * is set to 0. + */ +struct msi_map pci_msix_alloc_irq_at(struct pci_dev *dev, unsigned int index, + const struct irq_affinity_desc *affdesc) +{ + struct msi_map map = { .index = -ENOTSUPP }; + + if (!dev->msix_enabled) + return map; + + if (!pci_msix_can_alloc_dyn(dev)) + return map; + + return msi_domain_alloc_irq_at(&dev->dev, MSI_DEFAULT_DOMAIN, index, affdesc, NULL); +} +EXPORT_SYMBOL_GPL(pci_msix_alloc_irq_at); + +/** + * pci_msix_free_irq - Free an interrupt on a PCI/MSIX interrupt domain + * + * @dev: The PCI device to operate on + * @map: A struct msi_map describing the interrupt to free + * + * Undo an interrupt vector allocation. Does not disable MSI-X. + */ +void pci_msix_free_irq(struct pci_dev *dev, struct msi_map map) +{ + if (WARN_ON_ONCE(map.index < 0 || map.virq <= 0)) + return; + if (WARN_ON_ONCE(!pci_msix_can_alloc_dyn(dev))) + return; + msi_domain_free_irqs_range(&dev->dev, MSI_DEFAULT_DOMAIN, map.index, map.index); +} +EXPORT_SYMBOL_GPL(pci_msix_free_irq); + +/** + * pci_disable_msix() - Disable MSI-X interrupt mode on device + * @dev: the PCI device to operate on + * + * Legacy device driver API to disable MSI-X interrupt mode on device, + * free earlier-allocated interrupt vectors, and restore INTx. + * The PCI device Linux IRQ (@dev->irq) is restored to its default pin + * assertion IRQ. This is the cleanup pair of pci_enable_msix_range(). + * + * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API + * pair should, in general, be used instead. + */ +void pci_disable_msix(struct pci_dev *dev) +{ + if (!pci_msi_enabled() || !dev || !dev->msix_enabled) + return; + + msi_lock_descs(&dev->dev); + pci_msix_shutdown(dev); + pci_free_msi_irqs(dev); + msi_unlock_descs(&dev->dev); +} +EXPORT_SYMBOL(pci_disable_msix); + +/** + * pci_alloc_irq_vectors() - Allocate multiple device interrupt vectors + * @dev: the PCI device to operate on + * @min_vecs: minimum required number of vectors (must be >= 1) + * @max_vecs: maximum desired number of vectors + * @flags: One or more of: + * + * * %PCI_IRQ_MSIX Allow trying MSI-X vector allocations + * * %PCI_IRQ_MSI Allow trying MSI vector allocations + * + * * %PCI_IRQ_LEGACY Allow trying legacy INTx interrupts, if + * and only if @min_vecs == 1 + * + * * %PCI_IRQ_AFFINITY Auto-manage IRQs affinity by spreading + * the vectors around available CPUs + * + * Allocate up to @max_vecs interrupt vectors on device. MSI-X irq + * vector allocation has a higher precedence over plain MSI, which has a + * higher precedence over legacy INTx emulation. + * + * Upon a successful allocation, the caller should use pci_irq_vector() + * to get the Linux IRQ number to be passed to request_threaded_irq(). + * The driver must call pci_free_irq_vectors() on cleanup. + * + * Return: number of allocated vectors (which might be smaller than + * @max_vecs), -ENOSPC if less than @min_vecs interrupt vectors are + * available, other errnos otherwise. + */ +int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs, + unsigned int max_vecs, unsigned int flags) +{ + return pci_alloc_irq_vectors_affinity(dev, min_vecs, max_vecs, + flags, NULL); +} +EXPORT_SYMBOL(pci_alloc_irq_vectors); + +/** + * pci_alloc_irq_vectors_affinity() - Allocate multiple device interrupt + * vectors with affinity requirements + * @dev: the PCI device to operate on + * @min_vecs: minimum required number of vectors (must be >= 1) + * @max_vecs: maximum desired number of vectors + * @flags: allocation flags, as in pci_alloc_irq_vectors() + * @affd: affinity requirements (can be %NULL). + * + * Same as pci_alloc_irq_vectors(), but with the extra @affd parameter. + * Check that function docs, and &struct irq_affinity, for more details. + */ +int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs, + unsigned int max_vecs, unsigned int flags, + struct irq_affinity *affd) +{ + struct irq_affinity msi_default_affd = {0}; + int nvecs = -ENOSPC; + + if (flags & PCI_IRQ_AFFINITY) { + if (!affd) + affd = &msi_default_affd; + } else { + if (WARN_ON(affd)) + affd = NULL; + } + + if (flags & PCI_IRQ_MSIX) { + nvecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs, + affd, flags); + if (nvecs > 0) + return nvecs; + } + + if (flags & PCI_IRQ_MSI) { + nvecs = __pci_enable_msi_range(dev, min_vecs, max_vecs, affd); + if (nvecs > 0) + return nvecs; + } + + /* use legacy IRQ if allowed */ + if (flags & PCI_IRQ_LEGACY) { + if (min_vecs == 1 && dev->irq) { + /* + * Invoke the affinity spreading logic to ensure that + * the device driver can adjust queue configuration + * for the single interrupt case. + */ + if (affd) + irq_create_affinity_masks(1, affd); + pci_intx(dev, 1); + return 1; + } + } + + return nvecs; +} +EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity); + +/** + * pci_irq_vector() - Get Linux IRQ number of a device interrupt vector + * @dev: the PCI device to operate on + * @nr: device-relative interrupt vector index (0-based); has different + * meanings, depending on interrupt mode: + * + * * MSI-X the index in the MSI-X vector table + * * MSI the index of the enabled MSI