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 <asm/proc-fns.h>
21 #include <mach/cpuidle.h>
22 #include <mach/memory.h>
24 #define DAVINCI_CPUIDLE_MAX_STATES 2
27 void (*enter
) (u32 flags
);
28 void (*exit
) (u32 flags
);
32 /* fields in davinci_ops.flags */
33 #define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0)
35 static struct cpuidle_driver davinci_idle_driver
= {
36 .name
= "cpuidle-davinci",
40 static DEFINE_PER_CPU(struct cpuidle_device
, davinci_cpuidle_device
);
41 static void __iomem
*ddr2_reg_base
;
43 static void davinci_save_ddr_power(int enter
, bool pdown
)
47 val
= __raw_readl(ddr2_reg_base
+ DDR2_SDRCR_OFFSET
);
53 val
&= ~DDR2_SRPD_BIT
;
54 val
|= DDR2_LPMODEN_BIT
;
56 val
&= ~(DDR2_SRPD_BIT
| DDR2_LPMODEN_BIT
);
59 __raw_writel(val
, ddr2_reg_base
+ DDR2_SDRCR_OFFSET
);
62 static void davinci_c2state_enter(u32 flags
)
64 davinci_save_ddr_power(1, !!(flags
& DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN
));
67 static void davinci_c2state_exit(u32 flags
)
69 davinci_save_ddr_power(0, !!(flags
& DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN
));
72 static struct davinci_ops davinci_states
[DAVINCI_CPUIDLE_MAX_STATES
] = {
74 .enter
= davinci_c2state_enter
,
75 .exit
= davinci_c2state_exit
,
79 /* Actual code that puts the SoC in different idle states */
80 static int davinci_enter_idle(struct cpuidle_device
*dev
,
81 struct cpuidle_state
*state
)
83 struct davinci_ops
*ops
= cpuidle_get_statedata(state
);
84 struct timeval before
, after
;
88 do_gettimeofday(&before
);
90 if (ops
&& ops
->enter
)
91 ops
->enter(ops
->flags
);
92 /* Wait for interrupt state */
95 ops
->exit(ops
->flags
);
97 do_gettimeofday(&after
);
99 idle_time
= (after
.tv_sec
- before
.tv_sec
) * USEC_PER_SEC
+
100 (after
.tv_usec
- before
.tv_usec
);
104 static int __init
davinci_cpuidle_probe(struct platform_device
*pdev
)
107 struct cpuidle_device
*device
;
108 struct davinci_cpuidle_config
*pdata
= pdev
->dev
.platform_data
;
109 struct resource
*ddr2_regs
;
112 device
= &per_cpu(davinci_cpuidle_device
, smp_processor_id());
115 dev_err(&pdev
->dev
, "cannot get platform data\n");
119 ddr2_regs
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
121 dev_err(&pdev
->dev
, "cannot get DDR2 controller register base");
125 len
= resource_size(ddr2_regs
);
127 ddr2_regs
= request_mem_region(ddr2_regs
->start
, len
, ddr2_regs
->name
);
131 ddr2_reg_base
= ioremap(ddr2_regs
->start
, len
);
132 if (!ddr2_reg_base
) {
137 ret
= cpuidle_register_driver(&davinci_idle_driver
);
139 dev_err(&pdev
->dev
, "failed to register driver\n");
140 goto driver_register_fail
;
143 /* Wait for interrupt state */
144 device
->states
[0].enter
= davinci_enter_idle
;
145 device
->states
[0].exit_latency
= 1;
146 device
->states
[0].target_residency
= 10000;
147 device
->states
[0].flags
= CPUIDLE_FLAG_TIME_VALID
;
148 strcpy(device
->states
[0].name
, "WFI");
149 strcpy(device
->states
[0].desc
, "Wait for interrupt");
151 /* Wait for interrupt and DDR self refresh state */
152 device
->states
[1].enter
= davinci_enter_idle
;
153 device
->states
[1].exit_latency
= 10;
154 device
->states
[1].target_residency
= 10000;
155 device
->states
[1].flags
= CPUIDLE_FLAG_TIME_VALID
;
156 strcpy(device
->states
[1].name
, "DDR SR");
157 strcpy(device
->states
[1].desc
, "WFI and DDR Self Refresh");
158 if (pdata
->ddr2_pdown
)
159 davinci_states
[1].flags
|= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN
;
160 cpuidle_set_statedata(&device
->states
[1], &davinci_states
[1]);
162 device
->state_count
= DAVINCI_CPUIDLE_MAX_STATES
;
164 ret
= cpuidle_register_device(device
);
166 dev_err(&pdev
->dev
, "failed to register device\n");
167 goto device_register_fail
;
172 device_register_fail
:
173 cpuidle_unregister_driver(&davinci_idle_driver
);
174 driver_register_fail
:
175 iounmap(ddr2_reg_base
);
177 release_mem_region(ddr2_regs
->start
, len
);
181 static struct platform_driver davinci_cpuidle_driver
= {
183 .name
= "cpuidle-davinci",
184 .owner
= THIS_MODULE
,
188 static int __init
davinci_cpuidle_init(void)
190 return platform_driver_probe(&davinci_cpuidle_driver
,
191 davinci_cpuidle_probe
);
193 device_initcall(davinci_cpuidle_init
);