linux-kernel - [PATCH RFC 3/9] irqchip: gic: Remove spin locks from eoi

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Date:	Mon, 21 Jul 2014 15:47:14 +0100
From:	Daniel Thompson <daniel.thompson@...aro.org>
To:	Russell King <linux@....linux.org.uk>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>
Cc:	Daniel Thompson <daniel.thompson@...aro.org>,
	Marex Vasut <marex@...x.de>, Harro Haan <hrhaan@...il.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	patches@...aro.org, linaro-kernel@...ts.linaro.org,
	John Stultz <john.stultz@...aro.org>,
	Peter De Schrijver <pdeschrijver@...dia.com>
Subject: [PATCH RFC 3/9] irqchip: gic: Remove spin locks from eoi_irq

This patch is motivated by the comment it removes from gic_init_fiq,
namely that the spin locks in eoi_irq preclude certain platforms from
supporting FIQ.

Currently there is only one upstream platform (tegra) that actually
hooks gic_arch_extn.irq_eoi and it does not require these spin locks.

Signed-off-by: Daniel Thompson <daniel.thompson@...aro.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Jason Cooper <jason@...edaemon.net>
Cc: Peter De Schrijver <pdeschrijver@...dia.com>
---
 drivers/irqchip/irq-gic.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index d3c7559..5c934a4 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -191,11 +191,8 @@ static void gic_unmask_irq(struct irq_data *d)
 
 static void gic_eoi_irq(struct irq_data *d)
 {
-	if (gic_arch_extn.irq_eoi) {
-		raw_spin_lock(&irq_controller_lock);
+	if (gic_arch_extn.irq_eoi)
 		gic_arch_extn.irq_eoi(d);
-		raw_spin_unlock(&irq_controller_lock);
-	}
 
 	writel_relaxed(gic_irq(d), gic_cpu_base(d) + GIC_CPU_EOI);
 }
@@ -437,13 +434,6 @@ static void __init gic_init_fiq(struct gic_chip_data *gic,
 	unsigned int i;
 
 	/*
-	 * FIQ can only be supported on platforms without an extended irq_eoi
-	 * method (otherwise we take a lock during eoi handling).
-	 */
-	if (gic_arch_extn.irq_eoi)
-		return;
-
-	/*
 	 * If grouping is not available (not implemented or prohibited by
 	 * security mode) these registers a read-as-zero/write-ignored.
 	 * However as a precaution we restore the reset default regardless of
-- 
1.9.3

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