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Subject[PATCHv3 03/16] irqchip: irq-armada-370-xp: suspend/resume support
Date
This commit adds suspend/resume support to the irqchip driver used on
Armada XP platforms (amongst others). It does so by adding a set of
suspend/resume syscore_ops, that will respectively save and restore
the necessary registers to ensure interrupts continue to work after
resume.

It is worth mentioning that the affinity is lost during a
suspend/resume cycle, because when a secondary CPU is brought
off-line, all interrupts that are assigned to this CPU in terms of
affinity gets re-assigned to a still running CPU. Therefore, right
before entering suspend, all interrupts are assigned to the boot CPU.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: linux-kernel@vger.kernel.org
---
drivers/irqchip/irq-armada-370-xp.c | 52 +++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)

diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
index 3e238cd..4ec137b 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -26,6 +26,7 @@
#include <linux/of_pci.h>
#include <linux/irqdomain.h>
#include <linux/slab.h>
+#include <linux/syscore_ops.h>
#include <linux/msi.h>
#include <asm/mach/arch.h>
#include <asm/exception.h>
@@ -66,6 +67,7 @@
static void __iomem *per_cpu_int_base;
static void __iomem *main_int_base;
static struct irq_domain *armada_370_xp_mpic_domain;
+static u32 doorbell_mask_reg;
#ifdef CONFIG_PCI_MSI
static struct irq_domain *armada_370_xp_msi_domain;
static DECLARE_BITMAP(msi_used, PCI_MSI_DOORBELL_NR);
@@ -474,6 +476,54 @@ armada_370_xp_handle_irq(struct pt_regs *regs)
} while (1);
}

+static int armada_370_xp_mpic_suspend(void)
+{
+ doorbell_mask_reg = readl(per_cpu_int_base +
+ ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+ return 0;
+}
+
+static void armada_370_xp_mpic_resume(void)
+{
+ int nirqs;
+ irq_hw_number_t irq;
+
+ /* Re-enable interrupts */
+ nirqs = (readl(main_int_base + ARMADA_370_XP_INT_CONTROL) >> 2) & 0x3ff;
+ for (irq = 0; irq < nirqs; irq++) {
+ struct irq_data *data;
+ int virq;
+
+ virq = irq_linear_revmap(armada_370_xp_mpic_domain, irq);
+ if (virq == 0)
+ continue;
+
+ if (irq != ARMADA_370_XP_TIMER0_PER_CPU_IRQ)
+ writel(irq, per_cpu_int_base +
+ ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+ else
+ writel(irq, main_int_base +
+ ARMADA_370_XP_INT_SET_ENABLE_OFFS);
+
+ data = irq_get_irq_data(virq);
+ if (!irqd_irq_disabled(data))
+ armada_370_xp_irq_unmask(data);
+ }
+
+ /* Reconfigure doorbells for IPIs and MSIs */
+ writel(doorbell_mask_reg,
+ per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS);
+ if (doorbell_mask_reg & IPI_DOORBELL_MASK)
+ writel(0, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+ if (doorbell_mask_reg & PCI_MSI_DOORBELL_MASK)
+ writel(1, per_cpu_int_base + ARMADA_370_XP_INT_CLEAR_MASK_OFFS);
+}
+
+struct syscore_ops armada_370_xp_mpic_syscore_ops = {
+ .suspend = armada_370_xp_mpic_suspend,
+ .resume = armada_370_xp_mpic_resume,
+};
+
static int __init armada_370_xp_mpic_of_init(struct device_node *node,
struct device_node *parent)
{
@@ -530,6 +580,8 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
armada_370_xp_mpic_handle_cascade_irq);
}

+ register_syscore_ops(&armada_370_xp_mpic_syscore_ops);
+
return 0;
}

--
2.1.0


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