1 files changed, 247 insertions, 0 deletions
diff --git a/bsps/powerpc/shared/clock/clock.c b/bsps/powerpc/shared/clock/clock.c
new file mode 100644
index 0000000000..431488a901
--- /dev/null
+++ b/bsps/powerpc/shared/clock/clock.c
@@ -0,0 +1,247 @@
+/**
+ * @file
+ *
+ * @ingroup powerpc_shared
+ *
+ * @brief Source file for a clock driver.
+ */
+
+/*
+ * Copyright (c) 2008-2015 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#include <rtems.h>
+#include <rtems/clockdrv.h>
+#include <rtems/timecounter.h>
+
+#include <libcpu/powerpc-utility.h>
+#include <bsp/vectors.h>
+
+#define RTEMS_STATUS_CHECKS_USE_PRINTK
+
+#include <rtems/status-checks.h>
+
+/*
+ * This variable must be defined in the BSP and valid before clock driver
+ * initialization.
+ */
+extern uint32_t bsp_time_base_frequency;
+
+#define PPC405_PIT 0x3db
+
+#define PPC_CLOCK_DECREMENTER_MAX UINT32_MAX
+
+volatile uint32_t Clock_driver_ticks = 0;
+
+static uint32_t ppc_clock_decrementer_value = PPC_CLOCK_DECREMENTER_MAX;
+
+static uint32_t ppc_clock_next_time_base;
+
+static struct timecounter ppc_tc;
+
+static uint32_t ppc_get_timecount(struct timecounter *tc)
+{
+  return ppc_time_base();
+}
+
+static void ppc_clock_no_tick(void)
+{
+  /* Do nothing */
+}
+
+static void (*ppc_clock_tick)(void) = ppc_clock_no_tick;
+
+static int ppc_clock_exception_handler(
+  BSP_Exception_frame *frame,
+  unsigned number
+)
+{
+  uint32_t delta = ppc_clock_decrementer_value;
+  uint32_t next = ppc_clock_next_time_base;
+  uint32_t dec = 0;
+  uint32_t now = 0;
+  uint32_t msr = 0;
+
+  do {
+    /* Increment clock ticks */
+    Clock_driver_ticks += 1;
+
+    /* Enable external exceptions */
+    msr = ppc_external_exceptions_enable();
+
+    /* Call clock ticker  */
+    ppc_clock_tick();
+
+    /* Restore machine state */
+    ppc_external_exceptions_disable( msr);
+
+    /* Next time base */
+    next += delta;
+
+    /* Current time */
+    now = ppc_time_base();
+
+    /* New decrementer value */
+    dec = next - now;
+  } while (dec > delta);
+
+  /* Set decrementer */
+  ppc_set_decrementer_register( dec);
+
+  /* Expected next time base */
+  ppc_clock_next_time_base = next;
+
+  return 0;
+}
+
+static int ppc_clock_exception_handler_first(
+  BSP_Exception_frame *frame,
+  unsigned number
+)
+{
+  /* We have to clear the first pending decrementer exception this way */
+
+  if (ppc_decrementer_register() >= 0x80000000) {
+    ppc_clock_exception_handler( frame, number);
+  }
+
+  ppc_exc_set_handler( ASM_DEC_VECTOR, ppc_clock_exception_handler);
+
+  return 0;
+}
+
+static int ppc_clock_exception_handler_booke(
+  BSP_Exception_frame *frame,
+  unsigned number
+)
+{
+  uint32_t msr;
+
+  /* Acknowledge decrementer request */
+  PPC_SET_SPECIAL_PURPOSE_REGISTER( BOOKE_TSR, BOOKE_TSR_DIS);
+
+  /* Increment clock ticks */
+  Clock_driver_ticks += 1;
+
+  /* Enable external exceptions */
+  msr = ppc_external_exceptions_enable();
+
+  /* Call clock ticker  */
+  ppc_clock_tick();
+
+  /* Restore machine state */
+  ppc_external_exceptions_disable( msr);
+
+  return 0;
+}
+
