1 /* 2 * Freescale General-purpose Timers Module 3 * 4 * Copyright (c) Freescale Semiconductor, Inc. 2006. 5 * Shlomi Gridish <gridish@freescale.com> 6 * Jerry Huang <Chang-Ming.Huang@freescale.com> 7 * Copyright (c) MontaVista Software, Inc. 2008. 8 * Anton Vorontsov <avorontsov@ru.mvista.com> 9 * 10 * This program is free software; you can redistribute it and/or modify it 11 * under the terms of the GNU General Public License as published by the 12 * Free Software Foundation; either version 2 of the License, or (at your 13 * option) any later version. 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/err.h> 18 #include <linux/errno.h> 19 #include <linux/list.h> 20 #include <linux/io.h> 21 #include <linux/of.h> 22 #include <linux/of_address.h> 23 #include <linux/of_irq.h> 24 #include <linux/spinlock.h> 25 #include <linux/bitops.h> 26 #include <linux/slab.h> 27 #include <linux/export.h> 28 #include <asm/fsl_gtm.h> 29 30 #define GTCFR_STP(x) ((x) & 1 ? 1 << 5 : 1 << 1) 31 #define GTCFR_RST(x) ((x) & 1 ? 1 << 4 : 1 << 0) 32 33 #define GTMDR_ICLK_MASK (3 << 1) 34 #define GTMDR_ICLK_ICAS (0 << 1) 35 #define GTMDR_ICLK_ICLK (1 << 1) 36 #define GTMDR_ICLK_SLGO (2 << 1) 37 #define GTMDR_FRR (1 << 3) 38 #define GTMDR_ORI (1 << 4) 39 #define GTMDR_SPS(x) ((x) << 8) 40 41 struct gtm_timers_regs { 42 u8 gtcfr1; /* Timer 1, Timer 2 global config register */ 43 u8 res0[0x3]; 44 u8 gtcfr2; /* Timer 3, timer 4 global config register */ 45 u8 res1[0xB]; 46 __be16 gtmdr1; /* Timer 1 mode register */ 47 __be16 gtmdr2; /* Timer 2 mode register */ 48 __be16 gtrfr1; /* Timer 1 reference register */ 49 __be16 gtrfr2; /* Timer 2 reference register */ 50 __be16 gtcpr1; /* Timer 1 capture register */ 51 __be16 gtcpr2; /* Timer 2 capture register */ 52 __be16 gtcnr1; /* Timer 1 counter */ 53 __be16 gtcnr2; /* Timer 2 counter */ 54 __be16 gtmdr3; /* Timer 3 mode register */ 55 __be16 gtmdr4; /* Timer 4 mode register */ 56 __be16 gtrfr3; /* Timer 3 reference register */ 57 __be16 gtrfr4; /* Timer 4 reference register */ 58 __be16 gtcpr3; /* Timer 3 capture register */ 59 __be16 gtcpr4; /* Timer 4 capture register */ 60 __be16 gtcnr3; /* Timer 3 counter */ 61 __be16 gtcnr4; /* Timer 4 counter */ 62 __be16 gtevr1; /* Timer 1 event register */ 63 __be16 gtevr2; /* Timer 2 event register */ 64 __be16 gtevr3; /* Timer 3 event register */ 65 __be16 gtevr4; /* Timer 4 event register */ 66 __be16 gtpsr1; /* Timer 1 prescale register */ 67 __be16 gtpsr2; /* Timer 2 prescale register */ 68 __be16 gtpsr3; /* Timer 3 prescale register */ 69 __be16 gtpsr4; /* Timer 4 prescale register */ 70 u8 res2[0x40]; 71 } __attribute__ ((packed)); 72 73 struct gtm { 74 unsigned int clock; 75 struct gtm_timers_regs __iomem *regs; 76 struct gtm_timer timers[4]; 77 spinlock_t lock; 78 struct list_head list_node; 79 }; 80 81 static LIST_HEAD(gtms); 82 83 /** 84 * gtm_get_timer - request GTM timer to use it with the rest of GTM API 85 * Context: non-IRQ 86 * 87 * This function reserves GTM timer for later use. It returns gtm_timer 88 * structure to use with the rest of GTM API, you should use timer->irq 89 * to manage timer interrupt. 