arch/arm/plat-stmp3xxx/timer.c

   1 /*
   2  * System timer for Freescale STMP37XX/STMP378X
   3  *
   4  * Embedded Alley Solutions, Inc <source@embeddedalley.com>
   5  *
   6  * Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
   7  * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
   8  */
   9
  10 /*
  11  * The code contained herein is licensed under the GNU General Public
  12  * License. You may obtain a copy of the GNU General Public License
  13  * Version 2 or later at the following locations:
  14  *
  15  * http://www.opensource.org/licenses/gpl-license.html
  16  * http://www.gnu.org/copyleft/gpl.html
  17  */
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/clocksource.h>
  22 #include <linux/clockchips.h>
  23 #include <linux/io.h>
  24 #include <linux/irq.h>
  25 #include <linux/interrupt.h>
  26
  27 #include <asm/mach/time.h>
  28 #include <mach/stmp3xxx.h>
  29 #include <mach/platform.h>
  30 #include <mach/regs-timrot.h>
  31
  32 static irqreturn_t
  33 stmp3xxx_timer_interrupt(int irq, void *dev_id)
  34 {
  35         struct clock_event_device *c = dev_id;
  36
  37         /* timer 0 */
  38         if (__raw_readl(REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL0) &
  39                         BM_TIMROT_TIMCTRLn_IRQ) {
  40                 stmp3xxx_clearl(BM_TIMROT_TIMCTRLn_IRQ,
  41                                 REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL0);
  42                 c->event_handler(c);
  43         }
  44
  45         /* timer 1 */
  46         else if (__raw_readl(REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL1)
  47                         & BM_TIMROT_TIMCTRLn_IRQ) {
  48                 stmp3xxx_clearl(BM_TIMROT_TIMCTRLn_IRQ,
  49                                 REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL1);
  50                 stmp3xxx_clearl(BM_TIMROT_TIMCTRLn_IRQ_EN,
  51                                 REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL1);
  52                 __raw_writel(0xFFFF, REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT1);
  53         }
  54
  55         return IRQ_HANDLED;
  56 }
  57
  58 static cycle_t stmp3xxx_clock_read(struct clocksource *cs)
  59 {
  60         return ~((__raw_readl(REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT1)
  61                                 & 0xFFFF0000) >> 16);
  62 }
  63
  64 static int
  65 stmp3xxx_timrot_set_next_event(unsigned long delta,
  66                 struct clock_event_device *dev)
  67 {
  68         /* reload the timer */
  69         __raw_writel(delta, REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT0);
  70         return 0;
  71 }
  72
  73 static void
  74 stmp3xxx_timrot_set_mode(enum clock_event_mode mode,
  75                 struct clock_event_device *dev)
  76 {
  77 }
  78
  79 static struct clock_event_device ckevt_timrot = {
  80         .name           = "timrot",
  81         .features       = CLOCK_EVT_FEAT_ONESHOT,
  82         .shift          = 32,
  83         .set_next_event = stmp3xxx_timrot_set_next_event,
  84         .set_mode       = stmp3xxx_timrot_set_mode,
  85 };
  86
  87 static struct clocksource cksrc_stmp3xxx = {
  88         .name           = "cksrc_stmp3xxx",
  89         .rating         = 250,
  90         .read           = stmp3xxx_clock_read,
  91         .mask           = CLOCKSOURCE_MASK(16),
  92         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
  93 };
  94
  95 static struct irqaction stmp3xxx_timer_irq = {
  96         .name           = "stmp3xxx_timer",
  97         .flags          = IRQF_DISABLED | IRQF_TIMER,
  98         .handler        = stmp3xxx_timer_interrupt,
  99         .dev_id         = &ckevt_timrot,
 100 };
 101
 102
 103 /*
 104  * Set up timer interrupt, and return the current time in seconds.
