release/src-rt-6.x.4708/linux/linux-2.6.36/arch/arm/mach-u300/timer.c

   1 /*
   2  *
   3  * arch/arm/mach-u300/timer.c
   4  *
   5  *
   6  * Copyright (C) 2007-2009 ST-Ericsson AB
   7  * License terms: GNU General Public License (GPL) version 2
   8  * Timer COH 901 328, runs the OS timer interrupt.
   9  * Author: Linus Walleij <linus.walleij@stericsson.com>
  10  */
  11 #include <linux/interrupt.h>
  12 #include <linux/time.h>
  13 #include <linux/timex.h>
  14 #include <linux/clockchips.h>
  15 #include <linux/clocksource.h>
  16 #include <linux/types.h>
  17 #include <linux/io.h>
  18 #include <linux/clk.h>
  19 #include <linux/err.h>
  20
  21 #include <mach/hardware.h>
  22
  23 /* Generic stuff */
  24 #include <asm/mach/map.h>
  25 #include <asm/mach/time.h>
  26 #include <asm/mach/irq.h>
  27
  28 /* Be able to sleep for atleast 4 seconds (usually more) */
  29 #define APPTIMER_MIN_RANGE 4
  30
  31 /*
  32  * APP side special timer registers
  33  * This timer contains four timers which can fire an interrupt each.
  34  * OS (operating system) timer @ 32768 Hz
  35  * DD (device driver) timer @ 1 kHz
  36  * GP1 (general purpose 1) timer @ 1MHz
  37  * GP2 (general purpose 2) timer @ 1MHz
  38  */
  39
  40 /* Reset OS Timer 32bit (-/W) */
  41 #define U300_TIMER_APP_ROST                                     (0x0000)
  42 #define U300_TIMER_APP_ROST_TIMER_RESET                         (0x00000000)
  43 /* Enable OS Timer 32bit (-/W) */
  44 #define U300_TIMER_APP_EOST                                     (0x0004)
  45 #define U300_TIMER_APP_EOST_TIMER_ENABLE                        (0x00000000)
  46 /* Disable OS Timer 32bit (-/W) */
  47 #define U300_TIMER_APP_DOST                                     (0x0008)
  48 #define U300_TIMER_APP_DOST_TIMER_DISABLE                       (0x00000000)
  49 /* OS Timer Mode Register 32bit (-/W) */
  50 #define U300_TIMER_APP_SOSTM                                    (0x000c)
  51 #define U300_TIMER_APP_SOSTM_MODE_CONTINUOUS                    (0x00000000)
  52 #define U300_TIMER_APP_SOSTM_MODE_ONE_SHOT                      (0x00000001)
  53 /* OS Timer Status Register 32bit (R/-) */
  54 #define U300_TIMER_APP_OSTS                                     (0x0010)
  55 #define U300_TIMER_APP_OSTS_TIMER_STATE_MASK                    (0x0000000F)
  56 #define U300_TIMER_APP_OSTS_TIMER_STATE_IDLE                    (0x00000001)
  57 #define U300_TIMER_APP_OSTS_TIMER_STATE_ACTIVE                  (0x00000002)
  58 #define U300_TIMER_APP_OSTS_ENABLE_IND                          (0x00000010)
  59 #define U300_TIMER_APP_OSTS_MODE_MASK                           (0x00000020)
  60 #define U300_TIMER_APP_OSTS_MODE_CONTINUOUS                     (0x00000000)
  61 #define U300_TIMER_APP_OSTS_MODE_ONE_SHOT                       (0x00000020)
  62 #define U300_TIMER_APP_OSTS_IRQ_ENABLED_IND                     (0x00000040)
  63 #define U300_TIMER_APP_OSTS_IRQ_PENDING_IND                     (0x00000080)
  64 /* OS Timer Current Count Register 32bit (R/-) */
  65 #define U300_TIMER_APP_OSTCC                                    (0x0014)
  66 /* OS Timer Terminal Count Register 32bit (R/W) */
  67 #define U300_TIMER_APP_OSTTC                                    (0x0018)
  68 /* OS Timer Interrupt Enable Register 32bit (-/W) */
  69 #define U300_TIMER_APP_OSTIE                                    (0x001c)
  70 #define U300_TIMER_APP_OSTIE_IRQ_DISABLE                        (0x00000000)
  71 #define U300_TIMER_APP_OSTIE_IRQ_ENABLE                         (0x00000001)
  72 /* OS Timer Interrupt Acknowledge Register 32bit (-/W) */
  73 #define U300_TIMER_APP_OSTIA                                    (0x0020)
