Initial commit of firmware

Libs/platform/service/udelay/inc/sl_udelay.h

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+/***************************************************************************//**
+ * @file
+ * @brief Microsecond delay.
+ *******************************************************************************
+ * # License
+ * <b>Copyright 2020 Silicon Laboratories Inc. www.silabs.com</b>
+ *******************************************************************************
+ *
+ * SPDX-License-Identifier: Zlib
+ *
+ * The licensor of this software is Silicon Laboratories Inc.
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ *
+ ******************************************************************************/
+
+#ifndef UDELAY_H
+#define UDELAY_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/***************************************************************************//**
+ * @addtogroup udelay Microsecond Delay
+ * @brief Microsecond delay function
+ * @{
+ ******************************************************************************/
+
+/**
+ * @brief
+ *   Delay a number of microseconds
+ *
+ * @details
+ *   This function will use a busy loop to delay code execution by a certain
+ *   number of microseconds before returning to the caller. This function will
+ *   not return to the caller earlier than the time given as the input parameter.
+ *   This function will not use any hardware timing peripherals, it is using
+ *   the core clock frequency to calculate the delay.
+ *
+ *   Note that there will always be some overhead associated with calling this
+ *   function in addition to the internal delay loop. This overhead is relatively
+ *   small when the delay is large (>= 100us).
+ *
+ *   The accuracy of this delay loop will be affected by interrupts and context
+ *   switching. If accuracy is needed, a hardware timer should be used
+ *   to handle delays.
+ *
+ * @param[in] us
+ *   This is the number of microseconds to delay execution. This function will
+ *   return after this amount of time has elapsed. Minimum value is 0 us and
+ *   maximum value is 100 000 us (100 ms). It is however recommended to use
+ *   the sleeptimer api for delays of more than 1 ms as it is using a hardware
+ *   counter and will result in better accuracy.
+ */
+void sl_udelay_wait(unsigned us);
+
+#ifdef __cplusplus
+}
+#endif
+
+/** @} (end addtogroup udelay) */
+
+#endif

Libs/platform/service/udelay/src/sl_udelay.c

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+/***************************************************************************//**
+ * @file
+ * @brief Microsecond delay.
+ *******************************************************************************
+ * # License
+ * <b>Copyright 2020 Silicon Laboratories Inc. www.silabs.com</b>
+ *******************************************************************************
+ *
+ * SPDX-License-Identifier: Zlib
+ *
+ * The licensor of this software is Silicon Laboratories Inc.
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ *
+ ******************************************************************************/
+#include "sl_udelay.h"
+#include "em_device.h"
+#include "sl_assert.h"
+#include <stdbool.h>
+
+/* The Cortex-M33 has a faster execution of the hw loop
+ * with the same arm instructions. */
+#if defined(__CORTEX_M) && (__CORTEX_M == 33U)
+  #define HW_LOOP_CYCLE  3
+#else
+  #define HW_LOOP_CYCLE  4
+#endif
+
+void sli_delay_loop(unsigned n);
+
+void sl_udelay_wait(unsigned us)
+{
+  uint32_t freq_khz;
+  uint32_t ns_period;
+  uint32_t cycles;
+  uint32_t loops;
+
+  freq_khz = SystemCoreClockGet() / 1000U;
+  if (freq_khz == 0) {
+    EFM_ASSERT(false);
+    return;
+  }
+
+  ns_period = 1000000U / freq_khz;
+  if (ns_period == 0) {
+    EFM_ASSERT(false);
+    return;
+  }
+
+  cycles = us * 1000U / ns_period;
+  loops = cycles / HW_LOOP_CYCLE;
+  if (loops > 0U) {
+    sli_delay_loop(loops);
+  }
+}

Libs/platform/service/udelay/src/sl_udelay_armv6m_gcc.S

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+/***************************************************************************//**
+ * @file
+ * @brief Microsecond delay.
+ *******************************************************************************
+ * # License
+ * <b>Copyright 2020 Silicon Laboratories Inc. www.silabs.com</b>
+ *******************************************************************************
+ *
+ * SPDX-License-Identifier: Zlib
+ *
+ * The licensor of this software is Silicon Laboratories Inc.
+ *
+ * This software is provided 'as-is', without any express or implied
+ * warranty. In no event will the authors be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, subject to the following restrictions:
+ *
+ * 1. The origin of this software must not be misrepresented; you must not
+ *    claim that you wrote the original software. If you use this software
+ *    in a product, an acknowledgment in the product documentation would be
+ *    appreciated but is not required.
+ * 2. Altered source versions must be plainly marked as such, and must not be
+ *    misrepresented as being the original software.
+ * 3. This notice may not be removed or altered from any source distribution.
+ *
+ ******************************************************************************/
+
+    .text
+    .align 4
+    .syntax unified
+    .thumb_func
+    .global  sli_delay_loop
+
+/*
+ * @brief
+ *   Hardware delay loop
+ *
+ * @detail
+ *   This is the hardware specific delay loop. It is designed specifically to
+ *   execute in 4 or 3 cycles for each iteration depending on the architecture.
+ *   Using this information the caller can use the core clock frequency to
+ *   calculate the number of loops required in order to delay a specific time
+ *   period.
+ * 
+ * @param[in] n (r0)
+ *   n is the number of loops to execute. Each loop will execute in 4 cycles.
+ *   Note that we assume that r0 > 0, so this invariant should be checked by
+ *   the caller.
+ */
+sli_delay_loop:
+    subs  r0, r0, #1
+    beq   done
+    b.n   sli_delay_loop
+done:
+    bx    lr
+
+    .end