1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * CPU idle Marvell Kirkwood SoCs |
4 | * |
5 | * The cpu idle uses wait-for-interrupt and DDR self refresh in order |
6 | * to implement two idle states - |
7 | * #1 wait-for-interrupt |
8 | * #2 wait-for-interrupt and DDR self refresh |
9 | * |
10 | * Maintainer: Jason Cooper <jason@lakedaemon.net> |
11 | * Maintainer: Andrew Lunn <andrew@lunn.ch> |
12 | */ |
13 | |
14 | #include <linux/kernel.h> |
15 | #include <linux/module.h> |
16 | #include <linux/init.h> |
17 | #include <linux/platform_device.h> |
18 | #include <linux/cpuidle.h> |
19 | #include <linux/io.h> |
20 | #include <linux/export.h> |
21 | #include <asm/cpuidle.h> |
22 | |
23 | #define KIRKWOOD_MAX_STATES 2 |
24 | |
25 | static void __iomem *ddr_operation_base; |
26 | |
27 | /* Actual code that puts the SoC in different idle states */ |
28 | static int kirkwood_enter_idle(struct cpuidle_device *dev, |
29 | struct cpuidle_driver *drv, |
30 | int index) |
31 | { |
32 | writel(val: 0x7, addr: ddr_operation_base); |
33 | cpu_do_idle(); |
34 | |
35 | return index; |
36 | } |
37 | |
38 | static struct cpuidle_driver kirkwood_idle_driver = { |
39 | .name = "kirkwood_idle" , |
40 | .owner = THIS_MODULE, |
41 | .states[0] = ARM_CPUIDLE_WFI_STATE, |
42 | .states[1] = { |
43 | .enter = kirkwood_enter_idle, |
44 | .exit_latency = 10, |
45 | .target_residency = 100000, |
46 | .name = "DDR SR" , |
47 | .desc = "WFI and DDR Self Refresh" , |
48 | }, |
49 | .state_count = KIRKWOOD_MAX_STATES, |
50 | }; |
51 | |
52 | /* Initialize CPU idle by registering the idle states */ |
53 | static int kirkwood_cpuidle_probe(struct platform_device *pdev) |
54 | { |
55 | ddr_operation_base = devm_platform_ioremap_resource(pdev, index: 0); |
56 | if (IS_ERR(ptr: ddr_operation_base)) |
57 | return PTR_ERR(ptr: ddr_operation_base); |
58 | |
59 | return cpuidle_register(drv: &kirkwood_idle_driver, NULL); |
60 | } |
61 | |
62 | static int kirkwood_cpuidle_remove(struct platform_device *pdev) |
63 | { |
64 | cpuidle_unregister(drv: &kirkwood_idle_driver); |
65 | return 0; |
66 | } |
67 | |
68 | static struct platform_driver kirkwood_cpuidle_driver = { |
69 | .probe = kirkwood_cpuidle_probe, |
70 | .remove = kirkwood_cpuidle_remove, |
71 | .driver = { |
72 | .name = "kirkwood_cpuidle" , |
73 | }, |
74 | }; |
75 | |
76 | module_platform_driver(kirkwood_cpuidle_driver); |
77 | |
78 | MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>" ); |
79 | MODULE_DESCRIPTION("Kirkwood cpu idle driver" ); |
80 | MODULE_LICENSE("GPL v2" ); |
81 | MODULE_ALIAS("platform:kirkwood-cpuidle" ); |
82 | |