Handling of SPI hardware for STM32. More...

#include <libopencm3/cm3/nvic.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/exti.h>
#include <libopencm3/stm32/spi.h>
#include <libopencm3/stm32/dma.h>
#include "mcu_periph/spi.h"
#include "mcu_periph/gpio.h"
#include <BOARD_CONFIG>

Include dependency graph for spi_arch.c:

Go to the source code of this file.

Data Structures
struct	locm3_spi_comm
	Libopencm3 specifc communication parameters for a SPI peripheral in master mode. More...

struct	spi_periph_dma
	This structure keeps track of specific config for each SPI bus, which allows for more code reuse. More...

Macros
#define	NVIC_SPI_IRQ_PRIO 0

Functions
static void	spi_start_dma_transaction (struct spi_periph periph, struct spi_transaction trans)
	Start a new transaction with DMA. More...

static void	spi_next_transaction (struct spi_periph *periph)
	start next transaction if there is one in the queue More...

static void	spi_configure_dma (uint32_t dma, uint32_t rcc_dma, uint8_t chan, uint32_t periph_addr, uint32_t buf_addr, uint16_t len, enum SPIDataSizeSelect dss, bool increment)

static void	process_rx_dma_interrupt (struct spi_periph *periph)
	Processing done after rx completes. More...

static void	process_tx_dma_interrupt (struct spi_periph *periph)
	Processing done after tx completes. More...

static void	spi_arch_int_enable (struct spi_periph *spi)
	Enable DMA channel interrupts. More...

static void	spi_arch_int_disable (struct spi_periph *spi)
	Disable DMA channel interrupts. More...

static void	SpiSlaveUnselect (uint8_t slave)

static void	SpiSlaveSelect (uint8_t slave)

void	spi_slave_select (uint8_t slave)
	Select a slave. More...

void	spi_slave_unselect (uint8_t slave)
	Unselect a slave. More...

void	spi_init_slaves (void)
	Initialize all used slaves and unselect them. More...

bool	spi_submit (struct spi_periph p, struct spi_transaction t)
	Submit a spi transaction. More...

bool	spi_lock (struct spi_periph *p, uint8_t slave)
	Lock the SPI fifo. More...

bool	spi_resume (struct spi_periph *p, uint8_t slave)
	Resume the SPI fifo. More...

static void	set_default_comm_config (struct locm3_spi_comm *c)

static uint8_t	get_transaction_signature (struct spi_transaction *t)

static uint8_t	get_comm_signature (struct locm3_spi_comm *c)

static void	set_comm_from_transaction (struct locm3_spi_comm c, struct spi_transaction t)
	Update SPI communication conf from generic paparazzi SPI transaction. More...

void	spi1_arch_init (void)
	Architecture dependent SPI1 initialization. More...

void	spi2_arch_init (void)
	Architecture dependent SPI2 initialization. More...

static void	process_slave_tx_dma_interrupt (struct spi_periph *periph)
	SPI_MASTER. More...

static void	process_slave_rx_dma_interrupt (struct spi_periph *periph)

static void	spi_slave_set_config (struct spi_periph periph, struct spi_transaction trans)

bool	spi_slave_register (struct spi_periph periph, struct spi_transaction trans)
	Register a spi transaction in slave mode (only one transaction can be registered). More...

Variables
static struct spi_periph_dma	spi1_dma

static struct spi_periph_dma	spi2_dma

process_rx_dma_interrupt &	spi1
	receive transferred over DMA More...

process_rx_dma_interrupt &	spi2
	receive transferred over DMA More...

Detailed Description

Handling of SPI hardware for STM32.

SPI Master code.

When a transaction is submitted:

The transaction is added to the queue if there is space, otherwise it returns false
The pending state is set
SPI Interrupts (in this case the DMA interrupts) are disabled to prevent race conditions
The slave is selected if required, then the before_cb callback is run
The spi and dma registers are set up for the specific transaction
Spi, DMA and interrupts are enabled and the transaction starts

Obviously output_length and input_length will never both be 0 at the same time. In this case, spi_submit will just return false.

