[tip: irq/core] PCI/MSI: Provide pci_ims_alloc/free_irq()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     927889e50cc1f5364ae9ebc2065734dbdfa34362
Gitweb:        https://git.kernel.org/tip/927889e50cc1f5364ae9ebc2065734dbdfa34362
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Fri, 25 Nov 2022 00:26:31 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 05 Dec 2022 19:21:04 +01:00

PCI/MSI: Provide pci_ims_alloc/free_irq()

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@xxxxxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221124232326.961711347@xxxxxxxxxxxxx

---
 drivers/pci/msi/api.c | 50 ++++++++++++++++++++++++++++++++++++++++++-
 include/linux/pci.h   |  3 +++-
 2 files changed, 53 insertions(+)

diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
index c8816db..b8009aa 100644
--- a/drivers/pci/msi/api.c
+++ b/drivers/pci/msi/api.c
@@ -366,6 +366,56 @@ const struct cpumask *pci_irq_get_affinity(struct pci_dev *dev, int nr)
 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
  *
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1592b63..aa514b5 100644
--- 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>