release/src-rt-6.x.4708/linux/linux-2.6.36/arch/arm/plat-mxc/time.c

   1 /*
   2  *  linux/arch/arm/plat-mxc/time.c
   3  *
   4  *  Copyright (C) 2000-2001 Deep Blue Solutions
   5  *  Copyright (C) 2002 Shane Nay (shane@minirl.com)
   6  *  Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
   7  *  Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version 2
  12  * of the License, or (at your option) any later version.
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  21  * MA 02110-1301, USA.
  22  */
  23
  24 #include <linux/interrupt.h>
  25 #include <linux/irq.h>
  26 #include <linux/clockchips.h>
  27 #include <linux/clk.h>
  28
  29 #include <mach/hardware.h>
  30 #include <asm/mach/time.h>
  31 #include <mach/common.h>
  32
  33 /*
  34  * There are 2 versions of the timer hardware on Freescale MXC hardware.
  35  * Version 1: MX1/MXL, MX21, MX27.
  36  * Version 2: MX25, MX31, MX35, MX37, MX51
  37  */
  38
  39 /* defines common for all i.MX */
  40 #define MXC_TCTL                0x00
  41 #define MXC_TCTL_TEN            (1 << 0) /* Enable module */
  42 #define MXC_TPRER               0x04
  43
  44 /* MX1, MX21, MX27 */
  45 #define MX1_2_TCTL_CLK_PCLK1    (1 << 1)
  46 #define MX1_2_TCTL_IRQEN        (1 << 4)
  47 #define MX1_2_TCTL_FRR          (1 << 8)
  48 #define MX1_2_TCMP              0x08
  49 #define MX1_2_TCN               0x10
  50 #define MX1_2_TSTAT             0x14
  51
  52 /* MX21, MX27 */
  53 #define MX2_TSTAT_CAPT          (1 << 1)
  54 #define MX2_TSTAT_COMP          (1 << 0)
  55
  56 /* MX31, MX35, MX25, MXC91231, MX5 */
  57 #define V2_TCTL_WAITEN          (1 << 3) /* Wait enable mode */
  58 #define V2_TCTL_CLK_IPG         (1 << 6)
  59 #define V2_TCTL_FRR             (1 << 9)
  60 #define V2_IR                   0x0c
  61 #define V2_TSTAT                0x08
  62 #define V2_TSTAT_OF1            (1 << 0)
  63 #define V2_TCN                  0x24
  64 #define V2_TCMP                 0x10
  65
  66 #define timer_is_v1()   (cpu_is_mx1() || cpu_is_mx21() || cpu_is_mx27())
  67 #define timer_is_v2()   (!timer_is_v1())
  68
  69 static struct clock_event_device clockevent_mxc;
  70 static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
  71
  72 static void __iomem *timer_base;
  73
  74 static inline void gpt_irq_disable(void)
  75 {
  76         unsigned int tmp;
  77
  78         if (timer_is_v2())
  79                 __raw_writel(0, timer_base + V2_IR);
  80         else {
  81                 tmp = __raw_readl(timer_base + MXC_TCTL);
  82                 __raw_writel(tmp & ~MX1_2_TCTL_IRQEN, timer_base + MXC_TCTL);
  83         }
  84 }
  85
  86 static inline void gpt_irq_enable(void)
  87 {
  88         if (timer_is_v2())
  89                 __raw_writel(1<<0, timer_base + V2_IR);
  90         else {
  91                 __raw_writel(__raw_readl(timer_base + MXC_TCTL) | MX1_2_TCTL_IRQEN,
  92                         timer_base + MXC_TCTL);
  93         }
  94 }
  95
  96 static void gpt_irq_acknowledge(void)
  97 {
  98         if (timer_is_v1()) {
  99                 if (cpu_is_mx1())
 100                         __raw_writel(0, timer_base + MX1_2_TSTAT);
 101                 else
 102                         __raw_writel(MX2_TSTAT_CAPT | MX2_TSTAT_COMP,
 103                                 timer_base + MX1_2_TSTAT);
 104         } else if (timer_is_v2())
 105                 __raw_writel(V2_TSTAT_OF1, timer_base + V2_TSTAT);
 106 }
 107
 108 static cycle_t mx1_2_get_cycles(struct clocksource *cs)
 109 {
 110         return __raw_readl(timer_base + MX1_2_TCN);
 111 }
 112
 113 static cycle_t v2_get_cycles(struct clocksource *cs)
 114 {
