[PATCH v8 6/8] irqchip/gicv2m: implement msi_doorbell_info callback

[Eric Auger]

This patch implements the msi_doorbell_info callback in the
gicv2m driver.

The driver now is able to return its doorbell characteristics
(base, size, prot). A single doorbell is exposed.

This will allow the msi layer to iommu_map this doorbell when
requested.

Signed-off-by: Eric Auger <eric.auger at linaro.org>

---

v7 -> v8:
- gicv2m_msi_doorbell_info does not return a pointer to const
- remove spurious !v2m check
- add IOMMU_MMIO flag

v7: creation
---
 drivers/irqchip/irq-gic-v2m.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
index 28f047c..a1ea40c 100644
--- a/drivers/irqchip/irq-gic-v2m.c
+++ b/drivers/irqchip/irq-gic-v2m.c
@@ -24,6 +24,8 @@
 #include <linux/of_pci.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/percpu.h>
+#include <linux/iommu.h>
 
 /*
 * MSI_TYPER:
@@ -64,6 +66,7 @@ struct v2m_data {
 	u32 nr_spis;		/* The number of SPIs for MSIs */
 	unsigned long *bm;	/* MSI vector bitmap */
 	u32 flags;		/* v2m flags for specific implementation */
+	struct irq_chip_msi_doorbell_info doorbell_info;
 };
 
 static void gicv2m_mask_msi_irq(struct irq_data *d)
@@ -105,6 +108,14 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 		msg->data -= v2m->spi_start;
 }
 
+static inline struct irq_chip_msi_doorbell_info *
+gicv2m_msi_doorbell_info(struct irq_data *data)
+{
+	struct v2m_data *v2m = irq_data_get_irq_chip_data(data);
+
+	return &v2m->doorbell_info;
+}
+
 static struct irq_chip gicv2m_irq_chip = {
 	.name			= "GICv2m",
 	.irq_mask		= irq_chip_mask_parent,
@@ -112,6 +123,7 @@ static struct irq_chip gicv2m_irq_chip = {
 	.irq_eoi		= irq_chip_eoi_parent,
 	.irq_set_affinity	= irq_chip_set_affinity_parent,
 	.irq_compose_msi_msg	= gicv2m_compose_msi_msg,
+	.msi_doorbell_info	= gicv2m_msi_doorbell_info,
 };
 
 static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
@@ -247,6 +259,7 @@ static void gicv2m_teardown(void)
 
 	list_for_each_entry_safe(v2m, tmp, &v2m_nodes, entry) {
 		list_del(&v2m->entry);
+		free_percpu(v2m->doorbell_info.percpu_doorbells);
 		kfree(v2m->bm);
 		iounmap(v2m->base);
 		of_node_put(to_of_node(v2m->fwnode));
@@ -299,6 +312,7 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
 {
 	int ret;
 	struct v2m_data *v2m;
+	phys_addr_t __percpu *doorbell;
 
 	v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
 	if (!v2m) {
@@ -311,11 +325,23 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
 
 	memcpy(&v2m->res, res, sizeof(struct resource));
 
+	v2m->doorbell_info.percpu_doorbells =
+		alloc_percpu(phys_addr_t);
+	if (WARN_ON(!v2m->doorbell_info.percpu_doorbells)) {
+		ret = -ENOMEM;
+		goto err_free_v2m;
+	}
+	doorbell = per_cpu_ptr(v2m->doorbell_info.percpu_doorbells, 0);
+	*doorbell = v2m->res.start;
+	v2m->doorbell_info.size = 4;
+	v2m->doorbell_info.prot = IOMMU_WRITE | IOMMU_MMIO;
+	v2m->doorbell_info.nb_doorbells = 1;
+
 	v2m->base = ioremap(v2m->res.start, resource_size(&v2m->res));
 	if (!v2m->base) {
 		pr_err("Failed to map GICv2m resource\n");
 		ret = -ENOMEM;
-		goto err_free_v2m;
+		goto err_free_v2m_doorbells;
 	}
 
 	if (spi_start && nr_spis) {
@@ -359,6 +385,8 @@ static int __init gicv2m_init_one(struct fwnode_handle *fwnode,
 
 err_iounmap:
 	iounmap(v2m->base);
+err_free_v2m_doorbells:
+	free_percpu(v2m->doorbell_info.percpu_doorbells);
 err_free_v2m:
 	kfree(v2m);
 	return ret;
-- 
1.9.1