1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Freescale General-purpose Timers Module 4 * 5 * Copyright (c) Freescale Semiconductor, Inc. 2006. 6 * Shlomi Gridish <gridish@freescale.com> 7 * Jerry Huang <Chang-Ming.Huang@freescale.com> 8 * Copyright (c) MontaVista Software, Inc. 2008. 9 * Anton Vorontsov <avorontsov@ru.mvista.com> 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/err.h> 14 #include <linux/errno.h> 15 #include <linux/list.h> 16 #include <linux/io.h> 17 #include <linux/of.h> 18 #include <linux/of_address.h> 19 #include <linux/of_irq.h> 20 #include <linux/spinlock.h> 21 #include <linux/bitops.h> 22 #include <linux/slab.h> 23 #include <linux/export.h> 24 #include <asm/fsl_gtm.h> 25 26 #define GTCFR_STP(x) ((x) & 1 ? 1 << 5 : 1 << 1) 27 #define GTCFR_RST(x) ((x) & 1 ? 1 << 4 : 1 << 0) 28 29 #define GTMDR_ICLK_MASK (3 << 1) 30 #define GTMDR_ICLK_ICAS (0 << 1) 31 #define GTMDR_ICLK_ICLK (1 << 1) 32 #define GTMDR_ICLK_SLGO (2 << 1) 33 #define GTMDR_FRR (1 << 3) 34 #define GTMDR_ORI (1 << 4) 35 #define GTMDR_SPS(x) ((x) << 8) 36 37 struct gtm_timers_regs { 38 u8 gtcfr1; /* Timer 1, Timer 2 global config register */ 39 u8 res0[0x3]; 40 u8 gtcfr2; /* Timer 3, timer 4 global config register */ 41 u8 res1[0xB]; 42 __be16 gtmdr1; /* Timer 1 mode register */ 43 __be16 gtmdr2; /* Timer 2 mode register */ 44 __be16 gtrfr1; /* Timer 1 reference register */ 45 __be16 gtrfr2; /* Timer 2 reference register */ 46 __be16 gtcpr1; /* Timer 1 capture register */ 47 __be16 gtcpr2; /* Timer 2 capture register */ 48 __be16 gtcnr1; /* Timer 1 counter */ 49 __be16 gtcnr2; /* Timer 2 counter */ 50 __be16 gtmdr3; /* Timer 3 mode register */ 51 __be16 gtmdr4; /* Timer 4 mode register */ 52 __be16 gtrfr3; /* Timer 3 reference register */ 53 __be16 gtrfr4; /* Timer 4 reference register */ 54 __be16 gtcpr3; /* Timer 3 capture register */ 55 __be16 gtcpr4; /* Timer 4 capture register */ 56 __be16 gtcnr3; /* Timer 3 counter */ 57 __be16 gtcnr4; /* Timer 4 counter */ 58 __be16 gtevr1; /* Timer 1 event register */ 59 __be16 gtevr2; /* Timer 2 event register */ 60 __be16 gtevr3; /* Timer 3 event register */ 61 __be16 gtevr4; /* Timer 4 event register */ 62 __be16 gtpsr1; /* Timer 1 prescale register */ 63 __be16 gtpsr2; /* Timer 2 prescale register */ 64 __be16 gtpsr3; /* Timer 3 prescale register */ 65 __be16 gtpsr4; /* Timer 4 prescale register */ 66 u8 res2[0x40]; 67 } __attribute__ ((packed)); 68 69 struct gtm { 70 unsigned int clock; 71 struct gtm_timers_regs __iomem *regs; 72 struct gtm_timer timers[4]; 73 spinlock_t lock; 74 struct list_head list_node; 75 }; 76 77 static LIST_HEAD(gtms); 78 79 /** 80 * gtm_get_timer - request GTM timer to use it with the rest of GTM API 81 * Context: non-IRQ 82 * 83 * This function reserves GTM timer for later use. It returns gtm_timer 84 * structure to use with the rest of GTM API, you should use timer->irq 85 * to manage timer interrupt. 