| Message ID | 1407945127-27554-7-git-send-email-lorenzo.pieralisi@arm.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Aug 13, 2014 at 04:52:05PM +0100, Lorenzo Pieralisi wrote: > This patch implements a generic CPU idle driver for ARM64 machines. > > It relies on the DT idle states infrastructure to initialize idle > states count and respective parameters. Current code assumes the driver > is managing idle states on all possible CPUs but can be easily > generalized to support heterogenous systems and build cpumasks at > runtime using MIDRs or DT cpu nodes compatible properties. > > The driver relies on the arm64 CPU operations to call the idle > initialization hook used to parse and save suspend back-end specific > idle states information upon probing. > > Idle state index 0 is always initialized as a simple wfi state, ie always > considered present and functional on all ARM64 platforms. > > Idle state indices higher than 0 trigger idle state entry by calling > the cpu_suspend function, that triggers the suspend operation through > the CPU operations suspend back-end hook. cpu_suspend passes the idle > state index as a parameter so that the CPU operations suspend back-end > can retrieve the required idle state data by using the idle state > index to execute a look-up on its internal data structures. > > Reviewed-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > --- > drivers/cpuidle/Kconfig | 5 ++ > drivers/cpuidle/Kconfig.arm64 | 14 +++++ > drivers/cpuidle/Makefile | 4 ++ > drivers/cpuidle/cpuidle-arm64.c | 131 ++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 154 insertions(+) > create mode 100644 drivers/cpuidle/Kconfig.arm64 > create mode 100644 drivers/cpuidle/cpuidle-arm64.c > > diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig > index 8deb934..c5029c1 100644 > --- a/drivers/cpuidle/Kconfig > +++ b/drivers/cpuidle/Kconfig > @@ -33,6 +33,11 @@ depends on ARM > source "drivers/cpuidle/Kconfig.arm" > endmenu > > +menu "ARM64 CPU Idle Drivers" > +depends on ARM64 > +source "drivers/cpuidle/Kconfig.arm64" > +endmenu > + > menu "MIPS CPU Idle Drivers" > depends on MIPS > source "drivers/cpuidle/Kconfig.mips" > diff --git a/drivers/cpuidle/Kconfig.arm64 b/drivers/cpuidle/Kconfig.arm64 > new file mode 100644 > index 0000000..d0a08ed > --- /dev/null > +++ b/drivers/cpuidle/Kconfig.arm64 > @@ -0,0 +1,14 @@ > +# > +# ARM64 CPU Idle drivers > +# > + > +config ARM64_CPUIDLE > + bool "Generic ARM64 CPU idle Driver" > + select ARM64_CPU_SUSPEND > + select DT_IDLE_STATES > + help > + Select this to enable generic cpuidle driver for ARM64. > + It provides a generic idle driver whose idle states are configured > + at run-time through DT nodes. The CPUidle suspend backend is > + initialized by calling the CPU operations init idle hook > + provided by architecture code. > diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile > index 002b653..4d177b9 100644 > --- a/drivers/cpuidle/Makefile > +++ b/drivers/cpuidle/Makefile > @@ -23,6 +23,10 @@ obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += cpuidle-exynos.o > obj-$(CONFIG_MIPS_CPS_CPUIDLE) += cpuidle-cps.o > > ############################################################################### > +# ARM64 drivers > +obj-$(CONFIG_ARM64_CPUIDLE) += cpuidle-arm64.o > + > +############################################################################### > # POWERPC drivers > obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o > obj-$(CONFIG_POWERNV_CPUIDLE) += cpuidle-powernv.o > diff --git a/drivers/cpuidle/cpuidle-arm64.c b/drivers/cpuidle/cpuidle-arm64.c > new file mode 100644 > index 0000000..25ec622 > --- /dev/null > +++ b/drivers/cpuidle/cpuidle-arm64.c > @@ -0,0 +1,131 @@ > +/* > + * ARM64 generic CPU idle driver. > + * > + * Copyright (C) 2014 ARM Ltd. > + * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > + * > + * 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. > + */ > + > +#define pr_fmt(fmt) "CPUidle arm64: " fmt > + > +#include <linux/cpuidle.h> > +#include <linux/cpumask.h> > +#include <linux/cpu_pm.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/slab.h> > + > +#include <asm/cpuidle.h> > +#include <asm/suspend.h> > + > +#include "dt_idle_states.h" > + > +/* > + * arm_enter_idle_state - Programs CPU to enter the specified state > + * > + * dev: cpuidle device > + * drv: cpuidle driver > + * idx: state index > + * > + * Called from the CPUidle framework to program the device to the > + * specified target state selected by the governor. > + */ > +static int arm_enter_idle_state(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, int idx) Nitpick: for consistency, I would either prefix it arm64 or drop the prefix entirely (it's a static function anyway). > +struct cpuidle_driver arm64_idle_driver = { Should this be static? Otherwise: Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