+static int ppc_clock_exception_handler_ppc405(BSP_Exception_frame *frame, unsigned number)
+{
+  uint32_t msr;
+
+  /* Acknowledge PIT request */
+  PPC_SET_SPECIAL_PURPOSE_REGISTER(PPC405_TSR, BOOKE_TSR_DIS);
+
+  /* Increment clock ticks */
+  Clock_driver_ticks += 1;
+
+  /* Enable external exceptions */
+  msr = ppc_external_exceptions_enable();
+
+  /* Call clock ticker  */
+  ppc_clock_tick();
+
+  /* Restore machine state */
+  ppc_external_exceptions_disable(msr);
+
+  return 0;
+}
+
+void Clock_exit(void)
+{
+  /* Set the decrementer to the maximum value */
+  ppc_set_decrementer_register( PPC_CLOCK_DECREMENTER_MAX);
+
+  /* Use default clock handler */
+  ppc_clock_tick = ppc_clock_no_tick;
+}
+
+rtems_device_driver Clock_initialize(
+  rtems_device_major_number major,
+  rtems_device_minor_number minor,
+  void *arg
+)
+{
+  uint64_t frequency = bsp_time_base_frequency;
+  uint64_t us_per_tick = rtems_configuration_get_microseconds_per_tick();
+  uint32_t interval = (uint32_t) ((frequency * us_per_tick) / 1000000);
+
+  /*
+   * Set default ticker.
+   */
+  ppc_clock_tick = rtems_timecounter_tick;
+
+  if (ppc_cpu_is_bookE() != PPC_BOOKE_405) {
+    /* Decrementer value */
+    ppc_clock_decrementer_value = interval - 1;
+
+    /* Check decrementer value */
+    if (ppc_clock_decrementer_value == 0) {
+      ppc_clock_decrementer_value = PPC_CLOCK_DECREMENTER_MAX;
+      RTEMS_SYSLOG_ERROR( "decrementer value would be zero, will be set to maximum value instead\n");
+    }
+    if (ppc_cpu_is_bookE()) {
+      /* Set decrementer auto-reload value */
+      PPC_SET_SPECIAL_PURPOSE_REGISTER( BOOKE_DECAR, ppc_clock_decrementer_value);
+
+      /* Install exception handler */
+      ppc_exc_set_handler( ASM_BOOKE_DEC_VECTOR, ppc_clock_exception_handler_booke);
+
+      /* Enable decrementer and auto-reload */
+      PPC_SET_SPECIAL_PURPOSE_REGISTER_BITS( BOOKE_TCR, BOOKE_TCR_DIE | BOOKE_TCR_ARE);
+    } else {
+      /* Here the decrementer value is actually the interval */
+      ++ppc_clock_decrementer_value;
+
+      /* Initialize next time base */
+      ppc_clock_next_time_base = ppc_time_base() + ppc_clock_decrementer_value;
+
+      /* Install exception handler */
+      ppc_exc_set_handler( ASM_DEC_VECTOR, ppc_clock_exception_handler_first);
+    }
+
+    /* Set the decrementer value */
+    ppc_set_decrementer_register( ppc_clock_decrementer_value);
+  } else {
+    /* PIT interval value */
+    ppc_clock_decrementer_value = interval;
+
+    /* Install exception handler */
+    ppc_exc_set_handler(ASM_BOOKE_DEC_VECTOR, ppc_clock_exception_handler_ppc405);
+
+    /* Enable PIT and auto-reload */
+    PPC_SET_SPECIAL_PURPOSE_REGISTER_BITS(PPC405_TCR, BOOKE_TCR_DIE | BOOKE_TCR_ARE);
+
+    /* Set PIT auto-reload and initial value */
+    PPC_SET_SPECIAL_PURPOSE_REGISTER(PPC405_PIT, interval);
+  }
+
+  /* Install timecounter */
+  ppc_tc.tc_get_timecount = ppc_get_timecount;
+  ppc_tc.tc_counter_mask = 0xffffffff;
+  ppc_tc.tc_frequency = frequency;
+  ppc_tc.tc_quality = RTEMS_TIMECOUNTER_QUALITY_CLOCK_DRIVER;
+  rtems_timecounter_install(&ppc_tc);
+
+  return RTEMS_SUCCESSFUL;
+}