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 /* defines common for all i.MX */
  34 #define MXC_TCTL                0x00
  35 #define MXC_TCTL_TEN            (1 << 0)
  36 #define MXC_TPRER               0x04
  37
  38 /* MX1, MX21, MX27 */
  39 #define MX1_2_TCTL_CLK_PCLK1    (1 << 1)
  40 #define MX1_2_TCTL_IRQEN        (1 << 4)
  41 #define MX1_2_TCTL_FRR          (1 << 8)
  42 #define MX1_2_TCMP              0x08
  43 #define MX1_2_TCN               0x10
  44 #define MX1_2_TSTAT             0x14
  45
  46 /* MX21, MX27 */
  47 #define MX2_TSTAT_CAPT          (1 << 1)
  48 #define MX2_TSTAT_COMP          (1 << 0)
  49
  50 /* MX31, MX35, MX25, MXC91231 */
  51 #define MX3_TCTL_WAITEN         (1 << 3)
  52 #define MX3_TCTL_CLK_IPG        (1 << 6)
  53 #define MX3_TCTL_FRR            (1 << 9)
  54 #define MX3_IR                  0x0c
  55 #define MX3_TSTAT               0x08
  56 #define MX3_TSTAT_OF1           (1 << 0)
  57 #define MX3_TCN                 0x24
  58 #define MX3_TCMP                0x10
  59
  60 static struct clock_event_device clockevent_mxc;
  61 static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
  62
  63 static void __iomem *timer_base;
  64
  65 static inline void gpt_irq_disable(void)
  66 {
  67         unsigned int tmp;
  68
  69         if (cpu_is_mx3() || cpu_is_mx25())
  70                 __raw_writel(0, timer_base + MX3_IR);
  71         else {
  72                 tmp = __raw_readl(timer_base + MXC_TCTL);
  73                 __raw_writel(tmp & ~MX1_2_TCTL_IRQEN, timer_base + MXC_TCTL);
  74         }
  75 }
  76
  77 static inline void gpt_irq_enable(void)
  78 {
  79         if (cpu_is_mx3() || cpu_is_mx25())
  80                 __raw_writel(1<<0, timer_base + MX3_IR);
  81         else {
  82                 __raw_writel(__raw_readl(timer_base + MXC_TCTL) | MX1_2_TCTL_IRQEN,
  83                         timer_base + MXC_TCTL);
  84         }
  85 }
  86
  87 static void gpt_irq_acknowledge(void)
  88 {
  89         if (cpu_is_mx1())
  90                 __raw_writel(0, timer_base + MX1_2_TSTAT);
  91         if (cpu_is_mx2())
  92                 __raw_writel(MX2_TSTAT_CAPT | MX2_TSTAT_COMP, timer_base + MX1_2_TSTAT);
  93         if (cpu_is_mx3() || cpu_is_mx25())
  94                 __raw_writel(MX3_TSTAT_OF1, timer_base + MX3_TSTAT);
  95 }
  96
  97 static cycle_t mx1_2_get_cycles(struct clocksource *cs)
  98 {
  99         return __raw_readl(timer_base + MX1_2_TCN);
 100 }
 101
 102 static cycle_t mx3_get_cycles(struct clocksource *cs)
 103 {
 104         return __raw_readl(timer_base + MX3_TCN);
 105 }
 106
 107 static struct clocksource clocksource_mxc = {
 108         .name           = "mxc_timer1",
 109         .rating         = 200,
 110         .read           = mx1_2_get_cycles,
 111         .mask           = CLOCKSOURCE_MASK(32),
 112         .shift          = 20,
 113         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 114 };
 115
 116 static int __init mxc_clocksource_init(struct clk *timer_clk)
 117 {
 118         unsigned int c = clk_get_rate(timer_clk);
 119
 120         if (cpu_is_mx3() || cpu_is_mx25())
 121                 clocksource_mxc.read = mx3_get_cycles;
 122
 123         clocksource_mxc.mult = clocksource_hz2mult(c,
 124                                         clocksource_mxc.shift);
 125         clocksource_register(&clocksource_mxc);
 126
 127         return 0;
 128 }
 129
 130 /* clock event */
 131
 132 static int mx1_2_set_next_event(unsigned long evt,
 133                               struct clock_event_device *unused)
 134 {
 135         unsigned long tcmp;
 136
 137         tcmp = __raw_readl(timer_base + MX1_2_TCN) + evt;
 138
 139         __raw_writel(tcmp, timer_base + MX1_2_TCMP);
 140
 141         return (int)(tcmp - __raw_readl(timer_base + MX1_2_TCN)) < 0 ?
 142                                 -ETIME : 0;
 143 }
 144
 145 static int mx3_set_next_event(unsigned long evt,
 146                               struct clock_event_device *unused)
 147 {
 148         unsigned long tcmp;
 149
 150         tcmp = __raw_readl(timer_base + MX3_TCN) + evt;
 151
 152         __raw_writel(tcmp, timer_base + MX3_TCMP);
 153
 154         return (int)(tcmp - __raw_readl(timer_base + MX3_TCN)) < 0 ?
