LEON: GPTIMER driver, Timer Library and System Clock for LEON3

With this patch the LEON family can access the GRLIB GPTIMER using
the Timer library (TLIB).

A System Clock driver instead of BSP/clock/ck_init.c is provided
using the TLIB. The classic clock driver is split in two parts,
clock driver and timer driver. The BSPs need only to fullfill the
timer interface instead of the clock interface. Currently only
LEON3 uses it. The LEON2 Timer is not ported to TLIB.

The GPTIMER driver is implemented using the Driver Manager, so the
System Clock Driver is at this point only suitable for LEON3 when
the driver manager is initialized during BSP startup. When the DrvMgr
is not initialized during startup the standard BSP/clock dirver is
used.

LEON2 sometimes also needs to access GPTIMER when a off-chip GRLIB AMBA
systems is connected, for example AMBA-over-PCI.

1 files changed, 264 insertions, 0 deletions

diff --git a/c/src/lib/libbsp/sparc/shared/timer/tlib_ckinit.c b/c/src/lib/libbsp/sparc/shared/timer/tlib_ckinit.c
new file mode 100644
index 0000000000..5758f5bf0d
--- /dev/null
+++ b/c/src/lib/libbsp/sparc/shared/timer/tlib_ckinit.c
@@ -0,0 +1,264 @@
+/*
+ *  Clock Tick Device Driver using Timer Library implemented
+ *  by the GRLIB GPTIMER / LEON2 Timer drivers.
+ *
+ *  COPYRIGHT (c) 2010.
+ *  Cobham Gaisler AB.
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ *
+ */
+
+#include <stdlib.h>
+#include <bsp.h>
+#include <tlib.h>
+
+/* Undefine (default) this to save space in standard LEON configurations,
+ * it will assume that Prescaler is running at 1MHz.
+ */
+/*#undef CLOCK_DRIVER_DONT_ASSUME_PRESCALER_1MHZ*/
+
+/* Set the below defines from bsp.h if function needed.
+#undef CLOCK_DRIVER_ISRS_PER_TICK
+#undef CLOCK_DRIVER_USE_FAST_IDLE
+*/
+#define Clock_driver_support_at_tick()
+
+/*
+ *  Number of Clock ticks since initialization
+ */
+volatile uint32_t Clock_driver_ticks;
+
+/*
+ *  Timer Number in Timer Library. Defaults to the first Timer in
+ *  the System.
+ */
+int Clock_timer = 0;
+
+/*
+ * Timer Handle in Timer Library
+ */
+void *Clock_handle = NULL;
+
+#ifdef CLOCK_DRIVER_DONT_ASSUME_PRESCALER_1MHZ
+unsigned int Clock_basefreq;
+#endif
+
+void Clock_exit(void);
+
+/*
+ *  Major and minor number.
+ */
+
+rtems_device_major_number rtems_clock_major = UINT32_MAX;
+rtems_device_minor_number rtems_clock_minor;
+
+/*
+ *  Clock_isr
+ *
+ *  This is the clock tick interrupt handler.
+ *
+ *  Input parameters:
+ *    vector - vector number
+ *
+ *  Output parameters:  NONE
+ *
+ *  Return values:      NONE
+ *
+ */
+
+void Clock_isr(void *arg_unused)
+{
+  /*
+   *  Accurate count of ISRs
+   */
+
+  Clock_driver_ticks += 1;
+
+#ifdef CLOCK_DRIVER_USE_FAST_IDLE
+  do {
+    rtems_clock_tick();
+  } while ( _Thread_Executing == _Thread_Idle &&
+          _Thread_Heir == _Thread_Executing);
+
+  Clock_driver_support_at_tick();
+  return;
+
+#else
+
+  /*
+   * Add custom handling at every tick from bsp.h
+   */
+  Clock_driver_support_at_tick();
+
+#ifdef CLOCK_DRIVER_ISRS_PER_TICK
+  /*
+   *  The driver is multiple ISRs per clock tick.
+   */
+
+  if ( !Clock_driver_isrs ) {
+
+    rtems_clock_tick();
+
+    Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK;
+  }
+  Clock_driver_isrs--;
+#else
+
+  /*
+   *  The driver is one ISR per clock tick.
+   */
+  rtems_clock_tick();
+#endif
+#endif
+}
+
+/*
+ *  Clock_exit
+ *
+ *  This routine allows the clock driver to exit by masking the interrupt and