  74 #define U300_TIMER_APP_OSTIA_IRQ_ACK                            (0x00000080)
  75
  76 /* Reset DD Timer 32bit (-/W) */
  77 #define U300_TIMER_APP_RDDT                                     (0x0040)
  78 #define U300_TIMER_APP_RDDT_TIMER_RESET                         (0x00000000)
  79 /* Enable DD Timer 32bit (-/W) */
  80 #define U300_TIMER_APP_EDDT                                     (0x0044)
  81 #define U300_TIMER_APP_EDDT_TIMER_ENABLE                        (0x00000000)
  82 /* Disable DD Timer 32bit (-/W) */
  83 #define U300_TIMER_APP_DDDT                                     (0x0048)
  84 #define U300_TIMER_APP_DDDT_TIMER_DISABLE                       (0x00000000)
  85 /* DD Timer Mode Register 32bit (-/W) */
  86 #define U300_TIMER_APP_SDDTM                                    (0x004c)
  87 #define U300_TIMER_APP_SDDTM_MODE_CONTINUOUS                    (0x00000000)
  88 #define U300_TIMER_APP_SDDTM_MODE_ONE_SHOT                      (0x00000001)
  89 /* DD Timer Status Register 32bit (R/-) */
  90 #define U300_TIMER_APP_DDTS                                     (0x0050)
  91 #define U300_TIMER_APP_DDTS_TIMER_STATE_MASK                    (0x0000000F)
  92 #define U300_TIMER_APP_DDTS_TIMER_STATE_IDLE                    (0x00000001)
  93 #define U300_TIMER_APP_DDTS_TIMER_STATE_ACTIVE                  (0x00000002)
  94 #define U300_TIMER_APP_DDTS_ENABLE_IND                          (0x00000010)
  95 #define U300_TIMER_APP_DDTS_MODE_MASK                           (0x00000020)
  96 #define U300_TIMER_APP_DDTS_MODE_CONTINUOUS                     (0x00000000)
  97 #define U300_TIMER_APP_DDTS_MODE_ONE_SHOT                       (0x00000020)
  98 #define U300_TIMER_APP_DDTS_IRQ_ENABLED_IND                     (0x00000040)
  99 #define U300_TIMER_APP_DDTS_IRQ_PENDING_IND                     (0x00000080)
 100 /* DD Timer Current Count Register 32bit (R/-) */
 101 #define U300_TIMER_APP_DDTCC                                    (0x0054)
 102 /* DD Timer Terminal Count Register 32bit (R/W) */
 103 #define U300_TIMER_APP_DDTTC                                    (0x0058)
 104 /* DD Timer Interrupt Enable Register 32bit (-/W) */
 105 #define U300_TIMER_APP_DDTIE                                    (0x005c)
 106 #define U300_TIMER_APP_DDTIE_IRQ_DISABLE                        (0x00000000)
 107 #define U300_TIMER_APP_DDTIE_IRQ_ENABLE                         (0x00000001)
 108 /* DD Timer Interrupt Acknowledge Register 32bit (-/W) */
 109 #define U300_TIMER_APP_DDTIA                                    (0x0060)
 110 #define U300_TIMER_APP_DDTIA_IRQ_ACK                            (0x00000080)
 111
 112 /* Reset GP1 Timer 32bit (-/W) */
 113 #define U300_TIMER_APP_RGPT1                                    (0x0080)
 114 #define U300_TIMER_APP_RGPT1_TIMER_RESET                        (0x00000000)
 115 /* Enable GP1 Timer 32bit (-/W) */
 116 #define U300_TIMER_APP_EGPT1                                    (0x0084)
 117 #define U300_TIMER_APP_EGPT1_TIMER_ENABLE                       (0x00000000)
 118 /* Disable GP1 Timer 32bit (-/W) */
 119 #define U300_TIMER_APP_DGPT1                                    (0x0088)
 120 #define U300_TIMER_APP_DGPT1_TIMER_DISABLE                      (0x00000000)
 121 /* GP1 Timer Mode Register 32bit (-/W) */
 122 #define U300_TIMER_APP_SGPT1M                                   (0x008c)
 123 #define U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS                   (0x00000000)
 124 #define U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT                     (0x00000001)
 125 /* GP1 Timer Status Register 32bit (R/-) */
 126 #define U300_TIMER_APP_GPT1S                                    (0x0090)
