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| -rw-r--r-- | libmaple/dma.c | 104 | ||||
| -rw-r--r-- | libmaple/dma.h | 71 |
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 |