+ *  disabling the clock's counter.
+ *
+ *  Input parameters:   NONE
+ *
+ *  Output parameters:  NONE
+ *
+ *  Return values:      NONE
+ *
+ */
+
+void Clock_exit( void )
+{
+  /* Stop all activity of the Timer, no more ISRs.
+   * We could be using tlib_close(), however tlib_stop() is quicker
+   * and independent of IRQ unregister code.
+   */
+  if ( Clock_handle ) {
+    tlib_stop(Clock_handle);
+    Clock_handle = NULL;
+  }
+}
+
+uint32_t Clock_nanoseconds_since_last_tick(void)
+{
+  uint32_t clicks;
+  if ( !Clock_handle )
+    return 0;
+
+  tlib_get_counter(Clock_handle, (unsigned int *)&clicks);
+
+#ifdef CLOCK_DRIVER_DONT_ASSUME_PRESCALER_1MHZ
+  {
+    /* Down counter. Calc from BaseFreq. */
+    uint64_t tmp;
+    tmp = ((uint64_t)clicks * 1000000000) / ((uint64_t)Clock_basefreq);
+    return (uint32_t)tmp;
+  }
+#else
+  /* Down counter. Timer base frequency is initialized to 1 MHz */
+  return (uint32_t)
+     (rtems_configuration_get_microseconds_per_tick() - clicks) * 1000;
+#endif
+}
+
+/*
+ *  Clock_initialize
+ *
+ *  This routine initializes the clock driver and starts the Clock.
+ *
+ *  Input parameters:
+ *    major - clock device major number
+ *    minor - clock device minor number
+ *    parg  - pointer to optional device driver arguments
+ *
+ *  Output parameters:  NONE
+ *
+ *  Return values:
+ *    rtems_device_driver status code
+ */
+
+rtems_device_driver Clock_initialize(
+  rtems_device_major_number major,
+  rtems_device_minor_number minor,
+  void *pargp
+)
+{
+  unsigned int tick_hz;
+
+  /*
+   *  Take Timer that should be used as system timer.
+   *
+   */
+  Clock_handle = tlib_open(Clock_timer);
+  if ( Clock_handle == NULL ) {
+    /* System Clock Timer not found */
+    return RTEMS_NOT_DEFINED;
+  }
+
+  /*
+   *  Install Clock ISR before starting timer
+   */
+  tlib_irq_register(Clock_handle, Clock_isr, NULL);
+
+  /* Set Timer Frequency to tick at Configured value. The Timer
+   * Frequency is set in multiples of the timer base frequency.
+   *
+   * In standard LEON3 designs the base frequency is is 1MHz, to
+   * save instructions define CLOCK_DRIVER_ASSUME_PRESCALER_1MHZ
+   * to avoid 64-bit calculation.
+   */
+#ifdef CLOCK_DRIVER_DONT_ASSUME_PRESCALER_1MHZ
+  {
+    uint64_t tmp;
+
+    tlib_get_freq(Clock_handle, &Clock_basefreq, NULL);
+
+    tmp = (uint64_t)Clock_basefreq;
+    tmp = tmp * (unint64_t)rtems_configuration_get_microseconds_per_tick();
+    tick_hz = tmp / 1000000;
+  }
+#else
+  tick_hz = rtems_configuration_get_microseconds_per_tick();
+#endif
+
+  tlib_set_freq(Clock_handle, tick_hz);
+
+  rtems_clock_set_nanoseconds_extension(Clock_nanoseconds_since_last_tick);
+
+  /*
+   *  IRQ and Frequency is setup, now we start the Timer. IRQ is still
+   *  disabled globally during startup, so IRQ will hold for a while.
+   */
+  tlib_start(Clock_handle, 0);
+
+  /*
+   *  Register function called at system shutdown
+   */
+  atexit( Clock_exit );
+
+  /*
+   * make major/minor avail to others such as shared memory driver
+   */
+
+  rtems_clock_major = major;
+  rtems_clock_minor = minor;
+
+  /*
+   *  If we are counting ISRs per tick, then initialize the counter.
+   */
+
+#ifdef CLOCK_DRIVER_ISRS_PER_TICK
+  Clock_driver_isrs = CLOCK_DRIVER_ISRS_PER_TICK;
+#endif
+
+  return RTEMS_SUCCESSFUL;
+}
+
+/*** Timer Driver Interface ***/
+
+void Clock_timer_register(int timer_number)
+{
+  Clock_timer = timer_number;
+}