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 *scu_base_addr;
39 
40 static inline unsigned int get_auxcr(void)
41 {
42 	unsigned int val;
43 	asm("mrc p15, 0, %0, c1, c0, 1	@ get AUXCR" : "=r" (val) : : "cc");
44 	return val;
45 }
46 
47 static inline void set_auxcr(unsigned int val)
48 {
49 	asm volatile("mcr p15, 0, %0, c1, c0, 1	@ set AUXCR"
50 	  : : "r" (val) : "cc");
51 	isb();
52 }
53 
54 static noinline void calxeda_idle_restore(void)
55 {
56 	set_cr(get_cr() | CR_C);
57 	set_auxcr(get_auxcr() | 0x40);
58 	scu_power_mode(scu_base_addr, SCU_PM_NORMAL);
59 }
60 
61 static int calxeda_idle_finish(unsigned long val)
62 {
63 	/* Already flushed cache, but do it again as the outer cache functions
64 	 * dirty the cache with spinlocks */
65 	flush_cache_all();
66 
67 	set_auxcr(get_auxcr() & ~0x40);
68 	set_cr(get_cr() & ~CR_C);
69 
70 	scu_power_mode(scu_base_addr, SCU_PM_DORMANT);
71 
72 	cpu_do_idle();
73 
74 	/* Restore things if we didn't enter power-gating */
75 	calxeda_idle_restore();
76 	return 1;
77 }
78 
79 static int calxeda_pwrdown_idle(struct cpuidle_device *dev,
80 				struct cpuidle_driver *drv,
81 				int index)
82 {
83 	highbank_set_cpu_jump(smp_processor_id(), cpu_resume);
84 	cpu_suspend(0, calxeda_idle_finish);
85 	return index;
86 }
87 
88 static struct cpuidle_driver calxeda_idle_driver = {
89 	.name = "calxeda_idle",
90 	.states = {
91 		ARM_CPUIDLE_WFI_STATE,
92 		{
93 			.name = "PG",
94 			.desc = "Power Gate",
95 			.flags = CPUIDLE_FLAG_TIME_VALID,
96 			.exit_latency = 30,
97 			.power_usage = 50,
98 			.target_residency = 200,
99 			.enter = calxeda_pwrdown_idle,
100 		},
101 	},
102 	.state_count = 2,
103 };
104 
105 static int __init calxeda_cpuidle_init(void)
106 {
107 	if (!of_machine_is_compatible("calxeda,highbank"))
108 		return -ENODEV;
109 
110 	return cpuidle_register(&calxeda_idle_driver, NULL);
111 }
112 module_init(calxeda_cpuidle_init);
113