diff options
| -rw-r--r-- | MAINTAINERS | 9 | ||||
| -rw-r--r-- | arch/arm/mach-vexpress/tc2_pm.c | 2 | ||||
| -rw-r--r-- | drivers/cpuidle/Kconfig.arm | 10 | ||||
| -rw-r--r-- | drivers/cpuidle/Makefile | 1 | ||||
| -rw-r--r-- | drivers/cpuidle/cpuidle-big_little.c | 209 | ||||
| -rw-r--r-- | drivers/irqchip/irq-gic.c | 6 | ||||
| -rw-r--r-- | include/linux/irqchip/arm-gic.h | 1 |
7 files changed, 238 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 233ddce..7a78b9f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2307,6 +2307,15 @@ F: drivers/cpufreq/arm_big_little.h F: drivers/cpufreq/arm_big_little.c F: drivers/cpufreq/arm_big_little_dt.c +CPUIDLE DRIVER - ARM BIG LITTLE +M: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> +M: Daniel Lezcano <daniel.lezcano@linaro.org> +L: linux-pm@vger.kernel.org +L: linux-arm-kernel@lists.infradead.org +T: git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git +S: Maintained +F: drivers/cpuidle/cpuidle-big_little.c + CPUIDLE DRIVERS M: Rafael J. Wysocki <rjw@sisk.pl> M: Daniel Lezcano <daniel.lezcano@linaro.org> diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c index 2b7c93a..7aeb5d6 100644 --- a/arch/arm/mach-vexpress/tc2_pm.c +++ b/arch/arm/mach-vexpress/tc2_pm.c @@ -18,6 +18,7 @@ #include <linux/of_address.h> #include <linux/spinlock.h> #include <linux/errno.h> +#include <linux/irqchip/arm-gic.h> #include <asm/mcpm.h> #include <asm/proc-fns.h> @@ -230,6 +231,7 @@ static void tc2_pm_suspend(u64 residency) cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); ve_spc_set_resume_addr(cluster, cpu, virt_to_phys(mcpm_entry_point)); + gic_cpu_if_down(); tc2_pm_down(residency); } diff --git a/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm index b3302193..8e36603 100644 --- a/drivers/cpuidle/Kconfig.arm +++ b/drivers/cpuidle/Kconfig.arm @@ -27,3 +27,13 @@ config ARM_U8500_CPUIDLE help Select this to enable cpuidle for ST-E u8500 processors +config CPU_IDLE_BIG_LITTLE + bool "Support for ARM big.LITTLE processors" + depends on ARCH_VEXPRESS_TC2_PM + select ARM_CPU_SUSPEND + select CPU_IDLE_MULTIPLE_DRIVERS + help + Select this option to enable CPU idle driver for big.LITTLE based + ARM systems. Driver manages CPUs coordination through MCPM and + define different C-states for little and big cores through the + multiple CPU idle drivers infrastructure. diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index 0b9d200..cea5ef5 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_ARM_HIGHBANK_CPUIDLE) += cpuidle-calxeda.o obj-$(CONFIG_ARM_KIRKWOOD_CPUIDLE) += cpuidle-kirkwood.o obj-$(CONFIG_ARM_ZYNQ_CPUIDLE) += cpuidle-zynq.o obj-$(CONFIG_ARM_U8500_CPUIDLE) += cpuidle-ux500.o +obj-$(CONFIG_CPU_IDLE_BIG_LITTLE) += cpuidle-big_little.o diff --git a/drivers/cpuidle/cpuidle-big_little.c b/drivers/cpuidle/cpuidle-big_little.c new file mode 100644 index 0000000..b45fc62 --- /dev/null +++ b/drivers/cpuidle/cpuidle-big_little.c @@ -0,0 +1,209 @@ +/* + * Copyright (c) 2013 ARM/Linaro + * + * Authors: Daniel Lezcano <daniel.lezcano@linaro.org> + * Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + * Nicolas Pitre <nicolas.pitre@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Maintainer: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + * Maintainer: Daniel Lezcano <daniel.lezcano@linaro.org> + */ +#include <linux/cpuidle.h> +#include <linux/cpu_pm.h> +#include <linux/slab.h> +#include <linux/of.h> + +#include <asm/cpu.h> +#include <asm/cputype.h> +#include <asm/cpuidle.h> +#include <asm/mcpm.h> +#include <asm/smp_plat.h> +#include <asm/suspend.h> + +static int bl_enter_powerdown(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int idx); + +/* + * NB: Owing to current menu governor behaviour big and LITTLE + * index 1 states have to define exit_latency and target_residency for + * cluster state since, when all CPUs in a cluster hit it, the cluster + * can be shutdown. This means that when a single CPU enters this state + * the exit_latency and target_residency values are somewhat overkill. + * There is no notion of cluster states in the menu governor, so CPUs + * have to define CPU states where possibly the cluster will be shutdown + * depending on the state of other CPUs. idle states entry and exit happen + * at random times; however the cluster state provides target_residency + * values as if all CPUs in a cluster enter the state at once; this is + * somewhat optimistic and behaviour should be fixed either in the governor + * or in the MCPM back-ends. + * To make this driver 100% generic the number of states and the exit_latency + * target_residency values must be obtained from device tree bindings. + * + * exit_latency: refers to the TC2 vexpress test chip and depends on the + * current cluster operating point. It is the time it takes to get the CPU + * up and running when the CPU is powered up on cluster wake-up from shutdown. + * Current values for big and LITTLE clusters are provided for clusters + * running at default operating points. + * + * target_residency: it is the minimum amount of time the cluster has + * to be down to break even in terms of power consumption. cluster + * shutdown has inherent dynamic power costs (L2 writebacks to DRAM + * being the main factor) that depend on the current operating points. + * The current values for both clusters are provided for a CPU whose half + * of L2 lines are dirty and require cleaning to DRAM, and takes into + * account leakage static power values related to the vexpress TC2 testchip. + */ +static struct cpuidle_driver bl_idle_little_driver = { + .name = "little_idle", + .owner = THIS_MODULE, + .states[0] = ARM_CPUIDLE_WFI_STATE, + .states[1] = { + .enter = bl_enter_powerdown, + .exit_latency = 700, + .target_residency = 2500, + .flags = CPUIDLE_FLAG_TIME_VALID | + CPUIDLE_FLAG_TIMER_STOP, + .name = "C1", + .desc = "ARM little-cluster power down", + }, + .state_count = 2, +}; + +static struct cpuidle_driver bl_idle_big_driver = { + .name = "big_idle", + .owner = THIS_MODULE, + .states[0] = ARM_CPUIDLE_WFI_STATE, + .states[1] = { + .enter = bl_enter_powerdown, + .exit_latency = 500, + .target_residency = 2000, + .flags = CPUIDLE_FLAG_TIME_VALID | + CPUIDLE_FLAG_TIMER_STOP, + .name = "C1", + .desc = "ARM big-cluster power down", + }, + .state_count = 2, +}; + +/* + * notrace prevents trace shims from getting inserted where they + * should not. Global jumps and ldrex/strex must not be inserted + * in power down sequences where caches and MMU may be turned off. + */ +static int notrace bl_powerdown_finisher(unsigned long arg) +{ + /* MCPM works with HW CPU identifiers */ + unsigned int mpidr = read_cpuid_mpidr(); + unsigned int cluster = MPIDR_AFFINITY_LEVEL(mpidr, 1); + unsigned int cpu = MPIDR_AFFINITY_LEVEL(mpidr, 0); + + mcpm_set_entry_vector(cpu, cluster, cpu_resume); + + /* + * Residency value passed to