* Arun R Bharadwaj <[email protected]> [2009-08-19 18:27:16]: This patch creates the Thermal & Power Management Devices module, tpmd_idle which implements the cpuidle infrasture for pseries. It implements a tpmd_idle_loop() which would be the main idle loop called from cpu_idle(). It makes decision of entering either snooze or nap state based on the decision taken by the cpuidle governor.
Signed-off-by: Arun R Bharadwaj <[email protected]> --- arch/powerpc/platforms/pseries/Makefile | 1 arch/powerpc/platforms/pseries/tpmd.h | 10 + arch/powerpc/platforms/pseries/tpmd_idle.c | 192 +++++++++++++++++++++++++++++ 3 files changed, 203 insertions(+) Index: linux.trees.git/arch/powerpc/platforms/pseries/tpmd_idle.c =================================================================== --- /dev/null +++ linux.trees.git/arch/powerpc/platforms/pseries/tpmd_idle.c @@ -0,0 +1,192 @@ + +/* + * tpmd_idle - idle state submodule to the tpmd driver + * + * Copyright (C) 2009 Arun R Bharadwaj <[email protected]> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that 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, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/moduleparam.h> +#include <linux/cpuidle.h> +#include <linux/cpu.h> + +#include <asm/paca.h> +#include <asm/machdep.h> + +#include "plpar_wrappers.h" +#include "tpmd.h" + +MODULE_AUTHOR("Arun R Bharadwaj"); +MODULE_DESCRIPTION("TPMD Idle State Driver"); +MODULE_LICENSE("GPL"); + +struct cpuidle_driver tpmd_idle_driver = { + .name = "tpmd_idle", + .owner = THIS_MODULE, +}; + +void (*pm_idle)(void); +EXPORT_SYMBOL(pm_idle); + +static void (*old_idle_power_save)(void); + +DEFINE_PER_CPU(struct tpmd_processor_power, power); + +#define IDLE_STATE_COUNT 2 + +static int tpmd_idle_init(struct tpmd_processor_power *power) +{ + return cpuidle_register_device(&power->dev); +} + +void tpmd_idle_exit(struct tpmd_processor_power *power) +{ + cpuidle_unregister_device(&power->dev); +} + +static void snooze(void) +{ + local_irq_enable(); + set_thread_flag(TIF_POLLING_NRFLAG); + while (!need_resched()) { + HMT_low(); + HMT_very_low(); + } + clear_thread_flag(TIF_POLLING_NRFLAG); + local_irq_disable(); + smp_mb(); +} + +static void nap(void) +{ + HMT_medium(); + smp_mb(); + cede_processor(); +} + +static int tpmd_idle_loop(struct cpuidle_device *dev, struct cpuidle_state *st) +{ + ktime_t t1, t2; + s64 diff; + int ret; + + get_lppaca()->idle = 1; + get_lppaca()->donate_dedicated_cpu = 1; + + t1 = ktime_get(); + + if (strcmp(st->desc, "idle") == 0) + snooze(); + else + nap(); + + t2 = ktime_get(); + diff = ktime_to_us(ktime_sub(t2, t1)); + if (diff > INT_MAX) + diff = INT_MAX; + + ret = (int) diff; + + get_lppaca()->idle = 0; + get_lppaca()->donate_dedicated_cpu = 0; + + return ret; +} + +static int tpmd_setup_cpuidle(struct tpmd_processor_power *power) +{ + int i; + struct cpuidle_state *state; + struct cpuidle_device *dev = &power->dev; + + dev->cpu = power->id; + + dev->enabled = 0; + for (i = 0; i < IDLE_STATE_COUNT; i++) { + state = &dev->states[i]; + + snprintf(state->name, CPUIDLE_NAME_LEN, "TPM%d", i); + + switch (i) { + case 0: + strncpy(state->desc, "idle", CPUIDLE_DESC_LEN); + state->exit_latency = 0; + state->target_residency = 0; + state->enter = tpmd_idle_loop; + break; + + case 1: + strncpy(state->desc, "nap", CPUIDLE_DESC_LEN); + state->exit_latency = 1; + state->target_residency = 100; + state->enter = tpmd_idle_loop; + break; + } + } + + power->dev.state_count = i; + return 0; +} + +static int tpmd_processor_get_power_info(struct tpmd_processor_power *power, + int cpu) +{ + power->id = cpu; + power->count = 2; + return 0; +} + +static int __init tpmd_processor_init(void) +{ + int cpu; + int result = cpuidle_register_driver(&tpmd_idle_driver); + + if (result < 0) + return result; + + printk(KERN_DEBUG "TPMD idle driver registered\n"); + + for_each_online_cpu(cpu) { + tpmd_processor_get_power_info(&per_cpu(power, cpu), cpu); + tpmd_setup_cpuidle(&per_cpu(power, cpu)); + tpmd_idle_init(&per_cpu(power, cpu)); + } + + printk(KERN_DEBUG "Using cpuidle idle loop\n"); + old_idle_power_save = ppc_md.power_save; + ppc_md.power_save = pm_idle; + return 0; +} + +static void __exit tpmd_processor_exit(void) +{ + int cpu; + + ppc_md.power_save = old_idle_power_save; + for_each_online_cpu(cpu) + tpmd_idle_exit(&per_cpu(power, cpu)); + cpuidle_unregister_driver(&tpmd_idle_driver); + printk(KERN_DEBUG "TPMD idle driver removed\n"); +} + +module_init(tpmd_processor_init); +module_exit(tpmd_processor_exit); Index: linux.trees.git/arch/powerpc/platforms/pseries/tpmd.h =================================================================== --- /dev/null +++ linux.trees.git/arch/powerpc/platforms/pseries/tpmd.h @@ -0,0 +1,10 @@ +#include <linux/kernel.h> +#include <linux/cpuidle.h> + +struct tpmd_processor_power { + struct cpuidle_device dev; + int count; + int id; +}; + +extern struct cpuidle_driver tpmd_idle_driver; Index: linux.trees.git/arch/powerpc/platforms/pseries/Makefile =================================================================== --- linux.trees.git.orig/arch/powerpc/platforms/pseries/Makefile +++ linux.trees.git/arch/powerpc/platforms/pseries/Makefile @@ -26,3 +26,4 @@ obj-$(CONFIG_HCALL_STATS) += hvCall_inst obj-$(CONFIG_PHYP_DUMP) += phyp_dump.o obj-$(CONFIG_CMM) += cmm.o obj-$(CONFIG_DTL) += dtl.o +obj-$(CONFIG_TPMD) += tpmd_idle.o _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
