From: Alessandro Rubini rubini@unipv.it
This sets CONFIG_SYS_HZ to 1000 as required, and completely rewrites timer code, which is now both correct and much smaller. Unused functions like udelay_masked() have been removed as no driver uses them, even the ones that are not currently active for this board.
Signed-off-by: Alessandro Rubini rubini@unipv.it Acked-by: Andrea Gallo andrea.gallo@stericsson.com --- cpu/arm926ejs/nomadik/timer.c | 190 +++++++++++----------------------------- include/configs/nhk8815.h | 2 +- 2 files changed, 53 insertions(+), 139 deletions(-)
diff --git a/cpu/arm926ejs/nomadik/timer.c b/cpu/arm926ejs/nomadik/timer.c index 2870d24..3618c4a 100644 --- a/cpu/arm926ejs/nomadik/timer.c +++ b/cpu/arm926ejs/nomadik/timer.c @@ -1,20 +1,5 @@ /* - * (C) Copyright 2003 - * Texas Instruments <www.ti.com> - * - * (C) Copyright 2002 - * Sysgo Real-Time Solutions, GmbH <www.elinos.com> - * Marius Groeger mgroeger@sysgo.de - * - * (C) Copyright 2002 - * Sysgo Real-Time Solutions, GmbH <www.elinos.com> - * Alex Zuepke azu@sysgo.de - * - * (C) Copyright 2002-2004 - * Gary Jennejohn, DENX Software Engineering, garyj@denx.de - * - * (C) Copyright 2004 - * Philippe Robin, ARM Ltd. philippe.robin@arm.com + * (C) Copyright 2009 Alessandro Rubini * * See file CREDITS for list of people who contributed to this * project. @@ -38,145 +23,74 @@ #include <common.h> #include <asm/io.h>
-#define TIMER_LOAD_VAL 0xffffffff +/* + * Registers in the MTU block -- same as <mach/mtu.h> in linux +*/ + +#define MTU_IMSC 0x00 /* Interrupt mask set/clear */ +#define MTU_RIS 0x04 /* Raw interrupt status */ +#define MTU_MIS 0x08 /* Masked interrupt status */ +#define MTU_ICR 0x0C /* Interrupt clear register */ + +/* per-timer registers take 0..3 as argument */ +#define MTU_LR(x) (0x10 + 0x10 * (x) + 0x00) /* Load value */ +#define MTU_VAL(x) (0x10 + 0x10 * (x) + 0x04) /* Current value */ +#define MTU_CR(x) (0x10 + 0x10 * (x) + 0x08) /* Control reg */ +#define MTU_BGLR(x) (0x10 + 0x10 * (x) + 0x0c) /* At next overflow */ + +/* bits for the control register */ +#define MTU_CRn_ENA 0x80 +#define MTU_CRn_PERIODIC 0x40 /* if 0 = free-running */ +#define MTU_CRn_PRESCALE_MASK 0x0c +#define MTU_CRn_PRESCALE_1 0x00 +#define MTU_CRn_PRESCALE_16 0x04 +#define MTU_CRn_PRESCALE_256 0x08 +#define MTU_CRn_32BITS 0x02 +#define MTU_CRn_ONESHOT 0x01 /* if 0 = wraps reloading from BGLR*/
-/* macro to read the 32 bit timer */ -#define READ_TIMER readl(CONFIG_SYS_TIMERBASE + 20)
-static ulong timestamp; -static ulong lastdec; +/* + * The timer is a decrementer, we'll left it free running at 2.4MHz. + * We have 2.4 ticks per microsecond and an overflow in almost 30min + */ +#define TIMER_CLOCK (24*100*1000) +#define COUNT_TO_USEC(x) ((x)*5/12) /* overflows at 6min */ +#define USEC_TO_COUNT(x) ((x)*12/5) /* overflows at 6min */ +#define TICKS_PER_HZ (TIMER_CLOCK/CONFIG_SYS_HZ) +#define TICKS_TO_HZ(x) ((x)/TICKS_PER_HZ) + +/* macro to read the 32 bit timer: since it decrements, we invert read value */ +#define READ_TIMER() (~readl(CONFIG_SYS_TIMERBASE + MTU_VAL(0)))
-/* nothing really to do with interrupts, just starts up a counter. */ +/* Configure a free-running, auto-wrap counter with no prescaler */ int timer_init(void) { - /* Load timer with initial value */ - writel(TIMER_LOAD_VAL, CONFIG_SYS_TIMERBASE + 16); - - /* - * Set timer to be enabled, free-running, no interrupts, 256 divider, - * 32-bit, wrap-mode - */ - writel(0x8a, CONFIG_SYS_TIMERBASE + 24); - - /* init the timestamp and lastdec value */ - reset_timer_masked(); - + writel(MTU_CRn_ENA | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS, + CONFIG_SYS_TIMERBASE + MTU_CR(0)); + reset_timer(); return 0; }