90 */ 91 struct gtm_timer *gtm_get_timer16(void) 92 { 93 struct gtm *gtm = NULL; 94 int i; 95 96 list_for_each_entry(gtm, >ms, list_node) { 97 spin_lock_irq(>m->lock); 98 99 for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) { 100 if (!gtm->timers[i].requested) { 101 gtm->timers[i].requested = true; 102 spin_unlock_irq(>m->lock); 103 return >m->timers[i]; 104 } 105 } 106 107 spin_unlock_irq(>m->lock); 108 } 109 110 if (gtm) 111 return ERR_PTR(-EBUSY); 112 return ERR_PTR(-ENODEV); 113 } 114 EXPORT_SYMBOL(gtm_get_timer16); 115 116 /** 117 * gtm_get_specific_timer - request specific GTM timer 118 * @gtm: specific GTM, pass here GTM's device_node->data 119 * @timer: specific timer number, Timer1 is 0. 120 * Context: non-IRQ 121 * 122 * This function reserves GTM timer for later use. It returns gtm_timer 123 * structure to use with the rest of GTM API, you should use timer->irq 124 * to manage timer interrupt. 125 */ 126 struct gtm_timer *gtm_get_specific_timer16(struct gtm *gtm, 127 unsigned int timer) 128 { 129 struct gtm_timer *ret = ERR_PTR(-EBUSY); 130 131 if (timer > 3) 132 return ERR_PTR(-EINVAL); 133 134 spin_lock_irq(>m->lock); 135 136 if (gtm->timers[timer].requested) 137 goto out; 138 139 ret = >m->timers[timer]; 140 ret->requested = true; 141 142 out: 143 spin_unlock_irq(>m->lock); 144 return ret; 145 } 146 EXPORT_SYMBOL(gtm_get_specific_timer16); 147 148 /** 149 * gtm_put_timer16 - release 16 bits GTM timer 150 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 151 * Context: any 152 * 153 * This function releases GTM timer so others may request it. 154 */ 155 void gtm_put_timer16(struct gtm_timer *tmr) 156 { 157 gtm_stop_timer16(tmr); 158 159 spin_lock_irq(&tmr->gtm->lock); 160 tmr->requested = false; 161 spin_unlock_irq(&tmr->gtm->lock); 162 } 163 EXPORT_SYMBOL(gtm_put_timer16); 164 165 /* 166 * This is back-end for the exported functions, it's used to reset single 167 * timer in reference mode. 168 */ 169 static int gtm_set_ref_timer16(struct gtm_timer *tmr, int frequency, 170 int reference_value, bool free_run) 171 { 172 struct gtm *gtm = tmr->gtm; 173 int num = tmr - >m->timers[0]; 174 unsigned int prescaler; 175 u8 iclk = GTMDR_ICLK_ICLK; 176 u8 psr; 177 u8 sps; 178 unsigned long flags; 179 int max_prescaler = 256 * 256 * 16; 180 181 /* CPM2 doesn't have primary prescaler */ 182 if (!tmr->gtpsr) 183 max_prescaler /= 256; 184 185 prescaler = gtm->clock / frequency; 186 /* 187 * We have two 8 bit prescalers -- primary and secondary (psr, sps), 188 * plus "slow go" mode (clk / 16). So, total prescale value is 189 * 16 * (psr + 1) * (sps + 1). Though, for CPM2 GTMs we losing psr. 190 */ 191 if (prescaler > max_prescaler) 192 return -EINVAL; 193 194 if (prescaler > max_prescaler / 16) { 195 iclk = GTMDR_ICLK_SLGO; 196 prescaler /= 16; 197 } 198 199 if (prescaler <= 256) { 200 psr = 0; 201 sps = prescaler - 1; 202 } else { 203 psr = 256 - 1; 204 sps = prescaler / 256 - 1; 205 } 206 207 spin_lock_irqsave(>m->lock, flags); 208 209 /* 210 * Properly reset timers: stop, reset, set up prescalers, reference 211 * value and clear event register. 