1 /*
2  * Copyright 2012 Calxeda, Inc.
3  *
4  * Based on arch/arm/plat-mxc/cpuidle.c: #v3.7
5  * Copyright 2012 Freescale Semiconductor, Inc.
6  * Copyright 2012 Linaro Ltd.
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2, as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along with
18  * this program.  If not, see <http://www.gnu.org/licenses/>.
19  *
20  * Maintainer: Rob Herring <rob.herring@calxeda.com>
21  */
22 
23 #include <linux/cpuidle.h>
24 #include <linux/init.h>
25 #include <linux/io.h>
26 #include <linux/of.h>
27 #include <linux/time.h>
28 #include <linux/delay.h>
29 #include <linux/suspend.h>
30 #include <asm/cpuidle.h>
31 #include <asm/proc-fns.h>
32 #include <asm/smp_scu.h>
33 #include <asm/suspend.h>
34 #include <asm/cacheflush.h>
35 #include <asm/cp15.h>
36 
37 extern void highbank_set_cpu_jump(int cpu, void *jump_addr);
38 extern void __iomem *scu_base_addr;
39 
40 static noinline void calxeda_idle_restore(void)
41 {
42 	set_cr(get_cr() | CR_C);
43 	set_auxcr(get_auxcr() | 0x40);
44 	scu_power_mode(scu_base_addr, SCU_PM_NORMAL);
45 }
46 
47 static int calxeda_idle_finish(unsigned long val)
48 {
49 	/* Already flushed cache, but do it again as the outer cache functions
50 	 * dirty the cache with spinlocks */
51 	flush_cache_all();
52 
53 	set_auxcr(get_auxcr() & ~0x40);
54 	set_cr(get_cr() & ~CR_C);
55 
56 	scu_power_mode(scu_base_addr, SCU_PM_DORMANT);
57 
58 	cpu_do_idle();
59 
60 	/* Restore things if we didn't enter power-gating */
61 	calxeda_idle_restore();
62 	return 1;
63 }
64 
65 static int calxeda_pwrdown_idle(struct cpuidle_device *dev,
66 				struct cpuidle_driver *drv,
67 				int index)
68 {
69 	highbank_set_cpu_jump(smp_processor_id(), cpu_resume);
70 	cpu_suspend(0, calxeda_idle_finish);
71 	return index;
72 }
73 
74 static struct cpuidle_driver calxeda_idle_driver = {
75 	.name = "calxeda_idle",
76 	.states = {
77 		ARM_CPUIDLE_WFI_STATE,
78 		{
79 			.name = "PG",
80 			.desc = "Power Gate",
81 			.flags = CPUIDLE_FLAG_TIME_VALID,
82 			.exit_latency = 30,
83 			.power_usage = 50,
84 			.target_residency = 200,
85 			.enter = calxeda_pwrdown_idle,
86 		},
87 	},
88 	.state_count = 2,
89 };
90 
91 static int __init calxeda_cpuidle_init(void)
92 {
93 	if (!of_machine_is_compatible("calxeda,highbank"))
94 		return -ENODEV;
95 
96 	return cpuidle_register(&calxeda_idle_driver, NULL);
97 }
98 module_init(calxeda_cpuidle_init);
99