stm32f1: Resurrect DMA support. (sets up breaking change)

Breaking change set up: struct dma_handler_config is no longer part of
the public API in <libmaple/dma.h>. User code which was touching
these was always mistaken; it should be using dma_attach_interrupt()
or dma_detach_interrupt() instead.

Other than that, just move the nonportable bits in <libmaple/dma.h>
and libmaple/dma.c to the appropriate places under
libmaple/stm32f1/. (Ouch. This is almost everything.) Patch the
(new) STM32F1 <series/dma.h> here and there to make everything
compile; this is mostly limited to forward-declaring struct dma_dev
and providing a hack _dma_dev_regs() declaration so inline functions
in the series header can still access a device's registers.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

3 files changed, 810 insertions, 0 deletions

diff --git a/libmaple/stm32f1/dma.c b/libmaple/stm32f1/dma.c
new file mode 100644
index 0000000..14ac645
--- /dev/null
+++ b/libmaple/stm32f1/dma.c
@@ -0,0 +1,371 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Michael Hope.
+ * Copyright (c) 2012 LeafLabs, LLC.
+ *
+ * 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 libmaple/stm32f1/dma.c
+ * @author Marti Bolivar <mbolivar@leaflabs.com>;
+ *         Original implementation by Michael Hope
+ * @brief STM32F1 DMA support.
+ */
+
+#include <libmaple/dma.h>
+#include <libmaple/bitband.h>
+
+/*
+ * Devices
+ */
+
+static dma_dev dma1 = {
+    .regs     = DMA1_BASE,
+    .clk_id   = RCC_DMA1,
+    .handlers = {{ .handler = NULL, .irq_line = NVIC_DMA_CH1 },
+                 { .handler = NULL, .irq_line = NVIC_DMA_CH2 },
+                 { .handler = NULL, .irq_line = NVIC_DMA_CH3 },
+                 { .handler = NULL, .irq_line = NVIC_DMA_CH4 },
+                 { .handler = NULL, .irq_line = NVIC_DMA_CH5 },
+                 { .handler = NULL, .irq_line = NVIC_DMA_CH6 },
+                 { .handler = NULL, .irq_line = NVIC_DMA_CH7 }},
+};
+/** DMA1 device */
+dma_dev *DMA1 = &dma1;
+
+#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+static dma_dev dma2 = {
+    .regs     = DMA2_BASE,
+    .clk_id   = RCC_DMA2,
+    .handlers = {{ .handler = NULL, .irq_line = NVIC_DMA2_CH1   },
+                 { .handler = NULL, .irq_line = NVIC_DMA2_CH2   },
+                 { .handler = NULL, .irq_line = NVIC_DMA2_CH3   },
+                 { .handler = NULL, .irq_line = NVIC_DMA2_CH_4_5 },
+                 { .handler = NULL, .irq_line = NVIC_DMA2_CH_4_5 }}, /* !@#$ */
+};
+/** DMA2 device */
+dma_dev *DMA2 = &dma2;
+#endif
+
+/*
+ * Routines
+ */
+
+/**
+ * @brief Set up a DMA transfer.
+ *
+ * The channel will be disabled before being reconfigured.  The
+ * transfer will have low priority by default.  You may choose another
+ * priority before the transfer begins using dma_set_priority(), as
+ * well as performing any other configuration you desire.  When the
+ * channel is configured to your liking, enable it using dma_enable().
+ *
+ * @param dev DMA device.
+ * @param channel DMA channel.
+ * @param peripheral_address Base address of peripheral data register
+ *                           involved in the transfer.
+ * @param peripheral_size Peripheral data transfer size.
+ * @param memory_address Base memory address involved in the transfer.
+ * @param memory_size Memory data transfer size.
+ * @param mode Logical OR of dma_mode_flags
+ * @sideeffect Disables the given DMA channel.
+ * @see dma_xfer_size
+ * @see dma_mode_flags
+ * @see dma_set_num_transfers()
+ * @see dma_set_priority()
+ * @see dma_attach_interrupt()
+ * @see dma_enable()
+ */
+void dma_setup_transfer(dma_dev       *dev,
+                        dma_channel    channel,
+                        __io void     *peripheral_address,
+                        dma_xfer_size  peripheral_size,
+                        __io void     *memory_address,
+                        dma_xfer_size  memory_size,
+                        uint32         mode) {
+    dma_channel_reg_map *channel_regs = dma_channel_regs(dev, channel);
+
+    dma_disable(dev, channel);  /* can't write to CMAR/CPAR otherwise */
+    channel_regs->CCR = (memory_size << 10) | (peripheral_size << 8) | mode;
+    channel_regs->CMAR = (uint32)memory_address;
+    channel_regs->CPAR = (uint32)peripheral_address;
+}
+
+/**
+ * @brief Set the number of data to be transferred on a DMA channel.