On Wed, Aug 13, 2014 at 04:52:05PM +0100, Lorenzo Pieralisi wrote: > +static int __init arm64_idle_init(void) > +{ > + int i, ret; > + struct cpuidle_driver *drv = &arm64_idle_driver; > + > + drv->cpumask = kzalloc(cpumask_size(), GFP_KERNEL); > + if (!drv->cpumask) > + return -ENOMEM; > + > + cpumask_copy(drv->cpumask, cpu_possible_mask); > + /* > + * Initialize idle states data, starting at index 1. > + * This driver is DT only, if no DT idle states are detected (ret == 0) > + * let the driver initialization fail accordingly since there is no > + * reason to initialize the idle driver if only wfi is supported. > + */ > + ret = dt_init_idle_driver(drv, 1); > + if (ret <= 0) > + goto free_mem; > + /* > + * Call arch CPU operations in order to initialize > + * idle states suspend back-end specific data > + */ > + for_each_cpu(i, drv->cpumask) { > + ret = cpu_init_idle(i); > + if (ret) > + goto free_mem; > + } > + > + for (i = 1; i < drv->state_count; i++) > + drv->states[i].enter = arm_enter_idle_state; BTW, I've seen this pattern a few times already. Do you think it would be useful to change the dt_init_idle_driver() API to take a function pointer as argument and populate it there? The only drawback would be if we want different functions based on the states that have been populated (not sure whether we'll need the flexibility in the future). Either way, my ack on this patch stands.
On Mon, Aug 18, 2014 at 03:21:53PM +0100, Catalin Marinas wrote: > On Wed, Aug 13, 2014 at 04:52:05PM +0100, Lorenzo Pieralisi wrote: > > +static int __init arm64_idle_init(void) > > +{ > > + int i, ret; > > + struct cpuidle_driver *drv = &arm64_idle_driver; > > + > > + drv->cpumask = kzalloc(cpumask_size(), GFP_KERNEL); > > + if (!drv->cpumask) > > + return -ENOMEM; > > + > > + cpumask_copy(drv->cpumask, cpu_possible_mask); > > + /* > > + * Initialize idle states data, starting at index 1. > > + * This driver is DT only, if no DT idle states are detected (ret == 0) > > + * let the driver initialization fail accordingly since there is no > > + * reason to initialize the idle driver if only wfi is supported. > > + */ > > + ret = dt_init_idle_driver(drv, 1); > > + if (ret <= 0) > > + goto free_mem; > > + /* > > + * Call arch CPU operations in order to initialize > > + * idle states suspend back-end specific data > > + */ > > + for_each_cpu(i, drv->cpumask) { > > + ret = cpu_init_idle(i); > > + if (ret) > > + goto free_mem; > > + } > > + > > + for (i = 1; i < drv->state_count; i++) > > + drv->states[i].enter = arm_enter_idle_state; > > BTW, I've seen this pattern a few times already. Do you think it would > be useful to change the dt_init_idle_driver() API to take a function > pointer as argument and populate it there? The only drawback would be if > we want different functions based on the states that have been > populated (not sure whether we'll need the flexibility in the future). > Either way, my ack on this patch stands. Yes, you have a point I thought about that. My fear is legacy drivers that might require different function pointers for different states (but still want to get idle states data from DT when we convert them). I wanted to tread carefully as a first step, it should not be a blocker, but I will give it more thought. I do not think we need a function pointer per-state, I will talk to Daniel to make a final decision. Thank you ! Lorenzo -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Aug 18, 2014 at 03:21:43PM +0100, Catalin Marinas wrote: > On Wed, Aug 13, 2014 at 04:52:05PM +0100, Lorenzo Pieralisi wrote: > > This patch implements a generic CPU idle driver for ARM64 machines. > > > > It relies on the DT idle states infrastructure to initialize idle > > states count and respective parameters. Current code assumes the driver > > is managing idle states on all possible CPUs but can be easily > > generalized to support heterogenous systems and build cpumasks at > > runtime using MIDRs or DT cpu nodes compatible properties. > > > > The driver relies on the arm64 CPU operations to call the idle > > initialization hook used to parse and save suspend back-end specific > > idle states information upon probing. > > > > Idle state index 0 is always initialized as a simple wfi state, ie always > > considered present and functional on all ARM64 platforms. > > > > Idle