1 /*
2  * Power Management driver for Marvell Kirkwood SoCs
3  *
4  * Copyright (C) 2013 Ezequiel Garcia <ezequiel@free-electrons.com>
5  * Copyright (C) 2010 Simon Guinot <sguinot@lacie.com>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License,
9  * version 2 of the License.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  */
16 
17 #include <linux/kernel.h>
18 #include <linux/suspend.h>
19 #include <linux/io.h>
20 #include "kirkwood.h"
21 
22 static void __iomem *ddr_operation_base;
23 static void __iomem *memory_pm_ctrl;
24 
25 static void kirkwood_low_power(void)
26 {
27 	u32 mem_pm_ctrl;
28 
29 	mem_pm_ctrl = readl(memory_pm_ctrl);
30 
31 	/* Set peripherals to low-power mode */
32 	writel_relaxed(~0, memory_pm_ctrl);
33 
34 	/* Set DDR in self-refresh */
35 	writel_relaxed(0x7, ddr_operation_base);
36 
37 	/*
38 	 * Set CPU in wait-for-interrupt state.
39 	 * This disables the CPU core clocks,
40 	 * the array clocks, and also the L2 controller.
41 	 */
42 	cpu_do_idle();
43 
44 	writel_relaxed(mem_pm_ctrl, memory_pm_ctrl);
45 }
46 
47 static int kirkwood_suspend_enter(suspend_state_t state)
48 {
49 	switch (state) {
50 	case PM_SUSPEND_STANDBY:
51 		kirkwood_low_power();
52 		break;
53 	default:
54 		return -EINVAL;
55 	}
56 	return 0;
57 }
58 
59 static int kirkwood_pm_valid_standby(suspend_state_t state)
60 {
61 	return state == PM_SUSPEND_STANDBY;
62 }
63 
64 static const struct platform_suspend_ops kirkwood_suspend_ops = {
65 	.enter = kirkwood_suspend_enter,
66 	.valid = kirkwood_pm_valid_standby,
67 };
68 
69 int __init kirkwood_pm_init(void)
70 {
71 	ddr_operation_base = ioremap(DDR_OPERATION_BASE, 4);
72 	memory_pm_ctrl = ioremap(MEMORY_PM_CTRL_PHYS, 4);
73 
74 	suspend_set_ops(&kirkwood_suspend_ops);
75 	return 0;
76 }
77