/*
   * (C) Copyright 2000
   * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #include <common.h>
  #include <commproc.h>
  #include <mpc8xx_irq.h>
  #include <exports.h>
  
  DECLARE_GLOBAL_DATA_PTR;
  
  #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 const char usage[] = "
  [q, b, e, ?] ";
  
  int timer (int argc, char * const argv[])
  {
  	cpmtimer8xx_t *cpmtimerp;	/* Pointer to the CPM Timer structure   */
  	tid_8xx_cpmtimer_t hw;
  	tid_8xx_cpmtimer_t *hwp = &hw;
  	int c;
  	int running;
  
  	app_startup(argv);
  
  	/* Pointer to CPM Timer structure */
  	cpmtimerp = &((immap_t *) gd->bd->bi_immr_base)->im_cpmtimer;
  
  	printf ("TIMERS=0x%x
  ", (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;
  
  	printf ("Using timer %d
  "
  			"tgcr @ 0x%x, tmr @ 0x%x, trr @ 0x%x,"
  			" tcr @ 0x%x, tcn @ 0x%x, ter @ 0x%x
  ",
  			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);
  
  	puts(usage);
  	running = 0;
  	while ((c = getc()) != 'q') {
  	    if (c == 'b') {
  
  		setPeriod (hwp, TIMER_PERIOD);	/* Set period and start ticking */
  
  		/* Install interrupt handler (enable timer in CIMR) */
  		install_hdlr (hwp->cpm_vec, timer_handler, hwp);
  
  		printf ("Enabling timer
  ");
  
  		/* enable timer */
  		*hwp->tgcrp |= (CPMT_GCR_RST << TID_TIMER_ID);
  		running = 1;
  
  #ifdef	DEBUG
  		printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
  			" tcr=0x%x, tcn=0x%x, ter=0x%x
  ",
  				*hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
  				*hwp->tcrp,  *hwp->tcnp, *hwp->terp
  				);
  #endif
  	    } else if (c == 'e') {
  
  		printf ("Stopping timer
  ");
  
  		*hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
  		running = 0;
  
  #ifdef	DEBUG
  		printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
  			" tcr=0x%x, tcn=0x%x, ter=0x%x
  ",
  				*hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
  				*hwp->tcrp,  *hwp->tcnp, *hwp->terp
  			);
  #endif
  		/* Uninstall interrupt handler */
  		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
  
  		printf ("
  tgcr=0x%x, tmr=0x%x, trr=0x%x,"
  			" tcr=0x%x, tcn=0x%x, ter=0x%x
  ",
  				*hwp->tgcrp, *hwp->tmrp, *hwp->trrp,
  				*hwp->tcrp,  *hwp->tcnp, *hwp->terp
  			);
  #ifdef	DEBUG
  		printf ("SIUMCR=0x%08lx, SYPCR=0x%08lx,"
  			" SIMASK=0x%08lx, SIPEND=0x%08lx
  ",
  				siup->sc_siumcr,
  				siup->sc_sypcr,
  				siup->sc_simask,
  				siup->sc_sipend
  			);
  
  		printf ("CIMR=0x%08lx, CICR=0x%08lx, CIPR=0x%08lx
  ",
  			cpm_icp->cpic_cimr,
  			cpm_icp->cpic_cicr,
  			cpm_icp->cpic_cipr
  			);
  #endif
  	    } else {
  		printf ("
  Enter: q - quit, b - start timer, e - stop timer, ? - get status
  ");
  	    }
  	    puts(usage);
  	}
  	if (running) {
  		printf ("Stopping timer
  ");
  		*hwp->tgcrp &= ~(CPMT_GCR_MASK << TID_TIMER_ID);
  		free_hdlr (hwp->cpm_vec);
  	}
  
  	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;
  
  	printf ("Set interval %ld us
  ", interval);
  
  	/* Warn if requesting longer period than possible */
  	if (interval > CPMT_MAX_INTERVAL) {
  		printf ("Truncate interval %ld to maximum (%d)
  ",
  				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
  	printf ("clock/%d, prescale factor %d, reference %ld, ticks %ld
  ",
  			(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
  	printf ("tgcr=0x%x, tmr=0x%x, trr=0x%x,"
  		" tcr=0x%x, tcn=0x%x, ter=0x%x
  ",
  			*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 */
  	printf (".");
  
  	/* clear all possible events: Ref. and Cap. */
  	*hwp->terp = (CPMT_EVENT_CAP | CPMT_EVENT_REF);
  }