[kvm-unit-tests PATCH v3 1/3] arm: gic: Write one bit per time in gic_irq_set_clr_enable()

[Shaoqin Huang <shahuang@redhat.com>]

When use gic_irq_set_clr_enable() to disable an interrupt, it will
disable all interrupt since it first read from Interrupt Clear-Enable
Registers where '1' indicates that forwarding of the corresponding
interrupt is enabled and then write this value with a mask into
Interrupt Clear-Enable Registers where '1' indicates disable the
forwarding of the corresponding interrupt.

So directly write one bit per time to enable or disable interrupt.

Fixes: cb573c2 ("arm: gic: Introduce gic_irq_set_clr_enable() helper")
Signed-off-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
---
 lib/arm/gic.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/lib/arm/gic.c b/lib/arm/gic.c
index 1bfcfcf..89a15fe 100644
--- a/lib/arm/gic.c
+++ b/lib/arm/gic.c
@@ -176,7 +176,6 @@ void gic_ipi_send_mask(int irq, const cpumask_t *dest)
 void gic_irq_set_clr_enable(int irq, bool enable)
 {
 	u32 offset, split = 32, shift = (irq % 32);
-	u32 reg, mask = BIT(shift);
 	void *base;
 
 	assert(irq < 1020);
@@ -199,8 +198,7 @@ void gic_irq_set_clr_enable(int irq, bool enable)
 		assert(0);
 	}
 	base += offset + (irq / split) * 4;
-	reg = readl(base);
-	writel(reg | mask, base);
+	writel(BIT(shift), base);
 }
 
 enum gic_irq_state gic_irq_state(int irq)
-- 
2.39.1