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 #include "kirkwood-pm.h"
22 
23 static void __iomem *ddr_operation_base;
24 static void __iomem *memory_pm_ctrl;
25 
26 static void kirkwood_low_power(void)
27 {
28 	u32 mem_pm_ctrl;
29 
30 	mem_pm_ctrl = readl(memory_pm_ctrl);
31 
32 	/* Set peripherals to low-power mode */
33 	writel_relaxed(~0, memory_pm_ctrl);
34 
35 	/* Set DDR in self-refresh */
36 	writel_relaxed(0x7, ddr_operation_base);
37 
38 	/*
39 	 * Set CPU in wait-for-interrupt state.
40 	 * This disables the CPU core clocks,
41 	 * the array clocks, and also the L2 controller.
42 	 */
43 	cpu_do_idle();
44 
45 	writel_relaxed(mem_pm_ctrl, memory_pm_ctrl);
46 }
47 
48 static int kirkwood_suspend_enter(suspend_state_t state)
49 {
50 	switch (state) {
51 	case PM_SUSPEND_STANDBY:
52 		kirkwood_low_power();
53 		break;
54 	default:
55 		return -EINVAL;
56 	}
57 	return 0;
58 }
59 
60 static int kirkwood_pm_valid_standby(suspend_state_t state)
61 {
62 	return state == PM_SUSPEND_STANDBY;
63 }
64 
65 static const struct platform_suspend_ops kirkwood_suspend_ops = {
66 	.enter = kirkwood_suspend_enter,
67 	.valid = kirkwood_pm_valid_standby,
68 };
69 
70 void __init kirkwood_pm_init(void)
71 {
72 	ddr_operation_base = ioremap(DDR_OPERATION_BASE, 4);
73 	memory_pm_ctrl = ioremap(MEMORY_PM_CTRL_PHYS, 4);
74 
75 	suspend_set_ops(&kirkwood_suspend_ops);
76 }
77