[Patch V1 3/6] genirq: Introduce msi_irq_domain_{alloc|free}_irqs()

[Jiang Liu]

Introduce msi_irq_domain_{alloc|free}_irqs() to alloc/free interrupts
from irqdomain for generic MSI interrupts.

Signed-off-by: Jiang Liu <jiang.liu at linux.intel.com>
---
 include/linux/msi.h |   35 ++++++++++++++++++++++++++++++
 kernel/irq/msi.c    |   59 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 714716a3ffdd..6b356a1410b2 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -3,6 +3,7 @@
 
 #include <linux/kobject.h>
 #include <linux/list.h>
+#include <asm/hw_irq.h>		/* for msi_alloc_info_t */
 
 struct msi_msg {
 	u32	address_lo;	/* low 32 bits of msi message address */
@@ -100,7 +101,26 @@ struct irq_chip;
 struct device_node;
 struct msi_domain_info;
 
+#ifndef NUM_MSI_ALLOC_SCRATCHPAD_REGS
+#define NUM_MSI_ALLOC_SCRATCHPAD_REGS	2
+#endif
+
+/*
+ * Default structure for MSI interrupt allocation.
+ * Arch may overwrite it by define msi_alloc_info_t.
+ */
+struct msi_alloc_info {
+	struct msi_desc *desc;
+	irq_hw_number_t hwirq;
+	long		scratchpad[NUM_MSI_ALLOC_SCRATCHPAD_REGS];
+};
+
+#ifndef msi_alloc_info_t
+typedef struct msi_alloc_info msi_alloc_info_t;
+#endif
+
 struct msi_domain_ops {
+	/* Callbacks for msi_create_irq_domain() */
 	void		(*calc_hwirq)(struct msi_domain_info *info, void *arg,
 				      struct msi_desc *desc);
 	irq_hw_number_t	(*get_hwirq)(struct msi_domain_info *info, void *arg);
@@ -111,6 +131,19 @@ struct msi_domain_ops {
 	void		(*msi_free)(struct irq_domain *domain,
 				    struct msi_domain_info *info,
 				    unsigned int virq);
+
+	/* Callbacks for msi_irq_domain_alloc_irqs() based on msi_descs */
+	int		(*msi_check)(struct irq_domain *domain,
+				     struct msi_domain_info *info,
+				     struct device *dev);
+	int		(*msi_prepare)(struct irq_domain *domain,
+				       struct device *dev,
+				       msi_alloc_info_t *arg);
+	void		(*msi_finish)(msi_alloc_info_t *arg, int retval);
+	void		(*set_desc)(msi_alloc_info_t *arg,
+				    struct msi_desc *desc);
+	int		(*handle_error)(struct irq_domain *domain,
+					struct msi_desc *desc, int error);
 };
 
 struct msi_domain_info {
@@ -125,6 +158,8 @@ int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
 struct irq_domain *msi_create_irq_domain(struct device_node *of_node,
 					 struct msi_domain_info *info,
 					 struct irq_domain *parent);
+int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev);
+void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);
 struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain);
 
 #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 94d6d87ee23e..0b6665de3a60 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -13,6 +13,9 @@
 #include <linux/irqdomain.h>
 #include <linux/msi.h>
 
+/* Temparory solution for building, will be removed later */
+#include <linux/pci.h>
+
 void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 {
 	*msg = entry->msg;
@@ -124,6 +127,62 @@ struct irq_domain *msi_create_irq_domain(struct device_node *of_node,
 	return domain;
 }
 
+int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev)
+{
+	int i, ret, virq = -1;
+	msi_alloc_info_t arg;
+	struct msi_desc *desc;
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+
+	ret = ops->msi_check(domain, info, dev);
+	if (ret == 0)
+		ret = ops->msi_prepare(domain, dev, &arg);
+	if (ret)
+		return ret;
+
+	for_each_msi_entry(desc, dev) {
+		ops->set_desc(&arg, desc);
+
+		virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
+					       dev_to_node(dev), &arg, false);
+		if (virq < 0) {
+			ret = -ENOSPC;
+			if (ops->handle_error)
+				ret = ops->handle_error(domain, desc, ret);
+			if (ops->msi_finish)
+				ops->msi_finish(&arg, ret);
+			return ret;
+		}
+
+		for (i = 0; i < desc->nvec_used; i++)
+			irq_set_msi_desc_off(virq, i, desc);
+	}
+
+	if (ops->msi_finish)
+		ops->msi_finish(&arg, 0);
+
+	for_each_msi_entry(desc, dev) {
+		if (desc->nvec_used == 1)
+			dev_dbg(dev, "irq %d for MSI\n", virq);
+		else
+			dev_dbg(dev, "irq [%d-%d] for MSI\n",
+				virq, virq + desc->nvec_used - 1);
+	}
+
+	return 0;
+}
+
+void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
+{
+	struct msi_desc *desc;
+
+	for_each_msi_entry(desc, dev) {
+		irq_domain_free_irqs(desc->irq, desc->nvec_used);
+		desc->irq = 0;
+	}
+}
+
 struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
 {
 	return (struct msi_domain_info *)domain->host_data;
-- 
1.7.10.4