 115         return __raw_readl(timer_base + V2_TCN);
 116 }
 117
 118 static struct clocksource clocksource_mxc = {
 119         .name           = "mxc_timer1",
 120         .rating         = 200,
 121         .read           = mx1_2_get_cycles,
 122         .mask           = CLOCKSOURCE_MASK(32),
 123         .shift          = 20,
 124         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 125 };
 126
 127 static int __init mxc_clocksource_init(struct clk *timer_clk)
 128 {
 129         unsigned int c = clk_get_rate(timer_clk);
 130
 131         if (timer_is_v2())
 132                 clocksource_mxc.read = v2_get_cycles;
 133
 134         clocksource_mxc.mult = clocksource_hz2mult(c,
 135                                         clocksource_mxc.shift);
 136         clocksource_register(&clocksource_mxc);
 137
 138         return 0;
 139 }
 140
 141 /* clock event */
 142
 143 static int mx1_2_set_next_event(unsigned long evt,
 144                               struct clock_event_device *unused)
 145 {
 146         unsigned long tcmp;
 147
 148         tcmp = __raw_readl(timer_base + MX1_2_TCN) + evt;
 149
 150         __raw_writel(tcmp, timer_base + MX1_2_TCMP);
 151
 152         return (int)(tcmp - __raw_readl(timer_base + MX1_2_TCN)) < 0 ?
 153                                 -ETIME : 0;
 154 }
 155
 156 static int v2_set_next_event(unsigned long evt,
 157                               struct clock_event_device *unused)
 158 {
 159         unsigned long tcmp;
 160
 161         tcmp = __raw_readl(timer_base + V2_TCN) + evt;
 162
 163         __raw_writel(tcmp, timer_base + V2_TCMP);
 164
 165         return (int)(tcmp - __raw_readl(timer_base + V2_TCN)) < 0 ?
 166                                 -ETIME : 0;
 167 }
 168
 169 #ifdef DEBUG
 170 static const char *clock_event_mode_label[] = {
 171         [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
 172         [CLOCK_EVT_MODE_ONESHOT]  = "CLOCK_EVT_MODE_ONESHOT",
 173         [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
 174         [CLOCK_EVT_MODE_UNUSED]   = "CLOCK_EVT_MODE_UNUSED"
 175 };
 176 #endif /* DEBUG */
 177
 178 static void mxc_set_mode(enum clock_event_mode mode,
 179                                 struct clock_event_device *evt)
 180 {
 181         unsigned long flags;
 182
 183         /*
 184          * The timer interrupt generation is disabled at least
 185          * for enough time to call mxc_set_next_event()
 186          */
 187         local_irq_save(flags);
 188
 189         /* Disable interrupt in GPT module */
 190         gpt_irq_disable();
 191
 192         if (mode != clockevent_mode) {
 193                 /* Set event time into far-far future */
 194                 if (timer_is_v2())
 195                         __raw_writel(__raw_readl(timer_base + V2_TCN) - 3,
 196                                         timer_base + V2_TCMP);
 197                 else
 198                         __raw_writel(__raw_readl(timer_base + MX1_2_TCN) - 3,
 199                                         timer_base + MX1_2_TCMP);
 200
 201                 /* Clear pending interrupt */
 202                 gpt_irq_acknowledge();
 203         }
 204
 205 #ifdef DEBUG
 206         printk(KERN_INFO "mxc_set_mode: changing mode from %s to %s\n",
 207                 clock_event_mode_label[clockevent_mode],
 208                 clock_event_mode_label[mode]);
 209 #endif /* DEBUG */
 210
 211         /* Remember timer mode */
 212         clockevent_mode = mode;
 213         local_irq_restore(flags);
 214
 215         switch (mode) {
 216         case CLOCK_EVT_MODE_PERIODIC:
 217                 printk(KERN_ERR"mxc_set_mode: Periodic mode is not "