86 */ 87 struct gtm_timer *gtm_get_timer16(void) 88 { 89 struct gtm *gtm; 90 int i; 91 92 list_for_each_entry(gtm, >ms, list_node) { 93 spin_lock_irq(>m->lock); 94 95 for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) { 96 if (!gtm->timers[i].requested) { 97 gtm->timers[i].requested = true; 98 spin_unlock_irq(>m->lock); 99 return >m->timers[i]; 100 } 101 } 102 103 spin_unlock_irq(>m->lock); 104 } 105 106 if (!list_empty(>ms)) 107 return ERR_PTR(-EBUSY); 108 return ERR_PTR(-ENODEV); 109 } 110 EXPORT_SYMBOL(gtm_get_timer16); 111 112 /** 113 * gtm_get_specific_timer - request specific GTM timer 114 * @gtm: specific GTM, pass here GTM's device_node->data 115 * @timer: specific timer number, Timer1 is 0. 116 * Context: non-IRQ 117 * 118 * This function reserves GTM timer for later use. It returns gtm_timer 119 * structure to use with the rest of GTM API, you should use timer->irq 120 * to manage timer interrupt. 121 */ 122 struct gtm_timer *gtm_get_specific_timer16(struct gtm *gtm, 123 unsigned int timer) 124 { 125 struct gtm_timer *ret = ERR_PTR(-EBUSY); 126 127 if (timer > 3) 128 return ERR_PTR(-EINVAL); 129 130 spin_lock_irq(>m->lock); 131 132 if (gtm->timers[timer].requested) 133 goto out; 134 135 ret = >m->timers[timer]; 136 ret->requested = true; 137 138 out: 139 spin_unlock_irq(>m->lock); 140 return ret; 141 } 142 EXPORT_SYMBOL(gtm_get_specific_timer16); 143 144 /** 145 * gtm_put_timer16 - release 16 bits GTM timer 146 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 147 * Context: any 148 * 149 * This function releases GTM timer so others may request it. 150 */ 151 void gtm_put_timer16(struct gtm_timer *tmr) 152 { 153 gtm_stop_timer16(tmr); 154 155 spin_lock_irq(&tmr->gtm->lock); 156 tmr->requested = false; 157 spin_unlock_irq(&tmr->gtm->lock); 158 } 159 EXPORT_SYMBOL(gtm_put_timer16); 160 161 /* 162 * This is back-end for the exported functions, it's used to reset single 163 * timer in reference mode. 164 */ 165 static int gtm_set_ref_timer16(struct gtm_timer *tmr, int frequency, 166 int reference_value, bool free_run) 167 { 168 struct gtm *gtm = tmr->gtm; 169 int num = tmr - >m->timers[0]; 170 unsigned int prescaler; 171 u8 iclk = GTMDR_ICLK_ICLK; 172 u8 psr; 173 u8 sps; 174 unsigned long flags; 175 int max_prescaler = 256 * 256 * 16; 176 177 /* CPM2 doesn't have primary prescaler */ 178 if (!tmr->gtpsr) 179 max_prescaler /= 256; 180 181 prescaler = gtm->clock / frequency; 182 /* 183 * We have two 8 bit prescalers -- primary and secondary (psr, sps), 184 * plus "slow go" mode (clk / 16). So, total prescale value is 185 * 16 * (psr + 1) * (sps + 1). Though, for CPM2 GTMs we losing psr. 186 */ 187 if (prescaler > max_prescaler) 188 return -EINVAL; 189 190 if (prescaler > max_prescaler / 16) { 191 iclk = GTMDR_ICLK_SLGO; 192 prescaler /= 16; 193 } 194 195 if (prescaler <= 256) { 196 psr = 0; 197 sps = prescaler - 1; 198 } else { 199 psr = 256 - 1; 200 sps = prescaler / 256 - 1; 201 } 202 203 spin_lock_irqsave(>m->lock, flags); 204 205 /* 206 * Properly reset timers: stop, reset, set up prescalers, reference 207 * value and clear event register. 