 127 #define U300_TIMER_APP_GPT1S_TIMER_STATE_MASK                   (0x0000000F)
 128 #define U300_TIMER_APP_GPT1S_TIMER_STATE_IDLE                   (0x00000001)
 129 #define U300_TIMER_APP_GPT1S_TIMER_STATE_ACTIVE                 (0x00000002)
 130 #define U300_TIMER_APP_GPT1S_ENABLE_IND                         (0x00000010)
 131 #define U300_TIMER_APP_GPT1S_MODE_MASK                          (0x00000020)
 132 #define U300_TIMER_APP_GPT1S_MODE_CONTINUOUS                    (0x00000000)
 133 #define U300_TIMER_APP_GPT1S_MODE_ONE_SHOT                      (0x00000020)
 134 #define U300_TIMER_APP_GPT1S_IRQ_ENABLED_IND                    (0x00000040)
 135 #define U300_TIMER_APP_GPT1S_IRQ_PENDING_IND                    (0x00000080)
 136 /* GP1 Timer Current Count Register 32bit (R/-) */
 137 #define U300_TIMER_APP_GPT1CC                                   (0x0094)
 138 /* GP1 Timer Terminal Count Register 32bit (R/W) */
 139 #define U300_TIMER_APP_GPT1TC                                   (0x0098)
 140 /* GP1 Timer Interrupt Enable Register 32bit (-/W) */
 141 #define U300_TIMER_APP_GPT1IE                                   (0x009c)
 142 #define U300_TIMER_APP_GPT1IE_IRQ_DISABLE                       (0x00000000)
 143 #define U300_TIMER_APP_GPT1IE_IRQ_ENABLE                        (0x00000001)
 144 /* GP1 Timer Interrupt Acknowledge Register 32bit (-/W) */
 145 #define U300_TIMER_APP_GPT1IA                                   (0x00a0)
 146 #define U300_TIMER_APP_GPT1IA_IRQ_ACK                           (0x00000080)
 147
 148 /* Reset GP2 Timer 32bit (-/W) */
 149 #define U300_TIMER_APP_RGPT2                                    (0x00c0)
 150 #define U300_TIMER_APP_RGPT2_TIMER_RESET                        (0x00000000)
 151 /* Enable GP2 Timer 32bit (-/W) */
 152 #define U300_TIMER_APP_EGPT2                                    (0x00c4)
 153 #define U300_TIMER_APP_EGPT2_TIMER_ENABLE                       (0x00000000)
 154 /* Disable GP2 Timer 32bit (-/W) */
 155 #define U300_TIMER_APP_DGPT2                                    (0x00c8)
 156 #define U300_TIMER_APP_DGPT2_TIMER_DISABLE                      (0x00000000)
 157 /* GP2 Timer Mode Register 32bit (-/W) */
 158 #define U300_TIMER_APP_SGPT2M                                   (0x00cc)
 159 #define U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS                   (0x00000000)
 160 #define U300_TIMER_APP_SGPT2M_MODE_ONE_SHOT                     (0x00000001)
 161 /* GP2 Timer Status Register 32bit (R/-) */
 162 #define U300_TIMER_APP_GPT2S                                    (0x00d0)
 163 #define U300_TIMER_APP_GPT2S_TIMER_STATE_MASK                   (0x0000000F)
 164 #define U300_TIMER_APP_GPT2S_TIMER_STATE_IDLE                   (0x00000001)
 165 #define U300_TIMER_APP_GPT2S_TIMER_STATE_ACTIVE                 (0x00000002)
 166 #define U300_TIMER_APP_GPT2S_ENABLE_IND                         (0x00000010)
 167 #define U300_TIMER_APP_GPT2S_MODE_MASK                          (0x00000020)
 168 #define U300_TIMER_APP_GPT2S_MODE_CONTINUOUS                    (0x00000000)
 169 #define U300_TIMER_APP_GPT2S_MODE_ONE_SHOT                      (0x00000020)
 170 #define U300_TIMER_APP_GPT2S_IRQ_ENABLED_IND                    (0x00000040)
 171 #define U300_TIMER_APP_GPT2S_IRQ_PENDING_IND                    (0x00000080)
 172 /* GP2 Timer Current Count Register 32bit (R/-) */
 173 #define U300_TIMER_APP_GPT2CC                                   (0x00d4)
 174 /* GP2 Timer Terminal Count Register 32bit (R/W) */
 175 #define U300_TIMER_APP_GPT2TC                                   (0x00d8)
 176 /* GP2 Timer Interrupt Enable Register 32bit (-/W) */