For the DMA and interrupts:

If the output_len != input_len, a dummy DMA transfer is triggered for the remainder so the same amount of data is moved in and out. This simplifies keeping the clock going if output_len is greater and allows the rx dma interrupt to represent that the transaction has fully completed.
The dummy DMA transfer is initiated at the transaction setup if length is 0, otherwise after the first dma interrupt completes in the ISR directly.
The rx DMA transfer completed interrupt marks the end of a complete transaction.
The after_cb callback happens BEFORE the slave is unselected as configured.

Definition in file spi_arch.c.

Data Structure Documentation

struct locm3_spi_comm

Libopencm3 specifc communication parameters for a SPI peripheral in master mode.

Definition at line 76 of file spi_arch.c.

Data Fields
uint32_t	br	baudrate (clock divider)
uint32_t	cpha	clock phase
uint32_t	cpol	clock polarity
uint32_t	dff	data frame format 8/16 bits
uint32_t	lsbfirst	frame format lsb/msb first

struct spi_periph_dma

This structure keeps track of specific config for each SPI bus, which allows for more code reuse.

Definition at line 88 of file spi_arch.c.

Collaboration diagram for spi_periph_dma:

Data Fields
struct locm3_spi_comm	comm	current communication parameters
uint8_t	comm_sig	comm config signature used to check for changes
uint32_t	dma	DMA controller base address (DMA1 or DMA2)
uint32_t	rcc_dma	RCC DMA enable clock pin (RCC_DMA1 or RCC_DMA2)
uint8_t	rx_chan	receive DMA channel (or stream on F4) number
uint32_t	rx_chan_sel	F4 only: actual receive DMA channel number.
uint16_t	rx_dummy_buf	dummy rx buffer for receive only cases
bool	rx_extra_dummy_dma	extra rx dummy dma flag for tx_len > rx_len
uint8_t	rx_nvic_irq	receive interrupt
uint32_t	spi	SPI peripheral identifier.
uint32_t	spidr	SPI DataRegister address for DMA.
uint8_t	tx_chan	transmit DMA channel (or stream on F4) number
uint32_t	tx_chan_sel	F4 only: actual transmit DMA channel number.
uint16_t	tx_dummy_buf	dummy tx buffer for receive only cases
bool	tx_extra_dummy_dma	extra tx dummy dma flag for tx_len < rx_len
uint8_t	tx_nvic_irq	transmit interrupt

Macro Definition Documentation

#define NVIC_SPI_IRQ_PRIO 0

Definition at line 69 of file spi_arch.c.

Referenced by spi_arch_int_enable().

Function Documentation

static uint8_t get_comm_signature ( struct locm3_spi_comm * c )

static

Definition at line 342 of file spi_arch.c.

References SPICphaEdge1, SPICphaEdge2, SPICpolIdleHigh, SPICpolIdleLow, SPIDiv128, SPIDiv16, SPIDiv2, SPIDiv256, SPIDiv32, SPIDiv4, SPIDiv64, SPIDiv8, SPIDss16bit, SPIDss8bit, SPILSBFirst, and SPIMSBFirst.

Referenced by spi1_arch_init(), and spi2_arch_init().

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static uint8_t get_transaction_signature ( struct spi_transaction * t )

inlinestatic

Definition at line 336 of file spi_arch.c.

References spi_transaction::bitorder, spi_transaction::cdiv, spi_transaction::cpha, spi_transaction::cpol, and spi_transaction::dss.

Referenced by spi_slave_register(), spi_slave_set_config(), and spi_start_dma_transaction().

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void process_rx_dma_interrupt ( struct spi_periph * periph )

static

Processing done after rx completes.

Definition at line 1064 of file spi_arch.c.

