From a009d802250ea6a379b64547f1839010754f8b1c Mon Sep 17 00:00:00 2001
From: Balazs Racz <balazs.racz@gmail.com>
Date: Sat, 16 Apr 2022 17:12:14 +0200
Subject: [PATCH] Adds shared code for STM32 implementation of the crash
 blinker. (#617)

---
 src/freertos_drivers/st/Stm32Blinker.hxx | 161 +++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 src/freertos_drivers/st/Stm32Blinker.hxx

diff --git a/src/freertos_drivers/st/Stm32Blinker.hxx b/src/freertos_drivers/st/Stm32Blinker.hxx
new file mode 100644
index 000000000..fd2bc4680
--- /dev/null
+++ b/src/freertos_drivers/st/Stm32Blinker.hxx
@@ -0,0 +1,161 @@
+/** \copyright
+ * Copyright (c) 2022, Balazs Racz
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are  permitted provided that the following conditions are met:
+ *
+ *  - Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  - Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * \file Stm32Blinker.hxx
+ * Implements the crash blinker using an STM32 timer.
+ *
+ * @author Balazs Racz
+ * @date 10 April 2022
+ */
+
+#ifndef _FREERTOS_DRIVERS_ST_STM32BLINKER_HXX_
+#define _FREERTOS_DRIVERS_ST_STM32BLINKER_HXX_
+
+/* How to use:
+
+Add the following code to the hardware.hxx
+```
+    #define BLINKER_INTERRUPT_HANDLER timer14_interrupt_handler
+
+    struct BlinkerHw
+    {
+        static constexpr uint32_t TIMER_BASE = TIM14_BASE;
+        static constexpr auto TIMER_IRQn = TIM14_IRQn; 
+        static void clock_enable()
+        {
+            __HAL_RCC_TIM14_CLK_ENABLE();
+        }
+    };
+```
+
+then
+```
+#include "freertos_drivers/st/Stm32Blinker.hxx"
+```
+
+in HwInit.cxx after hardware.hxx was included. Call setup_blinker() in
+hw_preinit.
+*/
+
+#ifndef BLINKER_INTERRUPT_HANDLER
+#error must include hardware.hxx before Stm32Blinker.hxx
+#endif
+
+/// @return constexpr timer instance typecast to the correct struct pointer.
+static inline TIM_TypeDef *get_blinker_timer()
+{
+    return (TIM_TypeDef *)BlinkerHw::TIMER_BASE;
+}
+
+extern "C" {
+
+/// Call this function in hw_preinit to set up the blinker timer.
+void setup_blinker()
+{
+    BlinkerHw::clock_enable();
+    /* Initializes the blinker timer. */
+    TIM_HandleTypeDef TimHandle;
+    memset(&TimHandle, 0, sizeof(TimHandle));
+    TimHandle.Instance = get_blinker_timer();
+    TimHandle.Init.Period = configCPU_CLOCK_HZ / 10000 / 5;
+    TimHandle.Init.Prescaler = 10000;
+    TimHandle.Init.ClockDivision = 0;
+    TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
+    TimHandle.Init.RepetitionCounter = 0;
+    if (HAL_TIM_Base_Init(&TimHandle) != HAL_OK)
+    {
+        /* Initialization Error */
+        HASSERT(0);
+    }
+    if (HAL_TIM_Base_Start_IT(&TimHandle) != HAL_OK)
+    {
+        /* Starting Error */
+        HASSERT(0);
+    }
+    NVIC_SetPriority(BlinkerHw::TIMER_IRQn, 0);
+    NVIC_EnableIRQ(BlinkerHw::TIMER_IRQn);
+}
+
+/// Stores the canonical pattern for the blinker.
+uint32_t blinker_pattern = 0;
+/// Stores what is left of the pattern during the current period.
+static uint32_t rest_pattern = 0;
+
+extern void hw_set_to_safe(void);
+
+void resetblink(uint32_t pattern)
+{
+    blinker_pattern = pattern;
+    rest_pattern = pattern ? 1 : 0;
+    BLINKER_RAW_Pin::set(pattern ? true : false);
+    /* todo: make a timer event trigger immediately */
+}
+
+void setblink(uint32_t pattern)
+{
+    resetblink(pattern);
+}
+
+void BLINKER_INTERRUPT_HANDLER(void)
+{
+    //
+    // Clear the timer interrupt.
+    //
+    get_blinker_timer()->SR = ~TIM_IT_UPDATE;
+
+    // Set output LED.
+    BLINKER_RAW_Pin::set(rest_pattern & 1);
+
+    // Shift and maybe reset pattern.
+    rest_pattern >>= 1;
+    if (!rest_pattern)
+    {
+        rest_pattern = blinker_pattern;
+    }
+}
+
+void wait_with_blinker(void)
+{
+    if (get_blinker_timer()->SR & TIM_IT_UPDATE)
+    {
+        BLINKER_INTERRUPT_HANDLER();
+    }
+}
+
+void diewith(uint32_t pattern)
+{
+    asm("cpsid i\n");
+    hw_set_to_safe();
+    resetblink(pattern);
+    while (1)
+    {
+        wait_with_blinker();
+    }
+}
+
+} // extern "C"
+
+#endif // _FREERTOS_DRIVERS_ST_STM32BLINKER_HXX_