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Commit a35c6322 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc 

Pull ARM SoC driver update from Kevin Hilman:
 "This contains the ARM SoC related driver updates for v3.12.  The only
  thing this cycle are core PM updates and CPUidle support for ARM's TC2
  big.LITTLE development platform"

* tag 'drivers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
  cpuidle: big.LITTLE: vexpress-TC2 CPU idle driver
  ARM: vexpress: tc2: disable GIC CPU IF in tc2_pm_suspend
  drivers: irq-chip: irq-gic: introduce gic_cpu_if_down()
parents bef4a0ab 158a71f8

MAINTAINERS

+9 −0
Original line number Diff line number Diff line
@@ -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>

arch/arm/mach-vexpress/tc2_pm.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

}

drivers/cpuidle/Kconfig.arm

+10 −0
Original line number Diff line number Diff line
@@ -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.

drivers/cpuidle/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/cpuidle/cpuidle-big_little.c

0 → 100644
+209 −0
Original line number Diff line number Diff line 
/*

 * 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);