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

[Thomas Gleixner <tglx@linutronix.de>]

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>
---
 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
+ * @cookie:	Pointer to an IMS implementation specific device cookie
+ *		(PASID, queue id, pointer...). The cookie content is stored
+ *		in the MSI descriptor for the interrupt chip callbacks or
+ *		domain specific setup functions
+ * @affdesc:	Optional pointer to an interrupt affinity descriptor
+ *
+ * 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.
+ *
+ * Note: 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.
+ */
+struct msi_map pci_ims_alloc_irq(struct pci_dev *dev, union msi_dev_cookie *cookie,
+				 const struct irq_affinity_desc *affdesc)
+{
+	return msi_domain_alloc_irq_at(&dev->dev, MSI_SECONDARY_DOMAIN, MSI_ANY_INDEX,
+				       affdesc, cookie);
+}
+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
@@ -2485,6 +2485,9 @@ 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_dev_cookie *cookie,
+				 const struct irq_affinity_desc *affdesc);
+void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map);
 
 #include <linux/dma-mapping.h>