drivers/cpuidle/cpuidle-kirkwood.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * CPU idle Marvell Kirkwood SoCs
   4  *
   5  * The cpu idle uses wait-for-interrupt and DDR self refresh in order
   6  * to implement two idle states -
   7  * #1 wait-for-interrupt
   8  * #2 wait-for-interrupt and DDR self refresh
   9  *
  10  * Maintainer: Jason Cooper <jason@lakedaemon.net>
  11  * Maintainer: Andrew Lunn <andrew@lunn.ch>
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/init.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/cpuidle.h>
  19 #include <linux/io.h>
  20 #include <linux/export.h>
  21 #include <asm/cpuidle.h>
  22
  23 #define KIRKWOOD_MAX_STATES     2
  24
  25 static void __iomem *ddr_operation_base;
  26
  27 /* Actual code that puts the SoC in different idle states */
  28 static int kirkwood_enter_idle(struct cpuidle_device *dev,
  29                                struct cpuidle_driver *drv,
  30                                int index)
  31 {
  32         writel(0x7, ddr_operation_base);
  33         cpu_do_idle();
  34
  35         return index;
  36 }
  37
  38 static struct cpuidle_driver kirkwood_idle_driver = {
  39         .name                   = "kirkwood_idle",
  40         .owner                  = THIS_MODULE,
  41         .states[0]              = ARM_CPUIDLE_WFI_STATE,
  42         .states[1]              = {
  43                 .enter                  = kirkwood_enter_idle,
  44                 .exit_latency           = 10,
  45                 .target_residency       = 100000,
  46                 .name                   = "DDR SR",
  47                 .desc                   = "WFI and DDR Self Refresh",
  48         },
  49         .state_count = KIRKWOOD_MAX_STATES,
  50 };
  51
  52 /* Initialize CPU idle by registering the idle states */
  53 static int kirkwood_cpuidle_probe(struct platform_device *pdev)
  54 {
  55         ddr_operation_base = devm_platform_ioremap_resource(pdev, 0);
  56         if (IS_ERR(ddr_operation_base))
  57                 return PTR_ERR(ddr_operation_base);
  58
  59         return cpuidle_register(&kirkwood_idle_driver, NULL);
  60 }
  61
  62 static void kirkwood_cpuidle_remove(struct platform_device *pdev)
  63 {
  64         cpuidle_unregister(&kirkwood_idle_driver);
  65 }
  66
  67 static struct platform_driver kirkwood_cpuidle_driver = {
  68         .probe = kirkwood_cpuidle_probe,
  69         .remove = kirkwood_cpuidle_remove,
  70         .driver = {
  71                    .name = "kirkwood_cpuidle",
  72                    },
  73 };
  74
  75 module_platform_driver(kirkwood_cpuidle_driver);
  76
  77 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
  78 MODULE_DESCRIPTION("Kirkwood cpu idle driver");
  79 MODULE_LICENSE("GPL v2");
  80 MODULE_ALIAS("platform:kirkwood-cpuidle");