+ *
+ * You may not call this function while the channel is enabled.
+ *
+ * @param dev DMA device
+ * @param channel Channel through which the transfer occurs.
+ * @param num_transfers
+ */
+void dma_set_num_transfers(dma_dev *dev,
+                           dma_channel channel,
+                           uint16 num_transfers) {
+    dma_channel_reg_map *channel_regs;
+
+    ASSERT_FAULT(!dma_is_channel_enabled(dev, channel));
+
+    channel_regs = dma_channel_regs(dev, channel);
+    channel_regs->CNDTR = num_transfers;
+}
+
+/**
+ * @brief Set the priority of a DMA transfer.
+ *
+ * You may not call this function while the channel is enabled.
+ *
+ * @param dev DMA device
+ * @param channel DMA channel
+ * @param priority priority to set.
+ */
+void dma_set_priority(dma_dev *dev,
+                      dma_channel channel,
+                      dma_priority priority) {
+    dma_channel_reg_map *channel_regs;
+    uint32 ccr;
+
+    ASSERT_FAULT(!dma_is_channel_enabled(dev, channel));
+
+    channel_regs = dma_channel_regs(dev, channel);
+    ccr = channel_regs->CCR;
+    ccr &= ~DMA_CCR_PL;
+    ccr |= priority;
+    channel_regs->CCR = ccr;
+}
+
+/**
+ * @brief Attach an interrupt to a DMA transfer.
+ *
+ * Interrupts are enabled using appropriate mode flags in
+ * dma_setup_transfer().
+ *
+ * @param dev DMA device
+ * @param channel Channel to attach handler to
+ * @param handler Interrupt handler to call when channel interrupt fires.
+ * @see dma_setup_transfer()
+ * @see dma_get_irq_cause()
+ * @see dma_detach_interrupt()
+ */
+void dma_attach_interrupt(dma_dev *dev,
+                          dma_channel channel,
+                          void (*handler)(void)) {
+    dev->handlers[channel - 1].handler = handler;
+    nvic_irq_enable(dev->handlers[channel - 1].irq_line);
+}
+
+/**
+ * @brief Detach a DMA transfer interrupt handler.
+ *
+ * After calling this function, the given channel's interrupts will be
+ * disabled.
+ *
+ * @param dev DMA device
+ * @param channel Channel whose handler to detach
+ * @sideeffect Clears interrupt enable bits in the channel's CCR register.
+ * @see dma_attach_interrupt()
+ */
+void dma_detach_interrupt(dma_dev *dev, dma_channel channel) {
+    /* Don't use nvic_irq_disable()! Think about DMA2 channels 4 and 5. */
+    dma_channel_regs(dev, channel)->CCR &= ~0xF;
+    dev->handlers[channel - 1].handler = NULL;
+}
+
+/**
+ * @brief Discover the reason why a DMA interrupt was called.
+ *
+ * You may only call this function within an attached interrupt
+ * handler for the given channel.
+ *
+ * This function resets the internal DMA register state which encodes
+ * the cause of the interrupt; consequently, it can only be called
+ * once per interrupt handler invocation.
+ *
+ * @param dev DMA device
+ * @param channel Channel whose interrupt is being handled.
+ * @return Reason why the interrupt fired.
+ * @sideeffect Clears channel status flags in dev->regs->ISR.
+ * @see dma_attach_interrupt()
+ * @see dma_irq_cause
+ */
+dma_irq_cause dma_get_irq_cause(dma_dev *dev, dma_channel channel) {
+    uint8 status_bits = dma_get_isr_bits(dev, channel);
+
+    /* If the channel global interrupt flag is cleared, then
+     * something's very wrong. */
+    ASSERT(status_bits & BIT(0));
+
+    dma_clear_isr_bits(dev, channel);
+
+    /* ISR flags get set even if the corresponding interrupt enable
+     * bits in the channel's configuration register are cleared, so we
+     * can't use a switch here.
+     *
+     * Don't change the order of these if statements. */
+    if (status_bits & BIT(3)) {
+        return DMA_TRANSFER_ERROR;
+    } else if (status_bits & BIT(1)) {
+        return DMA_TRANSFER_COMPLETE;
+    } else if (status_bits & BIT(2)) {
+        return DMA_TRANSFER_HALF_COMPLETE;
+    } else if (status_bits & BIT(0)) {
+        /* Shouldn't happen (unless someone messed up an IFCR write). */
+        throb();
+    }
+#if DEBUG_LEVEL < DEBUG_ALL
+    else {
+        /* We shouldn't have been called, but the debug level is too
+         * low for the above ASSERT() to have had any effect.  In
+         * order to fail fast, mimic the DMA controller's behavior
+         * when an error occurs. */
+        dma_disable(dev, channel);
+    }
+#endif
+    return DMA_TRANSFER_ERROR;
+}
+
+/**
+ * @brief Enable a DMA channel.
