linux-kernel - [PATCH V2 2/2] irqchip/gic: Ensure gic_cpu_if

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Date:	Fri, 31 Jul 2015 09:44:12 +0100
From:	Jon Hunter <jonathanh@...dia.com>
To:	Marc Zyngier <marc.zyngier@....com>,
	Russell King <linux@....linux.org.uk>,
	Nicolas Pitre <nicolas.pitre@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Jason Cooper <jason@...edaemon.net>
CC:	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	Jon Hunter <jonathanh@...dia.com>
Subject: [PATCH V2 2/2] irqchip/gic: Ensure gic_cpu_if_up/down() programs correct GIC instance

Commit 3228950621d9 ("irqchip: gic: Preserve gic V2 bypass bits in cpu
ctrl register") added a new function, gic_cpu_if_up(), to program the
GIC CPU_CTRL register. This function assumes that there is only one GIC
instance present and hence always uses the chip data for the primary GIC
controller. Although it is not common for there to be a secondary, some
devices do support a secondary. Therefore, fix this by passing
gic_cpu_if_up() a pointer to the appropriate chip data structure.

Similarly, the function gic_cpu_if_down() only assumes that there is a
single GIC instance present. Update this function so that an instance
number is passed for the appropriate GIC and return an error code on
failure. The vexpress TC2 (which has a single GIC) is currently the only
user of this function and so update it accordingly. Note that because the
TC2 only has a single GIC, the call to gic_cpu_if_down() should always
be successful.

Signed-off-by: Jon Hunter <jonathanh@...dia.com>
---
V2 changes:
- Rebased on v4.2-rc4
- Added test to ensure GIC instance is valid to gic_cpu_if_down() and
  updated gic_cpu_if_down() to return an error code on failure.

 arch/arm/mach-vexpress/tc2_pm.c |  2 +-
 drivers/irqchip/irq-gic.c       | 18 ++++++++++++------
 include/linux/irqchip/arm-gic.h |  2 +-
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
index b3328cd46c33..1aa4ccece69f 100644
--- a/arch/arm/mach-vexpress/tc2_pm.c
+++ b/arch/arm/mach-vexpress/tc2_pm.c
@@ -80,7 +80,7 @@ static void tc2_pm_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
 	 * to the CPU by disabling the GIC CPU IF to prevent wfi
 	 * from completing execution behind power controller back
 	 */
-	gic_cpu_if_down();
+	gic_cpu_if_down(0);
 }
 
 static void tc2_pm_cluster_powerdown_prepare(unsigned int cluster)
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index dc5090543eca..fdd1b0e6e5c3 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -355,9 +355,9 @@ static u8 gic_get_cpumask(struct gic_chip_data *gic)
 	return mask;
 }
 
-static void gic_cpu_if_up(void)
+static void gic_cpu_if_up(struct gic_chip_data *gic)
 {
-	void __iomem *cpu_base = gic_data_cpu_base(&gic_data[0]);
+	void __iomem *cpu_base = gic_data_cpu_base(gic);
 	u32 bypass = 0;
 
 	/*
@@ -425,17 +425,23 @@ static void gic_cpu_init(struct gic_chip_data *gic)
 	gic_cpu_config(dist_base, NULL);
 
 	writel_relaxed(GICC_INT_PRI_THRESHOLD, base + GIC_CPU_PRIMASK);
-	gic_cpu_if_up();
+	gic_cpu_if_up(gic);
 }
 
-void gic_cpu_if_down(void)
+int gic_cpu_if_down(unsigned int gic_nr)
 {
-	void __iomem *cpu_base = gic_data_cpu_base(&gic_data[0]);
+	void __iomem *cpu_base;
 	u32 val = 0;
 
+	if (gic_nr >= MAX_GIC_NR)
+		return -EINVAL;
+
+	cpu_base = gic_data_cpu_base(&gic_data[gic_nr]);
 	val = readl(cpu_base + GIC_CPU_CTRL);
 	val &= ~GICC_ENABLE;
 	writel_relaxed(val, cpu_base + GIC_CPU_CTRL);
+
+	return 0;
 }
 
 #ifdef CONFIG_CPU_PM
@@ -571,7 +577,7 @@ static void gic_cpu_restore(unsigned int gic_nr)
 					dist_base + GIC_DIST_PRI + i * 4);
 
 	writel_relaxed(GICC_INT_PRI_THRESHOLD, cpu_base + GIC_CPU_PRIMASK);
-	gic_cpu_if_up();
+	gic_cpu_if_up(&gic_data[gic_nr]);
 }
 
 static int gic_notifier(struct notifier_block *self, unsigned long cmd,	void *v)
diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h
index 9de976b4f9a7..da6aced1105e 100644
--- a/include/linux/irqchip/arm-gic.h
+++ b/include/linux/irqchip/arm-gic.h
@@ -99,7 +99,7 @@ void gic_set_irqchip_flags(unsigned long flags);
 void gic_init_bases(unsigned int, int, void __iomem *, void __iomem *,
 		    u32 offset, struct device_node *);
 void gic_cascade_irq(unsigned int gic_nr, unsigned int irq);
-void gic_cpu_if_down(void);
+int gic_cpu_if_down(unsigned int gic_nr);
 
 static inline void gic_init(unsigned int nr, int start,
 			    void __iomem *dist , void __iomem *cpu)
-- 
2.1.4

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