arch/m68k/68000/timers.c

   1 /***************************************************************************/
   2
   3 /*
   4  *  timers.c - Generic hardware timer support.
   5  *
   6  *  Copyright (C) 1993 Hamish Macdonald
   7  *  Copyright (C) 1999 D. Jeff Dionne
   8  *  Copyright (C) 2001 Georges Menie, Ken Desmet
   9  *
  10  * This file is subject to the terms and conditions of the GNU General Public
  11  * License.  See the file COPYING in the main directory of this archive
  12  * for more details.
  13  */
  14
  15 /***************************************************************************/
  16
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/mm.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/irq.h>
  22 #include <linux/clocksource.h>
  23 #include <linux/rtc.h>
  24 #include <asm/setup.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/machdep.h>
  27 #include <asm/MC68VZ328.h>
  28
  29 /***************************************************************************/
  30
  31 #if defined(CONFIG_DRAGEN2)
  32 /* with a 33.16 MHz clock, this will give usec resolution to the time functions */
  33 #define CLOCK_SOURCE    TCTL_CLKSOURCE_SYSCLK
  34 #define CLOCK_PRE       7
  35 #define TICKS_PER_JIFFY 41450
  36
  37 #elif defined(CONFIG_XCOPILOT_BUGS)
  38 /*
  39  * The only thing I know is that CLK32 is not available on Xcopilot
  40  * I have little idea about what frequency SYSCLK has on Xcopilot.
  41  * The values for prescaler and compare registers were simply
  42  * taken from the original source
  43  */
  44 #define CLOCK_SOURCE    TCTL_CLKSOURCE_SYSCLK
  45 #define CLOCK_PRE       2
  46 #define TICKS_PER_JIFFY 0xd7e4
  47
  48 #else
  49 /* default to using the 32Khz clock */
  50 #define CLOCK_SOURCE    TCTL_CLKSOURCE_32KHZ
  51 #define CLOCK_PRE       31
  52 #define TICKS_PER_JIFFY 10
  53 #endif
  54
  55 static u32 m68328_tick_cnt;
  56 static irq_handler_t timer_interrupt;
  57
  58 /***************************************************************************/
  59
  60 static irqreturn_t hw_tick(int irq, void *dummy)
  61 {
  62         /* Reset Timer1 */
  63         TSTAT &= 0;
  64
  65         m68328_tick_cnt += TICKS_PER_JIFFY;
  66         return timer_interrupt(irq, dummy);
  67 }
  68
  69 /***************************************************************************/
  70
  71 static struct irqaction m68328_timer_irq = {
  72         .name    = "timer",
  73         .flags   = IRQF_TIMER,
  74         .handler = hw_tick,
  75 };
  76
  77 /***************************************************************************/
  78
  79 static cycle_t m68328_read_clk(struct clocksource *cs)
  80 {
  81         unsigned long flags;
  82         u32 cycles;
  83
  84         local_irq_save(flags);
  85         cycles = m68328_tick_cnt + TCN;
  86         local_irq_restore(flags);
  87
  88         return cycles;
  89 }
  90
  91 /***************************************************************************/
  92
  93 static struct clocksource m68328_clk = {
  94         .name   = "timer",
  95         .rating = 250,
  96         .read   = m68328_read_clk,
  97         .mask   = CLOCKSOURCE_MASK(32),
  98         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
  99 };
 100
 101 /***************************************************************************/
 102
 103 void hw_timer_init(irq_handler_t handler)
 104 {
 105         /* disable timer 1 */
 106         TCTL = 0;
 107
 108         /* set ISR */
 109         setup_irq(TMR_IRQ_NUM, &m68328_timer_irq);
 110
 111         /* Restart mode, Enable int, Set clock source */
 112         TCTL = TCTL_OM | TCTL_IRQEN | CLOCK_SOURCE;
 113         TPRER = CLOCK_PRE;
 114         TCMP = TICKS_PER_JIFFY;
 115
 116         /* Enable timer 1 */
 117         TCTL |= TCTL_TEN;
 118         clocksource_register_hz(&m68328_clk, TICKS_PER_JIFFY*HZ);
 119         timer_interrupt = handler;
 120 }
 121
 122 /***************************************************************************/
 123
 124 int m68328_hwclk(int set, struct rtc_time *t)
 125 {
 126         if (!set) {
 127                 long now = RTCTIME;
 128                 t->tm_year = t->tm_mon = t->tm_mday = 1;
 129                 t->tm_hour = (now >> 24) % 24;
 130                 t->tm_min = (now >> 16) % 60;
 131                 t->tm_sec = now % 60;
 132         }
 133
 134         return 0;
 135 }
 136
 137 /***************************************************************************/