diff options
Diffstat (limited to 'arch/powerpc/platforms/cell/cbe_cpufreq.c')
| -rw-r--r-- | arch/powerpc/platforms/cell/cbe_cpufreq.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/cbe_cpufreq.c b/arch/powerpc/platforms/cell/cbe_cpufreq.c new file mode 100644 index 00000000000..a3850fd1e94 --- /dev/null +++ b/arch/powerpc/platforms/cell/cbe_cpufreq.c @@ -0,0 +1,248 @@ +/* + * cpufreq driver for the cell processor + * + * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 + * + * 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/timer.h> + +#include <asm/hw_irq.h> +#include <asm/io.h> +#include <asm/processor.h> +#include <asm/prom.h> +#include <asm/time.h> + +#include "cbe_regs.h" + +static DEFINE_MUTEX(cbe_switch_mutex); + + +/* the CBE supports an 8 step frequency scaling */ +static struct cpufreq_frequency_table cbe_freqs[] = { + {1, 0}, + {2, 0}, + {3, 0}, + {4, 0}, + {5, 0}, + {6, 0}, + {8, 0}, + {10, 0}, + {0, CPUFREQ_TABLE_END}, +}; + +/* to write to MIC register */ +static u64 MIC_Slow_Fast_Timer_table[] = { + [0 ... 7] = 0x007fc00000000000ull, +}; + +/* more values for the MIC */ +static u64 MIC_Slow_Next_Timer_table[] = { + 0x0000240000000000ull, + 0x0000268000000000ull, + 0x000029C000000000ull, + 0x00002D0000000000ull, + 0x0000300000000000ull, + 0x0000334000000000ull, + 0x000039C000000000ull, + 0x00003FC000000000ull, +}; + +/* + * hardware specific functions + */ + +static int get_pmode(int cpu) +{ + int ret; + struct cbe_pmd_regs __iomem *pmd_regs; + + pmd_regs = cbe_get_cpu_pmd_regs(cpu); + ret = in_be64(&pmd_regs->pmsr) & 0x07; + + return ret; +} + +static int set_pmode(int cpu, unsigned int pmode) +{ + struct cbe_pmd_regs __iomem *pmd_regs; + struct cbe_mic_tm_regs __iomem *mic_tm_regs; + u64 flags; + u64 value; + + local_irq_save(flags); + + mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu); + pmd_regs = cbe_get_cpu_pmd_regs(cpu); + + pr_debug("pm register is mapped at %p\n", &pmd_regs->pmcr); + pr_debug("mic register is mapped at %p\n", &mic_tm_regs->slow_fast_timer_0); + + out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]); + out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]); + + out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]); + out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]); + + value = in_be64(&pmd_regs->pmcr); + /* set bits to zero */ + value &= 0xFFFFFFFFFFFFFFF8ull; + /* set bits to next pmode */ + value |= pmode; + + out_be64(&pmd_regs->pmcr, value); + + /* wait until new pmode appears in status register */ + value = in_be64(&pmd_regs->pmsr) & 0x07; + while(value != pmode) { + cpu_relax(); + value = in_be64(&pmd_regs->pmsr) & 0x07; + } + + local_irq_restore(flags); + + return 0; +} + +/* + * cpufreq functions + */ + +static int cbe_cpufreq_cpu_init (struct cpufreq_policy *policy) +{ + u32 *max_freq; + int i, cur_pmode; + struct device_node *cpu; + + cpu = of_get_cpu_node(policy->cpu, NULL); + + if(!cpu) + return -ENODEV; + + pr_debug("init cpufreq on CPU %d\n", policy->cpu); + + max_freq = (u32*) get_property(cpu, "clock-frequency", NULL); + + if(!max_freq) + return -EINVAL; + + // we need the freq in kHz + *max_freq /= 1000; + + pr_debug("max clock-frequency is at %u kHz\n", *max_freq); + pr_debug("initializing frequency table\n"); + + // initialize frequency table + for (i=0; cbe_freqs[i].frequency!=CPUFREQ_TABLE_END; i++) { + cbe_freqs[i].frequency = *max_freq / cbe_freqs[i].index; + pr_debug("%d: %d\n", i, cbe_freqs[i].frequency); + } + + policy->governor = CPUFREQ_DEFAULT_GOVERNOR; + /* if DEBUG is enabled set_pmode() measures the correct latency of a transition */ + policy->cpuinfo.transition_latency = 25000; + + cur_pmode = get_pmode(policy->cpu); + pr_debug("current pmode is at %d\n",cur_pmode); + + policy->cur = cbe_freqs[cur_pmode].frequency; + +#ifdef CONFIG_SMP + policy->cpus = cpu_sibling_map[policy->cpu]; +#endif + + cpufreq_frequency_table_get_attr (cbe_freqs, policy->cpu); + + /* this ensures that policy->cpuinfo_min and policy->cpuinfo_max are set correctly */ + return cpufreq_frequency_table_cpuinfo (policy, cbe_freqs); +} + +static int cbe_cpufreq_cpu_exit(struct cpufreq_policy *policy) +{ + cpufreq_frequency_table_put_attr(policy->cpu); + return 0; +} + +static int cbe_cpufreq_verify(struct cpufreq_policy *policy) +{ + return cpufreq_frequency_table_verify(policy, cbe_freqs); +} + + +static int cbe_cpufreq_target(struct cpufreq_policy *policy, unsigned int target_freq, + unsigned int relation) +{ + int rc; + struct cpufreq_freqs freqs; + int cbe_pmode_new; + + cpufreq_frequency_table_target(policy, + cbe_freqs, + target_freq, + relation, + &cbe_pmode_new); + + freqs.old = policy->cur; + freqs.new = cbe_freqs[cbe_pmode_new].frequency; + freqs.cpu = policy->cpu; + + mutex_lock (&cbe_switch_mutex); + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + + pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n", + policy->cpu, + cbe_freqs[cbe_pmode_new].frequency, + cbe_freqs[cbe_pmode_new].index); + + rc = set_pmode(policy->cpu, cbe_pmode_new); + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + mutex_unlock(&cbe_switch_mutex); + + return rc; +} + +static struct cpufreq_driver cbe_cpufreq_driver = { + .verify = cbe_cpufreq_verify, + .target = cbe_cpufreq_target, + .init = cbe_cpufreq_cpu_init, + .exit = cbe_cpufreq_cpu_exit, + .name = "cbe-cpufreq", + .owner = THIS_MODULE, + .flags = CPUFREQ_CONST_LOOPS, +}; + +/* + * module init and destoy + */ + +static int __init cbe_cpufreq_init(void) +{ + return cpufreq_register_driver(&cbe_cpufreq_driver); +} + +static void __exit cbe_cpufreq_exit(void) +{ + cpufreq_unregister_driver(&cbe_cpufreq_driver); +} + +module_init(cbe_cpufreq_init); +module_exit(cbe_cpufreq_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Christian Krafft <krafft@de.ibm.com>"); |