208 */ 209 clrsetbits_8(tmr->gtcfr, ~(GTCFR_STP(num) | GTCFR_RST(num)), 210 GTCFR_STP(num) | GTCFR_RST(num)); 211 212 setbits8(tmr->gtcfr, GTCFR_STP(num)); 213 214 if (tmr->gtpsr) 215 out_be16(tmr->gtpsr, psr); 216 clrsetbits_be16(tmr->gtmdr, 0xFFFF, iclk | GTMDR_SPS(sps) | 217 GTMDR_ORI | (free_run ? GTMDR_FRR : 0)); 218 out_be16(tmr->gtcnr, 0); 219 out_be16(tmr->gtrfr, reference_value); 220 out_be16(tmr->gtevr, 0xFFFF); 221 222 /* Let it be. */ 223 clrbits8(tmr->gtcfr, GTCFR_STP(num)); 224 225 spin_unlock_irqrestore(>m->lock, flags); 226 227 return 0; 228 } 229 230 /** 231 * gtm_set_timer16 - (re)set 16 bit timer with arbitrary precision 232 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 233 * @usec: timer interval in microseconds 234 * @reload: if set, the timer will reset upon expiry rather than 235 * continue running free. 236 * Context: any 237 * 238 * This function (re)sets the GTM timer so that it counts up to the requested 239 * interval value, and fires the interrupt when the value is reached. This 240 * function will reduce the precision of the timer as needed in order for the 241 * requested timeout to fit in a 16-bit register. 242 */ 243 int gtm_set_timer16(struct gtm_timer *tmr, unsigned long usec, bool reload) 244 { 245 /* quite obvious, frequency which is enough for µSec precision */ 246 int freq = 1000000; 247 unsigned int bit; 248 249 bit = fls_long(usec); 250 if (bit > 15) { 251 freq >>= bit - 15; 252 usec >>= bit - 15; 253 } 254 255 if (!freq) 256 return -EINVAL; 257 258 return gtm_set_ref_timer16(tmr, freq, usec, reload); 259 } 260 EXPORT_SYMBOL(gtm_set_timer16); 261 262 /** 263 * gtm_set_exact_utimer16 - (re)set 16 bits timer 264 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 265 * @usec: timer interval in microseconds 266 * @reload: if set, the timer will reset upon expiry rather than 267 * continue running free. 268 * Context: any 269 * 270 * This function (re)sets GTM timer so that it counts up to the requested 271 * interval value, and fires the interrupt when the value is reached. If reload 272 * flag was set, timer will also reset itself upon reference value, otherwise 273 * it continues to increment. 274 * 275 * The _exact_ bit in the function name states that this function will not 276 * crop precision of the "usec" argument, thus usec is limited to 16 bits 277 * (single timer width). 278 */ 279 int gtm_set_exact_timer16(struct gtm_timer *tmr, u16 usec, bool reload) 280 { 281 /* quite obvious, frequency which is enough for µSec precision */ 282 const int freq = 1000000; 283 284 /* 285 * We can lower the frequency (and probably power consumption) by 286 * dividing both frequency and usec by 2 until there is no remainder. 287 * But we won't bother with this unless savings are measured, so just 288 * run the timer as is. 289 */ 290 291 return gtm_set_ref_timer16(tmr, freq, usec, reload); 292 } 293 EXPORT_SYMBOL(gtm_set_exact_timer16); 294 295 /** 296 * gtm_stop_timer16 - stop single timer 297 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 298 * Context: any 299 * 300 * This function simply stops the GTM timer. 