arch/powerpc/sysdev/fsl_gtm.c

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