diff options
Diffstat (limited to 'c/src/lib/libcpu/sh/sh7032/clock')
| -rw-r--r-- | c/src/lib/libcpu/sh/sh7032/clock/Makefile.in | 2 | ||||
| -rw-r--r-- | c/src/lib/libcpu/sh/sh7032/clock/ckinit.c | 94 |
2 files changed, 86 insertions, 10 deletions
diff --git a/c/src/lib/libcpu/sh/sh7032/clock/Makefile.in b/c/src/lib/libcpu/sh/sh7032/clock/Makefile.in index c9bd2ac92d..5617ae594e 100644 --- a/c/src/lib/libcpu/sh/sh7032/clock/Makefile.in +++ b/c/src/lib/libcpu/sh/sh7032/clock/Makefile.in @@ -40,7 +40,7 @@ INSTALL_CHANGE = @INSTALL_CHANGE@ # DEFINES += -CPPFLAGS += -DMHZ=$(MHZ) +CPPFLAGS += CFLAGS += $(CFLAGS_OS_V) LD_PATHS += diff --git a/c/src/lib/libcpu/sh/sh7032/clock/ckinit.c b/c/src/lib/libcpu/sh/sh7032/clock/ckinit.c index 7aef64ed99..a8acc1ca20 100644 --- a/c/src/lib/libcpu/sh/sh7032/clock/ckinit.c +++ b/c/src/lib/libcpu/sh/sh7032/clock/ckinit.c @@ -29,19 +29,30 @@ #include <rtems/libio.h> #include <rtems/score/sh_io.h> #include <rtems/score/sh.h> -#include <rtems/score/cpu_isps.h> -#include <rtems/score/iosh7030.h> - -#define _ITU_COUNTER0_MICROSECOND (MHZ/4) +#include <rtems/score/ispsh7032.h> +#include <rtems/score/iosh7032.h> #ifndef CLOCKPRIO #define CLOCKPRIO 10 #endif +#define I_CLK_PHI_1 0 +#define I_CLK_PHI_2 1 +#define I_CLK_PHI_4 2 +#define I_CLK_PHI_8 3 + +/* + * Set I_CLK_PHI to one of the I_CLK_PHI_X values from above to choose + * a PHI/X clock rate. + */ + +#define I_CLK_PHI I_CLK_PHI_4 +#define CLOCK_SCALE (1<<I_CLK_PHI) + #define ITU0_STARTMASK 0xfe #define ITU0_SYNCMASK 0xfe #define ITU0_MODEMASK 0xfe -#define ITU0_TCRMASK 0x22 +#define ITU0_TCRMASK (0x20 | I_CLK_PHI) #define ITU_STAT_MASK 0xf8 #define ITU0_IRQMASK 0xfe #define ITU0_TIERMASK 0x01 @@ -49,6 +60,55 @@ #define ITU0_TIORVAL 0x08 /* + * clicks_per_tick := clicks_per_sec * usec_per_tick + * + * This is a very expensive function ;-) + * + * Below are two variants: + * 1. A variant applying integer arithmetics, only. + * 2. A variant applying floating point arithmetics + * + * The floating point variant pulls in the fmath routines when linking, + * resulting in slightly larger executables for applications that do not + * apply fmath otherwise. However, the imath variant is significantly slower + * than the fmath variant and more complex. + * + * Assuming that most applications will not use fmath, but are critical + * in memory size constraints, we apply the integer variant. + * + * To the sake of simplicity, we might abandon one of both variants in + * future. + */ +static unsigned int sh_clicks_per_tick( + unsigned int clicks_per_sec, + unsigned int usec_per_tick ) +{ +#if 1 + unsigned int clicks_per_tick = 0 ; + + unsigned int b = clicks_per_sec ; + unsigned int c = 1000000 ; + unsigned int d = 1 ; + unsigned int a = ( ( b / c ) * usec_per_tick ) / d; + + clicks_per_tick += a ; + + while ( ( b %= c ) > 0 ) + { + c /= 10 ; + d *= 10 ; + a = ( ( b / c ) * usec_per_tick ) / d ; + clicks_per_tick += a ; + } + return clicks_per_tick ; +#else + double fclicks_per_tick = + ((double) clicks_per_sec * (double) usec_per_tick) / 1000000.0 ; + return (unsigned32) fclicks_per_tick ; +#endif +} + +/* * The interrupt vector number associated with the clock tick device * driver. */ @@ -100,7 +160,6 @@ rtems_isr Clock_isr( /* * bump the number of clock driver ticks since initialization * - * determine if it is time to announce the passing of tick as configured * to RTEMS through the rtems_clock_tick directive * @@ -137,13 +196,31 @@ void Install_clock( ) { unsigned8 temp8 = 0; + unsigned32 microseconds_per_tick ; + unsigned32 cclicks_per_tick ; + unsigned16 Clock_limit ; /* * Initialize the clock tick device driver variables */ Clock_driver_ticks = 0; - Clock_isrs_const = rtems_configuration_get_microseconds_per_tick() / 10000; + + if ( rtems_configuration_get_microseconds_per_tick() != 0 ) + microseconds_per_tick = rtems_configuration_get_microseconds_per_tick() ; + else + microseconds_per_tick = 10000 ; /* 10000 us */ + + /* clock clicks per tick */ + cclicks_per_tick = + sh_clicks_per_tick( + rtems_cpu_configuration_get_clicks_per_second() / CLOCK_SCALE, + microseconds_per_tick ); + + Clock_isrs_const = cclicks_per_tick >> 16 ; + if ( ( cclicks_per_tick | 0xffff ) > 0 ) + Clock_isrs_const++ ; + Clock_limit = cclicks_per_tick / Clock_isrs_const ; Clock_isrs = Clock_isrs_const; /* @@ -191,8 +268,7 @@ void Install_clock( rtems_fatal_error_occurred( RTEMS_NOT_CONFIGURED); /* set counter limits */ - write16( _ITU_COUNTER0_MICROSECOND * rtems_configuration_get_microseconds_per_tick(), - ITU_GRA0); + write16( Clock_limit, ITU_GRA0); /* start counter */ temp8 = read8( ITU_TSTR) |~ITU0_STARTMASK; |