source: rtems/bsps/powerpc/beatnik/marvell/gt_timer.c

/* Driver for discovery timers and watchdog */

/* 
 * Acknowledgements:
 * Valuable information was obtained from the following drivers
 *   netbsd: (C) Allegro Networks Inc; Wasabi Systems Inc.
 *   linux:  (C) MontaVista, Software, Inc; Mark A. Greer.
 *   rtems:  (C) Brookhaven National Laboratory; K. Feng
 * but this implementation is original work by the author.
 */

/* 
 * Authorship
 * ----------
 * This software ('beatnik' RTEMS BSP for MVME6100 and MVME5500) was
 *     created by Till Straumann <strauman@slac.stanford.edu>, 2005-2007,
 *      Stanford Linear Accelerator Center, Stanford University.
 * 
 * Acknowledgement of sponsorship
 * ------------------------------
 * The 'beatnik' BSP was produced by
 *     the Stanford Linear Accelerator Center, Stanford University,
 *      under Contract DE-AC03-76SFO0515 with the Department of Energy.
 * 
 * Government disclaimer of liability
 * ----------------------------------
 * Neither the United States nor the United States Department of Energy,
 * nor any of their employees, makes any warranty, express or implied, or
 * assumes any legal liability or responsibility for the accuracy,
 * completeness, or usefulness of any data, apparatus, product, or process
 * disclosed, or represents that its use would not infringe privately owned
 * rights.
 * 
 * Stanford disclaimer of liability
 * --------------------------------
 * Stanford University makes no representations or warranties, express or
 * implied, nor assumes any liability for the use of this software.
 * 
 * Stanford disclaimer of copyright
 * --------------------------------
 * Stanford University, owner of the copyright, hereby disclaims its
 * copyright and all other rights in this software.  Hence, anyone may
 * freely use it for any purpose without restriction.  
 * 
 * Maintenance of notices
 * ----------------------
 * In the interest of clarity regarding the origin and status of this
 * SLAC software, this and all the preceding Stanford University notices
 * are to remain affixed to any copy or derivative of this software made
 * or distributed by the recipient and are to be affixed to any copy of
 * software made or distributed by the recipient that contains a copy or
 * derivative of this software.
 * 
 * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
 */ 

#include <rtems.h>
#include <bsp/gtreg.h>
#include <libcpu/io.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <rtems/bspIo.h>

#include <stdint.h>

#include <bsp/gt_timer.h>

#define DEBUG

static inline uint32_t gt_rd(uint32_t off)
{
  return in_le32( (volatile uint32_t *)(BSP_MV64x60_BASE+off) );
}

static inline void gt_wr(uint32_t off, uint32_t val)
{
  out_le32( (volatile uint32_t *)(BSP_MV64x60_BASE+off), val);
}

static inline uint32_t gt_timer_bitmod(uint32_t off, uint32_t clr, uint32_t set)
{
  unsigned  flags;
  uint32_t  rval;

  rtems_interrupt_disable(flags);
    rval = gt_rd( off );
    gt_wr( off, (rval & ~clr) | set );
  rtems_interrupt_enable(flags);
  return rval;
}

#define GT_TIMER_MAX      3
#define TIMER_ARGCHECK(t)  do { if ((t)>GT_TIMER_MAX) return -1; } while (0)

static struct {
  void (*isr)(void *);
  void  *arg;
} gt_timer_isrs[GT_TIMER_MAX+1] = {{0},};

uint32_t BSP_timer_read(uint32_t timer)
{
  TIMER_ARGCHECK(timer);
  return gt_rd(GT_TIMER_0 + (timer<<2));
}

int
BSP_timer_start(uint32_t timer, uint32_t period)
{
  TIMER_ARGCHECK(timer);
  gt_wr(GT_TIMER_0 + (timer<<2), period);
  return 0;
}

int
BSP_timer_stop(uint32_t timer)
{
  TIMER_ARGCHECK(timer);
  /* disable, clear period, re-enable */
  gt_timer_bitmod(GT_TIMER_0_3_Ctl, GT_TIMER_0_Ctl_Enb << (timer<<3), 0);
  gt_wr(GT_TIMER_0 + (timer<<2), 0);
  gt_timer_bitmod(GT_TIMER_0_3_Ctl, 0, GT_TIMER_0_Ctl_Enb << (timer<<3));
  return 0;
}

int
BSP_timer_setup(uint32_t timer, void (*isr)(void *arg), void *arg, int reload)
{
  TIMER_ARGCHECK(timer);
  if ( isr && gt_timer_isrs[timer].isr )
    return -1;

