genirq: Add generic msi irq domain support

Implement the basic functions for MSI interrupt support with
hierarchical interrupt domains.

[ tglx: Extracted and combined from several patches ]

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Yingjoe Chen <yingjoe.chen@mediatek.com>
Cc: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 152 insertions, 0 deletions

diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 4f2eb2b1f23b..9a76e3beda54 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -60,6 +60,16 @@ config IRQ_DOMAIN_HIERARCHY
         bool
         select IRQ_DOMAIN
 
+# Generic MSI interrupt support
+config GENERIC_MSI_IRQ
+        bool
+
+# Generic MSI hierarchical interrupt domain support
+config GENERIC_MSI_IRQ_DOMAIN
+        bool
+        select IRQ_DOMAIN_HIERARCHY
+        select GENERIC_MSI_IRQ
+
 config HANDLE_DOMAIN_IRQ
         bool
 
diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index fff17381f0af..d12123526e2b 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_IRQ_DOMAIN) += irqdomain.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
 obj-$(CONFIG_PM_SLEEP) += pm.o
+obj-$(CONFIG_GENERIC_MSI_IRQ) += msi.o
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
new file mode 100644
index 000000000000..5e0cef4741d9
--- /dev/null
+++ b/kernel/irq/msi.c
@@ -0,0 +1,141 @@
+/*
+ * linux/kernel/irq/msi.c
+ *
+ * Copyright (C) 2014 Intel Corp.
+ * Author: Jiang Liu <jiang.liu@linux.intel.com>
+ *
+ * This file is licensed under GPLv2.
+ *
+ * This file contains common code to support Message Signalled Interrupt for
+ * PCI compatible and non PCI compatible devices.
+ */
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/msi.h>
+
+#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
+/**
+ * msi_domain_set_affinity - Generic affinity setter function for MSI domains
+ * @irq_data:   The irq data associated to the interrupt
+ * @mask:       The affinity mask to set
+ * @force:      Flag to enforce setting (disable online checks)
+ *
+ * Intended to be used by MSI interrupt controllers which are
+ * implemented with hierarchical domains.
+ */
+int msi_domain_set_affinity(struct irq_data *irq_data,
+                            const struct cpumask *mask, bool force)
+{
+        struct irq_data *parent = irq_data->parent_data;
+        struct msi_msg msg;
+        int ret;
+
+        ret = parent->chip->irq_set_affinity(parent, mask, force);
+        if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
+                BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
+                irq_chip_write_msi_msg(irq_data, &msg);
+        }
+
+        return ret;
+}
+
+static void msi_domain_activate(struct irq_domain *domain,
+                                struct irq_data *irq_data)
+{
+        struct msi_msg msg;
+
+        BUG_ON(irq_chip_compose_msi_msg(irq_data, &msg));
+        irq_chip_write_msi_msg(irq_data, &msg);
+}
+
+static void msi_domain_deactivate(struct irq_domain *domain,
+                                  struct irq_data *irq_data)
+{
+        struct msi_msg msg;
+
+        memset(&msg, 0, sizeof(msg));
+        irq_chip_write_msi_msg(irq_data, &msg);
+}
+
+static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
+                            unsigned int nr_irqs, void *arg)
+{
+        struct msi_domain_info *info = domain->host_data;
+        struct msi_domain_ops *ops = info->ops;
+        irq_hw_number_t hwirq = ops->get_hwirq(info, arg);
+        int i, ret;
+
+        if (irq_find_mapping(domain, hwirq) > 0)
+                return -EEXIST;
+
+        ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
+        if (ret < 0)
+                return ret;
+
+        for (i = 0; i < nr_irqs; i++) {
+                ret = ops->msi_init(domain, info, virq + i, hwirq + i, arg);
+                if (ret < 0) {
+                        if (ops->msi_free) {
+                                for (i--; i > 0; i--)
+                                        ops->msi_free(domain, info, virq + i);
+                        }
+                        irq_domain_free_irqs_top(domain, virq, nr_irqs);
+                        return ret;
+                }
+        }
+
+        return 0;
+}
+
+static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
+                            unsigned int nr_irqs)
+{
+        struct msi_domain_info *info = domain->host_data;
+        int i;
+
+        if (info->ops->msi_free) {
+                for (i = 0; i < nr_irqs; i++)
+                        info->ops->msi_free(domain, info, virq + i);
+        }
+        irq_domain_free_irqs_top(domain, virq, nr_irqs);
+}
+
+static struct irq_domain_ops msi_domain_ops = {
+        .alloc          = msi_domain_alloc,
+        .free           = msi_domain_free,
+        .activate       = msi_domain_activate,
+        .deactivate     = msi_domain_deactivate,
+};
+
+/**
+ * msi_create_irq_domain - Create a MSI interrupt domain
+ * @of_node:    Optional device-tree node of the interrupt controller
+ * @info:       MSI domain info
+ * @parent:     Parent irq domain
+ */
+struct irq_domain *msi_create_irq_domain(struct device_node *of_node,
+                                         struct msi_domain_info *info,
+                                         struct irq_domain *parent)
+{
+        struct irq_domain *domain;
+
+        domain = irq_domain_add_tree(of_node, &msi_domain_ops, info);
+        if (domain)
+                domain->parent = parent;
+
+        return domain;
+}
+
+/**
+ * msi_get_domain_info - Get the MSI interrupt domain info for @domain
+ * @domain:     The interrupt domain to retrieve data from
+ *
+ * Returns the pointer to the msi_domain_info stored in
+ * @domain->host_data.
+ */
+struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
+{
+        return (struct msi_domain_info *)domain->host_data;
+}
+
+#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */