[patch V2 29/33] PCI/MSI: Provide pci_ims_alloc/free_irq()

Thomas Gleixner
2022-11-21T14:41:01Z

Single vector allocation which allocates the next free index in the IMS
space. The free function releases.

All allocated vectors are released also via pci_free_vectors() which is
also releasing MSI/MSI-X vectors.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/msi/api.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 3 +++
2 files changed, 53 insertions(+)

--- a/drivers/pci/msi/api.c
+++ b/drivers/pci/msi/api.c
@@ -361,6 +361,56 @@ const struct cpumask *pci_irq_get_affini
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 @cookie 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))
+ 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
*
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2491,6 +2491,9 @@ struct msi_domain_template;

bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
unsigned int hwsize, void *data);
+struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev, union msi_instance_cookie *icookie,
+ const struct irq_affinity_desc *affdesc);
+void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map);

#include <linux/dma-mapping.h>