+ * @param dev DMA device
+ * @param channel Channel to enable
+ */
+void dma_enable(dma_dev *dev, dma_channel channel) {
+    dma_channel_reg_map *chan_regs = dma_channel_regs(dev, channel);
+    bb_peri_set_bit(&chan_regs->CCR, DMA_CCR_EN_BIT, 1);
+}
+
+/**
+ * @brief Disable a DMA channel.
+ * @param dev DMA device
+ * @param channel Channel to disable
+ */
+void dma_disable(dma_dev *dev, dma_channel channel) {
+    dma_channel_reg_map *chan_regs = dma_channel_regs(dev, channel);
+    bb_peri_set_bit(&chan_regs->CCR, DMA_CCR_EN_BIT, 0);
+}
+
+/**
+ * @brief Set the base memory address where data will be read from or
+ *        written to.
+ *
+ * You must not call this function while the channel is enabled.
+ *
+ * If the DMA memory size is 16 bits, the address is automatically
+ * aligned to a half-word.  If the DMA memory size is 32 bits, the
+ * address is aligned to a word.
+ *
+ * @param dev DMA Device
+ * @param channel Channel whose base memory address to set.
+ * @param addr Memory base address to use.
+ */
+void dma_set_mem_addr(dma_dev *dev, dma_channel channel, __io void *addr) {
+    dma_channel_reg_map *chan_regs;
+
+    ASSERT_FAULT(!dma_is_channel_enabled(dev, channel));
+
+    chan_regs = dma_channel_regs(dev, channel);
+    chan_regs->CMAR = (uint32)addr;
+}
+
+/**
+ * @brief Set the base peripheral address where data will be read from
+ *        or written to.
+ *
+ * You must not call this function while the channel is enabled.
+ *
+ * If the DMA peripheral size is 16 bits, the address is automatically
+ * aligned to a half-word.  If the DMA peripheral size is 32 bits, the
+ * address is aligned to a word.
+ *
+ * @param dev DMA Device
+ * @param channel Channel whose peripheral data register base address to set.
+ * @param addr Peripheral memory base address to use.
+ */
+void dma_set_per_addr(dma_dev *dev, dma_channel channel, __io void *addr) {
+    dma_channel_reg_map *chan_regs;
+
+    ASSERT_FAULT(!dma_is_channel_enabled(dev, channel));
+
+    chan_regs = dma_channel_regs(dev, channel);
+    chan_regs->CPAR = (uint32)addr;
+}
+
+/*
+ * IRQ handlers
+ */
+
+static __always_inline void dispatch_handler(dma_dev *dev, int channel) {
+    void (*handler)(void) = dev->handlers[channel - 1].handler;
+    if (handler) {
+        handler();
+        dma_clear_isr_bits(dev, channel); /* in case handler doesn't */
+    }
+}
+
+void __irq_dma1_channel1(void) {
+    dispatch_handler(DMA1, DMA_CH1);
+}
+
+void __irq_dma1_channel2(void) {
+    dispatch_handler(DMA1, DMA_CH2);
+}
+
+void __irq_dma1_channel3(void) {
+    dispatch_handler(DMA1, DMA_CH3);
+}
+
+void __irq_dma1_channel4(void) {
+    dispatch_handler(DMA1, DMA_CH4);
+}
+
+void __irq_dma1_channel5(void) {
+    dispatch_handler(DMA1, DMA_CH5);
+}
+
+void __irq_dma1_channel6(void) {
+    dispatch_handler(DMA1, DMA_CH6);
+}
+
+void __irq_dma1_channel7(void) {
+    dispatch_handler(DMA1, DMA_CH7);
+}
+
+#ifdef STM32_HIGH_DENSITY
+void __irq_dma2_channel1(void) {
+    dispatch_handler(DMA2, DMA_CH1);
+}
+
+void __irq_dma2_channel2(void) {
+    dispatch_handler(DMA2, DMA_CH2);
+}
+
+void __irq_dma2_channel3(void) {
+    dispatch_handler(DMA2, DMA_CH3);
+}
+
+void __irq_dma2_channel4_5(void) {
+    dispatch_handler(DMA2, DMA_CH4);
+    dispatch_handler(DMA2, DMA_CH5);
+}
+#endif
diff --git a/libmaple/stm32f1/include/series/dma.h b/libmaple/stm32f1/include/series/dma.h
new file mode 100644
index 0000000..60582ea
--- /dev/null
+++ b/libmaple/stm32f1/include/series/dma.h
@@ -0,0 +1,438 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2010 Michael Hope.