  BSP_timer_stop(timer);
  /* mask and clear */
  gt_timer_bitmod(GT_TIMER_0_3_Intr_Msk, GT_TIMER_0_Intr<<timer, 0);
  gt_timer_bitmod(GT_TIMER_0_3_Intr_Cse, GT_TIMER_0_Intr<<timer, 0);

  /* set reload bit */
  if ( reload )
    gt_timer_bitmod(GT_TIMER_0_3_Ctl, 0, GT_TIMER_0_Ctl_Rld << (timer<<3));
  else
    gt_timer_bitmod(GT_TIMER_0_3_Ctl, GT_TIMER_0_Ctl_Rld << (timer<<3), 0);

  asm volatile("":::"memory");

  if ( isr ) {
    gt_timer_isrs[timer].isr = isr;
    gt_timer_isrs[timer].arg = arg;
    asm volatile("":::"memory");
    gt_timer_bitmod(GT_TIMER_0_3_Intr_Msk, 0, GT_TIMER_0_Intr<<timer);
  } else {
    gt_timer_isrs[timer].isr = 0;
    gt_timer_isrs[timer].arg = 0;
  }
  return 0;
}

static void
gt_timer_hdl(rtems_irq_hdl_param arg)
{
  int       iarg = (int)arg;
  int       timer;
  uint32_t  bit;

  for ( ; iarg; iarg >>= 4 ) {
    timer = (iarg & 0xf)-1;
    bit   = GT_TIMER_0_Intr<<timer;
    if ( gt_timer_bitmod(GT_TIMER_0_3_Intr_Cse, bit, 0) & bit ) {
      /* cause was set */
      if ( ! gt_timer_isrs[timer].isr ) {
        printk("gt_timer: warning; no ISR connected but and IRQ happened (timer # %i)\n", timer);
        /* mask */
        gt_timer_bitmod(GT_TIMER_0_3_Intr_Msk, bit, 0);
      } else {
        gt_timer_isrs[timer].isr(gt_timer_isrs[timer].arg);
      }
    }
  }
}

int
BSP_timers_initialize(void)
{
  rtems_irq_connect_data xx = {0};
  int                    i, ainc, arg;

  xx.hdl    = gt_timer_hdl;
  xx.on     = 0;
  xx.off    = 0;
  xx.isOn   = 0;

  switch (BSP_getDiscoveryVersion(0)) {
    case MV_64360:
      i    = 3;
      ainc = 1;
      arg  = 4;
      break;
    default:
      i    = 1;
      ainc = 0x0202;
      arg  = 0x0403;
      break;
  }

  for ( ; i>=0; i--, arg-=ainc ) {
    xx.name   = BSP_IRQ_TIME0_1 + i;
    xx.handle = (rtems_irq_hdl_param)arg;
    if ( !BSP_install_rtems_irq_handler(&xx) )
      return -1;
  }

  return 0;
}

#ifdef DEBUG_MODULAR
static int
BSP_timers_uninstall(void)
{
  rtems_irq_connect_data xx = {0};
  int                    i;

  xx.hdl    = gt_timer_hdl;
  xx.on     = 0;
  xx.off    = 0;
  xx.isOn   = 0;

  for ( i=0; i<= GT_TIMER_MAX; i++ ) {
    if ( BSP_timer_setup(i, 0, 0, 0) )
      return -1;
  }

  switch (BSP_getDiscoveryVersion(0)) {
    case MV_64360:
      i = 3;
      break;
    default:
      i = 1;
      break;
  }

  for ( ; i >= 0; i-- ) {
    xx.name  = BSP_IRQ_TIME0_1 + i;
    BSP_get_current_rtems_irq_handler(&xx);
    if ( !BSP_remove_rtems_irq_handler(&xx) )
      return -1;
  }

  return 0;
}
#endif

uint32_t
BSP_timer_clock_get(uint32_t timer)
{
  return BSP_bus_frequency;
}

int BSP_timer_instances(void)
{
  return GT_TIMER_MAX + 1;
}

/* On a 64260A we can't read the status (on/off), apparently
 * so we maintain it locally and assume the firmware has
 * not enabled the dog initially...
 */
static uint32_t wdog_on = 0x00ffffff;

static uint32_t rd_wdcnf(void)
{
  uint32_t cnf = gt_rd(GT_WDOG_Config);

