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bsp/tms570: fix get time resolution after infrastructure change to timecounter.

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The update fixes breakage of TMS570 support after Alexander Krutwig
switch of RTEMS time read to timecounter mechanism

bsps: Convert clock drivers to use a timecounter

Mechanism to specify odd (non 1 Mhz) time base update frequencies
implemented after objections of  Martin Galvan.

Code is adjusted to convert RTEMS configuration parameter
microseconds_per_tick to such odd base if
TMS570_PREFERRED_TC_FREQUENCY is specified appropriately.

Signed-off-by: Premysl Houdek <kom541000@gmail.com>
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
This commit is contained in:
Pavel Pisa
2015-07-16 07:14:30 -05:00
committed by Joel Sherrill
parent bea49c9477
commit 602e395b4d
1 changed files with 35 additions and 6 deletions
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41
c/src/lib/libbsp/arm/tms570/clock/clock.c
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@@ -39,6 +39,17 @@ static uint32_t tms570_rti_get_timecount(struct timecounter *tc)
return TMS570_RTI.RTIFRC0;
}
#ifndef TMS570_PREFERRED_TC_FREQUENCY
/*
* Define preferred main time base counter frequency
* The value of 1MHz is the best matching RTEMS
* timing system because then there is no need
* to scale RTEMS configuration microseconds_per_tick
* parameter
*/
#define TMS570_PREFERRED_TC_FREQUENCY 1000000
#endif /* TMS570_PREFERRED_TC_FREQUENCY */
/**
* @brief Initialize the HW peripheral for clock driver
*
@@ -49,13 +60,31 @@ static uint32_t tms570_rti_get_timecount(struct timecounter *tc)
static void tms570_clock_driver_support_initialize_hardware( void )
{
uint32_t microsec_per_tick = rtems_configuration_get_microseconds_per_tick();
uint32_t microsec_per_tick;
uint32_t tc_frequency;
uint32_t tc_prescaler;
uint32_t tc_increments_per_tick;
microsec_per_tick = rtems_configuration_get_microseconds_per_tick();
tc_frequency = TMS570_PREFERRED_TC_FREQUENCY;
rtems_counter_initialize_converter(BSP_PLL_OUT_CLOCK);
tc_prescaler = (BSP_PLL_OUT_CLOCK + tc_frequency) / (tc_frequency * 2);
/* Recompute actual most close frequency which can be realized */
tc_frequency = (BSP_PLL_OUT_CLOCK + tc_prescaler) / (tc_prescaler * 2);
/*
* Recompute tick period to adjust for configurable or exact
* preferred time base 1 usec resolution.
*/
tc_increments_per_tick = ((uint64_t)microsec_per_tick * tc_frequency +
500000) / 1000000;
/* Hardware specific initialize */
TMS570_RTI.RTIGCTRL = 0;
TMS570_RTI.RTICPUC0 = BSP_PLL_OUT_CLOCK /1000000 / 2; /* prescaler */
TMS570_RTI.RTICPUC0 = tc_prescaler - 1;
TMS570_RTI.RTITBCTRL = 2;
TMS570_RTI.RTICAPCTRL = 0;
TMS570_RTI.RTICOMPCTRL = 0;
@@ -66,9 +95,9 @@ static void tms570_clock_driver_support_initialize_hardware( void )
TMS570_RTI.RTICLEARINTENA = 0x00070f0f;
TMS570_RTI.RTIINTFLAG = 0x0007000f;
/* set timer */
TMS570_RTI.RTICOMP0 = TMS570_RTI.RTIFRC0 + microsec_per_tick;
TMS570_RTI.RTICOMP0CLR = TMS570_RTI.RTICOMP0 + microsec_per_tick / 2;
TMS570_RTI.RTIUDCP0 = microsec_per_tick;
TMS570_RTI.RTICOMP0 = TMS570_RTI.RTIFRC0 + tc_increments_per_tick;
TMS570_RTI.RTICOMP0CLR = TMS570_RTI.RTICOMP0 + tc_increments_per_tick / 2;
TMS570_RTI.RTIUDCP0 = tc_increments_per_tick;
/* enable interupt */
TMS570_RTI.RTISETINTENA = 0x1;
/* enable timer */
@@ -76,7 +105,7 @@ static void tms570_clock_driver_support_initialize_hardware( void )
/* set timecounter */
tms570_rti_tc.tc_get_timecount = tms570_rti_get_timecount;
tms570_rti_tc.tc_counter_mask = 0xffffffff;
tms570_rti_tc.tc_frequency = BSP_PLL_OUT_CLOCK;
tms570_rti_tc.tc_frequency = tc_frequency;
tms570_rti_tc.tc_quality = RTEMS_TIMECOUNTER_QUALITY_CLOCK_DRIVER;
rtems_timecounter_install(&tms570_rti_tc);
}