+ * Copyright (c) 2012 LeafLabs, LLC
+ *
+ * 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 libmaple/stm32f1/include/series/dma.h
+ * @author Marti Bolivar <mbolivar@leaflabs.com>;
+ *         Original implementation by Michael Hope
+ * @brief STM32F1 Direct Memory Access header
+ */
+
+/*
+ * See /notes/dma-stm32f1.txt for more information.
+ */
+
+#ifndef _LIBMAPLE_STM32F1_DMA_H_
+#define _LIBMAPLE_STM32F1_DMA_H_
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+#include <libmaple/libmaple_types.h>
+
+/*
+ * Register map and base pointers
+ */
+
+/**
+ * @brief DMA register map type.
+ *
+ * Note that DMA controller 2 (register map base pointer DMA2_BASE)
+ * only supports channels 1--5.
+ */
+typedef struct dma_reg_map {
+    __io uint32 ISR;            /**< Interrupt status register */
+    __io uint32 IFCR;           /**< Interrupt flag clear register */
+    __io uint32 CCR1;           /**< Channel 1 configuration register */
+    __io uint32 CNDTR1;         /**< Channel 1 number of data register */
+    __io uint32 CPAR1;          /**< Channel 1 peripheral address register */
+    __io uint32 CMAR1;          /**< Channel 1 memory address register */
+    const uint32 RESERVED1;     /**< Reserved. */
+    __io uint32 CCR2;           /**< Channel 2 configuration register */
+    __io uint32 CNDTR2;         /**< Channel 2 number of data register */
+    __io uint32 CPAR2;          /**< Channel 2 peripheral address register */
+    __io uint32 CMAR2;          /**< Channel 2 memory address register */
+    const uint32 RESERVED2;     /**< Reserved. */
+    __io uint32 CCR3;           /**< Channel 3 configuration register */
+    __io uint32 CNDTR3;         /**< Channel 3 number of data register */
+    __io uint32 CPAR3;          /**< Channel 3 peripheral address register */
+    __io uint32 CMAR3;          /**< Channel 3 memory address register */
+    const uint32 RESERVED3;     /**< Reserved. */
+    __io uint32 CCR4;           /**< Channel 4 configuration register */
+    __io uint32 CNDTR4;         /**< Channel 4 number of data register */
+    __io uint32 CPAR4;          /**< Channel 4 peripheral address register */
+    __io uint32 CMAR4;          /**< Channel 4 memory address register */
+    const uint32 RESERVED4;     /**< Reserved. */
+    __io uint32 CCR5;           /**< Channel 5 configuration register */
+    __io uint32 CNDTR5;         /**< Channel 5 number of data register */
+    __io uint32 CPAR5;          /**< Channel 5 peripheral address register */
+    __io uint32 CMAR5;          /**< Channel 5 memory address register */
+    const uint32 RESERVED5;     /**< Reserved. */
+    __io uint32 CCR6;           /**< Channel 6 configuration register */
+    __io uint32 CNDTR6;         /**< Channel 6 number of data register */
+    __io uint32 CPAR6;          /**< Channel 6 peripheral address register */
+    __io uint32 CMAR6;          /**< Channel 6 memory address register */
+    const uint32 RESERVED6;     /**< Reserved. */
+    __io uint32 CCR7;           /**< Channel 7 configuration register */
+    __io uint32 CNDTR7;         /**< Channel 7 number of data register */
+    __io uint32 CPAR7;          /**< Channel 7 peripheral address register */
+    __io uint32 CMAR7;          /**< Channel 7 memory address register */
+    const uint32 RESERVED7;     /**< Reserved. */
+} dma_reg_map;
+
+/** DMA controller 1 register map base pointer */
+#define DMA1_BASE                       ((struct dma_reg_map*)0x40020000)
+/** DMA controller 2 register map base pointer */
+#define DMA2_BASE                       ((struct dma_reg_map*)0x40020400)
+
+/*
+ * Register bit definitions
+ */
+