  /* BSD driver says that on the 64260A we always
   * read 0xffffffff so we have to maintain the
   * status locally (and hope we get the initial
   * value right).
   */
  if ( ~0 == cnf )
    cnf = wdog_on;
  return cnf;
}

/* change on/off state assume caller has IRQs disabled */
static void dog_toggle(uint32_t ctl)
{
  ctl &= ~( GT_WDOG_Config_Ctl1a | GT_WDOG_Config_Ctl1b \
          | GT_WDOG_Config_Ctl2a | GT_WDOG_Config_Ctl2b);
  gt_wr(GT_WDOG_Config, ctl | GT_WDOG_Config_Ctl1a);
  gt_wr(GT_WDOG_Config, ctl | GT_WDOG_Config_Ctl1b);
}

static void dog_pet(uint32_t ctl)
{
  ctl &= ~( GT_WDOG_Config_Ctl1a | GT_WDOG_Config_Ctl1b \
          | GT_WDOG_Config_Ctl2a | GT_WDOG_Config_Ctl2b);
  gt_wr(GT_WDOG_Config, ctl | GT_WDOG_Config_Ctl2a);
  gt_wr(GT_WDOG_Config, ctl | GT_WDOG_Config_Ctl2b);
}


/* Enable watchdog and set a timeout (in us)
 * a timeout of 0xffffffff selects the old/existing
 * timeout.
 *
 * RETURNS 0 on success
 */
int
BSP_watchdog_enable(uint32_t timeout_us)
{
  unsigned long long x = timeout_us;
  unsigned flags;
  uint32_t ctl;

  x *= BSP_bus_frequency;
  x /= 256;     /* there seems to be a prescaler */
    x /= 1000000; /* us/s                          */

  if ( x > (1<<24)-1 )
    x = (1<<24)-1;

  if ( 0xffffffff != timeout_us )
    timeout_us = x;

  rtems_interrupt_disable(flags);

  ctl = rd_wdcnf();

  /* if enabled, disable first */
  if ( GT_WDOG_Config_Enb & ctl ) {
    dog_toggle(ctl);
  }
  if ( 0xffffffff == timeout_us ) {
    timeout_us = ctl & ((1<<24)-1);
    dog_toggle(ctl);
    dog_pet(ctl);
  } else {
    gt_wr(GT_WDOG_Config, timeout_us | GT_WDOG_Config_Ctl1a);
    gt_wr(GT_WDOG_Config, timeout_us | GT_WDOG_Config_Ctl1b);
  }

  wdog_on = GT_WDOG_Config_Enb | timeout_us;

  rtems_interrupt_enable(flags);
  return 0;
}

/* Disable watchdog
 * RETURNS 0 on success
 */
int BSP_watchdog_disable(void)
{
unsigned long flags;
uint32_t      ctl;

  rtems_interrupt_disable(flags);

  ctl = rd_wdcnf();

  if ( (GT_WDOG_Config_Enb & ctl) ) {
    dog_toggle(ctl);
    wdog_on = ctl & ~(GT_WDOG_Config_Enb);
  }

  rtems_interrupt_enable(flags);
  return 0;
}

/* Check status -- unfortunately there seems to be no way
 * to read the running value...
 *
 * RETURNS nonzero if enabled/running, zero if disabled/stopped
 */
int BSP_watchdog_status(void)
{
  uint32_t ctl = rd_wdcnf();

  /* report also the current period */
  return GT_WDOG_Config_Enb & ctl ? ctl : 0;
}

/* Pet the watchdog (rearm to configured timeout)
 * RETURNS: 0 on success, nonzero on failure (watchdog
 * currently not running).
 */
int BSP_watchdog_pet(void)
{
  unsigned long flags;

  if ( !wdog_on )
    return -1;
  rtems_interrupt_disable(flags);
    dog_pet(rd_wdcnf());
  rtems_interrupt_enable(flags);
  return 0;
}


#ifdef DEBUG_MODULAR
int
_cexpModuleFinalize(void *unused)
{
  BSP_watchdog_disable();
  return BSP_timers_uninstall();
}

void
_cexpModuleInitialize(void *unused)
{
  BSP_timers_initialize();
}
#endif