Add support for cpuidle. Signed-off-by: Michal Simek <michal.si...@xilinx.com> --- Changes in v4: - Add record to MAINTAINERS file - Use long license in header + Maintainer record - Remove unused headers - Fix indentations - s/zynq_init_cpuidle/zynq_cpuidle_init/g - use cpuidle_register function - Do not use module_init, use device_initcall instead (Using it as module is not possible because some arm core functions are not exported for modules)
Changes in v3: - Move driver to drivers/cpuidle/ - Check zynq compatible string suggested by Arnd - Use zynq_ function prefix because of multiplatform kernel - Incorporate comments from Daniel Lezcano - Rebase on the top of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next Changes in v2: - Fix file header Changes in v1: - It was the part of Zynq core changes https://patchwork.kernel.org/patch/2342511/ MAINTAINERS | 1 + drivers/cpuidle/Kconfig | 6 +++ drivers/cpuidle/Makefile | 1 + drivers/cpuidle/cpuidle-zynq.c | 83 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 91 insertions(+) create mode 100644 drivers/cpuidle/cpuidle-zynq.c diff --git a/MAINTAINERS b/MAINTAINERS index 90f45f4..6e4d4e0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1309,6 +1309,7 @@ W: http://wiki.xilinx.com T: git git://git.xilinx.com/linux-xlnx.git S: Supported F: arch/arm/mach-zynq/ +F: drivers/cpuidle/cpuidle-zynq.c ARM64 PORT (AARCH64 ARCHITECTURE) M: Catalin Marinas <catalin.mari...@arm.com> diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index c4cc27e..8272a08 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -39,4 +39,10 @@ config CPU_IDLE_CALXEDA help Select this to enable cpuidle on Calxeda processors. +config CPU_IDLE_ZYNQ + bool "CPU Idle Driver for Xilinx Zynq processors" + depends on ARCH_ZYNQ + help + Select this to enable cpuidle on Xilinx Zynq processors. + endif diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index 0d8bd55..8767a7b 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -7,3 +7,4 @@ obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o obj-$(CONFIG_ARCH_KIRKWOOD) += cpuidle-kirkwood.o +obj-$(CONFIG_CPU_IDLE_ZYNQ) += cpuidle-zynq.o diff --git a/drivers/cpuidle/cpuidle-zynq.c b/drivers/cpuidle/cpuidle-zynq.c new file mode 100644 index 0000000..38e03a1 --- /dev/null +++ b/drivers/cpuidle/cpuidle-zynq.c @@ -0,0 +1,83 @@ +/* + * 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.si...@xilinx.com> + */ + +#include <linux/init.h> +#include <linux/cpu_pm.h> +#include <linux/cpuidle.h> +#include <linux/of.h> +#include <asm/proc-fns.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) +{ + /* Devices must be stopped here */ + cpu_pm_enter(); + + /* Add code for DDR self refresh start */ + cpu_do_idle(); + + /* Add code for DDR self refresh stop */ + cpu_pm_exit(); + + 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, + .flags = CPUIDLE_FLAG_TIME_VALID | + CPUIDLE_FLAG_TIMER_STOP, + .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 __init zynq_cpuidle_init(void) +{ + if (!of_machine_is_compatible("xlnx,zynq-7000")) + return -ENODEV; + + pr_info("Xilinx Zynq CpuIdle Driver started\n"); + + return cpuidle_register(&zynq_idle_driver, NULL); +} + +device_initcall(zynq_cpuidle_init); -- 1.8.2.3
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