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SubjectRe: [PATCH 1/2] irqchip/gic-v2m: Add PCI Multi-MSI support
On Wed, Feb 07, 2018 at 02:32:54PM +0000, Marc Zyngier wrote:
> 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>

Looks good to me. Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>

Best regards,
Liviu

> ---
> 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
>

--
====================
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
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