2 * CPU idle for DaVinci SoCs
4 * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/
6 * Derived from Marvell Kirkwood CPU idle code
7 * (arch/arm/mach-kirkwood/cpuidle.c)
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/platform_device.h>
17 #include <linux/cpuidle.h>
19 #include <linux/export.h>
20 #include <asm/proc-fns.h>
21 #include <asm/cpuidle.h>
23 #include <mach/cpuidle.h>
24 #include <mach/ddr2.h>
26 #define DAVINCI_CPUIDLE_MAX_STATES 2
29 void (*enter
) (u32 flags
);
30 void (*exit
) (u32 flags
);
34 /* Actual code that puts the SoC in different idle states */
35 static int davinci_enter_idle(struct cpuidle_device
*dev
,
36 struct cpuidle_driver
*drv
,
39 struct cpuidle_state_usage
*state_usage
= &dev
->states_usage
[index
];
40 struct davinci_ops
*ops
= cpuidle_get_statedata(state_usage
);
42 if (ops
&& ops
->enter
)
43 ops
->enter(ops
->flags
);
45 index
= cpuidle_wrap_enter(dev
, drv
, index
,
46 arm_cpuidle_simple_enter
);
49 ops
->exit(ops
->flags
);
54 /* fields in davinci_ops.flags */
55 #define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0)
57 static struct cpuidle_driver davinci_idle_driver
= {
58 .name
= "cpuidle-davinci",
60 .en_core_tk_irqen
= 1,
61 .states
[0] = ARM_CPUIDLE_WFI_STATE
,
63 .enter
= davinci_enter_idle
,
65 .target_residency
= 100000,
66 .flags
= CPUIDLE_FLAG_TIME_VALID
,
68 .desc
= "WFI and DDR Self Refresh",
70 .state_count
= DAVINCI_CPUIDLE_MAX_STATES
,
73 static DEFINE_PER_CPU(struct cpuidle_device
, davinci_cpuidle_device
);
74 static void __iomem
*ddr2_reg_base
;
76 static void davinci_save_ddr_power(int enter
, bool pdown
)
80 val
= __raw_readl(ddr2_reg_base
+ DDR2_SDRCR_OFFSET
);
86 val
&= ~DDR2_SRPD_BIT
;
87 val
|= DDR2_LPMODEN_BIT
;
89 val
&= ~(DDR2_SRPD_BIT
| DDR2_LPMODEN_BIT
);
92 __raw_writel(val
, ddr2_reg_base
+ DDR2_SDRCR_OFFSET
);
95 static void davinci_c2state_enter(u32 flags
)
97 davinci_save_ddr_power(1, !!(flags
& DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN
));
100 static void davinci_c2state_exit(u32 flags
)
102 davinci_save_ddr_power(0, !!(flags
& DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN
));
105 static struct davinci_ops davinci_states
[DAVINCI_CPUIDLE_MAX_STATES
] = {
107 .enter
= davinci_c2state_enter
,
108 .exit
= davinci_c2state_exit
,
112 static int __init
davinci_cpuidle_probe(struct platform_device
*pdev
)
115 struct cpuidle_device
*device
;
116 struct davinci_cpuidle_config
*pdata
= pdev
->dev
.platform_data
;
118 device
= &per_cpu(davinci_cpuidle_device
, smp_processor_id());
121 dev_err(&pdev
->dev
, "cannot get platform data\n");
125 ddr2_reg_base
= pdata
->ddr2_ctlr_base
;
127 if (pdata
->ddr2_pdown
)
128 davinci_states
[1].flags
|= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN
;
129 cpuidle_set_statedata(&device
->states_usage
[1], &davinci_states
[1]);
131 device
->state_count
= DAVINCI_CPUIDLE_MAX_STATES
;
133 ret
= cpuidle_register_driver(&davinci_idle_driver
);
135 dev_err(&pdev
->dev
, "failed to register driver\n");
139 ret
= cpuidle_register_device(device
);
141 dev_err(&pdev
->dev
, "failed to register device\n");
142 cpuidle_unregister_driver(&davinci_idle_driver
);
149 static struct platform_driver davinci_cpuidle_driver
= {
151 .name
= "cpuidle-davinci",
152 .owner
= THIS_MODULE
,
156 static int __init
davinci_cpuidle_init(void)
158 return platform_driver_probe(&davinci_cpuidle_driver
,
159 davinci_cpuidle_probe
);
161 device_initcall(davinci_cpuidle_init
);