+/* Interrupt status register */
+
+#define DMA_ISR_TEIF7_BIT               27
+#define DMA_ISR_HTIF7_BIT               26
+#define DMA_ISR_TCIF7_BIT               25
+#define DMA_ISR_GIF7_BIT                24
+#define DMA_ISR_TEIF6_BIT               23
+#define DMA_ISR_HTIF6_BIT               22
+#define DMA_ISR_TCIF6_BIT               21
+#define DMA_ISR_GIF6_BIT                20
+#define DMA_ISR_TEIF5_BIT               19
+#define DMA_ISR_HTIF5_BIT               18
+#define DMA_ISR_TCIF5_BIT               17
+#define DMA_ISR_GIF5_BIT                16
+#define DMA_ISR_TEIF4_BIT               15
+#define DMA_ISR_HTIF4_BIT               14
+#define DMA_ISR_TCIF4_BIT               13
+#define DMA_ISR_GIF4_BIT                12
+#define DMA_ISR_TEIF3_BIT               11
+#define DMA_ISR_HTIF3_BIT               10
+#define DMA_ISR_TCIF3_BIT               9
+#define DMA_ISR_GIF3_BIT                8
+#define DMA_ISR_TEIF2_BIT               7
+#define DMA_ISR_HTIF2_BIT               6
+#define DMA_ISR_TCIF2_BIT               5
+#define DMA_ISR_GIF2_BIT                4
+#define DMA_ISR_TEIF1_BIT               3
+#define DMA_ISR_HTIF1_BIT               2
+#define DMA_ISR_TCIF1_BIT               1
+#define DMA_ISR_GIF1_BIT                0
+
+#define DMA_ISR_TEIF7                   (1U << DMA_ISR_TEIF7_BIT)
+#define DMA_ISR_HTIF7                   (1U << DMA_ISR_HTIF7_BIT)
+#define DMA_ISR_TCIF7                   (1U << DMA_ISR_TCIF7_BIT)
+#define DMA_ISR_GIF7                    (1U << DMA_ISR_GIF7_BIT)
+#define DMA_ISR_TEIF6                   (1U << DMA_ISR_TEIF6_BIT)
+#define DMA_ISR_HTIF6                   (1U << DMA_ISR_HTIF6_BIT)
+#define DMA_ISR_TCIF6                   (1U << DMA_ISR_TCIF6_BIT)
+#define DMA_ISR_GIF6                    (1U << DMA_ISR_GIF6_BIT)
+#define DMA_ISR_TEIF5                   (1U << DMA_ISR_TEIF5_BIT)
+#define DMA_ISR_HTIF5                   (1U << DMA_ISR_HTIF5_BIT)
+#define DMA_ISR_TCIF5                   (1U << DMA_ISR_TCIF5_BIT)
+#define DMA_ISR_GIF5                    (1U << DMA_ISR_GIF5_BIT)
+#define DMA_ISR_TEIF4                   (1U << DMA_ISR_TEIF4_BIT)
+#define DMA_ISR_HTIF4                   (1U << DMA_ISR_HTIF4_BIT)
+#define DMA_ISR_TCIF4                   (1U << DMA_ISR_TCIF4_BIT)
+#define DMA_ISR_GIF4                    (1U << DMA_ISR_GIF4_BIT)
+#define DMA_ISR_TEIF3                   (1U << DMA_ISR_TEIF3_BIT)
+#define DMA_ISR_HTIF3                   (1U << DMA_ISR_HTIF3_BIT)
+#define DMA_ISR_TCIF3                   (1U << DMA_ISR_TCIF3_BIT)
+#define DMA_ISR_GIF3                    (1U << DMA_ISR_GIF3_BIT)
+#define DMA_ISR_TEIF2                   (1U << DMA_ISR_TEIF2_BIT)
+#define DMA_ISR_HTIF2                   (1U << DMA_ISR_HTIF2_BIT)
+#define DMA_ISR_TCIF2                   (1U << DMA_ISR_TCIF2_BIT)
+#define DMA_ISR_GIF2                    (1U << DMA_ISR_GIF2_BIT)
+#define DMA_ISR_TEIF1                   (1U << DMA_ISR_TEIF1_BIT)
+#define DMA_ISR_HTIF1                   (1U << DMA_ISR_HTIF1_BIT)
+#define DMA_ISR_TCIF1                   (1U << DMA_ISR_TCIF1_BIT)
+#define DMA_ISR_GIF1                    (1U << DMA_ISR_GIF1_BIT)
+
+/* Interrupt flag clear register */
+
+#define DMA_IFCR_CTEIF7_BIT             27
+#define DMA_IFCR_CHTIF7_BIT             26
+#define DMA_IFCR_CTCIF7_BIT             25
+#define DMA_IFCR_CGIF7_BIT              24
+#define DMA_IFCR_CTEIF6_BIT             23
+#define DMA_IFCR_CHTIF6_BIT             22
+#define DMA_IFCR_CTCIF6_BIT             21
+#define DMA_IFCR_CGIF6_BIT              20
+#define DMA_IFCR_CTEIF5_BIT             19
+#define DMA_IFCR_CHTIF5_BIT             18
+#define DMA_IFCR_CTCIF5_BIT             17
+#define DMA_IFCR_CGIF5_BIT              16