References spi_transaction::after_cb, spi_periph_dma::dma, spi_transaction::dss, FALSE, spi_periph::init_struct, spi_transaction::input_length, spi_transaction::output_length, spi_periph_dma::rcc_dma, spi_periph::reg_addr, spi_periph_dma::rx_chan, spi_periph_dma::rx_chan_sel, spi_periph_dma::rx_dummy_buf, spi_periph_dma::rx_extra_dummy_dma, spi_transaction::select, spi_transaction::slave_idx, spi_configure_dma(), spi_next_transaction(), spi_periph_dma::spidr, SPISelectUnselect, SpiSlaveUnselect(), SPITransSuccess, SPIUnselect, spi_transaction::status, spi_periph::trans, and spi_periph::trans_extract_idx.

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void process_slave_rx_dma_interrupt ( struct spi_periph * periph )

static

Definition at line 1693 of file spi_arch.c.

References spi_transaction::after_cb, spi_periph_dma::dma, spi_periph::init_struct, spi_periph::reg_addr, spi_periph_dma::rx_chan, spi_arch_int_disable(), SPITransSuccess, spi_transaction::status, spi_periph::trans, and spi_periph::trans_extract_idx.

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void process_slave_tx_dma_interrupt ( struct spi_periph * periph )

static

SPI_MASTER.

Definition at line 1721 of file spi_arch.c.

References spi_periph_dma::dma, spi_periph::init_struct, spi_periph::reg_addr, and spi_periph_dma::tx_chan.

void process_tx_dma_interrupt ( struct spi_periph * periph )

static

Processing done after tx completes.

Definition at line 1139 of file spi_arch.c.

References spi_periph_dma::dma, spi_transaction::dss, FALSE, spi_periph::init_struct, spi_transaction::input_length, spi_transaction::output_length, spi_periph_dma::rcc_dma, spi_periph::reg_addr, spi_configure_dma(), spi_periph_dma::spidr, spi_periph::trans, spi_periph::trans_extract_idx, spi_periph_dma::tx_chan, spi_periph_dma::tx_chan_sel, spi_periph_dma::tx_dummy_buf, and spi_periph_dma::tx_extra_dummy_dma.

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static void set_comm_from_transaction	(	struct locm3_spi_comm *	c,
		struct spi_transaction *	t
	)

static

Update SPI communication conf from generic paparazzi SPI transaction.

Definition at line 399 of file spi_arch.c.

References spi_transaction::bitorder, locm3_spi_comm::br, spi_transaction::cdiv, locm3_spi_comm::cpha, spi_transaction::cpha, locm3_spi_comm::cpol, spi_transaction::cpol, locm3_spi_comm::dff, spi_transaction::dss, locm3_spi_comm::lsbfirst, SPICphaEdge1, SPICpolIdleLow, SPIDiv128, SPIDiv16, SPIDiv2, SPIDiv256, SPIDiv32, SPIDiv4, SPIDiv64, SPIDiv8, SPIDss8bit, and SPIMSBFirst.

Referenced by spi_slave_set_config(), and spi_start_dma_transaction().

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static void set_default_comm_config ( struct locm3_spi_comm * c )

static

Definition at line 327 of file spi_arch.c.

Referenced by spi1_arch_init(), and spi2_arch_init().

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static void spi_arch_int_disable ( struct spi_periph * spi )

static

Disable DMA channel interrupts.

Definition at line 510 of file spi_arch.c.

References spi_periph::init_struct.

Referenced by process_slave_rx_dma_interrupt(), spi_lock(), spi_resume(), and spi_submit().

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static void spi_arch_int_enable ( struct spi_periph * spi )

static

Enable DMA channel interrupts.

Todo:: fix priority levels if necessary

Definition at line 498 of file spi_arch.c.

References spi_periph::init_struct, and NVIC_SPI_IRQ_PRIO.

Referenced by spi1_arch_init(), spi2_arch_init(), spi_lock(), spi_resume(), spi_slave_register(), and spi_submit().

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static void spi_configure_dma	(	uint32_t	dma,
		uint32_t	rcc_dma,
		uint8_t	chan,
		uint32_t	periph_addr,
		uint32_t	buf_addr,
		uint16_t	len,
		enum SPIDataSizeSelect	dss,
		bool	increment
	)