irqchip/gic-v2m: Add PCI Multi-MSI support

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>

1 files 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);
 }