From 8213f78a78de7d6618bc6b1c9c1a34db3cb5e52c Mon Sep 17 00:00:00 2001
From: "Jasper v. Blanckenburg" <j.blanckenburg@fasttube.de>
Date: Tue, 14 Mar 2023 16:22:58 +0100
Subject: [PATCH] Basic implementation for STM32F3

---
 FT_CAN_AL.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 FT_CAN_AL.h | 26 ++++++++++++++++++
 README.md   | 17 ++++++++++++
 3 files changed, 121 insertions(+)
 create mode 100644 FT_CAN_AL.c
 create mode 100644 FT_CAN_AL.h

diff --git a/FT_CAN_AL.c b/FT_CAN_AL.c
new file mode 100644
index 0000000..2b1501f
--- /dev/null
+++ b/FT_CAN_AL.c
@@ -0,0 +1,78 @@
+#include "FT_CAN_AL.h"
+
+#ifdef FTCAN_IS_BXCAN
+static CAN_HandleTypeDef *hcan;
+
+HAL_StatusTypeDef ftcan_init(CAN_HandleTypeDef *handle) {
+  hcan = handle;
+
+  HAL_StatusTypeDef status =
+      HAL_CAN_ActivateNotification(hcan, CAN_IT_RX_FIFO0_MSG_PENDING);
+  if (status != HAL_OK) {
+    return status;
+  }
+
+  return HAL_CAN_Start(hcan);
+}
+
+HAL_StatusTypeDef ftcan_transmit(uint8_t id, const uint8_t *data,
+                                 size_t datalen) {
+  static CAN_TxHeaderTypeDef header;
+  header.StdId = id;
+  header.IDE = CAN_ID_STD;
+  header.RTR = CAN_RTR_DATA;
+  header.DLC = datalen;
+  uint32_t mailbox;
+  return HAL_CAN_AddTxMessage(hcan, &header, data, &mailbox);
+}
+
+HAL_StatusTypeDef ftcan_add_filter(uint8_t id, uint8_t mask) {
+  static uint32_t next_filter_no = 0;
+  static CAN_FilterTypeDef filter;
+  if (next_filter_no % 2 == 0) {
+    filter.FilterIdHigh = id;
+    filter.FilterMaskIdHigh = mask;
+    filter.FilterIdLow = 0;
+    filter.FilterMaskIdLow = 0xFFFF;
+  } else {
+    // Leave high filter untouched from the last configuration
+    filter.FilterIdLow = id;
+    filter.FilterMaskIdLow = mask;
+  }
+  filter.FilterFIFOAssignment = CAN_FILTER_FIFO0;
+  filter.FilterBank = next_filter_no / 2;
+  if (filter.FilterBank > FTCAN_MAX_FILTER_NO) {
+    return HAL_ERROR;
+  }
+  filter.FilterMode = CAN_FILTERMODE_IDMASK;
+  filter.FilterScale = CAN_FILTERSCALE_16BIT;
+  filter.FilterActivation = CAN_FILTER_ENABLE;
+
+  // Disable slave filters
+  // TODO: Some STM32 have multiple CAN peripherals, and one uses the slave
+  // filter bank
+  filter.SlaveStartFilterBank = FTCAN_MAX_FILTER_NO + 1;
+
+  return HAL_CAN_ConfigFilter(hcan, &filter);
+}
+
+void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *handle) {
+  if (handle != hcan) {
+    return;
+  }
+  CAN_RxHeaderTypeDef header;
+  uint8_t data[8];
+  if (HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &header, data) != HAL_OK) {
+    return;
+  }
+
+  if (header.IDE != CAN_ID_STD) {
+    return;
+  }
+
+  ftcan_msg_received_cb(header.StdId, header.DLC, data);
+}
+#endif // CAN_IS_BXCAN
+
+__weak void ftcan_msg_received_cb(uint8_t id, size_t datalen,
+                                  const uint8_t *data) {}
diff --git a/FT_CAN_AL.h b/FT_CAN_AL.h
new file mode 100644
index 0000000..1e17eac
--- /dev/null
+++ b/FT_CAN_AL.h
@@ -0,0 +1,26 @@
+#ifndef FT_CAN_AL_H
+#define FT_CAN_AL_H
+
+#if defined(STM32F3)
+#include "stm32f3xx_hal.h"
+#define FTCAN_IS_BXCAN
+#define FTCAN_MAX_FILTER_NO 13
+#else
+#error "Couldn't detect STM family"
+#endif // STM32F3
+
+#ifdef FTCAN_IS_BXCAN
+HAL_StatusTypeDef ftcan_init(CAN_HandleTypeDef *handle);
+#endif // CAN_IS_BXCAN
+
+HAL_StatusTypeDef ftcan_transmit(uint8_t id, const uint8_t *data,
+                                 size_t datalen);
+
+HAL_StatusTypeDef ftcan_add_filter(uint8_t id, uint8_t mask);
+
+/**
+ * Define this function to be notified of incoming CAN messages
+ */
+void ftcan_msg_received_cb(uint8_t id, size_t datalen, const uint8_t *data);
+
+#endif // FT_CAN_AL_H
diff --git a/README.md b/README.md
index 2f8006d..d189681 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,8 @@
 This repository contains an abstraction layer to provide a simplified & unified
 interface to the STM32 bxCAN and FDCAN peripherals.
 
+**Warning**: Currently, only bxCAN (for the STM32F3 series) is supported.
+
 ## Installation
 
 Simply add the repository to your `Core/Lib` directory. You can also add it as a
@@ -11,3 +13,18 @@ git submodule:
     mkdir -p Core/Lib
     cd Core/Lib
     git submodule add ssh://git@git.fasttube.de:313/FaSTTUBe/FT_CAN_AL.git
+
+The library needs to be told what STM family you're using, so make sure one of
+the following symbols is defined when `FT_CAN_AL.c` is compiled or `FT_CAN_AL.h`
+is included:
+
+- STM32F3
+
+## Usage
+
+1. Include `FT_CAN_AL.h`
+2. Call `ftcan_init()` with the appropriate handle
+3. Call `ftcan_add_filter()` with all your filters
+4. To transmit messages, call `ftcan_transmit()`
+5. When a message is received, `ftcan_msg_received_cb()` is called. It has a
+   default empty implementation, which you can simply override.