diff options
Diffstat (limited to 'arch/powerpc/platforms/cell/cpufreq_spudemand.c')
| -rw-r--r-- | arch/powerpc/platforms/cell/cpufreq_spudemand.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/cpufreq_spudemand.c b/arch/powerpc/platforms/cell/cpufreq_spudemand.c new file mode 100644 index 000000000000..a3c6c01bd6db --- /dev/null +++ b/arch/powerpc/platforms/cell/cpufreq_spudemand.c @@ -0,0 +1,184 @@ +/* + * spu aware cpufreq governor for the cell processor + * + * © Copyright IBM Corporation 2006-2008 + * + * Author: Christian Krafft <krafft@de.ibm.com> + * + * 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, 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/cpufreq.h> +#include <linux/sched.h> +#include <linux/timer.h> +#include <linux/workqueue.h> +#include <asm/atomic.h> +#include <asm/machdep.h> +#include <asm/spu.h> + +#define POLL_TIME 100000 /* in µs */ +#define EXP 753 /* exp(-1) in fixed-point */ + +struct spu_gov_info_struct { + unsigned long busy_spus; /* fixed-point */ + struct cpufreq_policy *policy; + struct delayed_work work; + unsigned int poll_int; /* µs */ +}; +static DEFINE_PER_CPU(struct spu_gov_info_struct, spu_gov_info); + +static struct workqueue_struct *kspugov_wq; + +static int calc_freq(struct spu_gov_info_struct *info) +{ + int cpu; + int busy_spus; + + cpu = info->policy->cpu; + busy_spus = atomic_read(&cbe_spu_info[cpu_to_node(cpu)].busy_spus); + + CALC_LOAD(info->busy_spus, EXP, busy_spus * FIXED_1); + pr_debug("cpu %d: busy_spus=%d, info->busy_spus=%ld\n", + cpu, busy_spus, info->busy_spus); + + return info->policy->max * info->busy_spus / FIXED_1; +} + +static void spu_gov_work(struct work_struct *work) +{ + struct spu_gov_info_struct *info; + int delay; + unsigned long target_freq; + + info = container_of(work, struct spu_gov_info_struct, work.work); + + /* after cancel_delayed_work_sync we unset info->policy */ + BUG_ON(info->policy == NULL); + + target_freq = calc_freq(info); + __cpufreq_driver_target(info->policy, target_freq, CPUFREQ_RELATION_H); + + delay = usecs_to_jiffies(info->poll_int); + queue_delayed_work_on(info->policy->cpu, kspugov_wq, &info->work, delay); +} + +static void spu_gov_init_work(struct spu_gov_info_struct *info) +{ + int delay = usecs_to_jiffies(info->poll_int); + INIT_DELAYED_WORK_DEFERRABLE(&info->work, spu_gov_work); + queue_delayed_work_on(info->policy->cpu, kspugov_wq, &info->work, delay); +} + +static void spu_gov_cancel_work(struct spu_gov_info_struct *info) +{ + cancel_delayed_work_sync(&info->work); +} + +static int spu_gov_govern(struct cpufreq_policy *policy, unsigned int event) +{ + unsigned int cpu = policy->cpu; + struct spu_gov_info_struct *info, *affected_info; + int i; + int ret = 0; + + info = &per_cpu(spu_gov_info, cpu); + + switch (event) { + case CPUFREQ_GOV_START: + if (!cpu_online(cpu)) { + printk(KERN_ERR "cpu %d is not online\n", cpu); + ret = -EINVAL; + break; + } + + if (!policy->cur) { + printk(KERN_ERR "no cpu specified in policy\n"); + ret = -EINVAL; + break; + } + + /* initialize spu_gov_info for all affected cpus */ + for_each_cpu_mask(i, policy->cpus) { + affected_info = &per_cpu(spu_gov_info, i); + affected_info->policy = policy; + } + + info->poll_int = POLL_TIME; + + /* setup timer */ + spu_gov_init_work(info); + + break; + + case CPUFREQ_GOV_STOP: + /* cancel timer */ + spu_gov_cancel_work(info); + + /* clean spu_gov_info for all affected cpus */ + for_each_cpu_mask (i, policy->cpus) { + info = &per_cpu(spu_gov_info, i); + info->policy = NULL; + } + + break; + } + + return ret; +} + +static struct cpufreq_governor spu_governor = { + .name = "spudemand", + .governor = spu_gov_govern, + .owner = THIS_MODULE, +}; + +/* + * module init and destoy + */ + +static int __init spu_gov_init(void) +{ + int ret; + + kspugov_wq = create_workqueue("kspugov"); + if (!kspugov_wq) { + printk(KERN_ERR "creation of kspugov failed\n"); + ret = -EFAULT; + goto out; + } + + ret = cpufreq_register_governor(&spu_governor); + if (ret) { + printk(KERN_ERR "registration of governor failed\n"); + destroy_workqueue(kspugov_wq); + goto out; + } +out: + return ret; +} + +static void __exit spu_gov_exit(void) +{ + cpufreq_unregister_governor(&spu_governor); + destroy_workqueue(kspugov_wq); +} + + +module_init(spu_gov_init); +module_exit(spu_gov_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); + |