 218                                 "supported for i.MX\n");
 219                 break;
 220         case CLOCK_EVT_MODE_ONESHOT:
 221         /*
 222          * Do not put overhead of interrupt enable/disable into
 223          * mxc_set_next_event(), the core has about 4 minutes
 224          * to call mxc_set_next_event() or shutdown clock after
 225          * mode switching
 226          */
 227                 local_irq_save(flags);
 228                 gpt_irq_enable();
 229                 local_irq_restore(flags);
 230                 break;
 231         case CLOCK_EVT_MODE_SHUTDOWN:
 232         case CLOCK_EVT_MODE_UNUSED:
 233         case CLOCK_EVT_MODE_RESUME:
 234                 /* Left event sources disabled, no more interrupts appear */
 235                 break;
 236         }
 237 }
 238
 239 /*
 240  * IRQ handler for the timer
 241  */
 242 static irqreturn_t mxc_timer_interrupt(int irq, void *dev_id)
 243 {
 244         struct clock_event_device *evt = &clockevent_mxc;
 245         uint32_t tstat;
 246
 247         if (timer_is_v2())
 248                 tstat = __raw_readl(timer_base + V2_TSTAT);
 249         else
 250                 tstat = __raw_readl(timer_base + MX1_2_TSTAT);
 251
 252         gpt_irq_acknowledge();
 253
 254         evt->event_handler(evt);
 255
 256         return IRQ_HANDLED;
 257 }
 258
 259 static struct irqaction mxc_timer_irq = {
 260         .name           = "i.MX Timer Tick",
 261         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 262         .handler        = mxc_timer_interrupt,
 263 };
 264
 265 static struct clock_event_device clockevent_mxc = {
 266         .name           = "mxc_timer1",
 267         .features       = CLOCK_EVT_FEAT_ONESHOT,
 268         .shift          = 32,
 269         .set_mode       = mxc_set_mode,
 270         .set_next_event = mx1_2_set_next_event,
 271         .rating         = 200,
 272 };
 273
 274 static int __init mxc_clockevent_init(struct clk *timer_clk)
 275 {
 276         unsigned int c = clk_get_rate(timer_clk);
 277
 278         if (timer_is_v2())
 279                 clockevent_mxc.set_next_event = v2_set_next_event;
 280
 281         clockevent_mxc.mult = div_sc(c, NSEC_PER_SEC,
 282                                         clockevent_mxc.shift);
 283         clockevent_mxc.max_delta_ns =
 284                         clockevent_delta2ns(0xfffffffe, &clockevent_mxc);
 285         clockevent_mxc.min_delta_ns =
 286                         clockevent_delta2ns(0xff, &clockevent_mxc);
 287
 288         clockevent_mxc.cpumask = cpumask_of(0);
 289
 290         clockevents_register_device(&clockevent_mxc);
 291
 292         return 0;
 293 }
 294
 295 void __init mxc_timer_init(struct clk *timer_clk, void __iomem *base, int irq)
 296 {
 297         uint32_t tctl_val;
 298
 299         clk_enable(timer_clk);
 300
 301         timer_base = base;
 302
 303         /*
 304          * Initialise to a known state (all timers off, and timing reset)
 305          */
 306
 307         __raw_writel(0, timer_base + MXC_TCTL);
 308         __raw_writel(0, timer_base + MXC_TPRER); /* see datasheet note */
 309
 310         if (timer_is_v2())
 311                 tctl_val = V2_TCTL_CLK_IPG | V2_TCTL_FRR | V2_TCTL_WAITEN | MXC_TCTL_TEN;
 312         else
 313                 tctl_val = MX1_2_TCTL_FRR | MX1_2_TCTL_CLK_PCLK1 | MXC_TCTL_TEN;
 314
 315         __raw_writel(tctl_val, timer_base + MXC_TCTL);
 316
 317         /* init and register the timer to the framework */
 318         mxc_clocksource_init(timer_clk);
 319         mxc_clockevent_init(timer_clk);
 320
 321         /* Make irqs happen */
 322         setup_irq(irq, &mxc_timer_irq);
 323 }