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>

diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
index 993a842..1ff38af 100644 (file)
--- 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);
 }