diff options
Diffstat (limited to 'examples/timer.c')
| -rw-r--r-- | examples/timer.c | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/examples/timer.c b/examples/timer.c new file mode 100644 index 0000000..8d60fc8 --- /dev/null +++ b/examples/timer.c @@ -0,0 +1,338 @@ +/* + * (C) Copyright 2000 + * Wolfgang Denk, DENX Software Engineering, wd@denx.de. + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> +#include <commproc.h> +#include <mpc8xx_irq.h> +#include <syscall.h> + +#undef DEBUG + +#define TIMER_PERIOD 1000000 /* 1 second clock */ + +static void timer_handler (void *arg); + + +/* Access functions for the Machine State Register */ +static __inline__ unsigned long get_msr(void) +{ + unsigned long msr; + + asm volatile("mfmsr %0" : "=r" (msr) :); + return msr; +} + +static __inline__ void set_msr(unsigned long msr) +{ + asm volatile("mtmsr %0" : : "r" (msr)); +} + +/* + * Definitions to access the CPM Timer registers + * See 8xx_immap.h for Internal Memory Map layout, + * and commproc.h for CPM Interrupt vectors (aka "IRQ"s) + */ + +typedef struct tid_8xx_cpmtimer_s { + int cpm_vec; /* CPM Interrupt Vector for this timer */ + ushort *tgcrp; /* Pointer to Timer Global Config Reg. */ + ushort *tmrp; /* Pointer to Timer Mode Register */ + ushort *trrp; /* Pointer to Timer Reference Register */ + ushort *tcrp; /* Pointer to Timer Capture Register */ + ushort *tcnp; /* Pointer to Timer Counter Register */ + ushort *terp; /* Pointer to Timer Event Register */ +} tid_8xx_cpmtimer_t; + +#ifndef CLOCKRATE +# define CLOCKRATE 64 +#endif + +#define CPMT_CLOCK_DIV 16 +#define CPMT_MAX_PRESCALER 256 +#define CPMT_MAX_REFERENCE 65535 /* max. unsigned short */ + +#define CPMT_MAX_TICKS (CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER) +#define CPMT_MAX_TICKS_WITH_DIV (CPMT_MAX_REFERENCE * CPMT_MAX_PRESCALER * CPMT_CLOCK_DIV) +#define CPMT_MAX_INTERVAL (CPMT_MAX_TICKS_WITH_DIV / CLOCKRATE) + +/* For now: always use max. prescaler value */ +#define CPMT_PRESCALER (CPMT_MAX_PRESCALER) + +/* CPM Timer Event Register Bits */ +#define CPMT_EVENT_CAP 0x0001 /* Capture Event */ +#define CPMT_EVENT_REF 0x0002 /* Reference Counter Event */ + +/* CPM Timer Global Config Register */ +#define CPMT_GCR_RST 0x0001 /* Reset Timer */ +#define CPMT_GCR_STP 0x0002 /* Stop Timer */ +#define CPMT_GCR_FRZ 0x0004 /* Freeze Timer */ +#define CPMT_GCR_GM_CAS 0x0008 /* Gate Mode / Cascade Timers */ +#define CPMT_GCR_MASK (CPMT_GCR_RST|CPMT_GCR_STP|CPMT_GCR_FRZ|CPMT_GCR_GM_CAS) + +/* CPM Timer Mode register */ +#define CPMT_MR_GE 0x0001 /* Gate Enable */ +#define CPMT_MR_ICLK_CASC 0x0000 /* Clock internally cascaded */ +#define CPMT_MR_ICLK_CLK 0x0002 /* Clock = system clock */ +#define CPMT_MR_ICLK_CLKDIV 0x0004 /* Clock = system clock / 16 */ +#define CPMT_MR_ICLK_TIN 0x0006 /* Clock = TINx signal */ +#define CPMT_MR_FRR 0x0008 /* Free Run / Restart */ +#define CPMT_MR_ORI 0x0010 /* Out. Reference Interrupt En. */ +#define CPMT_MR_OM 0x0020 /* Output Mode */ +#define CPMT_MR_CE_DIS 0x0000 /* Capture/Interrupt disabled */ +#define CPMT_MR_CE_RISE 0x0040 /* Capt./Interr. on rising TIN */ +#define