linux-kernel - [patch V3 29/33] PCI/MSI: Provide pci_ims_alloc/free

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Date:   Fri, 25 Nov 2022 00:26:31 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Joerg Roedel <joro@...tes.org>,
        Will Deacon <will@...nel.org>, linux-pci@...r.kernel.org,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Marc Zyngier <maz@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jason Gunthorpe <jgg@...lanox.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Kevin Tian <kevin.tian@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Ashok Raj <ashok.raj@...el.com>, Jon Mason <jdmason@...zu.us>,
        Allen Hubbe <allenbh@...il.com>
Subject: [patch V3 29/33] 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@...utronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@...gle.com>
---
V3: s/cookie/icookie/ (Kevin)
---
 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 @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))
+		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>