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Subject[PATCH v2 3/5] ARM: gic: Use cpu pm notifiers to save gic state
Date
From: Colin Cross <ccross@android.com>

When the cpu is powered down in a low power mode, the gic cpu
interface may be reset, and when the cpu cluster is powered
down, the gic distributor may also be reset.

This patch uses CPU_PM_ENTER and CPU_PM_EXIT notifiers to save
and restore the gic cpu interface registers, and the
CPU_CLUSTER_PM_ENTER and CPU_CLUSTER_PM_EXIT notifiers to save
and restore the gic distributor registers.

Original-author: Gary King <gking@nvidia.com>
Signed-off-by: Colin Cross <ccross@android.com>
[santosh.shilimkar@ti.com: Rebased against 3.1-rc4, removed gic dist. disable]
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
arch/arm/common/gic.c | 187 +++++++++++++++++++++++++++++++++++
arch/arm/include/asm/hardware/gic.h | 8 ++
2 files changed, 195 insertions(+), 0 deletions(-)
diff --git a/arch/arm/common/gic.c b/arch/arm/common/gic.c
index 3227ca9..66c7c48 100644
--- a/arch/arm/common/gic.c
+++ b/arch/arm/common/gic.c
@@ -26,6 +26,7 @@
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/smp.h>
+#include <linux/cpu_pm.h>
#include <linux/cpumask.h>
#include <linux/io.h>

@@ -276,6 +277,8 @@ static void __init gic_dist_init(struct gic_chip_data *gic,
if (gic_irqs > 1020)
gic_irqs = 1020;

+ gic->gic_irqs = gic_irqs;
+
/*
* Set all global interrupts to be level triggered, active low.
*/
@@ -343,6 +346,189 @@ static void __cpuinit gic_cpu_init(struct gic_chip_data *gic)
writel_relaxed(1, base + GIC_CPU_CTRL);
}

