[PATCH] gic: change access of gicc_ctrl register to read modify write.

From: Feng Kan
Date: Thu Feb 13 2014 - 20:53:32 EST


This change is made to preserve the GIC v2 releated bits in the
GIC_CPU_CTRL register (also known as the GICC_CTLR register in spec).
The original code only set the enable/disable group bit in this register.
This code will preserve all other bits configured by the bootload except
the enable/disable bit. The main reason for this change is to allow the
bypass bits specified in the v2 spec to remain untouched by the current
GIC code. In the X-Gene platform, the bypass functionality is not used
and bypass must be disabled at all time.

Signed-off-by: Vinayak Kale <vkale@xxxxxxx>
Acked-by: Anup Patel <apatel@xxxxxxx>
Signed-off-by: Feng Kan <fkan@xxxxxxx>
---
drivers/irqchip/irq-gic.c | 19 ++++++++++++++++---
1 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 341c601..4a52a97e2 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -418,6 +418,7 @@ static void gic_cpu_init(struct gic_chip_data *gic)
void __iomem *dist_base = gic_data_dist_base(gic);
void __iomem *base = gic_data_cpu_base(gic);
unsigned int cpu_mask, cpu = smp_processor_id();
+ unsigned int ctrl_mask;
int i;

/*
@@ -449,13 +450,21 @@ static void gic_cpu_init(struct gic_chip_data *gic)
writel_relaxed(0xa0a0a0a0, dist_base + GIC_DIST_PRI + i * 4 / 4);

writel_relaxed(0xf0, base + GIC_CPU_PRIMASK);
- writel_relaxed(1, base + GIC_CPU_CTRL);
+
+ ctrl_mask = readl(base + GIC_CPU_CTRL);
+ ctrl_mask |= 0x1;
+ writel_relaxed(ctrl_mask, base + GIC_CPU_CTRL);
}

void gic_cpu_if_down(void)
{
+ unsigned int ctrl_mask;
+
void __iomem *cpu_base = gic_data_cpu_base(&gic_data[0]);
- writel_relaxed(0, cpu_base + GIC_CPU_CTRL);
+
+ ctrl_mask = readl(base + GIC_CPU_CTRL);
+ ctrl_mask &= 0xfffffffe;
+ writel_relaxed(ctrl_mask, cpu_base + GIC_CPU_CTRL);
}

#ifdef CONFIG_CPU_PM
@@ -566,6 +575,7 @@ static void gic_cpu_restore(unsigned int gic_nr)
{
int i;
u32 *ptr;
+ unsigned int ctrl_mask;
void __iomem *dist_base;
void __iomem *cpu_base;

@@ -590,7 +600,10 @@ static void gic_cpu_restore(unsigned int gic_nr)
writel_relaxed(0xa0a0a0a0, dist_base + GIC_DIST_PRI + i * 4);

writel_relaxed(0xf0, cpu_base + GIC_CPU_PRIMASK);
- writel_relaxed(1, cpu_base + GIC_CPU_CTRL);
+
+ ctrl_mask = readl(base + GIC_CPU_CTRL);
+ ctrl_mask |= 0x1;
+ writel_relaxed(ctrl_mask, cpu_base + GIC_CPU_CTRL);
}

static int gic_notifier(struct notifier_block *self, unsigned long cmd, void *v)
--
1.7.6.1

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