bsps: Shared ARMv7-M clock driver

1 files changed, 126 insertions, 0 deletions

diff --git a/c/src/lib/libbsp/arm/shared/armv7m/clock/armv7m-clock-config.c b/c/src/lib/libbsp/arm/shared/armv7m/clock/armv7m-clock-config.c
new file mode 100644
index 0000000000..82fefcee9f
--- /dev/null
+++ b/c/src/lib/libbsp/arm/shared/armv7m/clock/armv7m-clock-config.c
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2011-2012 Sebastian Huber.  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.com/license/LICENSE.
+ */
+
+#include <rtems.h>
+#include <rtems/score/armv7m.h>
+
+#include <bsp.h>
+
+#ifdef ARM_MULTILIB_ARCH_V7M
+
+/* This is defined in clockdrv_shell.h */
+rtems_isr Clock_isr(rtems_vector_number vector);
+
+#define _ARMV7M_Systick_get_factor(freq) \
+  ((1000000000ULL << 32) / (freq))
+
+#ifdef BSP_ARMV7M_SYSTICK_FREQUENCY
+  #define _ARMV7M_Systick_factor \
+    _ARMV7M_Systick_get_factor(BSP_ARMV7M_SYSTICK_FREQUENCY)
+#else
+  static uint64_t _ARMV7M_Systick_factor;
+#endif
+
+static void _ARMV7M_Systick_at_tick(void)
+{
+  volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
+
+  /* Clear COUNTFLAG */
+  systick->csr;
+}
+
+static void _ARMV7M_Systick_handler(void)
+{
+  _ARMV7M_Interrupt_service_enter();
+  Clock_isr(ARMV7M_VECTOR_SYSTICK);
+  _ARMV7M_Interrupt_service_leave();
+}
+
+static void _ARMV7M_Systick_handler_install(void)
+{
+  _ARMV7M_Set_exception_priority(
+    ARMV7M_VECTOR_SYSTICK,
+    ARMV7M_EXCEPTION_PRIORITY_LOWEST
+  );
+  _ARMV7M_Set_exception_handler(
+    ARMV7M_VECTOR_SYSTICK,
+    _ARMV7M_Systick_handler
+  );
+}
+
+static void _ARMV7M_Systick_initialize(void)
+{
+  volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
+  #ifdef BSP_ARMV7M_SYSTICK_FREQUENCY
+    uint64_t freq = BSP_ARMV7M_SYSTICK_FREQUENCY;
+  #else
+    uint64_t freq = ARMV7M_SYSTICK_CALIB_TENMS_GET(systick->calib) * 100ULL;
+  #endif
+  uint64_t us_per_tick = rtems_configuration_get_microseconds_per_tick();
+  uint64_t interval = (freq * us_per_tick) / 1000000ULL;
+
+  #ifndef BSP_ARMV7M_SYSTICK_FREQUENCY
+    _ARMV7M_Systick_factor = _ARMV7M_Systick_get_factor(freq);
+  #endif
+
+  systick->rvr = (uint32_t) interval;
+  systick->cvr = 0;
+  systick->csr = ARMV7M_SYSTICK_CSR_ENABLE
+    | ARMV7M_SYSTICK_CSR_TICKINT
+    | ARMV7M_SYSTICK_CSR_CLKSOURCE;
+}
+
+static void _ARMV7M_Systick_cleanup(void)
+{
+  volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
+
+  systick->csr = 0;
+}
+
+static uint32_t _ARMV7M_Systick_nanoseconds_since_last_tick(void)
+{
+  volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
+  volatile ARMV7M_SCB *scb = _ARMV7M_SCB;
+  uint32_t rvr = systick->rvr;
+  uint32_t c = rvr - systick->cvr;
+
+  if ((scb->icsr & ARMV7M_SCB_ICSR_PENDSTSET) != 0) {
+    c = rvr - systick->cvr + rvr;
+  }
+
+  return (uint32_t) ((c * _ARMV7M_Systick_factor) >> 32);
+}
+
+#define Clock_driver_support_at_tick() \
+  _ARMV7M_Systick_at_tick()
+
+#define Clock_driver_support_initialize_hardware() \
+  _ARMV7M_Systick_initialize()
+
+#define Clock_driver_support_install_isr(isr, old_isr) \
+  do { \
+    _ARMV7M_Systick_handler_install(); \
+    old_isr = NULL; \
+  } while (0)
+
+#define Clock_driver_support_shutdown_hardware() \
+  _ARMV7M_Systick_cleanup()
+
+#define Clock_driver_nanoseconds_since_last_tick \
+  _ARMV7M_Systick_nanoseconds_since_last_tick
+
+/* Include shared source clock driver code */
+#include "../../../../shared/clockdrv_shell.h"
+
+#endif /* ARM_MULTILIB_ARCH_V7M */