#include <asm/apic.h>
#include <linux/timex.h>
-#include <linux/config.h>
#include <asm/hpet.h>
#include <linux/hpet.h>
-unsigned long hpet_period; /* fsecs / HPET clock */
-unsigned long hpet_tick; /* hpet clks count per tick */
-unsigned long hpet_address; /* hpet memory map physical address */
+static unsigned long hpet_period; /* fsecs / HPET clock */
+unsigned long hpet_tick; /* hpet clks count per tick */
+unsigned long hpet_address; /* hpet memory map physical address */
+int hpet_use_timer;
static int use_hpet; /* can be used for runtime check of hpet */
static int boot_hpet_disable; /* boottime override for HPET timer */
return readl(hpet_virt_address + a);
}
-void hpet_writel(unsigned long d, unsigned long a)
+static void hpet_writel(unsigned long d, unsigned long a)
{
writel(d, hpet_virt_address + a);
}
* comparator value and continue. Next tick can be caught by checking
* for a change in the comparator value. Used in apic.c.
*/
-void __init wait_hpet_tick(void)
+static void __devinit wait_hpet_tick(void)
{
unsigned int start_cmp_val, end_cmp_val;
hpet_writel(0, HPET_COUNTER);
hpet_writel(0, HPET_COUNTER + 4);
- /*
- * Set up timer 0, as periodic with first interrupt to happen at
- * hpet_tick, and period also hpet_tick.
- */
- cfg = hpet_readl(HPET_T0_CFG);
- cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
- HPET_TN_SETVAL | HPET_TN_32BIT;
- hpet_writel(cfg, HPET_T0_CFG);
- /*
- * Some systems seems to need two writes to HPET_T0_CMP,
- * to get interrupts working
- */
- hpet_writel(tick, HPET_T0_CMP);
- hpet_writel(tick, HPET_T0_CMP);
+ if (hpet_use_timer) {
+ /*
+ * Set up timer 0, as periodic with first interrupt to happen at
+ * hpet_tick, and period also hpet_tick.
+ */
+ cfg = hpet_readl(HPET_T0_CFG);
+ cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
+ HPET_TN_SETVAL | HPET_TN_32BIT;
+ hpet_writel(cfg, HPET_T0_CFG);
+ /*
+ * The first write after writing TN_SETVAL to the config register sets
+ * the counter value, the second write sets the threshold.
+ */
+ hpet_writel(tick, HPET_T0_CMP);
+ hpet_writel(tick, HPET_T0_CMP);
+ }
/*
* Go!
*/
cfg = hpet_readl(HPET_CFG);
- cfg |= HPET_CFG_ENABLE | HPET_CFG_LEGACY;
+ if (hpet_use_timer)
+ cfg |= HPET_CFG_LEGACY;
+ cfg |= HPET_CFG_ENABLE;
hpet_writel(cfg, HPET_CFG);
return 0;
id = hpet_readl(HPET_ID);
/*
- * We are checking for value '1' or more in number field.
- * So, we are OK with HPET_EMULATE_RTC part too, where we need
- * to have atleast 2 timers.
+ * We are checking for value '1' or more in number field if
+ * CONFIG_HPET_EMULATE_RTC is set because we will need an
+ * additional timer for RTC emulation.
+ * However, we can do with one timer otherwise using the
+ * the single HPET timer for system time.