state indices higher than 0 trigger idle state entry by calling > > the cpu_suspend function, that triggers the suspend operation through > > the CPU operations suspend back-end hook. cpu_suspend passes the idle > > state index as a parameter so that the CPU operations suspend back-end > > can retrieve the required idle state data by using the idle state > > index to execute a look-up on its internal data structures. > > > > Reviewed-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > > --- > > drivers/cpuidle/Kconfig | 5 ++ > > drivers/cpuidle/Kconfig.arm64 | 14 +++++ > > drivers/cpuidle/Makefile | 4 ++ > > drivers/cpuidle/cpuidle-arm64.c | 131 ++++++++++++++++++++++++++++++++++++++++ > > 4 files changed, 154 insertions(+) > > create mode 100644 drivers/cpuidle/Kconfig.arm64 > > create mode 100644 drivers/cpuidle/cpuidle-arm64.c > > > > diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig > > index 8deb934..c5029c1 100644 > > --- a/drivers/cpuidle/Kconfig > > +++ b/drivers/cpuidle/Kconfig > > @@ -33,6 +33,11 @@ depends on ARM > > source "drivers/cpuidle/Kconfig.arm" > > endmenu > > > > +menu "ARM64 CPU Idle Drivers" > > +depends on ARM64 > > +source "drivers/cpuidle/Kconfig.arm64" > > +endmenu > > + > > menu "MIPS CPU Idle Drivers" > > depends on MIPS > > source "drivers/cpuidle/Kconfig.mips" > > diff --git a/drivers/cpuidle/Kconfig.arm64 b/drivers/cpuidle/Kconfig.arm64 > > new file mode 100644 > > index 0000000..d0a08ed > > --- /dev/null > > +++ b/drivers/cpuidle/Kconfig.arm64 > > @@ -0,0 +1,14 @@ > > +# > > +# ARM64 CPU Idle drivers > > +# > > + > > +config ARM64_CPUIDLE > > + bool "Generic ARM64 CPU idle Driver" > > + select ARM64_CPU_SUSPEND > > + select DT_IDLE_STATES > > + help > > + Select this to enable generic cpuidle driver for ARM64. > > + It provides a generic idle driver whose idle states are configured > > + at run-time through DT nodes. The CPUidle suspend backend is > > + initialized by calling the CPU operations init idle hook > > + provided by architecture code. > > diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile > > index 002b653..4d177b9 100644 > > --- a/drivers/cpuidle/Makefile > > +++ b/drivers/cpuidle/Makefile > > @@ -23,6 +23,10 @@ obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += cpuidle-exynos.o > > obj-$(CONFIG_MIPS_CPS_CPUIDLE) += cpuidle-cps.o > > > > ############################################################################### > > +# ARM64 drivers > > +obj-$(CONFIG_ARM64_CPUIDLE) += cpuidle-arm64.o > > + > > +############################################################################### > > # POWERPC drivers > > obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o > > obj-$(CONFIG_POWERNV_CPUIDLE) += cpuidle-powernv.o > > diff --git a/drivers/cpuidle/cpuidle-arm64.c b/drivers/cpuidle/cpuidle-arm64.c > > new file mode 100644 > > index 0000000..25ec622 > > --- /dev/null > > +++ b/drivers/cpuidle/cpuidle-arm64.c > > @@ -0,0 +1,131 @@ > > +/* > > + * ARM64 generic CPU idle driver. > > + * > > + * Copyright (C) 2014 ARM Ltd. > > + * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > > + * > > + * 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. > > + */ > > + > > +#define pr_fmt(fmt) "CPUidle arm64: " fmt > > + > > +#include <linux/cpuidle.h> > > +#include <linux/cpumask.h> > > +#include <linux/cpu_pm.h> > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/slab.h> > > + > > +#include <asm/cpuidle.h> > > +#include <asm/suspend.h> > > + > > +#include "dt_idle_states.h" > > + > > +/* > > + * arm_enter_idle_state - Programs CPU to enter the specified state > > + * > > + * dev: cpuidle device > > + * drv: cpuidle driver > > + * idx: state index > > + * > > + * Called from the CPUidle framework to program the device to the > > + * specified target state selected by the governor. > > + */ > > +static int arm_enter_idle_state(struct cpuidle_device *dev, > > + struct cpuidle_driver *drv, int idx) > > Nitpick: for consistency, I would either prefix it arm64 or drop the > prefix entirely (it's a static function anyway). Yes, that's right I will prefix it with arm64. > > +struct cpuidle_driver arm64_idle_driver = { > > Should this be static? Yes it should, I missed that, thanks. > Otherwise: > > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Thank you ! Lorenzo -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig index 8deb934..c5029c1 100644 --- a/drivers/cpuidle/Kconfig +++ b/drivers/cpuidle/Kconfig @@ -33,6 +33,11 @@ depends on ARM source "drivers/cpuidle/Kconfig.arm" endmenu +menu "ARM64 CPU Idle Drivers" +depends on ARM64 +source "drivers/cpuidle/Kconfig.arm64" +endmenu + menu "MIPS CPU Idle Drivers" depends on MIPS source "drivers/cpuidle/Kconfig.mips" diff --git a/drivers/cpuidle/Kconfig.arm64 b/drivers/cpuidle/Kconfig.arm64 new file mode 100644 index 0000000..d0a08ed --- /dev/null +++ b/drivers/cpuidle/Kconfig.arm64 @@ -0,0 +1,14 @@ +# +# ARM64 CPU Idle drivers +# + +config ARM64_CPUIDLE + bool "Generic ARM64 CPU idle Driver" + select ARM64_CPU_SUSPEND + select DT_IDLE_STATES + help + Select this to enable generic cpuidle driver for ARM64. + It provides a generic idle driver whose idle states are configured + at run-time through DT nodes. The CPUidle suspend backend is + initialized by calling the CPU operations init idle hook + provided by architecture code. diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index 002b653..4d177b9 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -23,6 +23,10 @@ obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += cpuidle-exynos.o obj-$(CONFIG_MIPS_CPS_CPUIDLE) += cpuidle-cps.o ############################################################################### +# ARM64 drivers +obj-$(CONFIG_ARM64_CPUIDLE) += cpuidle-arm64.o + +############################################################################### # POWERPC drivers obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o obj-$(CONFIG_POWERNV_CPUIDLE) += cpuidle-powernv.o diff --git a/drivers/cpuidle/cpuidle-arm64.c b/drivers/cpuidle/cpuidle-arm64.c new file mode 100644 index 0000000..25ec622 --- /dev/null +++ b/drivers/cpuidle/cpuidle-arm64.c @@ -0,0 +1,131 @@ +/* + * ARM64 generic CPU idle driver. + * + * Copyright (C) 2014 ARM Ltd. + * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + * + * 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. + */ + +#define pr_fmt(fmt) "CPUidle arm64: " fmt + +#include <linux/cpuidle.h> +#include <linux/cpumask.h> +#include <linux/cpu_pm.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/slab.h> + +#include <asm/cpuidle.h> +#include <asm/suspend.h> + +#include "dt_idle_states.h" + +/* + * arm_enter_idle_state - Programs CPU to enter the specified state + * + * dev: cpuidle device + * drv: cpuidle driver + * idx: state index + * + * Called from the CPUidle framework to program the device to the + * specified target state selected by the governor. + */ +static int arm_enter_idle_state(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int idx) +{ + int ret; + + if (!idx) { + cpu_do_idle(); + return idx; + } + + ret = cpu_pm_enter(); + if (!ret) { + /* + * Pass idle state index to cpu_suspend which in turn will + * call the CPU ops suspend protocol with idle index as a + * parameter. + */ + ret = cpu_suspend(idx); + + cpu_pm_exit(); + } + + return ret ? -1 : idx; +} + +struct cpuidle_driver arm64_idle_driver = { + .name = "arm64_idle", + .owner = THIS_MODULE, + /* + * State at index 0 is standby wfi and considered standard + * on all ARM platforms. If in some platforms simple wfi + * can't be used as "state 0", DT bindings must be implemented + * to work around this issue and allow installing a special + * handler for idle state index 0. + */ + .states[0] = { + .enter = arm_enter_idle_state, + .exit_latency = 1, + .target_residency = 1, + .power_usage = UINT_MAX, + .flags = CPUIDLE_FLAG_TIME_VALID, + .name = "WFI", + .desc = "ARM64 WFI", + } +}; + +/* + * arm64_idle_init + * + * Registers the arm64 specific cpuidle driver with the cpuidle + * framework. It relies on core code to parse the idle states + * and initialize them using driver data structures accordingly. + */ +static int __init arm64_idle_init(void) +{ + int i, ret; + struct cpuidle_driver *drv = &arm64_idle_driver; + + drv->cpumask = kzalloc(cpumask_size(), GFP_KERNEL); + if (!drv->cpumask) + return -ENOMEM; + + cpumask_copy(drv->cpumask, cpu_possible_mask); + /* + * Initialize idle states data, starting at index 1. + * This driver is DT only, if no DT idle states are detected (ret == 0) + * let the driver initialization fail accordingly since there is no + * reason to initialize the idle driver if only wfi is supported. + */ + ret = dt_init_idle_driver(drv, 1); + if (ret <= 0) + goto free_mem; + /* + * Call arch CPU operations in order to initialize + * idle states suspend back-end specific data + */ + for_each_cpu(i, drv->cpumask) { + ret = cpu_init_idle(i); + if (ret) + goto free_mem; + } + + for (i = 1; i < drv->state_count; i++) + drv->states[i].enter = arm_enter_idle_state; + + ret = cpuidle_register(drv, NULL); + if (ret) + goto free_mem; + + return 0; +free_mem: + kfree(drv->cpumask); + return ret; +} +device_initcall(arm64_idle_init);