 177 #define U300_TIMER_APP_GPT2IE                                   (0x00dc)
 178 #define U300_TIMER_APP_GPT2IE_IRQ_DISABLE                       (0x00000000)
 179 #define U300_TIMER_APP_GPT2IE_IRQ_ENABLE                        (0x00000001)
 180 /* GP2 Timer Interrupt Acknowledge Register 32bit (-/W) */
 181 #define U300_TIMER_APP_GPT2IA                                   (0x00e0)
 182 #define U300_TIMER_APP_GPT2IA_IRQ_ACK                           (0x00000080)
 183
 184 /* Clock request control register - all four timers */
 185 #define U300_TIMER_APP_CRC                                      (0x100)
 186 #define U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE                 (0x00000001)
 187
 188 #define TICKS_PER_JIFFY ((CLOCK_TICK_RATE + (HZ/2)) / HZ)
 189 #define US_PER_TICK ((1000000 + (HZ/2)) / HZ)
 190
 191 /*
 192  * The u300_set_mode() function is always called first, if we
 193  * have oneshot timer active, the oneshot scheduling function
 194  * u300_set_next_event() is called immediately after.
 195  */
 196 static void u300_set_mode(enum clock_event_mode mode,
 197                           struct clock_event_device *evt)
 198 {
 199         switch (mode) {
 200         case CLOCK_EVT_MODE_PERIODIC:
 201                 /* Disable interrupts on GPT1 */
 202                 writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 203                        U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IE);
 204                 /* Disable GP1 while we're reprogramming it. */
 205                 writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 206                        U300_TIMER_APP_VBASE + U300_TIMER_APP_DGPT1);
 207                 /*
 208                  * Set the periodic mode to a certain number of ticks per
 209                  * jiffy.
 210                  */
 211                 writel(TICKS_PER_JIFFY,
 212                        U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1TC);
 213                 /*
 214                  * Set continuous mode, so the timer keeps triggering
 215                  * interrupts.
 216                  */
 217                 writel(U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS,
 218                        U300_TIMER_APP_VBASE + U300_TIMER_APP_SGPT1M);
 219                 /* Enable timer interrupts */
 220                 writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
 221                        U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IE);
 222                 /* Then enable the OS timer again */
 223                 writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
 224                        U300_TIMER_APP_VBASE + U300_TIMER_APP_EGPT1);
 225                 break;
 226         case CLOCK_EVT_MODE_ONESHOT:
 227                 /* Just break; here? */
 228                 /*
 229                  * The actual event will be programmed by the next event hook,
 230                  * so we just set a dummy value somewhere at the end of the
 231                  * universe here.
 232                  */
 233                 /* Disable interrupts on GPT1 */
 234                 writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 235                        U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IE);
 236                 /* Disable GP1 while we're reprogramming it. */
 237                 writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 238                        U300_TIMER_APP_VBASE + U300_TIMER_APP_DGPT1);
 239                 /*
 240                  * Expire far in the future, u300_set_next_event() will be
 241                  * called soon...