vectors + * * INTx must be 0 + * + * Return: the Linux IRQ number, or -EINVAL if @nr is out of range + */ +int pci_irq_vector(struct pci_dev *dev, unsigned int nr) +{ + unsigned int irq; + + if (!dev->msi_enabled && !dev->msix_enabled) + return !nr ? dev->irq : -EINVAL; + + irq = msi_get_virq(&dev->dev, nr); + return irq ? irq : -EINVAL; +} +EXPORT_SYMBOL(pci_irq_vector); + +/** + * pci_irq_get_affinity() - Get a device interrupt vector affinity + * @dev: the PCI device to operate on + * @nr: device-relative interrupt vector index (0-based); has different + * meanings, depending on interrupt mode: + * + * * MSI-X the index in the MSI-X vector table + * * MSI the index of the enabled MSI vectors + * * INTx must be 0 + * + * Return: MSI/MSI-X vector affinity, NULL if @nr is out of range or if + * the MSI(-X) vector was allocated without explicit affinity + * requirements (e.g., by pci_enable_msi(), pci_enable_msix_range(), or + * pci_alloc_irq_vectors() without the %PCI_IRQ_AFFINITY flag). Return a + * generic set of CPU IDs representing all possible CPUs available + * during system boot if the device is in legacy INTx mode. + */ +const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr) +{ + int idx, irq = pci_irq_vector(dev, nr); + struct msi_desc *desc; + + if (WARN_ON_ONCE(irq <= 0)) + return NULL; + + desc = irq_get_msi_desc(irq); + /* Non-MSI does not have the information handy */ + if (!desc) + return cpu_possible_mask; + + /* MSI[X] interrupts can be allocated without affinity descriptor */ + if (!desc->affinity) + return NULL; + + /* + * MSI has a mask array in the descriptor. + * MSI-X has a single mask. + */ + idx = dev->msi_enabled ? nr : 0; + return &desc->affinity[idx].mask; +} +EXPORT_SYMBOL(pci_irq_get_affinity); + +/** + * pci_ims_alloc_irq - Allocate an interrupt on a PCI/IMS interrupt domain + * @dev: The PCI device to operate on + * @icookie: Pointer to an IMS implementation specific cookie for this + * IMS instance (PASID, queue ID, pointer...). + * The cookie content is copied into the MSI descriptor for the + * interrupt chip callbacks or domain specific setup functions. + * @affdesc: Optional pointer to an interrupt affinity descriptor + * + * There is no index for IMS allocations as IMS is an implementation + * specific storage and does not have any direct associations between + * index, which might be a pure software construct, and device + * functionality. This association is established by the driver either via + * the index - if there is a hardware table - or in case of purely software + * managed IMS implementation the association happens via the + * irq_write_msi_msg() callback of the implementation specific interrupt + * chip, which utilizes the provided @icookie to store the MSI message in + * the appropriate place. + * + * Return: A struct msi_map + * + * On success msi_map::index contains the allocated index (>= 0) and + * msi_map::virq the allocated Linux interrupt number (> 0). + * + * On fail msi_map::index contains the error code and msi_map::virq + * is set to 0. + */ +struct msi_map pci_ims_alloc_irq(struct pci_dev *dev, union msi_instance_cookie *icookie, + const struct irq_affinity_desc *affdesc) +{ + return msi_domain_alloc_irq_at(&dev->dev, MSI_SECONDARY_DOMAIN, MSI_ANY_INDEX, + affdesc, icookie); +} +EXPORT_SYMBOL_GPL(pci_ims_alloc_irq); + +/** + * pci_ims_free_irq - Allocate an interrupt on a PCI/IMS interrupt domain + * which was allocated via pci_ims_alloc_irq() + * @dev: The PCI device to operate on + * @map: A struct msi_map describing the interrupt to free as + * returned from pci_ims_alloc_irq() + */ +void pci_ims_free_irq(struct pci_dev *dev, struct msi_map map) +{ + if (WARN_ON_ONCE(map.index < 0 || map.virq <= 0)) + return; + msi_domain_free_irqs_range(&dev->dev, MSI_SECONDARY_DOMAIN, map.index, map.index); +} +EXPORT_SYMBOL_GPL(pci_ims_free_irq); + +/** + * pci_free_irq_vectors() - Free previously allocated IRQs for a device + * @dev: the PCI device to operate on + * + * Undo the interrupt vector allocations and possible device MSI/MSI-X + * enablement earlier done through pci_alloc_irq_vectors_affinity() or + * pci_alloc_irq_vectors(). + */ +void pci_free_irq_vectors(struct pci_dev *dev) +{ + pci_disable_msix(dev); + pci_disable_msi(dev); +} +EXPORT_SYMBOL(pci_free_irq_vectors); + +/** + * pci_restore_msi_state() - Restore cached MSI(-X) state on device + * @dev: the PCI device to operate on + * + * Write the Linux-cached MSI(-X) state back on device. This is + * typically useful upon system resume, or after an error-recovery PCI + * adapter reset. + */ +void pci_restore_msi_state(struct pci_dev *dev) +{ + __pci_restore_msi_state(dev); + __pci_restore_msix_state(dev); +} +EXPORT_SYMBOL_GPL(pci_restore_msi_state); + +/** + * pci_msi_enabled() - Are MSI(-X) interrupts enabled system-wide? + * + * Return: true if MSI has not been globally disabled through ACPI FADT, + * PCI bridge quirks, or the "pci=nomsi" kernel command-line option. + */ +int pci_msi_enabled(void) +{ + return pci_msi_enable; +} +EXPORT_SYMBOL(pci_msi_enabled); |