+#define DMA_IFCR_CTEIF4_BIT             15
+#define DMA_IFCR_CHTIF4_BIT             14
+#define DMA_IFCR_CTCIF4_BIT             13
+#define DMA_IFCR_CGIF4_BIT              12
+#define DMA_IFCR_CTEIF3_BIT             11
+#define DMA_IFCR_CHTIF3_BIT             10
+#define DMA_IFCR_CTCIF3_BIT             9
+#define DMA_IFCR_CGIF3_BIT              8
+#define DMA_IFCR_CTEIF2_BIT             7
+#define DMA_IFCR_CHTIF2_BIT             6
+#define DMA_IFCR_CTCIF2_BIT             5
+#define DMA_IFCR_CGIF2_BIT              4
+#define DMA_IFCR_CTEIF1_BIT             3
+#define DMA_IFCR_CHTIF1_BIT             2
+#define DMA_IFCR_CTCIF1_BIT             1
+#define DMA_IFCR_CGIF1_BIT              0
+
+#define DMA_IFCR_CTEIF7                 (1U << DMA_IFCR_CTEIF7_BIT)
+#define DMA_IFCR_CHTIF7                 (1U << DMA_IFCR_CHTIF7_BIT)
+#define DMA_IFCR_CTCIF7                 (1U << DMA_IFCR_CTCIF7_BIT)
+#define DMA_IFCR_CGIF7                  (1U << DMA_IFCR_CGIF7_BIT)
+#define DMA_IFCR_CTEIF6                 (1U << DMA_IFCR_CTEIF6_BIT)
+#define DMA_IFCR_CHTIF6                 (1U << DMA_IFCR_CHTIF6_BIT)
+#define DMA_IFCR_CTCIF6                 (1U << DMA_IFCR_CTCIF6_BIT)
+#define DMA_IFCR_CGIF6                  (1U << DMA_IFCR_CGIF6_BIT)
+#define DMA_IFCR_CTEIF5                 (1U << DMA_IFCR_CTEIF5_BIT)
+#define DMA_IFCR_CHTIF5                 (1U << DMA_IFCR_CHTIF5_BIT)
+#define DMA_IFCR_CTCIF5                 (1U << DMA_IFCR_CTCIF5_BIT)
+#define DMA_IFCR_CGIF5                  (1U << DMA_IFCR_CGIF5_BIT)
+#define DMA_IFCR_CTEIF4                 (1U << DMA_IFCR_CTEIF4_BIT)
+#define DMA_IFCR_CHTIF4                 (1U << DMA_IFCR_CHTIF4_BIT)
+#define DMA_IFCR_CTCIF4                 (1U << DMA_IFCR_CTCIF4_BIT)
+#define DMA_IFCR_CGIF4                  (1U << DMA_IFCR_CGIF4_BIT)
+#define DMA_IFCR_CTEIF3                 (1U << DMA_IFCR_CTEIF3_BIT)
+#define DMA_IFCR_CHTIF3                 (1U << DMA_IFCR_CHTIF3_BIT)
+#define DMA_IFCR_CTCIF3                 (1U << DMA_IFCR_CTCIF3_BIT)
+#define DMA_IFCR_CGIF3                  (1U << DMA_IFCR_CGIF3_BIT)
+#define DMA_IFCR_CTEIF2                 (1U << DMA_IFCR_CTEIF2_BIT)
+#define DMA_IFCR_CHTIF2                 (1U << DMA_IFCR_CHTIF2_BIT)
+#define DMA_IFCR_CTCIF2                 (1U << DMA_IFCR_CTCIF2_BIT)
+#define DMA_IFCR_CGIF2                  (1U << DMA_IFCR_CGIF2_BIT)
+#define DMA_IFCR_CTEIF1                 (1U << DMA_IFCR_CTEIF1_BIT)
+#define DMA_IFCR_CHTIF1                 (1U << DMA_IFCR_CHTIF1_BIT)
+#define DMA_IFCR_CTCIF1                 (1U << DMA_IFCR_CTCIF1_BIT)
+#define DMA_IFCR_CGIF1                  (1U << DMA_IFCR_CGIF1_BIT)
+
+/* Channel configuration register */
+
+#define DMA_CCR_MEM2MEM_BIT             14
+#define DMA_CCR_MINC_BIT                7
+#define DMA_CCR_PINC_BIT                6
+#define DMA_CCR_CIRC_BIT                5
+#define DMA_CCR_DIR_BIT                 4
+#define DMA_CCR_TEIE_BIT                3
+#define DMA_CCR_HTIE_BIT                2
+#define DMA_CCR_TCIE_BIT                1
+#define DMA_CCR_EN_BIT                  0
+
+#define DMA_CCR_MEM2MEM                 (1U << DMA_CCR_MEM2MEM_BIT)
+#define DMA_CCR_PL                      (0x3 << 12)
+#define DMA_CCR_PL_LOW                  (0x0 << 12)
+#define DMA_CCR_PL_MEDIUM               (0x1 << 12)
+#define DMA_CCR_PL_HIGH                 (0x2 << 12)
+#define DMA_CCR_PL_VERY_HIGH            (0x3 << 12)
+#define DMA_CCR_MSIZE                   (0x3 << 10)
+#define DMA_CCR_MSIZE_8BITS             (0x0 << 10)
+#define DMA_CCR_MSIZE_16BITS            (0x1 << 10)
+#define DMA_CCR_MSIZE_32BITS            (0x2 << 10)
+#define DMA_CCR_PSIZE                   (0x3 << 8)
