drivers/cpuidle/cpuidle-kirkwood.c

   1 /*
   2  * arch/arm/mach-kirkwood/cpuidle.c
   3  *
   4  * CPU idle Marvell Kirkwood SoCs
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2.  This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  *
  10  * The cpu idle uses wait-for-interrupt and DDR self refresh in order
  11  * to implement two idle states -
  12  * #1 wait-for-interrupt
  13  * #2 wait-for-interrupt and DDR self refresh
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/cpuidle.h>
  21 #include <linux/io.h>
  22 #include <linux/export.h>
  23 #include <asm/proc-fns.h>
  24 #include <asm/cpuidle.h>
  25
  26 #define KIRKWOOD_MAX_STATES     2
  27
  28 static void __iomem *ddr_operation_base;
  29
  30 /* Actual code that puts the SoC in different idle states */
  31 static int kirkwood_enter_idle(struct cpuidle_device *dev,
  32                                struct cpuidle_driver *drv,
  33                                int index)
  34 {
  35         writel(0x7, ddr_operation_base);
  36         cpu_do_idle();
  37
  38         return index;
  39 }
  40
  41 static struct cpuidle_driver kirkwood_idle_driver = {
  42         .name                   = "kirkwood_idle",
  43         .owner                  = THIS_MODULE,
  44         .states[0]              = ARM_CPUIDLE_WFI_STATE,
  45         .states[1]              = {
  46                 .enter                  = kirkwood_enter_idle,
  47                 .exit_latency           = 10,
  48                 .target_residency       = 100000,
  49                 .flags                  = CPUIDLE_FLAG_TIME_VALID,
  50                 .name                   = "DDR SR",
  51                 .desc                   = "WFI and DDR Self Refresh",
  52         },
  53         .state_count = KIRKWOOD_MAX_STATES,
  54 };
  55 static struct cpuidle_device *device;
  56
  57 static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device);
  58
  59 /* Initialize CPU idle by registering the idle states */
  60 static int kirkwood_cpuidle_probe(struct platform_device *pdev)
  61 {
  62         struct resource *res;
  63
  64         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  65         if (res == NULL)
  66                 return -EINVAL;
  67
  68         ddr_operation_base = devm_ioremap_resource(&pdev->dev, res);
  69         if (IS_ERR(ddr_operation_base))
  70                 return PTR_ERR(ddr_operation_base);
  71
  72         device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id());
  73         device->state_count = KIRKWOOD_MAX_STATES;
  74
  75         cpuidle_register_driver(&kirkwood_idle_driver);
  76         if (cpuidle_register_device(device)) {
  77                 pr_err("kirkwood_init_cpuidle: Failed registering\n");
  78                 return -EIO;
  79         }
  80         return 0;
  81 }
  82
  83 int kirkwood_cpuidle_remove(struct platform_device *pdev)
  84 {
  85         cpuidle_unregister_device(device);
  86         cpuidle_unregister_driver(&kirkwood_idle_driver);
  87
  88         return 0;
  89 }
  90
  91 static struct platform_driver kirkwood_cpuidle_driver = {
  92         .probe = kirkwood_cpuidle_probe,
  93         .remove = kirkwood_cpuidle_remove,
  94         .driver = {
  95                    .name = "kirkwood_cpuidle",
  96                    .owner = THIS_MODULE,
  97                    },
  98 };
  99
 100 module_platform_driver(kirkwood_cpuidle_driver);
 101
 102 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
 103 MODULE_DESCRIPTION("Kirkwood cpu idle driver");
 104 MODULE_LICENSE("GPL v2");
 105 MODULE_ALIAS("platform:kirkwood-cpuidle");