1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012-2013 Xilinx
5 * CPU idle support for Xilinx Zynq
7 * based on arch/arm/mach-at91/cpuidle.c
9 * The cpu idle uses wait-for-interrupt and RAM self refresh in order
10 * to implement two idle states -
11 * #1 wait-for-interrupt
12 * #2 wait-for-interrupt and RAM self refresh
14 * Maintainer: Michal Simek <michal.simek@xilinx.com>
17 #include <linux/init.h>
18 #include <linux/cpuidle.h>
19 #include <linux/platform_device.h>
20 #include <asm/cpuidle.h>
22 #define ZYNQ_MAX_STATES 2
24 /* Actual code that puts the SoC in different idle states */
25 static int zynq_enter_idle(struct cpuidle_device *dev,
26 struct cpuidle_driver *drv, int index)
28 /* Add code for DDR self refresh start */
34 static struct cpuidle_driver zynq_idle_driver = {
38 ARM_CPUIDLE_WFI_STATE,
40 .enter = zynq_enter_idle,
42 .target_residency = 10000,
44 .desc = "WFI and RAM Self Refresh",
47 .safe_state_index = 0,
48 .state_count = ZYNQ_MAX_STATES,
51 /* Initialize CPU idle by registering the idle states */
52 static int zynq_cpuidle_probe(struct platform_device *pdev)
54 pr_info("Xilinx Zynq CpuIdle Driver started\n");
56 return cpuidle_register(&zynq_idle_driver, NULL);
59 static struct platform_driver zynq_cpuidle_driver = {
61 .name = "cpuidle-zynq",
63 .probe = zynq_cpuidle_probe,
65 builtin_platform_driver(zynq_cpuidle_driver);