/* * cpufreq driver for the cell processor * * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 * * Author: Christian Krafft * * 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 #include #include #include #include #include #include #include #include #include #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 struct of_device *pmi_dev; static int set_pmode_pmi(int cpu, unsigned int pmode) { int ret; pmi_message_t pmi_msg; #ifdef DEBUG u64 time; #endif pmi_msg.type = PMI_TYPE_FREQ_CHANGE; pmi_msg.data1 = cbe_cpu_to_node(cpu); pmi_msg.data2 = pmode; #ifdef DEBUG time = (u64) get_cycles(); #endif pmi_send_message(pmi_dev, pmi_msg); ret = pmi_msg.data2; pr_debug("PMI returned slow mode %d\n", ret); #ifdef DEBUG time = (u64) get_cycles() - time; /* actual cycles (not cpu cycles!) */ time = 1000000000 * time / CLOCK_TICK_RATE; /* time in ns (10^-9) */ pr_debug("had to wait %lu ns for a transition\n", time); #endif return ret; } 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_reg(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; } static int set_pmode(int cpu, unsigned int slow_mode) { if (pmi_dev) return set_pmode_pmi(cpu, slow_mode); else return set_pmode_reg(cpu, slow_mode); } static void cbe_cpufreq_handle_pmi(struct of_device *dev, pmi_message_t pmi_msg) { struct cpufreq_policy policy; u8 cpu; u8 cbe_pmode_new; BUG_ON(pmi_msg.type != PMI_TYPE_FREQ_CHANGE); cpu = cbe_node_to_cpu(pmi_msg.data1); cbe_pmode_new = pmi_msg.data2; cpufreq_get_policy(&policy, cpu); policy.max = min(policy.max, cbe_freqs[cbe_pmode_new].frequency); policy.min = min(policy.min, policy.max); pr_debug("cbe_handle_pmi: new policy.min=%d policy.max=%d\n", policy.min, policy.max); cpufreq_set_policy(&policy); } static struct pmi_handler cbe_pmi_handler = { .type = PMI_TYPE_FREQ_CHANGE, .handle_pmi_message = cbe_cpufreq_handle_pmi, }; /* * cpufreq functions */ static int cbe_cpufreq_cpu_init(struct cpufreq_policy *policy) { const u32 *max_freqp; 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_freqp = of_get_property(cpu, "clock-frequency", NULL); if (!max_freqp) return -EINVAL; /* we need the freq in kHz */ max_freq = *max_freqp / 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) { struct device_node *np; if (!machine_is(cell)) return -ENODEV; np = of_find_node_by_type(NULL, "ibm,pmi"); pmi_dev = of_find_device_by_node(np); if (pmi_dev) pmi_register_handler(pmi_dev, &cbe_pmi_handler); return cpufreq_register_driver(&cbe_cpufreq_driver); } static void __exit cbe_cpufreq_exit(void) { if (pmi_dev) pmi_unregister_handler(pmi_dev, &cbe_pmi_handler); cpufreq_unregister_driver(&cbe_cpufreq_driver); } module_init(cbe_cpufreq_init); module_exit(cbe_cpufreq_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Christian Krafft ");