mcpm_cpu_suspend back-end + * has to be given clear semantics. Set to 0 as a + * temporary value. + */ + mcpm_cpu_suspend(0); + + /* return value != 0 means failure */ + return 1; +} + +/** + * bl_enter_powerdown - Programs CPU to enter the specified state + * @dev: cpuidle device + * @drv: The target state to be programmed + * @idx: state index + * + * Called from the CPUidle framework to program the device to the + * specified target state selected by the governor. + */ +static int bl_enter_powerdown(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int idx) +{ + cpu_pm_enter(); + + cpu_suspend(0, bl_powerdown_finisher); + + /* signals the MCPM core that CPU is out of low power state */ + mcpm_cpu_powered_up(); + + cpu_pm_exit(); + + return idx; +} + +static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int cpu_id) +{ + struct cpuinfo_arm *cpu_info; + struct cpumask *cpumask; + unsigned long cpuid; + int cpu; + + cpumask = kzalloc(cpumask_size(), GFP_KERNEL); + if (!cpumask) + return -ENOMEM; + + for_each_possible_cpu(cpu) { + cpu_info = &per_cpu(cpu_data, cpu); + cpuid = is_smp() ? cpu_info->cpuid : read_cpuid_id(); + + /* read cpu id part number */ + if ((cpuid & 0xFFF0) == cpu_id) + cpumask_set_cpu(cpu, cpumask); + } + + drv->cpumask = cpumask; + + return 0; +} + +static int __init bl_idle_init(void) +{ + int ret; + + /* + * Initialize the driver just for a compliant set of machines + */ + if (!of_machine_is_compatible("arm,vexpress,v2p-ca15_a7")) + return -ENODEV; + /* + * For now the differentiation between little and big cores + * is based on the part number. A7 cores are considered little + * cores, A15 are considered big cores. This distinction may + * evolve in the future with a more generic matching approach. + */ + ret = bl_idle_driver_init(&bl_idle_little_driver, + ARM_CPU_PART_CORTEX_A7); + if (ret) + return ret; + + ret = bl_idle_driver_init(&bl_idle_big_driver, ARM_CPU_PART_CORTEX_A15); + if (ret) + goto out_uninit_little; + + ret = cpuidle_register(&bl_idle_little_driver, NULL); + if (ret) + goto out_uninit_big; + + ret = cpuidle_register(&bl_idle_big_driver, NULL); + if (ret) + goto out_unregister_little; + + return 0; + +out_unregister_little: + cpuidle_unregister(&bl_idle_little_driver); +out_uninit_big: + kfree(bl_idle_big_driver.cpumask); +out_uninit_little: + kfree(bl_idle_little_driver.cpumask); + + return ret; +} +device_initcall(bl_idle_init); diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index ee7c503..d0e9480 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -453,6 +453,12 @@ static void gic_cpu_init(struct gic_chip_data *gic) writel_relaxed(1, base + GIC_CPU_CTRL); } +void gic_cpu_if_down(void) +{ + void __iomem *cpu_base = gic_data_cpu_base(&gic_data[0]); + writel_relaxed(0, cpu_base + GIC_CPU_CTRL); +} + #ifdef CONFIG_CPU_PM /* * Saves the GIC distributor registers during suspend or idle. Must be called diff --git a/include/linux/irqchip/arm-gic.h b/include/linux/irqchip/arm-gic.h index 3e203eb..0e5d9ec 100644 --- a/include/linux/irqchip/arm-gic.h +++ b/include/linux/irqchip/arm-gic.h @@ -66,6 +66,7 @@ extern struct irq_chip gic_arch_extn; void gic_init_bases(unsigned int, int, void __iomem *, void __iomem *, u32 offset, struct device_node *); void gic_cascade_irq(unsigned int gic_nr, unsigned int irq); +void gic_cpu_if_down(void); static inline void gic_init(unsigned int nr, int start, void __iomem *dist , void __iomem *cpu) |
