cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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cpuidle-kirkwood.c (2241B)

      1/*
      2 * CPU idle Marvell Kirkwood SoCs
      3 *
      4 * This file is licensed under the terms of the GNU General Public
      5 * License version 2.  This program is licensed "as is" without any
      6 * warranty of any kind, whether express or implied.
      7 *
      8 * The cpu idle uses wait-for-interrupt and DDR self refresh in order
      9 * to implement two idle states -
     10 * #1 wait-for-interrupt
     11 * #2 wait-for-interrupt and DDR self refresh
     12 *
     13 * Maintainer: Jason Cooper <jason@lakedaemon.net>
     14 * Maintainer: Andrew Lunn <andrew@lunn.ch>
     15 */
     16
     17#include <linux/kernel.h>
     18#include <linux/module.h>
     19#include <linux/init.h>
     20#include <linux/platform_device.h>
     21#include <linux/cpuidle.h>
     22#include <linux/io.h>
     23#include <linux/export.h>
     24#include <asm/cpuidle.h>
     25
     26#define KIRKWOOD_MAX_STATES	2
     27
     28static void __iomem *ddr_operation_base;
     29
     30/* Actual code that puts the SoC in different idle states */
     31static 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
     41static 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		.name			= "DDR SR",
     50		.desc			= "WFI and DDR Self Refresh",
     51	},
     52	.state_count = KIRKWOOD_MAX_STATES,
     53};
     54
     55/* Initialize CPU idle by registering the idle states */
     56static int kirkwood_cpuidle_probe(struct platform_device *pdev)
     57{
     58	ddr_operation_base = devm_platform_ioremap_resource(pdev, 0);
     59	if (IS_ERR(ddr_operation_base))
     60		return PTR_ERR(ddr_operation_base);
     61
     62	return cpuidle_register(&kirkwood_idle_driver, NULL);
     63}
     64
     65static int kirkwood_cpuidle_remove(struct platform_device *pdev)
     66{
     67	cpuidle_unregister(&kirkwood_idle_driver);
     68	return 0;
     69}
     70
     71static struct platform_driver kirkwood_cpuidle_driver = {
     72	.probe = kirkwood_cpuidle_probe,
     73	.remove = kirkwood_cpuidle_remove,
     74	.driver = {
     75		   .name = "kirkwood_cpuidle",
     76		   },
     77};
     78
     79module_platform_driver(kirkwood_cpuidle_driver);
     80
     81MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
     82MODULE_DESCRIPTION("Kirkwood cpu idle driver");
     83MODULE_LICENSE("GPL v2");
     84MODULE_ALIAS("platform:kirkwood-cpuidle");