 242                  */
 243                 writel(0xFFFFFFFF, U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1TC);
 244                 /* We run one shot per tick here! */
 245                 writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
 246                        U300_TIMER_APP_VBASE + U300_TIMER_APP_SGPT1M);
 247                 /* Enable interrupts for this timer */
 248                 writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
 249                        U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IE);
 250                 /* Enable timer */
 251                 writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
 252                        U300_TIMER_APP_VBASE + U300_TIMER_APP_EGPT1);
 253                 break;
 254         case CLOCK_EVT_MODE_UNUSED:
 255         case CLOCK_EVT_MODE_SHUTDOWN:
 256                 /* Disable interrupts on GP1 */
 257                 writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 258                        U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IE);
 259                 /* Disable GP1 */
 260                 writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 261                        U300_TIMER_APP_VBASE + U300_TIMER_APP_DGPT1);
 262                 break;
 263         case CLOCK_EVT_MODE_RESUME:
 264                 /* Ignore this call */
 265                 break;
 266         }
 267 }
 268
 269 /*
 270  * The app timer in one shot mode obviously has to be reprogrammed
 271  * in EXACTLY this sequence to work properly. Do NOT try to e.g. replace
 272  * the interrupt disable + timer disable commands with a reset command,
 273  * it will fail miserably. Apparently (and I found this the hard way)
 274  * the timer is very sensitive to the instruction order, though you don't
 275  * get that impression from the data sheet.
 276  */
 277 static int u300_set_next_event(unsigned long cycles,
 278                                struct clock_event_device *evt)
 279
 280 {
 281         /* Disable interrupts on GPT1 */
 282         writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
 283                U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IE);
 284         /* Disable GP1 while we're reprogramming it. */
 285         writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
 286                U300_TIMER_APP_VBASE + U300_TIMER_APP_DGPT1);
 287         /* Reset the General Purpose timer 1. */
 288         writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
 289                U300_TIMER_APP_VBASE + U300_TIMER_APP_RGPT1);
 290         /* IRQ in n * cycles */
 291         writel(cycles, U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1TC);
 292         /*
 293          * We run one shot per tick here! (This is necessary to reconfigure,
 294          * the timer will tilt if you don't!)
 295          */
 296         writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
 297                U300_TIMER_APP_VBASE + U300_TIMER_APP_SGPT1M);
 298         /* Enable timer interrupts */
 299         writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
 300                U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IE);
 301         /* Then enable the OS timer again */
 302         writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
 303                U300_TIMER_APP_VBASE + U300_TIMER_APP_EGPT1);
 304         return 0;
 305 }
 306
 307
 308 /* Use general purpose timer 1 as clock event */
 309 static struct clock_event_device clockevent_u300_1mhz = {
 310         .name           = "GPT1",
 311         .rating         = 300, /* Reasonably fast and accurate clock event */
 312         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
 313         .set_next_event = u300_set_next_event,
 314         .set_mode       = u300_set_mode,
 315 };
 316
 317 /* Clock event timer interrupt handler */
 318 static irqreturn_t u300_timer_interrupt(int irq, void *dev_id)
 319 {
 320         struct clock_event_device *evt = &clockevent_u300_1mhz;
 321         /* ACK/Clear timer IRQ for the APP GPT1 Timer */
 322         writel(U300_TIMER_APP_GPT1IA_IRQ_ACK,
 323                 U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT1IA);
 324         evt->event_handler(evt);
 325         return IRQ_HANDLED;
 326 }
 327
 328 static struct irqaction u300_timer_irq = {
 329         .name           = "U300 Timer Tick",
 330         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 331         .handler        = u300_timer_interrupt,
 332 };
 333
 334 /* Use general purpose timer 2 as clock source */
 335 static cycle_t u300_get_cycles(struct clocksource *cs)
 336 {
 337         return (cycles_t) readl(U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT2CC);
 338 }
 339
 340 static struct clocksource clocksource_u300_1mhz = {
 341         .name           = "GPT2",
 342         .rating         = 300, /* Reasonably fast and accurate clock source */
 343         .read           = u300_get_cycles,
 344         .mask           = CLOCKSOURCE_MASK(32), /* 32 bits */
 345         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 346 };
 347
 348 /*
 349  * Override the global weak sched_clock symbol with this
 350  * local implementation which uses the clocksource to get some
 351  * better resolution when scheduling the kernel. We accept that
 352  * this wraps around for now, since it is just a relative time
 353  * stamp. (Inspired by OMAP implementation.)