212 */ 213 clrsetbits_8(tmr->gtcfr, ~(GTCFR_STP(num) | GTCFR_RST(num)), 214 GTCFR_STP(num) | GTCFR_RST(num)); 215 216 setbits8(tmr->gtcfr, GTCFR_STP(num)); 217 218 if (tmr->gtpsr) 219 out_be16(tmr->gtpsr, psr); 220 clrsetbits_be16(tmr->gtmdr, 0xFFFF, iclk | GTMDR_SPS(sps) | 221 GTMDR_ORI | (free_run ? GTMDR_FRR : 0)); 222 out_be16(tmr->gtcnr, 0); 223 out_be16(tmr->gtrfr, reference_value); 224 out_be16(tmr->gtevr, 0xFFFF); 225 226 /* Let it be. */ 227 clrbits8(tmr->gtcfr, GTCFR_STP(num)); 228 229 spin_unlock_irqrestore(>m->lock, flags); 230 231 return 0; 232 } 233 234 /** 235 * gtm_set_timer16 - (re)set 16 bit timer with arbitrary precision 236 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 237 * @usec: timer interval in microseconds 238 * @reload: if set, the timer will reset upon expiry rather than 239 * continue running free. 240 * Context: any 241 * 242 * This function (re)sets the GTM timer so that it counts up to the requested 243 * interval value, and fires the interrupt when the value is reached. This 244 * function will reduce the precision of the timer as needed in order for the 245 * requested timeout to fit in a 16-bit register. 246 */ 247 int gtm_set_timer16(struct gtm_timer *tmr, unsigned long usec, bool reload) 248 { 249 /* quite obvious, frequency which is enough for µSec precision */ 250 int freq = 1000000; 251 unsigned int bit; 252 253 bit = fls_long(usec); 254 if (bit > 15) { 255 freq >>= bit - 15; 256 usec >>= bit - 15; 257 } 258 259 if (!freq) 260 return -EINVAL; 261 262 return gtm_set_ref_timer16(tmr, freq, usec, reload); 263 } 264 EXPORT_SYMBOL(gtm_set_timer16); 265 266 /** 267 * gtm_set_exact_utimer16 - (re)set 16 bits timer 268 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 269 * @usec: timer interval in microseconds 270 * @reload: if set, the timer will reset upon expiry rather than 271 * continue running free. 272 * Context: any 273 * 274 * This function (re)sets GTM timer so that it counts up to the requested 275 * interval value, and fires the interrupt when the value is reached. If reload 276 * flag was set, timer will also reset itself upon reference value, otherwise 277 * it continues to increment. 278 * 279 * The _exact_ bit in the function name states that this function will not 280 * crop precision of the "usec" argument, thus usec is limited to 16 bits 281 * (single timer width). 282 */ 283 int gtm_set_exact_timer16(struct gtm_timer *tmr, u16 usec, bool reload) 284 { 285 /* quite obvious, frequency which is enough for µSec precision */ 286 const int freq = 1000000; 287 288 /* 289 * We can lower the frequency (and probably power consumption) by 290 * dividing both frequency and usec by 2 until there is no remainder. 291 * But we won't bother with this unless savings are measured, so just 292 * run the timer as is. 293 */ 294 295 return gtm_set_ref_timer16(tmr, freq, usec, reload); 296 } 297 EXPORT_SYMBOL(gtm_set_exact_timer16); 298 299 /** 300 * gtm_stop_timer16 - stop single timer 301 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 302 * Context: any 303 * 304 * This function simply stops the GTM timer. 