CPMT_MR_CE_FALL 0x0080 /* Capt./Interr. on falling TIN */ +#define CPMT_MR_CE_ANY 0x00C0 /* Capt./Interr. on any TIN edge*/ + + + +/* + * which CPM timer to use - index starts at 0 (= timer 1) + */ +#define TID_TIMER_ID 0 /* use CPM timer 1 */ + +void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval); + +static char *usage = "\n[q, b, e, ?] "; + +int timer (int argc, char *argv[]) +{ + DECLARE_GLOBAL_DATA_PTR; + + cpmtimer8xx_t *cpmtimerp; /* Pointer to the CPM Timer structure */ + tid_8xx_cpmtimer_t hw; + tid_8xx_cpmtimer_t *hwp = &hw; + int c; + + /* Pointer to CPM Timer structure */ + cpmtimerp = &((immap_t *) gd->bd->bi_immr_base)->im_cpmtimer; + + mon_printf ("TIMERS=0x%x\n", (unsigned) cpmtimerp); + + /* Initialize pointers depending on which timer we use */ + switch (TID_TIMER_ID) { + case 0: + hwp->tmrp = &(cpmtimerp->cpmt_tmr1); + hwp->trrp = &(cpmtimerp->cpmt_trr1); + hwp->tcrp = &(cpmtimerp->cpmt_tcr1); + hwp->tcnp = &(cpmtimerp->cpmt_tcn1); + hwp->terp = &(cpmtimerp->cpmt_ter1); + hwp->cpm_vec = CPMVEC_TIMER1; + break; + case 1: + hwp->tmrp = &(cpmtimerp->cpmt_tmr2); + hwp->trrp = &(cpmtimerp->cpmt_trr2); + hwp->tcrp = &(cpmtimerp->cpmt_tcr2); + hwp->tcnp = &(cpmtimerp->cpmt_tcn2); + hwp->terp = &(cpmtimerp->cpmt_ter2); + hwp->cpm_vec = CPMVEC_TIMER2; + break; + case 2: + hwp->tmrp = &(cpmtimerp->cpmt_tmr3); + hwp->trrp = &(cpmtimerp->cpmt_trr3); + hwp->tcrp = &(cpmtimerp->cpmt_tcr3); + hwp->tcnp = &(cpmtimerp->cpmt_tcn3); + hwp->terp = &(cpmtimerp->cpmt_ter3); + hwp->cpm_vec = CPMVEC_TIMER3; + break; + case 3: + hwp->tmrp = &(cpmtimerp->cpmt_tmr4); + hwp->trrp = &(cpmtimerp->cpmt_trr4); + hwp->tcrp = &(cpmtimerp->cpmt_tcr4); + hwp->tcnp = &(cpmtimerp->cpmt_tcn4); + hwp->terp = &(cpmtimerp->cpmt_ter4); + hwp->cpm_vec = CPMVEC_TIMER4; + break; + } + + hwp->tgcrp = &cpmtimerp->cpmt_tgcr; + + mon_printf ("Using timer %d\n" + "tgcr @ 0x%x, tmr @ 0x%x, trr @ 0x%x," + " tcr @ 0x%x, tcn @ 0x%x, ter @ 0x%x\n", + TID_TIMER_ID + 1, + (unsigned) hwp->tgcrp, + (unsigned) hwp->tmrp, + (unsigned) hwp->trrp, + (unsigned) hwp->tcrp, + (unsigned) hwp->tcnp, + (unsigned) hwp->terp + ); + + /* reset timer */ + *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID); + + /* clear all events */ + *hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF); + + mon_printf (usage); + while ((c = mon_getc()) != 'q') { + if (c == 'b') { + + setPeriod (hwp, TIMER_PERIOD); /* Set period and start ticking */ + + /* Install interrupt handler (enable timer in CIMR) */ + mon_install_hdlr (hwp->cpm_vec, timer_handler, hwp); + + mon_printf ("Enabling timer\n"); + + /* enable timer */ + *hwp->tgcrp |= (CPMT_GCR_RST << TID_TIMER_ID); + +#ifdef DEBUG + mon_printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x," + " tcr=0x%x, tcn=0x%x, ter=0x%x\n", + *hwp->tgcrp, *hwp->tmrp, *hwp->trrp, + *hwp->tcrp, *hwp->tcnp, *hwp->terp + ); +#endif + } else if (c == 'e') { + + mon_printf ("Stopping timer\n"); + + *hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID); + +#ifdef DEBUG + mon_printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x," + " tcr=0x%x, tcn=0x%x, ter=0x%x\n", + *hwp->tgcrp, *hwp->tmrp, *hwp->trrp, + *hwp->tcrp, *hwp->tcnp, *hwp->terp + ); +#endif + /* Uninstall interrupt handler */ + mon_free_hdlr (hwp->cpm_vec); + + } else if (c == '?') { +#ifdef DEBUG + cpic8xx_t *cpm_icp = &((immap_t *) gd->bd->bi_immr_base)->im_cpic; + sysconf8xx_t *siup = &((immap_t *) gd->bd->bi_immr_base)->im_siu_conf; +#endif + + mon_printf ("\ntgcr=0x%x, tmr=0x%x, trr=0x%x," + " tcr=0x%x, tcn=0x%x, ter=0x%x\n", + *hwp->tgcrp, *hwp->tmrp, *hwp->trrp, + *hwp->tcrp, *hwp->tcnp, *hwp->terp + ); +#ifdef DEBUG + mon_printf ("SIUMCR=0x%08lx, SYPCR=0x%08lx," + " SIMASK=0x%08lx, SIPEND=0x%08lx\n", + siup->sc_siumcr, + siup->sc_sypcr, + siup->sc_simask, + siup->sc_sipend + ); + + mon_printf ("CIMR=0x%08lx, CICR=0x%08lx, CIPR=0x%08lx\n", + cpm_icp->cpic_cimr, + cpm_icp->cpic_cicr, + cpm_icp->cpic_cipr + ); +#endif + } else { + mon_printf ("\nEnter: q - quit, b - start timer, e - stop timer, ? - get status\n"); + } + mon_printf (usage); + } + return (0); +} + + +/* Set period in microseconds and start. + * Truncate to maximum period if more than this is requested - but warn about it. + */ + +void setPeriod (tid_8xx_cpmtimer_t *hwp, ulong interval) +{ + unsigned short prescaler; + unsigned long ticks; + + mon_printf ("Set interval %ld us\n", interval); + + /* Warn if requesting longer period than possible */ + if (interval > CPMT_MAX_INTERVAL) { + mon_printf ("Truncate interval %ld to maximum (%d)\n", + interval, CPMT_MAX_INTERVAL); + interval = CPMT_MAX_INTERVAL; + } + /* + * Check if we want to use clock divider: + * Since the reference counter can be incremented only in integer steps, + * we try to keep it as big as possible to allow the resulting period to be + * as precise as possible. + */ + /* prescaler, enable interrupt, restart after ref count is reached */ + prescaler = (ushort) ((CPMT_PRESCALER - 1) << 8) | + CPMT_MR_ORI | + CPMT_MR_FRR; + + ticks = ((ulong) CLOCKRATE * interval); + + if (ticks > CPMT_MAX_TICKS) { + ticks /= CPMT_CLOCK_DIV; + prescaler |= CPMT_MR_ICLK_CLKDIV; /* use system clock divided by 16 */ + } else { + prescaler |= CPMT_MR_ICLK_CLK; /* use system clock without divider */ + } + +#ifdef DEBUG + mon_printf ("clock/%d, prescale factor %d, reference %ld, ticks %ld\n", + (ticks > CPMT_MAX_TICKS) ? CPMT_CLOCK_DIV : 1, + CPMT_PRESCALER, + (ticks / CPMT_PRESCALER), + ticks + ); +#endif + + /* set prescaler register */ + *hwp->tmrp = prescaler; + + /* clear timer counter */ + *hwp->tcnp = 0; + + /* set reference register */ + *hwp->trrp = (unsigned short) (ticks / CPMT_PRESCALER); + +#ifdef DEBUG + mon_printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x," + " tcr=0x%x, tcn=0x%x, ter=0x%x\n", + *hwp->tgcrp, *hwp->tmrp, *hwp->trrp, + *hwp->tcrp, *hwp->tcnp, *hwp->terp + ); +#endif +} + +/* + * Handler for CPMVEC_TIMER1 interrupt + */ +static +void timer_handler (void *arg) +{ + tid_8xx_cpmtimer_t *hwp = (tid_8xx_cpmtimer_t *)arg; + + /* printf ("** TER1=%04x ** ", *hwp->terp); */ + + /* just for demonstration */ + mon_printf ("."); + + /* clear all possible events: Ref. and Cap. */ + *hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF); +} |