diff options
Diffstat (limited to 'drivers/cpuidle/cpuidle-zynq.c')
-rw-r--r-- | drivers/cpuidle/cpuidle-zynq.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/cpuidle/cpuidle-zynq.c b/drivers/cpuidle/cpuidle-zynq.c new file mode 100644 index 000000000..543292b1d --- /dev/null +++ b/drivers/cpuidle/cpuidle-zynq.c @@ -0,0 +1,77 @@ +/* + * Copyright (C) 2012-2013 Xilinx + * + * CPU idle support for Xilinx Zynq + * + * based on arch/arm/mach-at91/cpuidle.c + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + * + * The cpu idle uses wait-for-interrupt and RAM self refresh in order + * to implement two idle states - + * #1 wait-for-interrupt + * #2 wait-for-interrupt and RAM self refresh + * + * Maintainer: Michal Simek <michal.simek@xilinx.com> + */ + +#include <linux/init.h> +#include <linux/cpuidle.h> +#include <linux/platform_device.h> +#include <asm/cpuidle.h> + +#define ZYNQ_MAX_STATES 2 + +/* Actual code that puts the SoC in different idle states */ +static int zynq_enter_idle(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) +{ + /* Add code for DDR self refresh start */ + cpu_do_idle(); + + return index; +} + +static struct cpuidle_driver zynq_idle_driver = { + .name = "zynq_idle", + .owner = THIS_MODULE, + .states = { + ARM_CPUIDLE_WFI_STATE, + { + .enter = zynq_enter_idle, + .exit_latency = 10, + .target_residency = 10000, + .name = "RAM_SR", + .desc = "WFI and RAM Self Refresh", + }, + }, + .safe_state_index = 0, + .state_count = ZYNQ_MAX_STATES, +}; + +/* Initialize CPU idle by registering the idle states */ +static int zynq_cpuidle_probe(struct platform_device *pdev) +{ + pr_info("Xilinx Zynq CpuIdle Driver started\n"); + + return cpuidle_register(&zynq_idle_driver, NULL); +} + +static struct platform_driver zynq_cpuidle_driver = { + .driver = { + .name = "cpuidle-zynq", + }, + .probe = zynq_cpuidle_probe, +}; + +module_platform_driver(zynq_cpuidle_driver); |