301 */ 302 void gtm_stop_timer16(struct gtm_timer *tmr) 303 { 304 struct gtm *gtm = tmr->gtm; 305 int num = tmr - >m->timers[0]; 306 unsigned long flags; 307 308 spin_lock_irqsave(>m->lock, flags); 309 310 setbits8(tmr->gtcfr, GTCFR_STP(num)); 311 out_be16(tmr->gtevr, 0xFFFF); 312 313 spin_unlock_irqrestore(>m->lock, flags); 314 } 315 EXPORT_SYMBOL(gtm_stop_timer16); 316 317 /** 318 * gtm_ack_timer16 - acknowledge timer event (free-run timers only) 319 * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer 320 * @events: events mask to ack 321 * Context: any 322 * 323 * Thus function used to acknowledge timer interrupt event, use it inside the 324 * interrupt handler. 325 */ 326 void gtm_ack_timer16(struct gtm_timer *tmr, u16 events) 327 { 328 out_be16(tmr->gtevr, events); 329 } 330 EXPORT_SYMBOL(gtm_ack_timer16); 331 332 static void __init gtm_set_shortcuts(struct device_node *np, 333 struct gtm_timer *timers, 334 struct gtm_timers_regs __iomem *regs) 335 { 336 /* 337 * Yeah, I don't like this either, but timers' registers a bit messed, 338 * so we have to provide shortcuts to write timer independent code. 339 * Alternative option is to create gt*() accessors, but that will be 340 * even uglier and cryptic. 341 */ 342 timers[0].gtcfr = ®s->gtcfr1; 343 timers[0].gtmdr = ®s->gtmdr1; 344 timers[0].gtcnr = ®s->gtcnr1; 345 timers[0].gtrfr = ®s->gtrfr1; 346 timers[0].gtevr = ®s->gtevr1; 347 348 timers[1].gtcfr = ®s->gtcfr1; 349 timers[1].gtmdr = ®s->gtmdr2; 350 timers[1].gtcnr = ®s->gtcnr2; 351 timers[1].gtrfr = ®s->gtrfr2; 352 timers[1].gtevr = ®s->gtevr2; 353 354 timers[2].gtcfr = ®s->gtcfr2; 355 timers[2].gtmdr = ®s->gtmdr3; 356 timers[2].gtcnr = ®s->gtcnr3; 357 timers[2].gtrfr = ®s->gtrfr3; 358 timers[2].gtevr = ®s->gtevr3; 359 360 timers[3].gtcfr = ®s->gtcfr2; 361 timers[3].gtmdr = ®s->gtmdr4; 362 timers[3].gtcnr = ®s->gtcnr4; 363 timers[3].gtrfr = ®s->gtrfr4; 364 timers[3].gtevr = ®s->gtevr4; 365 366 /* CPM2 doesn't have primary prescaler */ 367 if (!of_device_is_compatible(np, "fsl,cpm2-gtm")) { 368 timers[0].gtpsr = ®s->gtpsr1; 369 timers[1].gtpsr = ®s->gtpsr2; 370 timers[2].gtpsr = ®s->gtpsr3; 371 timers[3].gtpsr = ®s->gtpsr4; 372 } 373 } 374 375 static int __init fsl_gtm_init(void) 376 { 377 struct device_node *np; 378 379 for_each_compatible_node(np, NULL, "fsl,gtm") { 380 int i; 381 struct gtm *gtm; 382 const u32 *clock; 383 int size; 384 385 gtm = kzalloc(sizeof(*gtm), GFP_KERNEL); 386 if (!gtm) { 387 pr_err("%pOF: unable to allocate memory\n", 388 np); 389 continue; 390 } 391 392 spin_lock_init(>m->lock); 393 394 clock = of_get_property(np, "clock-frequency", &size); 395 if (!clock || size != sizeof(*clock)) { 396 pr_err("%pOF: no clock-frequency\n", np); 397 goto err; 398 } 399 gtm->clock = *clock; 400 401 for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) { 402 unsigned int irq; 403 404 irq = irq_of_parse_and_map(np, i); 405 if (!irq) { 406 pr_err("%pOF: not enough interrupts specified\n", 407 np); 408 goto err; 409 } 410 gtm->timers[i].irq = irq; 411 gtm->timers[i].gtm = gtm; 412 } 413 414 gtm->regs = of_iomap(np, 0); 415 if (!gtm->regs) { 416 pr_err("%pOF: unable to iomap registers\n", 417 np); 418 goto err; 419 } 420 421 gtm_set_shortcuts(np, gtm->timers, gtm->regs); 422 list_add(>m->list_node, >ms); 423 424 /* We don't want to lose the node and its ->data */ 425 np->data = gtm; 426 of_node_get(np); 427 428 continue; 429 err: 430 kfree(gtm); 431 } 432 return 0; 433 } 434 arch_initcall(fsl_gtm_init); 435