+#ifdef CONFIG_CPU_PM
+/*
+ * Saves the GIC distributor registers during suspend or idle. Must be called
+ * with interrupts disabled but before powering down the GIC. After calling
+ * this function, no interrupts will be delivered by the GIC, and another
+ * platform-specific wakeup source must be enabled.
+ */
+static void gic_dist_save(unsigned int gic_nr)
+{
+ unsigned int gic_irqs;
+ void __iomem *dist_base;
+ int i;
+
+ if (gic_nr >= MAX_GIC_NR)
+ BUG();
+
+ gic_irqs = gic_data[gic_nr].gic_irqs;
+ dist_base = gic_data[gic_nr].dist_base;
+
+ if (!dist_base)
+ return;
+
+ for (i = 0; i < DIV_ROUND_UP(gic_irqs, 16); i++)
+ gic_data[gic_nr].saved_spi_conf[i] =
+ readl_relaxed(dist_base + GIC_DIST_CONFIG + i * 4);
+
+ for (i = 0; i < DIV_ROUND_UP(gic_irqs, 4); i++)
+ gic_data[gic_nr].saved_spi_target[i] =
+ readl_relaxed(dist_base + GIC_DIST_TARGET + i * 4);
+
+ for (i = 0; i < DIV_ROUND_UP(gic_irqs, 32); i++)
+ gic_data[gic_nr].saved_spi_enable[i] =
+ readl_relaxed(dist_base + GIC_DIST_ENABLE_SET + i * 4);
+}
+
+/*
+ * Restores the GIC distributor registers during resume or when coming out of
+ * idle. Must be called before enabling interrupts. If a level interrupt
+ * that occured while the GIC was suspended is still present, it will be
+ * handled normally, but any edge interrupts that occured will not be seen by
+ * the GIC and need to be handled by the platform-specific wakeup source.
+ */
+static void gic_dist_restore(unsigned int gic_nr)
+{
+ unsigned int gic_irqs;
+ unsigned int i;
+ void __iomem *dist_base;
+
+ if (gic_nr >= MAX_GIC_NR)
+ BUG();
+
+ gic_irqs = gic_data[gic_nr].gic_irqs;
+ dist_base = gic_data[gic_nr].dist_base;
+
+ if (!dist_base)
+ return;
+
+ writel_relaxed(0, dist_base + GIC_DIST_CTRL);
+
+ for (i = 0; i < DIV_ROUND_UP(gic_irqs, 16); i++)
+ writel_relaxed(gic_data[gic_nr].saved_spi_conf[i],
+ dist_base + GIC_DIST_CONFIG + i * 4);
+
+ for (i = 0; i < DIV_ROUND_UP(gic_irqs, 4); i++)
+ writel_relaxed(0xa0a0a0a0,
+ dist_base + GIC_DIST_PRI + i * 4);
+
+ for (i = 0; i < DIV_ROUND_UP(gic_irqs, 4); i++)
+ writel_relaxed(gic_data[gic_nr].saved_spi_target[i],
+ dist_base + GIC_DIST_TARGET + i * 4);
+
+ for (i = 0; i < DIV_ROUND_UP(gic_irqs, 32); i++)
+ writel_relaxed(gic_data[gic_nr].saved_spi_enable[i],
+ dist_base + GIC_DIST_ENABLE_SET + i * 4);
+
+ writel_relaxed(1, dist_base + GIC_DIST_CTRL);
+}
+
+static void gic_cpu_save(unsigned int gic_nr)
+{
+ int i;
+ u32 *ptr;
+ void __iomem *dist_base;
+ void __iomem *cpu_base;
+
+ if (gic_nr >= MAX_GIC_NR)
+ BUG();
+
+ dist_base = gic_data[gic_nr].dist_base;
+ cpu_base = gic_data[gic_nr].cpu_base;
+
+ if (!dist_base || !cpu_base)
+ return;
+
+ ptr = __this_cpu_ptr(gic_data[gic_nr].saved_ppi_enable);
+ for (i = 0; i < DIV_ROUND_UP(32, 32); i++)
+ ptr[i] = readl_relaxed(dist_base + GIC_DIST_ENABLE_SET + i * 4);
+
+ ptr = __this_cpu_ptr(gic_data[gic_nr].saved_ppi_conf);
+ for (i = 0; i < DIV_ROUND_UP(32, 16); i++)
+ ptr[i] = readl_relaxed(dist_base + GIC_DIST_CONFIG + i * 4);
+
+}
+
+static void gic_cpu_restore(unsigned int gic_nr)
+{
+ int i;
+ u32 *ptr;
+ void __iomem *dist_base;
+ void __iomem *cpu_base;
+
+ if (gic_nr >= MAX_GIC_NR)
+ BUG();
+
+ dist_base = gic_data[gic_nr].dist_base;
+ cpu_base = gic_data[gic_nr].cpu_base;
+
+ if (!dist_base || !cpu_base)
+ return;
+
+ ptr = __this_cpu_ptr(gic_data[gic_nr].saved_ppi_enable);
+ for (i = 0; i < DIV_ROUND_UP(32, 32); i++)
+ writel_relaxed(ptr[i], dist_base + GIC_DIST_ENABLE_SET + i * 4);
+
+ ptr = __this_cpu_ptr(gic_data[gic_nr].saved_ppi_conf);
+ for (i = 0; i < DIV_ROUND_UP(32, 16); i++)
+ writel_relaxed(ptr[i], dist_base + GIC_DIST_CONFIG + i * 4);
+
+ for (i = 0; i < DIV_ROUND_UP(32, 4); i++)
+ 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);
+}
+
+static int gic_notifier(struct notifier_block *self, unsigned long cmd, void *v)
+{
+ int i;
+
+ for (i = 0; i < MAX_GIC_NR; i++) {
+ switch (cmd) {
+ case CPU_PM_ENTER:
+ gic_cpu_save(i);
+ break;
+ case CPU_PM_ENTER_FAILED:
+ case CPU_PM_EXIT:
+ gic_cpu_restore(i);
+ break;
+ case CPU_CLUSTER_PM_ENTER:
+ gic_dist_save(i);
+ break;
+ case CPU_CLUSTER_PM_ENTER_FAILED:
+ case CPU_CLUSTER_PM_EXIT:
+ gic_dist_restore(i);
+ break;
+ }
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block gic_notifier_block = {
+ .notifier_call = gic_notifier,
+};
+
+static void __init gic_pm_init(struct gic_chip_data *gic)
+{
+ gic->saved_ppi_enable = __alloc_percpu(DIV_ROUND_UP(32, 32) * 4,
+ sizeof(u32));
+ BUG_ON(!gic->saved_ppi_enable);
+
+ gic->saved_ppi_conf = __alloc_percpu(DIV_ROUND_UP(32, 16) * 4,
+ sizeof(u32));
+ BUG_ON(!gic->saved_ppi_conf);
+
+ cpu_pm_register_notifier(&gic_notifier_block);
+}
+#else
+static void __init gic_pm_init(struct gic_chip_data *gic)
+{
+}
+#endif
+
void __init gic_init(unsigned int gic_nr, unsigned int irq_start,
void __iomem *dist_base, void __iomem *cpu_base)
{
@@ -360,6 +546,7 @@ void __init gic_init(unsigned int gic_nr, unsigned int irq_start,

gic_dist_init(gic, irq_start);
gic_cpu_init(gic);
+ gic_pm_init(gic);
}

void __cpuinit gic_secondary_init(unsigned int gic_nr)
diff --git a/arch/arm/include/asm/hardware/gic.h b/arch/arm/include/asm/hardware/gic.h
index 435d3f8..c562705 100644
--- a/arch/arm/include/asm/hardware/gic.h
+++ b/arch/arm/include/asm/hardware/gic.h
@@ -46,6 +46,14 @@ struct gic_chip_data {
unsigned int irq_offset;
void __iomem *dist_base;
void __iomem *cpu_base;
+#ifdef CONFIG_CPU_PM
+ u32 saved_spi_enable[DIV_ROUND_UP(1020, 32)];
+ u32 saved_spi_conf[DIV_ROUND_UP(1020, 16)];
+ u32 saved_spi_target[DIV_ROUND_UP(1020, 4)];
+ u32 __percpu *saved_ppi_enable;
+ u32 __percpu *saved_ppi_conf;
+#endif
+ unsigned int gic_irqs;
};
#endif

--
1.7.4.1


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