arch/arm/mach-kirkwood/pm.c

/*
 * Power Management driver for Marvell Kirkwood SoCs
 *
 * Copyright (C) 2013 Ezequiel Garcia <ezequiel@free-electrons.com>
 * Copyright (C) 2010 Simon Guinot <sguinot@lacie.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License,
 * version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/suspend.h>
#include <linux/io.h>
#include <mach/bridge-regs.h>

static void __iomem *ddr_operation_base;

static void kirkwood_low_power(void)
{
	u32 mem_pm_ctrl;

	mem_pm_ctrl = readl(MEMORY_PM_CTRL);

	/* Set peripherals to low-power mode */
	writel_relaxed(~0, MEMORY_PM_CTRL);

	/* Set DDR in self-refresh */
	writel_relaxed(0x7, ddr_operation_base);

	/*
	 * Set CPU in wait-for-interrupt state.
	 * This disables the CPU core clocks,
	 * the array clocks, and also the L2 controller.
	 */
	cpu_do_idle();

	writel_relaxed(mem_pm_ctrl, MEMORY_PM_CTRL);
}

static int kirkwood_suspend_enter(suspend_state_t state)
{
	switch (state) {
	case PM_SUSPEND_STANDBY:
		kirkwood_low_power();
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

static int kirkwood_pm_valid_standby(suspend_state_t state)
{
	return state == PM_SUSPEND_STANDBY;
}

static const struct platform_suspend_ops kirkwood_suspend_ops = {
	.enter = kirkwood_suspend_enter,
	.valid = kirkwood_pm_valid_standby,
};

int __init kirkwood_pm_init(void)
{
	ddr_operation_base = ioremap(DDR_OPERATION_BASE, 4);
	suspend_set_ops(&kirkwood_suspend_ops);
	return 0;
}