 105  */
 106 static void __init stmp3xxx_init_timer(void)
 107 {
 108         ckevt_timrot.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC,
 109                                 ckevt_timrot.shift);
 110         ckevt_timrot.min_delta_ns = clockevent_delta2ns(2, &ckevt_timrot);
 111         ckevt_timrot.max_delta_ns = clockevent_delta2ns(0xFFF, &ckevt_timrot);
 112         ckevt_timrot.cpumask = cpumask_of(0);
 113
 114         stmp3xxx_reset_block(REGS_TIMROT_BASE, false);
 115
 116         /* clear two timers */
 117         __raw_writel(0, REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT0);
 118         __raw_writel(0, REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT1);
 119
 120         /* configure them */
 121         __raw_writel(
 122                 (8 << BP_TIMROT_TIMCTRLn_SELECT) |  /* 32 kHz */
 123                 BM_TIMROT_TIMCTRLn_RELOAD |
 124                 BM_TIMROT_TIMCTRLn_UPDATE |
 125                 BM_TIMROT_TIMCTRLn_IRQ_EN,
 126                         REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL0);
 127         __raw_writel(
 128                 (8 << BP_TIMROT_TIMCTRLn_SELECT) |  /* 32 kHz */
 129                 BM_TIMROT_TIMCTRLn_RELOAD |
 130                 BM_TIMROT_TIMCTRLn_UPDATE |
 131                 BM_TIMROT_TIMCTRLn_IRQ_EN,
 132                         REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL1);
 133
 134         __raw_writel(CLOCK_TICK_RATE / HZ - 1,
 135                         REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT0);
 136         __raw_writel(0xFFFF, REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT1);
 137
 138         setup_irq(IRQ_TIMER0, &stmp3xxx_timer_irq);
 139
 140         clocksource_register_hz(&cksrc_stmp3xxx, CLOCK_TICK_RATE);
 141         clockevents_register_device(&ckevt_timrot);
 142 }
 143
 144 #ifdef CONFIG_PM
 145
 146 void stmp3xxx_suspend_timer(void)
 147 {
 148         stmp3xxx_clearl(BM_TIMROT_TIMCTRLn_IRQ_EN | BM_TIMROT_TIMCTRLn_IRQ,
 149                         REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL0);
 150         stmp3xxx_setl(BM_TIMROT_ROTCTRL_CLKGATE,
 151                         REGS_TIMROT_BASE + HW_TIMROT_ROTCTRL);
 152 }
 153
 154 void stmp3xxx_resume_timer(void)
 155 {
 156         stmp3xxx_clearl(BM_TIMROT_ROTCTRL_SFTRST | BM_TIMROT_ROTCTRL_CLKGATE,
 157                         REGS_TIMROT_BASE + HW_TIMROT_ROTCTRL);
 158         __raw_writel(
 159                 8 << BP_TIMROT_TIMCTRLn_SELECT |  /* 32 kHz */
 160                 BM_TIMROT_TIMCTRLn_RELOAD |
 161                 BM_TIMROT_TIMCTRLn_UPDATE |
 162                 BM_TIMROT_TIMCTRLn_IRQ_EN,
 163                         REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL0);
 164         __raw_writel(
 165                 8 << BP_TIMROT_TIMCTRLn_SELECT |  /* 32 kHz */
 166                 BM_TIMROT_TIMCTRLn_RELOAD |
 167                 BM_TIMROT_TIMCTRLn_UPDATE |
 168                 BM_TIMROT_TIMCTRLn_IRQ_EN,
 169                         REGS_TIMROT_BASE + HW_TIMROT_TIMCTRL1);
 170         __raw_writel(CLOCK_TICK_RATE / HZ - 1,
 171                         REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT0);
 172         __raw_writel(0xFFFF, REGS_TIMROT_BASE + HW_TIMROT_TIMCOUNT1);
 173 }
 174
 175 #else
 176
 177 #define stmp3xxx_suspend_timer  NULL
 178 #define stmp3xxx_resume_timer   NULL
 179
 180 #endif  /* CONFIG_PM */
 181
 182 struct sys_timer stmp3xxx_timer = {
 183         .init           = stmp3xxx_init_timer,
 184         .suspend        = stmp3xxx_suspend_timer,
 185         .resume         = stmp3xxx_resume_timer,
 186 };