 155                                 -ETIME : 0;
 156 }
 157
 158 #ifdef DEBUG
 159 static const char *clock_event_mode_label[] = {
 160         [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
 161         [CLOCK_EVT_MODE_ONESHOT]  = "CLOCK_EVT_MODE_ONESHOT",
 162         [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
 163         [CLOCK_EVT_MODE_UNUSED]   = "CLOCK_EVT_MODE_UNUSED"
 164 };
 165 #endif /* DEBUG */
 166
 167 static void mxc_set_mode(enum clock_event_mode mode,
 168                                 struct clock_event_device *evt)
 169 {
 170         unsigned long flags;
 171
 172         /*
 173          * The timer interrupt generation is disabled at least
 174          * for enough time to call mxc_set_next_event()
 175          */
 176         local_irq_save(flags);
 177
 178         /* Disable interrupt in GPT module */
 179         gpt_irq_disable();
 180
 181         if (mode != clockevent_mode) {
 182                 /* Set event time into far-far future */
 183                 if (cpu_is_mx3() || cpu_is_mx25())
 184                         __raw_writel(__raw_readl(timer_base + MX3_TCN) - 3,
 185                                         timer_base + MX3_TCMP);
 186                 else
 187                         __raw_writel(__raw_readl(timer_base + MX1_2_TCN) - 3,
 188                                         timer_base + MX1_2_TCMP);
 189
 190                 /* Clear pending interrupt */
 191                 gpt_irq_acknowledge();
 192         }
 193
 194 #ifdef DEBUG
 195         printk(KERN_INFO "mxc_set_mode: changing mode from %s to %s\n",
 196                 clock_event_mode_label[clockevent_mode],
 197                 clock_event_mode_label[mode]);
 198 #endif /* DEBUG */
 199
 200         /* Remember timer mode */
 201         clockevent_mode = mode;
 202         local_irq_restore(flags);
 203
 204         switch (mode) {
 205         case CLOCK_EVT_MODE_PERIODIC:
 206                 printk(KERN_ERR"mxc_set_mode: Periodic mode is not "
 207                                 "supported for i.MX\n");
 208                 break;
 209         case CLOCK_EVT_MODE_ONESHOT:
 210         /*
 211          * Do not put overhead of interrupt enable/disable into
 212          * mxc_set_next_event(), the core has about 4 minutes
 213          * to call mxc_set_next_event() or shutdown clock after
 214          * mode switching
 215          */
 216                 local_irq_save(flags);
 217                 gpt_irq_enable();
 218                 local_irq_restore(flags);
 219                 break;
 220         case CLOCK_EVT_MODE_SHUTDOWN:
 221         case CLOCK_EVT_MODE_UNUSED:
 222         case CLOCK_EVT_MODE_RESUME:
 223                 /* Left event sources disabled, no more interrupts appear */
 224                 break;
 225         }
 226 }
 227
 228 /*
 229  * IRQ handler for the timer
 230  */
 231 static irqreturn_t mxc_timer_interrupt(int irq, void *dev_id)
 232 {
 233         struct clock_event_device *evt = &clockevent_mxc;
 234         uint32_t tstat;
 235
 236         if (cpu_is_mx3() || cpu_is_mx25())
 237                 tstat = __raw_readl(timer_base + MX3_TSTAT);
 238         else
 239                 tstat = __raw_readl(timer_base + MX1_2_TSTAT);
 240
 241         gpt_irq_acknowledge();
 242
 243         evt->event_handler(evt);
 244
 245         return IRQ_HANDLED;
 246 }
 247
 248 static struct irqaction mxc_timer_irq = {
 249         .name           = "i.MX Timer Tick",
 250         .flags          = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 251         .handler        = mxc_timer_interrupt,
 252 };
 253
 254 static struct clock_event_device clockevent_mxc = {
 255         .name           = "mxc_timer1",
 256         .features       = CLOCK_EVT_FEAT_ONESHOT,
 257         .shift          = 32,
 258         .set_mode       = mxc_set_mode,
 259         .set_next_event = mx1_2_set_next_event,
 260         .rating         = 200,
 261 };
 262
 263 static int __init mxc_clockevent_init(struct clk *timer_clk)
 264 {
 265         unsigned int c = clk_get_rate(timer_clk);
 266
 267         if (cpu_is_mx3() || cpu_is_mx25())
 268                 clockevent_mxc.set_next_event = mx3_set_next_event;
 269
 270         clockevent_mxc.mult = div_sc(c, NSEC_PER_SEC,
 271                                         clockevent_mxc.shift);
 272         clockevent_mxc.max_delta_ns =
 273                         clockevent_delta2ns(0xfffffffe, &clockevent_mxc);
 274         clockevent_mxc.min_delta_ns =
 275                         clockevent_delta2ns(0xff, &clockevent_mxc);
 276
 277         clockevent_mxc.cpumask = cpumask_of(0);
 278
 279         clockevents_register_device(&clockevent_mxc);
 280
 281         return 0;
 282 }
 283
 284 void __init mxc_timer_init(struct clk *timer_clk, void __iomem *base, int irq)
 285 {
 286         uint32_t tctl_val;
 287
 288         clk_enable(timer_clk);
 289
 290         timer_base = base;
 291
 292         /*
 293          * Initialise to a known state (all timers off, and timing reset)
 294          */
 295
 296         __raw_writel(0, timer_base + MXC_TCTL);
 297         __raw_writel(0, timer_base + MXC_TPRER); /* see datasheet note */
 298
 299         if (cpu_is_mx3() || cpu_is_mx25())
 300                 tctl_val = MX3_TCTL_CLK_IPG | MX3_TCTL_FRR | MX3_TCTL_WAITEN | MXC_TCTL_TEN;
 301         else
 302                 tctl_val = MX1_2_TCTL_FRR | MX1_2_TCTL_CLK_PCLK1 | MXC_TCTL_TEN;
 303
 304         __raw_writel(tctl_val, timer_base + MXC_TCTL);
 305
 306         /* init and register the timer to the framework */
 307         mxc_clocksource_init(timer_clk);
 308         mxc_clockevent_init(timer_clk);
 309
 310         /* Make irqs happen */
 311         setup_irq(irq, &mxc_timer_irq);
 312 }