diff options
Diffstat (limited to 'drivers/acpi/acpica/hwtimer.c')
| -rw-r--r-- | drivers/acpi/acpica/hwtimer.c | 29 |
1 files changed, 14 insertions, 15 deletions
diff --git a/drivers/acpi/acpica/hwtimer.c b/drivers/acpi/acpica/hwtimer.c index a2f4e25d45b1..5b4282902a83 100644 --- a/drivers/acpi/acpica/hwtimer.c +++ b/drivers/acpi/acpica/hwtimer.c @@ -150,10 +150,10 @@ ACPI_EXPORT_SYMBOL(acpi_get_timer) * ******************************************************************************/ acpi_status -acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed) +acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 *time_elapsed) { acpi_status status; - u32 delta_ticks; + u64 delta_ticks; u64 quotient; ACPI_FUNCTION_TRACE(acpi_get_timer_duration); @@ -168,30 +168,29 @@ acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed) return_ACPI_STATUS(AE_SUPPORT); } + if (start_ticks == end_ticks) { + *time_elapsed = 0; + return_ACPI_STATUS(AE_OK); + } + /* * Compute Tick Delta: * Handle (max one) timer rollovers on 24-bit versus 32-bit timers. */ - if (start_ticks < end_ticks) { - delta_ticks = end_ticks - start_ticks; - } else if (start_ticks > end_ticks) { + delta_ticks = end_ticks; + if (start_ticks > end_ticks) { if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { /* 24-bit Timer */ - delta_ticks = - (((0x00FFFFFF - start_ticks) + - end_ticks) & 0x00FFFFFF); + delta_ticks |= (u64)1 << 24; } else { /* 32-bit Timer */ - delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks; + delta_ticks |= (u64)1 << 32; } - } else { /* start_ticks == end_ticks */ - - *time_elapsed = 0; - return_ACPI_STATUS(AE_OK); } + delta_ticks -= start_ticks; /* * Compute Duration (Requires a 64-bit multiply and divide): @@ -199,10 +198,10 @@ acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed) * time_elapsed (microseconds) = * (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY; */ - status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC, + status = acpi_ut_short_divide(delta_ticks * ACPI_USEC_PER_SEC, ACPI_PM_TIMER_FREQUENCY, "ient, NULL); - *time_elapsed = (u32) quotient; + *time_elapsed = (u32)quotient; return_ACPI_STATUS(status); } |