+#define DMA_CCR_PSIZE_8BITS             (0x0 << 8)
+#define DMA_CCR_PSIZE_16BITS            (0x1 << 8)
+#define DMA_CCR_PSIZE_32BITS            (0x2 << 8)
+#define DMA_CCR_MINC                    (1U << DMA_CCR_MINC_BIT)
+#define DMA_CCR_PINC                    (1U << DMA_CCR_PINC_BIT)
+#define DMA_CCR_CIRC                    (1U << DMA_CCR_CIRC_BIT)
+#define DMA_CCR_DIR                     (1U << DMA_CCR_DIR_BIT)
+#define DMA_CCR_TEIE                    (1U << DMA_CCR_TEIE_BIT)
+#define DMA_CCR_HTIE                    (1U << DMA_CCR_HTIE_BIT)
+#define DMA_CCR_TCIE                    (1U << DMA_CCR_TCIE_BIT)
+#define DMA_CCR_EN                      (1U << DMA_CCR_EN_BIT)
+
+/*
+ * Devices
+ */
+
+struct dma_dev;
+extern struct dma_dev *DMA1;
+#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+extern struct dma_dev *DMA2;
+#endif
+
+/*
+ * Convenience routines.
+ */
+
+/* This hack is due to a circular dependency between us and
+ * <libmaple/dma.h>. */
+static __always_inline dma_reg_map* _dma_dev_regs(struct dma_dev*);
+
+/** Flags for DMA transfer configuration. */
+typedef enum dma_mode_flags {
+    DMA_MEM_2_MEM  = 1 << 14, /**< Memory to memory mode */
+    DMA_MINC_MODE  = 1 << 7,  /**< Auto-increment memory address */
+    DMA_PINC_MODE  = 1 << 6,  /**< Auto-increment peripheral address */
+    DMA_CIRC_MODE  = 1 << 5,  /**< Circular mode */
+    DMA_FROM_MEM   = 1 << 4,  /**< Read from memory to peripheral */
+    DMA_TRNS_ERR   = 1 << 3,  /**< Interrupt on transfer error */
+    DMA_HALF_TRNS  = 1 << 2,  /**< Interrupt on half-transfer */
+    DMA_TRNS_CMPLT = 1 << 1   /**< Interrupt on transfer completion */
+} dma_mode_flags;
+
+/** Source and destination transfer sizes. */
+typedef enum dma_xfer_size {
+    DMA_SIZE_8BITS  = 0,        /**< 8-bit transfers */
+    DMA_SIZE_16BITS = 1,        /**< 16-bit transfers */
+    DMA_SIZE_32BITS = 2         /**< 32-bit transfers */
+} dma_xfer_size;
+
+/** DMA channel */
+typedef enum dma_channel {
+    DMA_CH1 = 1,                /**< Channel 1 */
+    DMA_CH2 = 2,                /**< Channel 2 */
+    DMA_CH3 = 3,                /**< Channel 3 */
+    DMA_CH4 = 4,                /**< Channel 4 */
+    DMA_CH5 = 5,                /**< Channel 5 */
+    DMA_CH6 = 6,                /**< Channel 6 */
+    DMA_CH7 = 7,                /**< Channel 7 */
+} dma_channel;
+
+void dma_setup_transfer(struct dma_dev *dev,
+                        dma_channel     channel,
+                        __io void      *peripheral_address,
+                        dma_xfer_size   peripheral_size,
+                        __io void      *memory_address,
+                        dma_xfer_size   memory_size,
+                        uint32          mode);
+
+void dma_set_num_transfers(struct dma_dev *dev,
+                           dma_channel channel,
+                           uint16 num_transfers);
+
+/** DMA transfer priority. */
+typedef enum dma_priority {
+    DMA_PRIORITY_LOW       = DMA_CCR_PL_LOW,      /**< Low priority */
+    DMA_PRIORITY_MEDIUM    = DMA_CCR_PL_MEDIUM,   /**< Medium priority */
+    DMA_PRIORITY_HIGH      = DMA_CCR_PL_HIGH,     /**< High priority */
+    DMA_PRIORITY_VERY_HIGH = DMA_CCR_PL_VERY_HIGH /**< Very high priority */
+} dma_priority;
+
+void dma_set_priority(struct dma_dev *dev,
+                      dma_channel channel,
+                      dma_priority priority);
+
+void dma_attach_interrupt(struct dma_dev *dev,
+                          dma_channel channel,
+                          void (*handler)(void));
+void dma_detach_interrupt(struct dma_dev *dev, dma_channel channel);
+
+/**
+ * Encodes the reason why a DMA interrupt was called.
