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/machdep.h>
  26 #include <asm/MC68VZ328.h>
  27
  28 /***************************************************************************/
  29
  30 #if defined(CONFIG_DRAGEN2)
  31 /* with a 33.16 MHz clock, this will give usec resolution to the time functions */
  32 #define CLOCK_SOURCE    TCTL_CLKSOURCE_SYSCLK
  33 #define CLOCK_PRE       7
  34 #define TICKS_PER_JIFFY 41450
  35
  36 #elif defined(CONFIG_XCOPILOT_BUGS)
  37 /*
  38  * The only thing I know is that CLK32 is not available on Xcopilot
  39  * I have little idea about what frequency SYSCLK has on Xcopilot.
  40  * The values for prescaler and compare registers were simply
  41  * taken from the original source
  42  */
  43 #define CLOCK_SOURCE    TCTL_CLKSOURCE_SYSCLK
  44 #define CLOCK_PRE       2
  45 #define TICKS_PER_JIFFY 0xd7e4
  46
  47 #else
  48 /* default to using the 32Khz clock */
  49 #define CLOCK_SOURCE    TCTL_CLKSOURCE_32KHZ
  50 #define CLOCK_PRE       31
  51 #define TICKS_PER_JIFFY 10
  52 #endif
  53
  54 static u32 m68328_tick_cnt;
  55 static irq_handler_t timer_interrupt;
  56
  57 /***************************************************************************/
  58
  59 static irqreturn_t hw_tick(int irq, void *dummy)
  60 {
  61         /* Reset Timer1 */
  62         TSTAT &= 0;
  63
  64         m68328_tick_cnt += TICKS_PER_JIFFY;
  65         return timer_interrupt(irq, dummy);
  66 }
  67
  68 /***************************************************************************/
  69
  70 static u64 m68328_read_clk(struct clocksource *cs)
  71 {
  72         unsigned long flags;
  73         u32 cycles;
  74
  75         local_irq_save(flags);
  76         cycles = m68328_tick_cnt + TCN;
  77         local_irq_restore(flags);
  78
  79         return cycles;
  80 }
  81
  82 /***************************************************************************/
  83
  84 static struct clocksource m68328_clk = {
  85         .name   = "timer",
  86         .rating = 250,
  87         .read   = m68328_read_clk,
  88         .mask   = CLOCKSOURCE_MASK(32),
  89         .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
  90 };
  91
  92 /***************************************************************************/
  93
  94 void hw_timer_init(irq_handler_t handler)
  95 {
  96         int ret;
  97
  98         /* disable timer 1 */
  99         TCTL = 0;
 100
 101         /* set ISR */
 102         ret = request_irq(TMR_IRQ_NUM, hw_tick, IRQF_TIMER, "timer", NULL);
 103         if (ret) {
 104                 pr_err("Failed to request irq %d (timer): %pe\n", TMR_IRQ_NUM,
 105                        ERR_PTR(ret));
 106         }
 107
 108         /* Restart mode, Enable int, Set clock source */
 109         TCTL = TCTL_OM | TCTL_IRQEN | CLOCK_SOURCE;
 110         TPRER = CLOCK_PRE;
 111         TCMP = TICKS_PER_JIFFY;
 112
 113         /* Enable timer 1 */
 114         TCTL |= TCTL_TEN;
 115         clocksource_register_hz(&m68328_clk, TICKS_PER_JIFFY*HZ);
 116         timer_interrupt = handler;
 117 }
 118
 119 /***************************************************************************/
 120
 121 int m68328_hwclk(int set, struct rtc_time *t)
 122 {
 123         if (!set) {
 124                 long now = RTCTIME;
 125                 t->tm_year = 1;
 126                 t->tm_mon = 0;
 127                 t->tm_mday = 1;
 128                 t->tm_hour = (now >> 24) % 24;
 129                 t->tm_min = (now >> 16) % 60;
 130                 t->tm_sec = now % 60;
 131         }
 132
 133         return 0;
 134 }
 135
 136 /***************************************************************************/