*/
- if (!(id & HPET_ID_NUMBER) ||
- !(id & HPET_ID_LEGSUP))
+#ifdef CONFIG_HPET_EMULATE_RTC
+ if (!(id & HPET_ID_NUMBER)) {
+ iounmap(hpet_virt_address);
+ hpet_virt_address = NULL;
return -1;
+ }
+#endif
+
hpet_period = hpet_readl(HPET_PERIOD);
- if ((hpet_period < HPET_MIN_PERIOD) || (hpet_period > HPET_MAX_PERIOD))
+ if ((hpet_period < HPET_MIN_PERIOD) || (hpet_period > HPET_MAX_PERIOD)) {
+ iounmap(hpet_virt_address);
+ hpet_virt_address = NULL;
return -1;
+ }
/*
* 64 bit math
if (hpet_tick_rem > (hpet_period >> 1))
hpet_tick++; /* rounding the result */
- if (hpet_timer_stop_set_go(hpet_tick))
+ hpet_use_timer = id & HPET_ID_LEGSUP;
+
+ if (hpet_timer_stop_set_go(hpet_tick)) {
+ iounmap(hpet_virt_address);
+ hpet_virt_address = NULL;
return -1;
+ }
use_hpet = 1;
#endif
#ifdef CONFIG_X86_LOCAL_APIC
- wait_timer_tick = wait_hpet_tick;
+ if (hpet_use_timer)
+ wait_timer_tick = wait_hpet_tick;
#endif
return 0;
}
#include <linux/mc146818rtc.h>
#include <linux/rtc.h>
-extern irqreturn_t rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs);
-
#define DEFAULT_RTC_INT_FREQ 64
#define RTC_NUM_INTS 1
static unsigned long PIE_count;
static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */
+static unsigned int hpet_t1_cmp; /* cached comparator register */
/*
* Timer 1 for RTC, we do not use periodic interrupt feature,
hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
local_irq_save(flags);
+
cnt = hpet_readl(HPET_COUNTER);
cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq);
hpet_writel(cnt, HPET_T1_CMP);
- local_irq_restore(flags);
+ hpet_t1_cmp = cnt;
cfg = hpet_readl(HPET_T1_CFG);
- cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
+ cfg &= ~HPET_TN_PERIODIC;
+ cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
hpet_writel(cfg, HPET_T1_CFG);
+ local_irq_restore(flags);
+
return 1;
}
static void hpet_rtc_timer_reinit(void)
{
- unsigned int cfg, cnt;
+ unsigned int cfg, cnt, ticks_per_int, lost_ints;
- if (!(PIE_on | AIE_on | UIE_on))
+ if (unlikely(!(PIE_on | AIE_on | UIE_on))) {
+ cfg = hpet_readl(HPET_T1_CFG);
+ cfg &= ~HPET_TN_ENABLE;
+ hpet_writel(cfg, HPET_T1_CFG);
return;
+ }
if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ))
hpet_rtc_int_freq = PIE_freq;
hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
/* It is more accurate to use the comparator value than current count.*/
- cnt = hpet_readl(HPET_T1_CMP);
- cnt += hpet_tick*HZ/hpet_rtc_int_freq;
- hpet_writel(cnt, HPET_T1_CMP);
+ ticks_per_int = hpet_tick * HZ / hpet_rtc_int_freq;
+ hpet_t1_cmp += ticks_per_int;
+ hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
- cfg = hpet_readl(HPET_T1_CFG);
- cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT;
- hpet_writel(cfg, HPET_T1_CFG);
+ /*
+ * If the interrupt handler was delayed too long, the write above tries
+ * to schedule the next interrupt in the past and the hardware would
+ * not interrupt until the counter had wrapped around.
+ * So we have to check that the comparator wasn't set to a past time.
+ */
+ cnt = hpet_readl(HPET_COUNTER);
+ if (unlikely((int)(cnt - hpet_t1_cmp) > 0)) {
+ lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1;
+ /* Make sure that, even with the time needed to execute
+ * this code, the next scheduled interrupt has been moved
+ * back to the future: */
+ lost_ints++;
+
+ hpet_t1_cmp += lost_ints * ticks_per_int;
+ hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
- return;
+ if (PIE_on)
+ PIE_count += lost_ints;
+
+ printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
+ hpet_rtc_int_freq);
+ }
}
/*
return 1;
}
-irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
{
struct rtc_time curr_time;
unsigned long rtc_int_flag = 0;
}
if (call_rtc_interrupt) {
rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
- rtc_interrupt(rtc_int_flag, dev_id, regs);
+ rtc_interrupt(rtc_int_flag, dev_id);
}
return IRQ_HANDLED;
}
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