 354  */
 355 unsigned long long notrace sched_clock(void)
 356 {
 357         return clocksource_cyc2ns(clocksource_u300_1mhz.read(
 358                                   &clocksource_u300_1mhz),
 359                                   clocksource_u300_1mhz.mult,
 360                                   clocksource_u300_1mhz.shift);
 361 }
 362
 363
 364 /*
 365  * This sets up the system timers, clock source and clock event.
 366  */
 367 static void __init u300_timer_init(void)
 368 {
 369         struct clk *clk;
 370         unsigned long rate;
 371
 372         /* Clock the interrupt controller */
 373         clk = clk_get_sys("apptimer", NULL);
 374         BUG_ON(IS_ERR(clk));
 375         clk_enable(clk);
 376         rate = clk_get_rate(clk);
 377
 378         /*
 379          * Disable the "OS" and "DD" timers - these are designed for Symbian!
 380          * Example usage in cnh1601578 cpu subsystem pd_timer_app.c
 381          */
 382         writel(U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE,
 383                 U300_TIMER_APP_VBASE + U300_TIMER_APP_CRC);
 384         writel(U300_TIMER_APP_ROST_TIMER_RESET,
 385                 U300_TIMER_APP_VBASE + U300_TIMER_APP_ROST);
 386         writel(U300_TIMER_APP_DOST_TIMER_DISABLE,
 387                 U300_TIMER_APP_VBASE + U300_TIMER_APP_DOST);
 388         writel(U300_TIMER_APP_RDDT_TIMER_RESET,
 389                 U300_TIMER_APP_VBASE + U300_TIMER_APP_RDDT);
 390         writel(U300_TIMER_APP_DDDT_TIMER_DISABLE,
 391                 U300_TIMER_APP_VBASE + U300_TIMER_APP_DDDT);
 392
 393         /* Reset the General Purpose timer 1. */
 394         writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
 395                 U300_TIMER_APP_VBASE + U300_TIMER_APP_RGPT1);
 396
 397         /* Set up the IRQ handler */
 398         setup_irq(IRQ_U300_TIMER_APP_GP1, &u300_timer_irq);
 399
 400         /* Reset the General Purpose timer 2 */
 401         writel(U300_TIMER_APP_RGPT2_TIMER_RESET,
 402                 U300_TIMER_APP_VBASE + U300_TIMER_APP_RGPT2);
 403         /* Set this timer to run around forever */
 404         writel(0xFFFFFFFFU, U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT2TC);
 405         /* Set continuous mode so it wraps around */
 406         writel(U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS,
 407                U300_TIMER_APP_VBASE + U300_TIMER_APP_SGPT2M);
 408         /* Disable timer interrupts */
 409         writel(U300_TIMER_APP_GPT2IE_IRQ_DISABLE,
 410                 U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT2IE);
 411         /* Then enable the GP2 timer to use as a free running us counter */
 412         writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE,
 413                 U300_TIMER_APP_VBASE + U300_TIMER_APP_EGPT2);
 414
 415         clocksource_calc_mult_shift(&clocksource_u300_1mhz,
 416                                     rate, APPTIMER_MIN_RANGE);
 417         if (clocksource_register(&clocksource_u300_1mhz))
 418                 printk(KERN_ERR "timer: failed to initialize clock "
 419                        "source %s\n", clocksource_u300_1mhz.name);
 420
 421         clockevents_calc_mult_shift(&clockevent_u300_1mhz,
 422                                     rate, APPTIMER_MIN_RANGE);
 423         /* 32bit counter, so 32bits delta is max */
 424         clockevent_u300_1mhz.max_delta_ns =
 425                 clockevent_delta2ns(0xffffffff, &clockevent_u300_1mhz);
 426         /* This timer is slow enough to set for 1 cycle == 1 MHz */
 427         clockevent_u300_1mhz.min_delta_ns =
 428                 clockevent_delta2ns(1, &clockevent_u300_1mhz);
 429         clockevent_u300_1mhz.cpumask = cpumask_of(0);
 430         clockevents_register_device(&clockevent_u300_1mhz);
 431         /*
 432          * TODO: init and register the rest of the timers too, they can be
 433          * used by hrtimers!
 434          */
 435 }
 436
 437 /*
 438  * Very simple system timer that only register the clock event and
 439  * clock source.
 440  */
 441 struct sys_timer u300_timer = {
 442         .init           = u300_timer_init,
 443 };