+ * @see dma_get_irq_cause()
+ */
+typedef enum dma_irq_cause {
+    DMA_TRANSFER_COMPLETE,      /**< Transfer is complete. */
+    DMA_TRANSFER_HALF_COMPLETE, /**< Transfer is half complete. */
+    DMA_TRANSFER_ERROR,         /**< Error occurred during transfer. */
+} dma_irq_cause;
+
+dma_irq_cause dma_get_irq_cause(struct dma_dev *dev, dma_channel channel);
+
+void dma_enable(struct dma_dev *dev, dma_channel channel);
+void dma_disable(struct dma_dev *dev, dma_channel channel);
+
+void dma_set_mem_addr(struct dma_dev *dev,
+                      dma_channel channel,
+                      __io void *address);
+void dma_set_per_addr(struct dma_dev *dev,
+                      dma_channel channel,
+                      __io void *address);
+
+/**
+ * @brief DMA channel register map type.
+ *
+ * Provides access to an individual channel's registers.
+ */
+typedef struct dma_channel_reg_map {
+    __io uint32 CCR;           /**< Channel configuration register */
+    __io uint32 CNDTR;         /**< Channel number of data register */
+    __io uint32 CPAR;          /**< Channel peripheral address register */
+    __io uint32 CMAR;          /**< Channel memory address register */
+} dma_channel_reg_map;
+
+#define DMA_CHANNEL_NREGS 5
+
+/**
+ * @brief Obtain a pointer to an individual DMA channel's registers.
+ *
+ * For example, dma_channel_regs(DMA1, DMA_CH1)->CCR is DMA1_BASE->CCR1.
+ *
+ * @param dev DMA device
+ * @param channel DMA channel whose channel register map to obtain.
+ */
+static inline dma_channel_reg_map* dma_channel_regs(struct dma_dev *dev,
+                                                    dma_channel channel) {
+    __io uint32 *ccr1 = &_dma_dev_regs(dev)->CCR1;
+    return (dma_channel_reg_map*)(ccr1 + DMA_CHANNEL_NREGS * (channel - 1));
+}
+
+/**
+ * @brief Check if a DMA channel is enabled
+ * @param dev DMA device
+ * @param channel Channel whose enabled bit to check.
+ */
+static inline uint8 dma_is_channel_enabled(struct dma_dev *dev,
+                                           dma_channel channel) {
+    return (uint8)(dma_channel_regs(dev, channel)->CCR & DMA_CCR_EN);
+}
+
+/**
+ * @brief Get the ISR status bits for a DMA channel.
+ *
+ * The bits are returned right-aligned, in the following order:
+ * transfer error flag, half-transfer flag, transfer complete flag,
+ * global interrupt flag.
+ *
+ * If you're attempting to figure out why a DMA interrupt fired; you
+ * may find dma_get_irq_cause() more convenient.
+ *
+ * @param dev DMA device
+ * @param channel Channel whose ISR bits to return.
+ * @see dma_get_irq_cause().
+ */
+static inline uint8 dma_get_isr_bits(struct dma_dev *dev,
+                                     dma_channel channel) {
+    uint8 shift = (channel - 1) * 4;
+    return (_dma_dev_regs(dev)->ISR >> shift) & 0xF;
+}
+
+/**
+ * @brief Clear the ISR status bits for a given DMA channel.
+ *
+ * If you're attempting to clean up after yourself in a DMA interrupt,
+ * you may find dma_get_irq_cause() more convenient.
+ *
+ * @param dev DMA device
+ * @param channel Channel whose ISR bits to clear.
+ * @see dma_get_irq_cause()
+ */
+static inline void dma_clear_isr_bits(struct dma_dev *dev,
+                                      dma_channel channel) {
+    _dma_dev_regs(dev)->IFCR = (1U << (4 * (channel - 1)));
+}
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif
diff --git a/libmaple/stm32f1/rules.mk b/libmaple/stm32f1/rules.mk
index 52ceea6..b67f446 100644
--- a/libmaple/stm32f1/rules.mk
+++ b/libmaple/stm32f1/rules.mk
@@ -13,6 +13,7 @@ sSRCS_$(d) += vector_table_performance.S
 
 cSRCS_$(d) := adc.c
 cSRCS_$(d) += bkp.c
+cSRCS_$(d) += dma.c
 cSRCS_$(d) += fsmc.c
 cSRCS_$(d) += gpio.c
 cSRCS_$(d) += rcc.c