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