linux-kernel - [PATCH 1/4] irqchip, gicv3-its: Read typer register outside the loop

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Message-Id: <1435673643-31676-2-git-send-email-rric@kernel.org>
Date:	Tue, 30 Jun 2015 16:14:00 +0200
From:	Robert Richter <rric@...nel.org>
To:	Marc Zygnier <marc.zyngier@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>
Cc:	Tirumalesh Chalamarla <tchalamarla@...ium.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Robert Richter <rrichter@...ium.com>
Subject: [PATCH 1/4] irqchip, gicv3-its: Read typer register outside the loop

From: Robert Richter <rrichter@...ium.com>

No need to read the typer register in the loop. Values do not change.

Signed-off-by: Robert Richter <rrichter@...ium.com>
---
 drivers/irqchip/irq-gic-v3-its.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 1b7e155869f6..c5ce21277920 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -803,6 +803,8 @@ static int its_alloc_tables(struct its_node *its)
 	int psz = SZ_64K;
 	u64 shr = GITS_BASER_InnerShareable;
 	u64 cache = GITS_BASER_WaWb;
+	u64 typer = readq_relaxed(its->base + GITS_TYPER);
+	u32 ids = GITS_TYPER_DEVBITS(typer);
 
 	for (i = 0; i < GITS_BASER_NR_REGS; i++) {
 		u64 val = readq_relaxed(its->base + GITS_BASER + i * 8);
@@ -825,9 +827,6 @@ static int its_alloc_tables(struct its_node *its)
 		 * For other tables, only allocate a single page.
 		 */
 		if (type == GITS_BASER_TYPE_DEVICE) {
-			u64 typer = readq_relaxed(its->base + GITS_TYPER);
-			u32 ids = GITS_TYPER_DEVBITS(typer);
-
 			/*
 			 * 'order' was initialized earlier to the default page
 			 * granule of the the ITS.  We can't have an allocation
-- 
2.1.1

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