-/* - * timer without interrupts - */ +/* Restart counting from 0 */ void reset_timer(void) { - reset_timer_masked(); + writel(0, CONFIG_SYS_TIMERBASE + MTU_LR(0)); /* Immediate effect */ }
+/* Return how many HZ passed since "base" */ ulong get_timer(ulong base) { - return get_timer_masked() - base; -} - -void set_timer(ulong t) -{ - timestamp = t; + ulong res = TICKS_TO_HZ(READ_TIMER()) - base; + return res; }
-/* delay x useconds AND perserve advance timstamp value */ +/* Delay x useconds */ void udelay(unsigned long usec) { - ulong tmo, tmp; - - if (usec >= 1000) { - /* if "big" number, spread normalization to seconds */ - tmo = usec / 1000; /* start to normalize */ - tmo *= CONFIG_SYS_HZ; /* find number of "ticks" */ - tmo /= 1000; /* finish normalize. */ - } else { - /* small number, don't kill it prior to HZ multiply */ - tmo = usec * CONFIG_SYS_HZ; - tmo /= (1000 * 1000); - } - - tmp = get_timer(0); /* get current timestamp */ - if ((tmo + tmp + 1) < tmp) /* will roll time stamp? */ - reset_timer_masked(); /* reset to 0, set lastdec value */ - else - tmo += tmp; - - while (get_timer_masked() < tmo) - /* nothing */ ; -} - -void reset_timer_masked(void) -{ - /* reset time */ - lastdec = READ_TIMER; /* capure current decrementer value time */ - timestamp = 0; /* start "advancing" time stamp from 0 */ -} - -ulong get_timer_masked(void) -{ - ulong now = READ_TIMER; /* current tick value */ - - if (lastdec >= now) { /* normal mode (non roll) */ - /* move stamp fordward */ - timestamp += lastdec - now; - } else { - /* - * An overflow is expected. - * nts = ts + ld + (TLV - now) - * ts=old stamp, ld=time that passed before passing through -1 - * (TLV-now) amount of time after passing though -1 - * nts = new "advancing time stamp"...it could also roll - */ - timestamp += lastdec + TIMER_LOAD_VAL - now; - } - lastdec = now; - - return timestamp; -} - -/* waits specified delay value and resets timestamp */ -void udelay_masked(unsigned long usec) -{ - ulong tmo; - - if (usec >= 1000) { - /* if "big" number, spread normalization to seconds */ - tmo = usec / 1000; /* start to normalize */ - tmo *= CONFIG_SYS_HZ; /* find number of "ticks" */ - tmo /= 1000; /* finish normalize. */ - } else { - /* else small number, don't kill it prior to HZ multiply */ - tmo = usec * CONFIG_SYS_HZ; - tmo /= (1000*1000); - } - - reset_timer_masked(); - /* set "advancing" timestamp to 0, set lastdec vaule */ - - while (get_timer_masked() < tmo) - /* nothing */ ; -} - -/* - * This function is derived from PowerPC code (read timebase as long long). - * On ARM it just returns the timer value. - */ -unsigned long long get_ticks(void) -{ - return get_timer(0); -} - -/* - * This function is derived from PowerPC code (timebase clock frequency). - * On ARM it returns the number of timer ticks per second. - */ -ulong get_tbclk(void) -{ - ulong tbclk; + ulong ini, end;
- tbclk = CONFIG_SYS_HZ; - return tbclk; + ini = READ_TIMER(); + end = ini + USEC_TO_COUNT(usec); + while ((signed)(end - READ_TIMER()) > 0) + ; } diff --git a/include/configs/nhk8815.h b/include/configs/nhk8815.h index bf1a915..3e2e09f 100644 --- a/include/configs/nhk8815.h +++ b/include/configs/nhk8815.h @@ -96,7 +96,7 @@ #define CONFIG_MISC_INIT_R /* call misc_init_r during start up */
/* timing informazion */ -#define CONFIG_SYS_HZ (2400000 / 256) /* Timer0: 2.4Mhz + divider */ +#define CONFIG_SYS_HZ 1000 /* Mandatory... */ #define CONFIG_SYS_TIMERBASE 0x101E2000
/* serial port (PL011) configuration */