Multiple frames implementation (#2)

* Add rx event handlers * Fix compile errors and add constness * Pass sender id * Change api interface * Revert changes * Add filter fifo * Add default setup * Add receive function * Remove interrupt activation * Activate RX interrupts * Merge remote changes * Add event list constructor * Fix compilation bug * Send and receive multiple frames * Refactor * Refactor * Fix compile error * Use known syntax * Refactor * Provide storage * Add frame end * Add some documentation * Turn macros into functions * Refactor * Refactor * Fix compile error * Use ExtendedIds Co-authored-by: Riccardo998 <riccardo.storchi98@gmail.com>
2021-12-09 11:39:39 +01:00
parent 90d1836dfa
commit 7b09401b00
9 changed files with 346 additions and 50 deletions
@@ -0,0 +1,130 @@
+#include <stdbool.h>
+#include "mmr_can.h"
+#include "mmr_can_util.h"
+
+
+static HalStatus sendNormal(CanHandle *hcan, CanTxHeader *header, MmrCanPacket *packet);
+static HalStatus sendMulti(CanHandle *hcan, CanTxHeader *header, MmrCanPacket *packet);
+static HalStatus sendSingleMultiFrame(CanHandle *hcan, CanTxHeader *header, MmrCanPacket *packet, uint8_t *offset);
+static uint8_t computeFramesToSend(MmrCanPacket *packet);
+static uint8_t computeNextMessageLength(MmrCanPacket *packet, uint8_t offset);
+
+
+HalStatus MMR_CAN_Send(CanHandle *hcan, MmrCanPacket packet) {
+  CanTxHeader header = {
+    .IDE = CAN_ID_EXT,
+    .RTR = CAN_RTR_DATA,
+    .DLC = packet.length,
+    .ExtId = packet.remoteId << 5,
+    .TransmitGlobalTime = DISABLE,
+  };
+
+  return packet.length <= MMR_CAN_MAX_DATA_LENGTH
+    ? sendNormal(hcan, &header, &packet)
+    : sendMulti(hcan, &header, &packet);
+}
+
+
+static HalStatus sendNormal(
+  CanHandle *hcan,
+  CanTxHeader *header,
+  MmrCanPacket *packet
+) {
+  header->ExtId |= MMR_CAN_MESSAGE_TYPE_NORMAL;
+  return
+    HAL_CAN_AddTxMessage(hcan, header, packet->data, packet->mailbox);
+}
+
+
+static HalStatus sendMulti(
+  CanHandle *hcan,
+  CanTxHeader *header,
+  MmrCanPacket *packet
+) {
+  HalStatus status = HAL_OK;
+  uint8_t offset = 0;
+  uint8_t framesToSend = computeFramesToSend(packet);
+
+  header->ExtId |= MMR_CAN_MESSAGE_TYPE_MULTI_FRAME;
+  do {
+    bool isLastFrame = framesToSend <= 1;
+    if (isLastFrame) {
+      header->ExtId |= MMR_CAN_MESSAGE_TYPE_MULTI_FRAME_END;
+    }
+
+    status |=
+      sendSingleMultiFrame(hcan, header, packet, &offset);
+  }
+  while (framesToSend-- > 1 && status == HAL_OK);
+
+  return status;
+}
+
+
+static HalStatus sendSingleMultiFrame(
+  CanHandle *hcan,
+  CanTxHeader *header,
+  MmrCanPacket *packet,
+  uint8_t *offset
+) {
+  uint8_t *dataStart = packet->data + (*offset);
+  uint8_t length = computeNextMessageLength(packet, *offset);
+
+  header->DLC = length;
+  *offset += length;
+
+  return HAL_CAN_AddTxMessage(hcan, header, dataStart, packet->mailbox);
+}
+
+
+/**
+ * @brief 
+ * Computes the frames that will need to be sent for a packet.
+ * 
+ * For example, if a packet has 15 bytes, the function will return
+ * 2, as one packet is needed for the first 8 bytes and another is
+ * needed for the remaining 7.
+ * 
+ * @example
+ * The computation is pretty simple
+ * Given
+ *               length = 17 (bytes)
+ * We'll have
+ *         framesToSend = 17 / 8 = 2 (frames)
+ *            remainder = 17 % 8 = 1 (bytes)
+ * maybeOneForRemainder = 1 > 0  = 1 (frame)
+ * -------------------------------------------
+ *               result = 2 + 1  = 3 (frames) 
+ */
+static uint8_t computeFramesToSend(MmrCanPacket *packet) {
+  uint8_t length = packet->length;
+  uint8_t framesToSend = length / MMR_CAN_MAX_DATA_LENGTH;
+  uint8_t remainder = length % MMR_CAN_MAX_DATA_LENGTH;
+  uint8_t maybeOneForRemainder = remainder > 0;
+
+  return framesToSend + maybeOneForRemainder;
+}
+
+
+/**
+ * @brief 
+ * Returns the length for the next message, either
+ * 8 bytes or a lower value, keeping the offset into count.
+ * 
+ * @example
+ * Given
+ *  - a 17 bytes packet
+ *  - an offset starting at 0 and supposedly incrementing
+ *    of 8 after each call
+ * 
+ * Three subsequent calls to this function will return
+ *  First call  -> min(17 - 0, 8)  = min(17, 8) = 8 (bytes)
+ *  Second call -> min(17 - 8, 8)  = min(9, 8)  = 8 (bytes)
+ *  Third call  -> min(17 - 16, 8) = min(1, 8)  = 1 (byte)
+ */
+static uint8_t computeNextMessageLength(MmrCanPacket *packet, uint8_t offset) {
+  uint8_t remainingBytes = packet->length - offset;
+  return min(
+    remainingBytes, MMR_CAN_MAX_DATA_LENGTH
+  );
+}