1 /*
2 * CPU idle Marvell Kirkwood SoCs
3 *
4 * This file is licensed under the terms of the GNU General Public
5 * License version 2. This program is licensed "as is" without any
6 * warranty of any kind, whether express or implied.
7 *
8 * The cpu idle uses wait-for-interrupt and DDR self refresh in order
9 * to implement two idle states -
10 * #1 wait-for-interrupt
11 * #2 wait-for-interrupt and DDR self refresh
12 *
13 * Maintainer: Jason Cooper <jason@lakedaemon.net>
14 * Maintainer: Andrew Lunn <andrew@lunn.ch>
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/platform_device.h>
21 #include <linux/cpuidle.h>
22 #include <linux/io.h>
23 #include <linux/export.h>
24 #include <asm/proc-fns.h>
25 #include <asm/cpuidle.h>
26
27 #define KIRKWOOD_MAX_STATES 2
28
29 static void __iomem *ddr_operation_base;
30
31 /* Actual code that puts the SoC in different idle states */
kirkwood_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)32 static int kirkwood_enter_idle(struct cpuidle_device *dev,
33 struct cpuidle_driver *drv,
34 int index)
35 {
36 writel(0x7, ddr_operation_base);
37 cpu_do_idle();
38
39 return index;
40 }
41
42 static struct cpuidle_driver kirkwood_idle_driver = {
43 .name = "kirkwood_idle",
44 .owner = THIS_MODULE,
45 .states[0] = ARM_CPUIDLE_WFI_STATE,
46 .states[1] = {
47 .enter = kirkwood_enter_idle,
48 .exit_latency = 10,
49 .target_residency = 100000,
50 .flags = CPUIDLE_FLAG_TIME_VALID,
51 .name = "DDR SR",
52 .desc = "WFI and DDR Self Refresh",
53 },
54 .state_count = KIRKWOOD_MAX_STATES,
55 };
56
57 /* Initialize CPU idle by registering the idle states */
kirkwood_cpuidle_probe(struct platform_device * pdev)58 static int kirkwood_cpuidle_probe(struct platform_device *pdev)
59 {
60 struct resource *res;
61
62 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
63 if (res == NULL)
64 return -EINVAL;
65
66 ddr_operation_base = devm_ioremap_resource(&pdev->dev, res);
67 if (IS_ERR(ddr_operation_base))
68 return PTR_ERR(ddr_operation_base);
69
70 return cpuidle_register(&kirkwood_idle_driver, NULL);
71 }
72
kirkwood_cpuidle_remove(struct platform_device * pdev)73 int kirkwood_cpuidle_remove(struct platform_device *pdev)
74 {
75 cpuidle_unregister(&kirkwood_idle_driver);
76 return 0;
77 }
78
79 static struct platform_driver kirkwood_cpuidle_driver = {
80 .probe = kirkwood_cpuidle_probe,
81 .remove = kirkwood_cpuidle_remove,
82 .driver = {
83 .name = "kirkwood_cpuidle",
84 .owner = THIS_MODULE,
85 },
86 };
87
88 module_platform_driver(kirkwood_cpuidle_driver);
89
90 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
91 MODULE_DESCRIPTION("Kirkwood cpu idle driver");
92 MODULE_LICENSE("GPL v2");
93 MODULE_ALIAS("platform:kirkwood-cpuidle");
94