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Subject[PATCH 1/2] irqchip/gic-v2m: Add PCI Multi-MSI support
Date
We'd never implemented Multi-MSI support with GICv2m, because
it is weird and clunky, and you'd think people would rather use
MSI-X.

Turns out there is still plenty of devices out there that rely
on Multi-MSI. Oh well, let's teach that trick to the v2m widget,
it is not a big deal anyway.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
drivers/irqchip/irq-gic-v2m.c | 46 +++++++++++++++++++++----------------------
1 file changed, 22 insertions(+), 24 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
index 993a8426a453..1ff38aff9f29 100644
--- a/drivers/irqchip/irq-gic-v2m.c
+++ b/drivers/irqchip/irq-gic-v2m.c
@@ -94,7 +94,7 @@ static struct irq_chip gicv2m_msi_irq_chip = {

static struct msi_domain_info gicv2m_msi_domain_info = {
.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
- MSI_FLAG_PCI_MSIX),
+ MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
.chip = &gicv2m_msi_irq_chip,
};

@@ -155,18 +155,12 @@ static int gicv2m_irq_gic_domain_alloc(struct irq_domain *domain,
return 0;
}

-static void gicv2m_unalloc_msi(struct v2m_data *v2m, unsigned int hwirq)
+static void gicv2m_unalloc_msi(struct v2m_data *v2m, unsigned int hwirq,
+ int nr_irqs)
{
- int pos;
-
- pos = hwirq - v2m->spi_start;
- if (pos < 0 || pos >= v2m->nr_spis) {
- pr_err("Failed to teardown msi. Invalid hwirq %d\n", hwirq);
- return;
- }
-
spin_lock(&v2m_lock);
- __clear_bit(pos, v2m->bm);
+ bitmap_release_region(v2m->bm, hwirq - v2m->spi_start,
+ get_count_order(nr_irqs));
spin_unlock(&v2m_lock);
}

@@ -174,13 +168,13 @@ static int gicv2m_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
unsigned int nr_irqs, void *args)
{
struct v2m_data *v2m = NULL, *tmp;
- int hwirq, offset, err = 0;
+ int hwirq, offset, i, err = 0;

spin_lock(&v2m_lock);
list_for_each_entry(tmp, &v2m_nodes, entry) {
- offset = find_first_zero_bit(tmp->bm, tmp->nr_spis);
- if (offset < tmp->nr_spis) {
- __set_bit(offset, tmp->bm);
+ offset = bitmap_find_free_region(tmp->bm, tmp->nr_spis,
+ get_count_order(nr_irqs));
+ if (offset >= 0) {
v2m = tmp;
break;
}
@@ -192,16 +186,21 @@ static int gicv2m_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,

hwirq = v2m->spi_start + offset;

- err = gicv2m_irq_gic_domain_alloc(domain, virq, hwirq);
- if (err) {
- gicv2m_unalloc_msi(v2m, hwirq);
- return err;
- }
+ for (i = 0; i < nr_irqs; i++) {
+ err = gicv2m_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
+ if (err)
+ goto fail;

- irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
- &gicv2m_irq_chip, v2m);
+ irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+ &gicv2m_irq_chip, v2m);
+ }

return 0;
+
+fail:
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+ gicv2m_unalloc_msi(v2m, hwirq, get_count_order(nr_irqs));
+ return err;
}

static void gicv2m_irq_domain_free(struct irq_domain *domain,
@@ -210,8 +209,7 @@ static void gicv2m_irq_domain_free(struct irq_domain *domain,
struct irq_data *d = irq_domain_get_irq_data(domain, virq);
struct v2m_data *v2m = irq_data_get_irq_chip_data(d);

- BUG_ON(nr_irqs != 1);
- gicv2m_unalloc_msi(v2m, d->hwirq);
+ gicv2m_unalloc_msi(v2m, d->hwirq, nr_irqs);
irq_domain_free_irqs_parent(domain, virq, nr_irqs);
}

--
2.14.2
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