305 */ 306 void gtm_stop_timer16(struct gtm_timer *tmr) 307 { 308 struct gtm *gtm = tmr->gtm; 309 int num = tmr - >m->timers[0]; 310 unsigned long flags; 311 312 spin_lock_irqsave(>m->lock, flags); 313 314 setbits8(tmr->gtcfr, GTCFR_STP(num)); 315 out_be16(tmr->gtevr, 0xFFFF); 316 317 spin_unlock_irqrestore(>m->lock, flags); 318 } 319 EXPORT_SYMBOL(gtm_stop_timer16); 320 321 /** 322 * gtm_ack_timer16 - acknowledge timer event (free-run timers only) 323 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 324 * @events: events mask to ack 325 * Context: any 326 * 327 * Thus function used to acknowledge timer interrupt event, use it inside the 328 * interrupt handler. 329 */ 330 void gtm_ack_timer16(struct gtm_timer *tmr, u16 events) 331 { 332 out_be16(tmr->gtevr, events); 333 } 334 EXPORT_SYMBOL(gtm_ack_timer16); 335 336 static void __init gtm_set_shortcuts(struct device_node *np, 337 struct gtm_timer *timers, 338 struct gtm_timers_regs __iomem *regs) 339 { 340 /* 341 * Yeah, I don't like this either, but timers' registers a bit messed, 342 * so we have to provide shortcuts to write timer independent code. 343 * Alternative option is to create gt*() accessors, but that will be 344 * even uglier and cryptic. 345 */ 346 timers[0].gtcfr = ®s->gtcfr1; 347 timers[0].gtmdr = ®s->gtmdr1; 348 timers[0].gtcnr = ®s->gtcnr1; 349 timers[0].gtrfr = ®s->gtrfr1; 350 timers[0].gtevr = ®s->gtevr1; 351 352 timers[1].gtcfr = ®s->gtcfr1; 353 timers[1].gtmdr = ®s->gtmdr2; 354 timers[1].gtcnr = ®s->gtcnr2; 355 timers[1].gtrfr = ®s->gtrfr2; 356 timers[1].gtevr = ®s->gtevr2; 357 358 timers[2].gtcfr = ®s->gtcfr2; 359 timers[2].gtmdr = ®s->gtmdr3; 360 timers[2].gtcnr = ®s->gtcnr3; 361 timers[2].gtrfr = ®s->gtrfr3; 362 timers[2].gtevr = ®s->gtevr3; 363 364 timers[3].gtcfr = ®s->gtcfr2; 365 timers[3].gtmdr = ®s->gtmdr4; 366 timers[3].gtcnr = ®s->gtcnr4; 367 timers[3].gtrfr = ®s->gtrfr4; 368 timers[3].gtevr = ®s->gtevr4; 369 370 /* CPM2 doesn't have primary prescaler */ 371 if (!of_device_is_compatible(np, "fsl,cpm2-gtm")) { 372 timers[0].gtpsr = ®s->gtpsr1; 373 timers[1].gtpsr = ®s->gtpsr2; 374 timers[2].gtpsr = ®s->gtpsr3; 375 timers[3].gtpsr = ®s->gtpsr4; 376 } 377 } 378 379 static int __init fsl_gtm_init(void) 380 { 381 struct device_node *np; 382 383 for_each_compatible_node(np, NULL, "fsl,gtm") { 384 int i; 385 struct gtm *gtm; 386 const u32 *clock; 387 int size; 388 389 gtm = kzalloc(sizeof(*gtm), GFP_KERNEL); 390 if (!gtm) { 391 pr_err("%s: unable to allocate memory\n", 392 np->full_name); 393 continue; 394 } 395 396 spin_lock_init(>m->lock); 397 398 clock = of_get_property(np, "clock-frequency", &size); 399 if (!clock || size != sizeof(*clock)) { 400 pr_err("%s: no clock-frequency\n", np->full_name); 401 goto err; 402 } 403 gtm->clock = *clock; 404 405 for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) { 406 unsigned int irq; 407 408 irq = irq_of_parse_and_map(np, i); 409 if (irq == NO_IRQ) { 410 pr_err("%s: not enough interrupts specified\n", 411 np->full_name); 412 goto err; 413 } 414 gtm->timers[i].irq = irq; 415 gtm->timers[i].gtm = gtm; 416 } 417 418 gtm->regs = of_iomap(np, 0); 419 if (!gtm->regs) { 420 pr_err("%s: unable to iomap registers\n", 421 np->full_name); 422 goto err; 423 } 424 425 gtm_set_shortcuts(np, gtm->timers, gtm->regs); 426 list_add(>m->list_node, >ms); 427 428 /* We don't want to lose the node and its ->data */ 429 np->data = gtm; 430 of_node_get(np); 431 432 continue; 433 err: 434 kfree(gtm); 435 } 436 return 0; 437 } 438 arch_initcall(fsl_gtm_init); 439