1 /* 2 * Copyright (C) 2007 PA Semi, Inc 3 * 4 * Authors: Egor Martovetsky <egor@pasemi.com> 5 * Olof Johansson <olof@lixom.net> 6 * 7 * Maintained by: Olof Johansson <olof@lixom.net> 8 * 9 * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c: 10 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License as published by 14 * the Free Software Foundation; either version 2, or (at your option) 15 * any later version. 16 * 17 * This program is distributed in the hope that it will be useful, 18 * but WITHOUT ANY WARRANTY; without even the implied warranty of 19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 20 * GNU General Public License for more details. 21 * 22 * You should have received a copy of the GNU General Public License 23 * along with this program; if not, write to the Free Software 24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 25 * 26 */ 27 28 #include <linux/cpufreq.h> 29 #include <linux/timer.h> 30 #include <linux/module.h> 31 #include <linux/of_address.h> 32 33 #include <asm/hw_irq.h> 34 #include <asm/io.h> 35 #include <asm/prom.h> 36 #include <asm/time.h> 37 #include <asm/smp.h> 38 39 #define SDCASR_REG 0x0100 40 #define SDCASR_REG_STRIDE 0x1000 41 #define SDCPWR_CFGA0_REG 0x0100 42 #define SDCPWR_PWST0_REG 0x0000 43 #define SDCPWR_GIZTIME_REG 0x0440 44 45 /* SDCPWR_GIZTIME_REG fields */ 46 #define SDCPWR_GIZTIME_GR 0x80000000 47 #define SDCPWR_GIZTIME_LONGLOCK 0x000000ff 48 49 /* Offset of ASR registers from SDC base */ 50 #define SDCASR_OFFSET 0x120000 51 52 static void __iomem *sdcpwr_mapbase; 53 static void __iomem *sdcasr_mapbase; 54 55 /* Current astate, is used when waking up from power savings on 56 * one core, in case the other core has switched states during 57 * the idle time. 58 */ 59 static int current_astate; 60 61 /* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */ 62 static struct cpufreq_frequency_table pas_freqs[] = { 63 {0, 0, 0}, 64 {0, 1, 0}, 65 {0, 2, 0}, 66 {0, 3, 0}, 67 {0, 4, 0}, 68 {0, 0, CPUFREQ_TABLE_END}, 69 }; 70 71 /* 72 * hardware specific functions 73 */ 74 75 static int get_astate_freq(int astate) 76 { 77 u32 ret; 78 ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10)); 79 80 return ret & 0x3f; 81 } 82 83 static int get_cur_astate(int cpu) 84 { 85 u32 ret; 86 87 ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG); 88 ret = (ret >> (cpu * 4)) & 0x7; 89 90 return ret; 91 } 92 93 static int get_gizmo_latency(void) 94 { 95 u32 giztime, ret; 96 97 giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG); 98 99 /* just provide the upper bound */ 100 if (giztime & SDCPWR_GIZTIME_GR) 101 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000; 102 else 103 ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000; 104 105 return ret; 106 } 107 108 static void set_astate(int cpu, unsigned int astate) 109 { 110 unsigned long flags; 111 112 /* Return if called before init has run */ 113 if (unlikely(!sdcasr_mapbase)) 114 return; 115 116 local_irq_save(flags); 117 118 out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate); 119 120 local_irq_restore(flags); 121 } 122 123 int check_astate(void) 124 { 125 return get_cur_astate(hard_smp_processor_id()); 126 } 127 128 void restore_astate(int cpu) 129 { 130 set_astate(cpu, current_astate); 131 } 132 133 /* 134 * cpufreq functions 135 */ 136 137 static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy) 138 { 139 struct cpufreq_frequency_table *pos; 140 const u32 *max_freqp; 141 u32 max_freq; 142 int cur_astate, idx; 143 struct resource res; 144 struct device_node *cpu, *dn; 145 int err = -ENODEV; 146 147 cpu = of_get_cpu_node(policy->cpu, NULL); 148 149 of_node_put(cpu); 150 if (!cpu) 151 goto out; 152 153 dn = of_find_compatible_node(NULL, NULL, "1682m-sdc"); 154 if (!dn) 155 dn = of_find_compatible_node(NULL, NULL, 156 "pasemi,pwrficient-sdc"); 157 if (!dn) 158 goto out; 159 err = of_address_to_resource(dn, 0, &res); 160 of_node_put(dn); 161 if (err) 162 goto out; 163 sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000); 164 if (!sdcasr_mapbase) { 165 err = -EINVAL; 166 goto out; 167 } 168 169 dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo"); 170 if (!dn) 171 dn = of_find_compatible_node(NULL, NULL, 172 "pasemi,pwrficient-gizmo"); 173 if (!dn) { 174 err = -ENODEV; 175 goto out_unmap_sdcasr; 176 } 177 err = of_address_to_resource(dn, 0, &res); 178 of_node_put(dn); 179 if (err) 180 goto out_unmap_sdcasr; 181 sdcpwr_mapbase = ioremap(res.start, 0x1000); 182 if (!sdcpwr_mapbase) { 183 err = -EINVAL; 184 goto out_unmap_sdcasr; 185 } 186 187 pr_debug("init cpufreq on CPU %d\n", policy->cpu); 188 189 max_freqp = of_get_property(cpu, "clock-frequency", NULL); 190 if (!max_freqp) { 191 err = -EINVAL; 192 goto out_unmap_sdcpwr; 193 } 194 195 /* we need the freq in kHz */ 196 max_freq = *max_freqp / 1000; 197 198 pr_debug("max clock-frequency is at %u kHz\n", max_freq); 199 pr_debug("initializing frequency table\n"); 200 201 /* initialize frequency table */ 202 cpufreq_for_each_entry_idx(pos, pas_freqs, idx) { 203 pos->frequency = get_astate_freq(pos->driver_data) * 100000; 204 pr_debug("%d: %d\n", idx, pos->frequency); 205 } 206 207 cur_astate = get_cur_astate(policy->cpu); 208 pr_debug("current astate is at %d\n",cur_astate); 209 210 policy->cur = pas_freqs[cur_astate].frequency; 211 ppc_proc_freq = policy->cur * 1000ul; 212 213 return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency()); 214 215 out_unmap_sdcpwr: 216 iounmap(sdcpwr_mapbase); 217 218 out_unmap_sdcasr: 219 iounmap(sdcasr_mapbase); 220 out: 221 return err; 222 } 223 224 static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy) 225 { 226 /* 227 * We don't support CPU hotplug. Don't unmap after the system 228 * has already made it to a running state. 229 */ 230 if (system_state >= SYSTEM_RUNNING) 231 return 0; 232 233 if (sdcasr_mapbase) 234 iounmap(sdcasr_mapbase); 235 if (sdcpwr_mapbase) 236 iounmap(sdcpwr_mapbase); 237 238 return 0; 239 } 240 241 static int pas_cpufreq_target(struct cpufreq_policy *policy, 242 unsigned int pas_astate_new) 243 { 244 int i; 245 246 pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n", 247 policy->cpu, 248 pas_freqs[pas_astate_new].frequency, 249 pas_freqs[pas_astate_new].driver_data); 250 251 current_astate = pas_astate_new; 252 253 for_each_online_cpu(i) 254 set_astate(i, pas_astate_new); 255 256 ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul; 257 return 0; 258 } 259 260 static struct cpufreq_driver pas_cpufreq_driver = { 261 .name = "pas-cpufreq", 262 .flags = CPUFREQ_CONST_LOOPS, 263 .init = pas_cpufreq_cpu_init, 264 .exit = pas_cpufreq_cpu_exit, 265 .verify = cpufreq_generic_frequency_table_verify, 266 .target_index = pas_cpufreq_target, 267 .attr = cpufreq_generic_attr, 268 }; 269 270 /* 271 * module init and destoy 272 */ 273 274 static int __init pas_cpufreq_init(void) 275 { 276 if (!of_machine_is_compatible("PA6T-1682M") && 277 !of_machine_is_compatible("pasemi,pwrficient")) 278 return -ENODEV; 279 280 return cpufreq_register_driver(&pas_cpufreq_driver); 281 } 282 283 static void __exit pas_cpufreq_exit(void) 284 { 285 cpufreq_unregister_driver(&pas_cpufreq_driver); 286 } 287 288 module_init(pas_cpufreq_init); 289 module_exit(pas_cpufreq_exit); 290 291 MODULE_LICENSE("GPL"); 292 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>"); 293