arch/arm/mach-s3c44b0x/time.c

   1 /*
   2  * for 2.6.8.1 port by
   3  *    Hyok S. Choi <hyok.choi@samsung.com>
   4  * linux/arch/armnommu/mach-s3c44b0x/time.c
   5  */
   6
   7 #include <linux/init.h>
   8 #include <linux/time.h>
   9 #include <linux/timex.h>
  10 #include <linux/types.h>
  11 #include <linux/sched.h>
  12 #include <linux/interrupt.h>
  13 #include <asm/io.h>
  14 #include <asm/arch/hardware.h>
  15 #include <asm/uaccess.h>
  16 #include <asm/hardware.h>
  17 #include <asm/mach/time.h>
  18 #include <asm/arch/timex.h>
  19
  20 #define S3C44B0X_SYSTIMER_DIVIDER       2
  21 extern int s3c44b0x_fMHZ;
  22 extern int s3c44b0x_finMHZ;
  23
  24 /* the system clock is in MHz unit, here I use the prescale value for 1 us resolution */
  25
  26 #if     CONFIG_ARM_CLK_ADJUST
  27 void s3c44b0x_systimer_setup(void)
  28 #else
  29 void __init s3c44b0x_systimer_setup(void)
  30 #endif
  31 {
  32         int prescale = s3c44b0x_fMHZ / S3C44B0X_SYSTIMER_DIVIDER;
  33         int cnt = s3c44b0x_fMHZ * 1000000 / prescale / S3C44B0X_SYSTIMER_DIVIDER / HZ;
  34
  35         SYSREG_CLR      (S3C44B0X_TCON,0x7<<24);                        // stop timer 5
  36         SYSREG_SET      (S3C44B0X_TCNTB5, cnt);
  37         SYSREG_OR_SET   (S3C44B0X_TCON, 2<<24);                         // update timer5 counter
  38
  39         SYSREG_OR_SET   (S3C44B0X_TCFG0, (prescale - 1) << 16);         // set prescale, bit 16-23
  40         SYSREG_AND_SET  (S3C44B0X_TCFG1, 0xff0fffff);                   // set timer5 divider, bit 20-23.  0 for 1/2
  41 }
  42
  43 void __inline__ s3c44b0x_systimer_start(void)
  44 {
  45         SYSREG_CLR      (S3C44B0X_TCON, 0x02<<24);
  46         SYSREG_OR_SET   (S3C44B0X_TCON, 0x05<<24);
  47 }
  48
  49 /*
  50  * Set up timer interrupt.
  51  */
  52 #if     CONFIG_ARM_CLK_ADJUST
  53 void s3c44b0x_led_off(int);
  54 void s3c44b0x_led_on(int);
  55 #endif
  56
  57 unsigned long s3c44b0x_gettimeoffset (void)
  58 {
  59         return SYSREG_GETW(S3C44B0X_TCNTB5);
  60 }
  61
  62 static irqreturn_t s3c44b0x_timer_interrupt(int irq, void *dev_id)
  63 {
  64 #if     CONFIG_DEBUG_NICKMIT
  65         static int cnt = 0;
  66         ++cnt;
  67         if (cnt == HZ) {
  68                 static int stat = 0;
  69                 cnt = 0;
  70                 if (stat)
  71                         s3c44b0x_led_on(0);
  72                 else
  73                         s3c44b0x_led_off(0);
  74                 stat = 1 - stat;
  75         }
  76 #endif
  77         timer_tick();
  78
  79         return IRQ_HANDLED;
  80 }
  81
  82 static struct irqaction s3c44b0x_timer_irq = {
  83         .name           = "S3C44B0X Timer Tick",
  84         .flags          = IRQF_DISABLED | IRQF_TIMER,
  85         .handler        = s3c44b0x_timer_interrupt
  86 };
  87
  88
  89 void __init s3c44b0x_time_init(void)
  90 {
  91         s3c44b0x_systimer_setup();
  92         /*
  93          * @todo do those really need to be function pointers ?
  94          */
  95         gettimeoffset     = s3c44b0x_gettimeoffset;
  96         s3c44b0x_timer_irq.handler = s3c44b0x_timer_interrupt;
  97
  98         setup_irq(S3C44B0X_INTERRUPT_TIMER5, &s3c44b0x_timer_irq);
  99         s3c44b0x_clear_pb(S3C44B0X_INTERRUPT_TIMER5);
 100         s3c44b0x_unmask_irq(S3C44B0X_INTERRUPT_TIMER5);
 101
 102         s3c44b0x_systimer_start();
 103 }
 104