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i.MX31: switch to CFG_HZ=1000 

Switch to the standard CFG_HZ=1000 value, while at it, minor white-space
cleanup, remove CFG_CLKS_IN_HZ from config-headers. Tested on mx31ads,
provides 2% or 0.4% precision depending on the
CONFIG_MX31_TIMER_HIGH_PRECISION flag. Measured with stop-watch on 100s
boot-delay.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
This commit is contained in:
Guennadi Liakhovetski 2008-09-25 20:54:37 +02:00 committed by Jean-Christophe PLAGNIOL-VILLARD
parent f41b144c11
commit 1ed7a7f0f5
4 changed files with 51 additions and 34 deletions
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75
cpu/arm1136/mx31/interrupts.c
View File

@ -27,30 +27,49 @@
#define TIMER_BASE 0x53f90000 /* General purpose timer 1 */
/* General purpose timers registers */
#define GPTCR __REG(TIMER_BASE) /* Control register */
#define GPTPR __REG(TIMER_BASE + 0x4) /* Prescaler register */
#define GPTSR __REG(TIMER_BASE + 0x8) /* Status register */
#define GPTCNT __REG(TIMER_BASE + 0x24) /* Counter register */
#define GPTCR __REG(TIMER_BASE) /* Control register */
#define GPTPR __REG(TIMER_BASE + 0x4) /* Prescaler register */
#define GPTSR __REG(TIMER_BASE + 0x8) /* Status register */
#define GPTCNT __REG(TIMER_BASE + 0x24) /* Counter register */
/* General purpose timers bitfields */
#define GPTCR_SWR (1<<15) /* Software reset */
#define GPTCR_FRR (1<<9) /* Freerun / restart */
#define GPTCR_CLKSOURCE_32 (4<<6) /* Clock source */
#define GPTCR_TEN (1) /* Timer enable */
#define GPTCR_SWR (1 << 15) /* Software reset */
#define GPTCR_FRR (1 << 9) /* Freerun / restart */
#define GPTCR_CLKSOURCE_32 (4 << 6) /* Clock source */
#define GPTCR_TEN 1 /* Timer enable */
/* "time" is measured in 1 / CFG_HZ seconds, "tick" is internal timer period */
#ifdef CONFIG_MX31_TIMER_HIGH_PRECISION
/* ~0.4% error - measured with stop-watch on 100s boot-delay */
#define TICK_TO_TIME(t) ((t) * CFG_HZ / CONFIG_MX31_CLK32)
#define TIME_TO_TICK(t) ((unsigned long long)(t) * CONFIG_MX31_CLK32 / CFG_HZ)
#define US_TO_TICK(t) (((unsigned long long)(t) * CONFIG_MX31_CLK32 + \
999999) / 1000000)
#else
/* ~2% error */
#define TICK_PER_TIME ((CONFIG_MX31_CLK32 + CFG_HZ / 2) / CFG_HZ)
#define US_PER_TICK (1000000 / CONFIG_MX31_CLK32)
#define TICK_TO_TIME(t) ((t) / TICK_PER_TIME)
#define TIME_TO_TICK(t) ((unsigned long long)(t) * TICK_PER_TIME)
#define US_TO_TICK(t) (((t) + US_PER_TICK - 1) / US_PER_TICK)
#endif
static ulong timestamp;
static ulong lastinc;
/* nothing really to do with interrupts, just starts up a counter. */
/* The 32768Hz 32-bit timer overruns in 131072 seconds */
int interrupt_init (void)
{
int i;
/* setup GP Timer 1 */
GPTCR = GPTCR_SWR;
for ( i=0; i<100; i++) GPTCR = 0; /* We have no udelay by now */
for (i = 0; i < 100; i++)
GPTCR = 0; /* We have no udelay by now */
GPTPR = 0; /* 32Khz */
GPTCR |= GPTCR_CLKSOURCE_32 | GPTCR_TEN; /* Freerun Mode, PERCLK1 input */
/* Freerun Mode, PERCLK1 input */
GPTCR |= GPTCR_CLKSOURCE_32 | GPTCR_TEN;
return 0;
}
@ -67,7 +86,7 @@ void reset_timer(void)
reset_timer_masked();
}
ulong get_timer_masked (void)
unsigned long long get_ticks (void)
{
ulong now = GPTCNT; /* current tick value */
@ -80,6 +99,17 @@ ulong get_timer_masked (void)
return timestamp;
}
ulong get_timer_masked (void)
{
/*
* get_ticks() returns a long long (64 bit), it wraps in
* 2^64 / CONFIG_MX31_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
* 5 * 10^9 days... and get_ticks() * CFG_HZ wraps in
* 5 * 10^6 days - long enough.
*/
return TICK_TO_TIME(get_ticks());
}
ulong get_timer (ulong base)
{
return get_timer_masked () - base;
@ -87,29 +117,20 @@ ulong get_timer (ulong base)
void set_timer (ulong t)
{
timestamp = TIME_TO_TICK(t);
}
/* delay x useconds AND perserve advance timstamp value */
void udelay (unsigned long usec)
{
ulong tmo, tmp;
unsigned long long tmp;
ulong tmo;
if (usec >= 1000) { /* if "big" number, spread normalization to seconds */
tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
tmo *= CFG_HZ; /* find number of "ticks" to wait to achieve target */
tmo /= 1000; /* finish normalize. */
} else { /* else small number, don't kill it prior to HZ multiply */
tmo = usec * CFG_HZ;
tmo /= (1000*1000);
}
tmo = US_TO_TICK(usec);
tmp = get_ticks() + tmo; /* get current timestamp */
tmp = get_timer (0); /* get current timestamp */
if ( (tmo + tmp + 1) < tmp )/* if setting this forward will roll time stamp */
reset_timer_masked (); /* reset "advancing" timestamp to 0, set lastinc value */
else
tmo += tmp; /* else, set advancing stamp wake up time */
while (get_timer_masked () < tmo)/* loop till event */
/*NOP*/;
while (get_ticks() < tmp) /* loop till event */
/*NOP*/;
}
void reset_cpu (ulong addr)

4
include/configs/imx31_litekit.h
View File

@ -122,11 +122,9 @@
#define CFG_MEMTEST_START 0 /* memtest works on */
#define CFG_MEMTEST_END 0x10000
#undef CFG_CLKS_IN_HZ /* everything, incl board info, in Hz */
#define CFG_LOAD_ADDR 0 /* default load address */
#define CFG_HZ 32000
#define CFG_HZ 1000
#define CONFIG_CMDLINE_EDITING 1

2
include/configs/imx31_phycore.h
View File

@ -126,7 +126,7 @@
#define CFG_LOAD_ADDR 0 /* default load address */
#define CFG_HZ 32000
#define CFG_HZ 1000
#define CONFIG_CMDLINE_EDITING 1

4
include/configs/mx31ads.h
View File

@ -139,11 +139,9 @@
#define CFG_MEMTEST_START 0 /* memtest works on */
#define CFG_MEMTEST_END 0x10000
#undef CFG_CLKS_IN_HZ /* everything, incl board info, in Hz */
#define CFG_LOAD_ADDR CONFIG_LOADADDR
#define CFG_HZ CONFIG_MX31_CLK32 /* use 32kHz clock as source */
#define CFG_HZ 1000
#define CONFIG_CMDLINE_EDITING 1