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authorMichael Hope <michaelh@juju.net.nz>2010-10-20 20:53:43 +1300
committerMichael Hope <michaelh@juju.net.nz>2010-10-20 20:53:43 +1300
commit457fac0997eb8dbbaac913c15a8659637e58f186 (patch)
tree2cf0d8a5d4c3b75cac4b0cc654e32489fbf5e0ed /libmaple
parentc855c5bb49a809019802273004cc3a7045e7be76 (diff)
downloadlibrambutan-457fac0997eb8dbbaac913c15a8659637e58f186.tar.gz
librambutan-457fac0997eb8dbbaac913c15a8659637e58f186.zip
Added basic DMA support
Diffstat (limited to 'libmaple')
-rw-r--r--libmaple/dma.c104
-rw-r--r--libmaple/dma.h71
2 files changed, 175 insertions, 0 deletions
diff --git a/libmaple/dma.c b/libmaple/dma.c
new file mode 100644
index 0000000..4ad7fd2
--- /dev/null
+++ b/libmaple/dma.c
@@ -0,0 +1,104 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Michael Hope.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *****************************************************************************/
+
+/**
+ * @file dma.c
+ *
+ * @brief Direct Memory Access peripheral support
+ */
+
+#include "libmaple.h"
+#include "dma.h"
+#include "rcc.h"
+
+#define DMA_EN BIT(0)
+
+typedef struct dma_regs
+{
+ uint32 CCR;
+ uint32 CNDTR;
+ uint32 CPAR;
+ uint32 CMAR;
+} dma_regs;
+
+/** Get the base address of the given channel, asserting and returning
+ * NULL on illegal
+ */
+static dma_regs *dma_get_regs(uint8 channel) {
+ if (channel >= 1 && channel <= 7) {
+ return (dma_regs *)(DMA1_CCR1 + DMA_CHANNEL_STRIDE * (channel-1));
+ }
+ else {
+ ASSERT(false);
+ return NULL;
+ }
+}
+
+/** Initialise a DMA channel. Start the transfer using dma_start().
+ *
+ * @param channel the channel number (1..7)
+ * @param peripheral address of the peripheral
+ * @param from_peripheral true if transfer goes from the peripheral
+ * to memory
+ * @param mode OR of the dma_mode_flags
+ */
+void dma_init(uint8 channel, volatile void *peripheral, bool from_peripheral, enum dma_mode_flags mode) {
+ volatile dma_regs *regs = dma_get_regs(channel);
+
+ if (regs != NULL) {
+ rcc_clk_enable(RCC_DMA1);
+
+ /* Disable the channel. PENDING: May not be needed */
+ regs->CCR = 0;
+
+ uint32 cr = 0
+ | (0 << 12) // Low priority
+ | (0 << 10) // Memory size = 8 bits
+ | (1 << 8) // Peripheral size = 16 bits
+ | (mode << 5) // Increment and circular modes
+ | (0 << 0); // Not enabled
+
+ regs->CPAR = peripheral;
+
+ if (!from_peripheral) {
+ cr |= 1 << 4; // From memory
+ }
+
+ /* Stay disabled until started */
+ regs->CCR = cr;
+ }
+}
+
+void dma_start(uint8 channel, volatile void *buffer, uint16 count)
+{
+ volatile dma_regs *regs = dma_get_regs(channel);
+
+ if (regs != NULL) {
+ regs->CCR &= ~DMA_EN;
+ regs->CMAR = (uint32)buffer;
+ regs->CNDTR = count;
+
+ regs->CCR |= DMA_EN;
+ }
+}
diff --git a/libmaple/dma.h b/libmaple/dma.h
new file mode 100644
index 0000000..339b826
--- /dev/null
+++ b/libmaple/dma.h
@@ -0,0 +1,71 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Michael Hope.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *****************************************************************************/
+
+/**
+ * @file dma.h
+ *
+ * @brief Direct Memory Access peripheral support
+ */
+
+#ifndef _DMA_H_
+#define _DMA_H_
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+/** Base address of the DMA1 peripheral */
+#define DMA1_BASE 0x40020000
+/** DMA Interrupt Status Register */
+#define DMA1_ISR (DMA1_BASE + 0x00)
+/** DMA Interrput Flag Clear Register */
+#define DMA1_IFCR (DMA1_BASE + 0x04)
+/** DMA Channel Configuration Register */
+#define DMA1_CCR1 (DMA1_BASE + 0x08)
+/** DMA Channel Number of Data Register */
+#define DMA1_CNDTR1 (DMA1_BASE + 0x0C)
+/** DMA Channel Peripheral Address Register */
+#define DMA1_CPAR1 (DMA1_BASE + 0x10)
+/** DMA Channel Memory Address Register */
+#define DMA1_CMAR1 (DMA1_BASE + 0x14)
+/** Spacing between channel registers */
+#define DMA_CHANNEL_STRIDE 20
+
+typedef enum dma_mode_flags {
+ /** Auto-increment memory address */
+ DMA_MINC_MODE = 4,
+ /** Auto-increment peripheral address */
+ DMA_PINC_MODE = 2,
+ /** Circular mode */
+ DMA_CIRC_MODE = 1,
+} dma_mode_flags;
+
+void dma_init(uint8 channel, volatile void *peripheral, bool from_peripheral, dma_mode_flags mode);
+void dma_start(uint8 channel, volatile void *buffer, uint16 count);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif