linux-kernel - [PATCH v3 28/59] irqchip/gic-v3-its: Allow doorbell interrupts to be injected/cleared

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Message-Id: <20170731172637.29355-29-marc.zyngier@arm.com>
Date:   Mon, 31 Jul 2017 18:26:06 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org
Cc:     Christoffer Dall <christoffer.dall@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Eric Auger <eric.auger@...hat.com>,
        Shanker Donthineni <shankerd@...eaurora.org>,
        Mark Rutland <mark.rutland@....com>,
        Shameerali Kolothum Thodi 
        <shameerali.kolothum.thodi@...wei.com>
Subject: [PATCH v3 28/59] irqchip/gic-v3-its: Allow doorbell interrupts to be injected/cleared

While the doorbell interrupts are usually driven by the HW itself,
having a way to trigger them independently has proved to be a
really useful debug feature. As it is actually very little code,
let's add it to the VPE irqchip operations.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 drivers/irqchip/irq-gic-v3-its.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 210840e0ec92..a177af0b1657 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2404,12 +2404,41 @@ static void its_vpe_unmask_irq(struct irq_data *d)
 	its_vpe_send_inv(d);
 }
 
+/* This is really a debug feature */
+static int its_vpe_set_irqchip_state(struct irq_data *d,
+				     enum irqchip_irq_state which,
+				     bool state)
+{
+	struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
+
+	if (which != IRQCHIP_STATE_PENDING)
+		return -EINVAL;
+
+	if (gic_rdists->has_direct_lpi) {
+		void __iomem *rdbase;
+
+		rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
+		if (state)
+			gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_SETLPIR);
+		else
+			gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_CLRLPIR);
+	} else {
+		if (state)
+			its_vpe_send_cmd(vpe, its_send_int);
+		else
+			its_vpe_send_cmd(vpe, its_send_clear);
+	}
+
+	return 0;
+}
+
 static struct irq_chip its_vpe_irq_chip = {
 	.name			= "GICv4-vpe",
 	.irq_mask		= its_vpe_mask_irq,
 	.irq_unmask		= its_vpe_unmask_irq,
 	.irq_eoi		= irq_chip_eoi_parent,
 	.irq_set_affinity	= its_vpe_set_affinity,
+	.irq_set_irqchip_state	= its_vpe_set_irqchip_state,
 	.irq_set_vcpu_affinity	= its_vpe_set_vcpu_affinity,
 };
 
-- 
2.11.0