avr32: Power Management support ("standby" and "mem" modes)

Implement Standby support. In this mode, we'll suspend all drivers,
put the SDRAM in self-refresh mode and switch off the HSB bus
("frozen" mode.)

Implement Suspend-to-mem support. In this mode, we suspend all
drivers, put the SDRAM into self-refresh mode and switch off all
internal clocks except the 32 kHz oscillator ("stop" mode.)

The lowest-level suspend code runs from a small portion of SRAM
allocated at startup time. This gets rid of a small potential race
with the SDRAM where we might try to enter self-refresh mode in the
middle of an icache burst. We also relocate all interrupt and
exception handlers to SRAM during the small window when we enter and
exit the low-power modes.

We don't need to do any special tricks to start and stop the PLL. The
main clock is automatically gated by hardware until the PLL is stable.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>

1 files changed, 53 insertions, 1 deletions

diff --git a/arch/avr32/mach-at32ap/intc.c b/arch/avr32/mach-at32ap/intc.c
index 644a3fb..994c4545 100644
--- a/arch/avr32/mach-at32ap/intc.c
+++ b/arch/avr32/mach-at32ap/intc.c
@@ -22,6 +22,10 @@ struct intc {
 	void __iomem		*regs;
 	struct irq_chip		chip;
 	struct sys_device	sysdev;
+#ifdef CONFIG_PM
+	unsigned long		suspend_ipr;
+	unsigned long		saved_ipr[64];
+#endif
 };
 
 extern struct platform_device at32_intc0_device;
@@ -138,8 +142,56 @@ fail:
 	panic("Interrupt controller initialization failed!\n");
 }
 
+#ifdef CONFIG_PM
+void intc_set_suspend_handler(unsigned long offset)
+{
+	intc0.suspend_ipr = offset;
+}
+
+static int intc_suspend(struct sys_device *sdev, pm_message_t state)
+{
+	struct intc *intc = container_of(sdev, struct intc, sysdev);
+	int i;
+
+	if (unlikely(!irqs_disabled())) {
+		pr_err("intc_suspend: called with interrupts enabled\n");
+		return -EINVAL;
+	}
+
+	if (unlikely(!intc->suspend_ipr)) {
+		pr_err("intc_suspend: suspend_ipr not initialized\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < 64; i++) {
+		intc->saved_ipr[i] = intc_readl(intc, INTPR0 + 4 * i);
+		intc_writel(intc, INTPR0 + 4 * i, intc->suspend_ipr);
+	}
+
+	return 0;
+}
+
+static int intc_resume(struct sys_device *sdev)
+{
+	struct intc *intc = container_of(sdev, struct intc, sysdev);
+	int i;
+
+	WARN_ON(!irqs_disabled());
+
+	for (i = 0; i < 64; i++)
+		intc_writel(intc, INTPR0 + 4 * i, intc->saved_ipr[i]);
+
+	return 0;
+}
+#else
+#define intc_suspend	NULL
+#define intc_resume	NULL
+#endif
+
 static struct sysdev_class intc_class = {
-	.name	= "intc",
+	.name		= "intc",
+	.suspend	= intc_suspend,
+	.resume		= intc_resume,
 };
 
 static int __init intc_init_sysdev(void)