Diff: targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/dma_api.c

Revision:

0:9b334a45a8ff

Child:

50:a417edff4437

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_Silicon_Labs/TARGET_EFM32/dma_api.c	Thu Oct 01 15:25:22 2015 +0300
@@ -0,0 +1,103 @@
+/***************************************************************************//**
+ * @file dma_api.c
+ *******************************************************************************
+ * @section License
+ * <b>(C) Copyright 2015 Silicon Labs, http://www.silabs.com</b>
+ *******************************************************************************
+ *
+ * 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.
+ * 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.
+ *
+ * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
+ * obligation to support this Software. Silicon Labs is providing the
+ * Software "AS IS", with no express or implied warranties of any kind,
+ * including, but not limited to, any implied warranties of merchantability
+ * or fitness for any particular purpose or warranties against infringement
+ * of any proprietary rights of a third party.
+ *
+ * Silicon Labs will not be liable for any consequential, incidental, or
+ * special damages, or any other relief, or for any claim by any third party,
+ * arising from your use of this Software.
+ *
+ ******************************************************************************/
+
+#include <stdint.h>
+#include "dma_api_HAL.h"
+#include "em_dma.h"
+#include "em_cmu.h"
+
+/** DMA control block array, requires proper alignment. */
+#if defined (__ICCARM__)
+#pragma data_alignment=DMACTRL_ALIGNMENT
+DMA_DESCRIPTOR_TypeDef dmaControlBlock[DMACTRL_CH_CNT * 2];
+
+#elif defined (__CC_ARM)
+DMA_DESCRIPTOR_TypeDef dmaControlBlock[DMACTRL_CH_CNT * 2] __attribute__ ((aligned(DMACTRL_ALIGNMENT)));
+
+#elif defined (__GNUC__)
+DMA_DESCRIPTOR_TypeDef dmaControlBlock[DMACTRL_CH_CNT * 2] __attribute__ ((aligned(DMACTRL_ALIGNMENT), section("dma")));
+
+#else
+#error Undefined toolkit, need to define alignment
+#endif
+
+uint32_t channels = 0; // Bit vector of taken channels
+bool enabled = false;
+
+void dma_init(void)
+{
+    if (enabled) return;
+    DMA_Init_TypeDef   dmaInit;
+
+    CMU_ClockEnable(cmuClock_DMA, true);
+    CMU_ClockEnable(cmuClock_HFPER, true);
+
+    /* Configure general DMA issues */
+    dmaInit.hprot        = 0;
+    dmaInit.controlBlock = dmaControlBlock;
+    DMA_Init(&dmaInit);
+    enabled = true;
+}
+
+int dma_channel_allocate(uint32_t capabilities)
+{
+    int i;
+    // Check if 2d copy is required
+    if (DMA_CAP_2DCOPY & capabilities) {
+        if (channels & 1) {
+            // Channel already in use
+            return DMA_ERROR_OUT_OF_CHANNELS;
+        } else {
+            channels |= 1 << 0;
+            return 0;
+        }
+    }
+    for (i = 1; i < DMA_CHAN_COUNT; i++) {
+        if ((channels & (1 << i)) == 0) {
+            // Channel available
+            channels |= 1 << i;
+            return i;
+        }
+    }
+    // Check if channel 0 is available
+    if ((channels & 1 ) == 0) {
+        channels |= 1 << 0;
+        return 0;
+    }
+    // Couldn't find a channel.
+    return DMA_ERROR_OUT_OF_CHANNELS;
+}
+
+int dma_channel_free(int channelid)
+{
+    channels &= ~(1 << channelid);
+    return 0;
+}
+