[PATCH v9 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.au...@linaro.org>

---
v8 -> v9:
- use global_doorbell instead of percpu_doorbells

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 | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
index 28f047c..c77c41f 100644
--- a/drivers/irqchip/irq-gic-v2m.c
+++ b/drivers/irqchip/irq-gic-v2m.c
@@ -24,6 +24,7 @@
 #include <linux/of_pci.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/iommu.h>
 
 /*
 * MSI_TYPER:
@@ -64,6 +65,7 @@ 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 +107,14 @@ static void gicv2m_compose_msi_msg(struct irq_data *data, 
struct msi_msg *msg)
                msg->data -= v2m->spi_start;
 }
 
+static 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 +122,7 @@ 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,
@@ -311,6 +322,11 @@ static int __init gicv2m_init_one(struct fwnode_handle 
*fwnode,
 
        memcpy(&v2m->res, res, sizeof(struct resource));
 
+       v2m->doorbell_info.global_doorbell = v2m->res.start;
+       v2m->doorbell_info.doorbell_is_percpu = false;
+       v2m->doorbell_info.size = sizeof(u32);
+       v2m->doorbell_info.prot = IOMMU_WRITE | IOMMU_MMIO;
+
        v2m->base = ioremap(v2m->res.start, resource_size(&v2m->res));
        if (!v2m->base) {
                pr_err("Failed to map GICv2m resource\n");
-- 
1.9.1