drivers/cpuidle/cpuidle-calxeda.c

   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);