cris-artpec3-cpufreq.c revision 361db10f61b1d113eadd1b7b1db5f16f63c4eb49
1#include <linux/init.h> 2#include <linux/module.h> 3#include <linux/cpufreq.h> 4#include <hwregs/reg_map.h> 5#include <hwregs/reg_rdwr.h> 6#include <hwregs/clkgen_defs.h> 7#include <hwregs/ddr2_defs.h> 8 9static int 10cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val, 11 void *data); 12 13static struct notifier_block cris_sdram_freq_notifier_block = { 14 .notifier_call = cris_sdram_freq_notifier 15}; 16 17static struct cpufreq_frequency_table cris_freq_table[] = { 18 {0x01, 6000}, 19 {0x02, 200000}, 20 {0, CPUFREQ_TABLE_END}, 21}; 22 23static unsigned int cris_freq_get_cpu_frequency(unsigned int cpu) 24{ 25 reg_clkgen_rw_clk_ctrl clk_ctrl; 26 clk_ctrl = REG_RD(clkgen, regi_clkgen, rw_clk_ctrl); 27 return clk_ctrl.pll ? 200000 : 6000; 28} 29 30static void cris_freq_set_cpu_state(struct cpufreq_policy *policy, 31 unsigned int state) 32{ 33 struct cpufreq_freqs freqs; 34 reg_clkgen_rw_clk_ctrl clk_ctrl; 35 clk_ctrl = REG_RD(clkgen, regi_clkgen, rw_clk_ctrl); 36 37 freqs.old = cris_freq_get_cpu_frequency(policy->cpu); 38 freqs.new = cris_freq_table[state].frequency; 39 40 cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); 41 42 local_irq_disable(); 43 44 /* Even though we may be SMP they will share the same clock 45 * so all settings are made on CPU0. */ 46 if (cris_freq_table[state].frequency == 200000) 47 clk_ctrl.pll = 1; 48 else 49 clk_ctrl.pll = 0; 50 REG_WR(clkgen, regi_clkgen, rw_clk_ctrl, clk_ctrl); 51 52 local_irq_enable(); 53 54 cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); 55}; 56 57static int cris_freq_target(struct cpufreq_policy *policy, 58 unsigned int target_freq, 59 unsigned int relation) 60{ 61 unsigned int newstate = 0; 62 63 if (cpufreq_frequency_table_target(policy, cris_freq_table, 64 target_freq, relation, &newstate)) 65 return -EINVAL; 66 67 cris_freq_set_cpu_state(policy, newstate); 68 69 return 0; 70} 71 72static int cris_freq_cpu_init(struct cpufreq_policy *policy) 73{ 74 /* cpuinfo and default policy values */ 75 policy->cpuinfo.transition_latency = 1000000; /* 1ms */ 76 policy->cur = cris_freq_get_cpu_frequency(0); 77 78 return cpufreq_table_validate_and_show(policy, cris_freq_table); 79} 80 81 82static struct cpufreq_driver cris_freq_driver = { 83 .get = cris_freq_get_cpu_frequency, 84 .verify = cpufreq_generic_frequency_table_verify, 85 .target = cris_freq_target, 86 .init = cris_freq_cpu_init, 87 .exit = cpufreq_generic_exit, 88 .name = "cris_freq", 89 .attr = cpufreq_generic_attr, 90}; 91 92static int __init cris_freq_init(void) 93{ 94 int ret; 95 ret = cpufreq_register_driver(&cris_freq_driver); 96 cpufreq_register_notifier(&cris_sdram_freq_notifier_block, 97 CPUFREQ_TRANSITION_NOTIFIER); 98 return ret; 99} 100 101static int 102cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val, 103 void *data) 104{ 105 int i; 106 struct cpufreq_freqs *freqs = data; 107 if (val == CPUFREQ_PRECHANGE) { 108 reg_ddr2_rw_cfg cfg = 109 REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg); 110 cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46); 111 112 if (freqs->new == 200000) 113 for (i = 0; i < 50000; i++); 114 REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing); 115 } 116 return 0; 117} 118 119 120module_init(cris_freq_init); 121