Messages in this thread Patch in this message | | | From | Michal Simek <> | Subject | [PATCH v3] arm: zynq: Add cpuidle support | Date | Mon, 3 Jun 2013 15:40:29 +0200 |
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Add support for cpuidle.
Signed-off-by: Michal Simek <michal.simek@xilinx.com> --- 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/
drivers/cpuidle/Kconfig | 6 +++ drivers/cpuidle/Makefile | 1 + drivers/cpuidle/cpuidle-zynq.c | 100 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 107 insertions(+) create mode 100644 drivers/cpuidle/cpuidle-zynq.c
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..afe6af3 --- /dev/null +++ b/drivers/cpuidle/cpuidle-zynq.c @@ -0,0 +1,100 @@ +/* + * Copyright (C) 2012-2013 Xilinx + * + * CPU idle support for Xilinx Zynq + * + * based on arch/arm/mach-at91/cpuidle.c + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * 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 + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/cpuidle.h> +#include <linux/io.h> +#include <linux/export.h> +#include <linux/clockchips.h> +#include <linux/cpu_pm.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/of.h> +#include <asm/proc-fns.h> +#include <asm/cpuidle.h> + +#define ZYNQ_MAX_STATES 2 + +static DEFINE_PER_CPU(struct cpuidle_device, zynq_cpuidle_device); + +/* 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 zynq_init_cpuidle(void) +{ + unsigned int cpu; + struct cpuidle_device *device; + int ret; + + if (!of_machine_is_compatible("xlnx,zynq-7000")) + return -ENODEV; + + ret = cpuidle_register_driver(&zynq_idle_driver); + if (ret) { + pr_err("%s: Driver registration failed\n", __func__); + return ret; + } + + for_each_possible_cpu(cpu) { + device = &per_cpu(zynq_cpuidle_device, cpu); + device->cpu = cpu; + ret = cpuidle_register_device(device); + if (ret) { + pr_err("%s: Device registration failed\n", __func__); + return ret; + } + } + + pr_info("Xilinx Zynq CpuIdle Driver started\n"); + return 0; +} +module_init(zynq_init_cpuidle); -- 1.8.2.3 [unhandled content-type:application/pgp-signature] | |