[PATCH v2 1/7] mailbox: bcm-flexrm-mailbox: Set IRQ affinity hint for FlexRM ring IRQs

From: Anup Patel
Date: Fri Jul 21 2017 - 02:56:15 EST


This patch set IRQ affinity hint for FlexRM ring IRQ at time of
enabling ring (i.e. flexrm_startup()). The IRQ affinity hint will
allow FlexRM driver to distribute FlexRM ring IRQs across online
CPUs so that all FlexRM ring IRQs don't land in CPU0 by default.

Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxxxx>
Reviewed-by: Ray Jui <ray.jui@xxxxxxxxxxxx>
Reviewed-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
---
drivers/mailbox/bcm-flexrm-mailbox.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/drivers/mailbox/bcm-flexrm-mailbox.c b/drivers/mailbox/bcm-flexrm-mailbox.c
index da67882..e8c3666 100644
--- a/drivers/mailbox/bcm-flexrm-mailbox.c
+++ b/drivers/mailbox/bcm-flexrm-mailbox.c
@@ -260,6 +260,7 @@ struct flexrm_ring {
void __iomem *regs;
bool irq_requested;
unsigned int irq;
+ cpumask_t irq_aff_hint;
unsigned int msi_timer_val;
unsigned int msi_count_threshold;
struct ida requests_ida;
@@ -1217,6 +1218,18 @@ static int flexrm_startup(struct mbox_chan *chan)
}
ring->irq_requested = true;

+ /* Set IRQ affinity hint */
+ ring->irq_aff_hint = CPU_MASK_NONE;
+ val = ring->mbox->num_rings;
+ val = (num_online_cpus() < val) ? val / num_online_cpus() : 1;
+ cpumask_set_cpu((ring->num / val) % num_online_cpus(),
+ &ring->irq_aff_hint);
+ ret = irq_set_affinity_hint(ring->irq, &ring->irq_aff_hint);
+ if (ret) {
+ dev_err(ring->mbox->dev, "failed to set IRQ affinity hint\n");
+ goto fail_free_irq;
+ }
+
/* Disable/inactivate ring */
writel_relaxed(0x0, ring->regs + RING_CONTROL);

@@ -1261,6 +1274,9 @@ static int flexrm_startup(struct mbox_chan *chan)

return 0;

+fail_free_irq:
+ free_irq(ring->irq, ring);
+ ring->irq_requested = false;
fail_free_cmpl_memory:
dma_pool_free(ring->mbox->cmpl_pool,
ring->cmpl_base, ring->cmpl_dma_base);
@@ -1314,6 +1330,7 @@ static void flexrm_shutdown(struct mbox_chan *chan)

/* Release IRQ */
if (ring->irq_requested) {
+ irq_set_affinity_hint(ring->irq, NULL);
free_irq(ring->irq, ring);
ring->irq_requested = false;
}
--
2.7.4