Diff: targets/hal/TARGET_Atmel/TARGET_SAM_CortexM0P/sercom_dma.c

Revision:

15:a81a8d6c1dfe

Child:

64:41a834223ea3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_Atmel/TARGET_SAM_CortexM0P/sercom_dma.c	Wed Nov 04 16:30:11 2015 +0000
@@ -0,0 +1,91 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "mbed_assert.h"
+
+#include "cmsis.h"
+#include "sercom.h"
+#include "dma_api.h"
+#include "dma_api_HAL.h"
+#include "sercom_dma.h"
+
+static struct sercom_dma sercom_channels[SERCOM_INST_NUM] = {{0}};
+
+/** Allocate a channel for TX
+ *
+ * @param[in] sercom_index	index of sercom instance
+ * @param[out] tx_id		pointer to channel id
+ * @return allocated channel id
+ */
+uint8_t sercom_setup_tx_channel(uint8_t sercom_index, uint8_t *tx_id)
+{
+    if (sercom_channels[sercom_index].tx_status & DMA_ALLOCATED) {
+        *tx_id = sercom_channels[sercom_index].tx_channel_id;
+    } else {
+        /* Try to allocate a channel */
+        sercom_channels[sercom_index].tx_channel_id = dma_channel_allocate(DMA_CAP_NONE);
+        if (sercom_channels[sercom_index].tx_channel_id != (uint8_t)DMA_ERROR_OUT_OF_CHANNELS) {
+            *tx_id = sercom_channels[sercom_index].tx_channel_id;
+            sercom_channels[sercom_index].tx_status = DMA_ALLOCATED;
+        } else {
+            /* Couldn't find a channel */
+            return DMA_ERROR_OUT_OF_CHANNELS;
+        }
+    }
+    return *tx_id;
+}
+
+/** Allocate a channel for RX
+ *
+ * @param[in] sercom_index	index of sercom instance
+ * @param[out] rx_id		pointer to channel id
+ * @return allocated channel id
+ */
+uint8_t sercom_setup_rx_channel(uint8_t sercom_index, uint8_t *rx_id)
+{
+    if (sercom_channels[sercom_index].rx_status & DMA_ALLOCATED) {
+        *rx_id = sercom_channels[sercom_index].rx_channel_id;
+    } else {
+        /* Try to allocate a channel */
+        sercom_channels[sercom_index].rx_channel_id = dma_channel_allocate(DMA_CAP_NONE);
+        if (sercom_channels[sercom_index].rx_channel_id != (uint8_t)DMA_ERROR_OUT_OF_CHANNELS) {
+            *rx_id = sercom_channels[sercom_index].rx_channel_id;
+            sercom_channels[sercom_index].rx_status = DMA_ALLOCATED;
+        } else {
+            /* Couldn't find a channel */
+            return DMA_ERROR_OUT_OF_CHANNELS;
+        }
+    }
+    return *rx_id;
+}
+
+/** Release DMA channels if allocated
+ *
+ * @param[in] sercom_index	index of sercom instance
+ * @return void
+ */
+void sercom_release_channel(uint8_t sercom_index)
+{
+    if (sercom_channels[sercom_index].rx_status & DMA_ALLOCATED) {
+        if (0 == dma_channel_free(sercom_channels[sercom_index].rx_channel_id)) {
+            sercom_channels[sercom_index].rx_status = DMA_NOT_USED;
+        }
+    }
+    if (sercom_channels[sercom_index].tx_status & DMA_ALLOCATED) {
+        if (0 == dma_channel_free(sercom_channels[sercom_index].tx_channel_id)) {
+            sercom_channels[sercom_index].tx_status = DMA_NOT_USED;
+        }
+    }
+}