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/* libhw/rp2040_dma.h - Utilities for using DMA on the RP2040 (replaces <hardware/dma.h>)
*
* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (C) 2025 Luke T. Shumaker <lukeshu@lukeshu.com>
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#ifndef _LIBHW_RP2040_DMA_H_
#define _LIBHW_RP2040_DMA_H_
#include <assert.h>
#include <stdint.h> /* for uint32_t */
#include <hardware/regs/dreq.h> /* for DREQ_* for use with DMA_CTRL_TREQ_SEL() */
#include <hardware/structs/dma.h> /* for dma_hw, dma_channel_hw_t, DMA_NUM_CHANNELS */
#include <libmisc/macro.h> /* for LM_FLOORLOG2() */
/* Borrowed from <hardware/dma.h> *********************************************/
static inline dma_channel_hw_t *dma_channel_hw_addr(uint channel) {
assert(channel < NUM_DMA_CHANNELS);
return &dma_hw->ch[channel];
}
enum dma_channel_transfer_size {
DMA_SIZE_8 = 0, ///< Byte transfer (8 bits)
DMA_SIZE_16 = 1, ///< Half word transfer (16 bits)
DMA_SIZE_32 = 2 ///< Word transfer (32 bits)
};
static inline bool dma_channel_is_busy(uint channel) {
assert(channel < NUM_DMA_CHANNELS);
return dma_hw->ch[channel].al1_ctrl & DMA_CH0_CTRL_TRIG_BUSY_BITS;
}
/* Our own code ***************************************************************/
#define DMA_CTRL_ENABLE (1<<0)
#define DMA_CTRL_HI_PRIO (1<<1)
#define DMA_CTRL_DATA_SIZE(sz) ((sz)<<2)
#define DMA_CTRL_INCR_READ (1<<4)
#define DMA_CTRL_INCR_WRITE (1<<5)
#define _DMA_CTRL_RING_BITS(b) ((b)<<6)
#define _DMA_CTRL_RING_RD (0)
#define _DMA_CTRL_RING_WR (1<<10)
#define DMA_CTRL_RING(rdwr, bits) (_DMA_CTRL_RING_##rdwr | _DMA_CTRL_RING_BITS(bits))
#define DMA_CTRL_CHAIN_TO(ch) ((ch)<<11)
#define DMA_CTRL_TREQ_SEL(dreq) ((dreq)<<15)
#define DMA_CTRL_IRQ_QUIET (1<<21)
#define DMA_CTRL_BSWAP (1<<22)
#define DMA_CTRL_SNIFF_EN (1<<23)
/* | elem | val | name */
#define READ_ADDR /*|*/volatile const void/*|*/ * /*|*/read_addr
#define WRITE_ADDR /*|*/volatile void/*|*/ * /*|*/write_addr
#define TRANS_COUNT /*|*/ /*|*/uint32_t/*|*/trans_count
#define CTRL /*|*/ /*|*/uint32_t/*|*/ctrl
/* { +0x0 ; +0x4 ; +0x8 ; +0xC (Trigger) */
struct dma_alias0 { READ_ADDR ; WRITE_ADDR ; TRANS_COUNT ; CTRL ; };
struct dma_alias1 { CTRL ; READ_ADDR ; WRITE_ADDR ; TRANS_COUNT ; };
struct dma_alias2 { CTRL ; TRANS_COUNT ; READ_ADDR ; WRITE_ADDR ; };
struct dma_alias3 { CTRL ; WRITE_ADDR ; TRANS_COUNT ; READ_ADDR ; };
struct dma_alias0_short2 { TRANS_COUNT ; CTRL ; };
struct dma_alias1_short2 { WRITE_ADDR ; TRANS_COUNT ; };
struct dma_alias2_short2 { READ_ADDR ; WRITE_ADDR ; };
struct dma_alias3_short2 { TRANS_COUNT ; READ_ADDR ; };
struct dma_alias0_short3 { CTRL ; };
struct dma_alias1_short3 { TRANS_COUNT ; };
struct dma_alias2_short3 { WRITE_ADDR ; };
struct dma_alias3_short3 { READ_ADDR ; };
#undef CTRL
#undef TRANS_COUNT
#undef WRITE_ADDR
#undef READ_ADDR
#define DMA_CHAN_ADDR(CH, TYP) ((TYP *volatile)_Generic((TYP){}, \
struct dma_alias0: &dma_channel_hw_addr(CH)->read_addr, \
struct dma_alias1: &dma_channel_hw_addr(CH)->al1_ctrl, \
struct dma_alias2: &dma_channel_hw_addr(CH)->al2_ctrl, \
struct dma_alias3: &dma_channel_hw_addr(CH)->al3_ctrl, \
struct dma_alias0_short2: &dma_channel_hw_addr(CH)->transfer_count, \
struct dma_alias1_short2: &dma_channel_hw_addr(CH)->al1_write_addr, \
struct dma_alias2_short2: &dma_channel_hw_addr(CH)->al2_read_addr, \
struct dma_alias3_short2: &dma_channel_hw_addr(CH)->al3_transfer_count, \
struct dma_alias0_short3: &dma_channel_hw_addr(CH)->ctrl_trig, \
struct dma_alias1_short3: &dma_channel_hw_addr(CH)->al1_transfer_count_trig, \
struct dma_alias2_short3: &dma_channel_hw_addr(CH)->al2_write_addr_trig, \
struct dma_alias3_short3: &dma_channel_hw_addr(CH)->al3_read_addr_trig))
#define DMA_CHAN_WR_TRANS_COUNT(TYP) \
(sizeof(TYP)/4)
#define DMA_CHAN_WR_CTRL(TYP) ( DMA_CTRL_DATA_SIZE(DMA_SIZE_32) \
| DMA_CTRL_INCR_WRITE \
| DMA_CTRL_RING(WR, LM_FLOORLOG2(sizeof(TYP))) \
)
#define DMA_NONTRIGGER(CH, FIELD) (DMA_CHAN_ADDR(CH, _DMA_NONTRIGGER_##FIELD)->FIELD)
#define _DMA_NONTRIGGER_read_addr struct dma_alias0
#define _DMA_NONTRIGGER_write_addr struct dma_alias0
#define _DMA_NONTRIGGER_trans_count struct dma_alias0
#define _DMA_NONTRIGGER_ctrl struct dma_alias1
#define DMA_TRIGGER(CH, FIELD) (DMA_CHAN_ADDR(CH, _DMA_TRIGGER_##FIELD)->FIELD)
#define _DMA_TRIGGER_read_addr struct dma_alias3
#define _DMA_TRIGGER_write_addr struct dma_alias2
#define _DMA_TRIGGER_trans_count struct dma_alias1
#define _DMA_TRIGGER_ctrl struct dma_alias0
#endif /* _LIBHW_RP2040_DMA_H_ */
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