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// SPI functions on STM32H7
//
// Copyright (C) 2019-2025 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include "board/io.h" // readb, writeb
#include "command.h" // shutdown
#include "gpio.h" // spi_setup
#include "internal.h" // gpio_peripheral
#include "sched.h" // sched_shutdown
#include "board/misc.h" // timer_is_before
struct spi_info {
SPI_TypeDef *spi;
uint8_t miso_pin, mosi_pin, sck_pin, function;
};
DECL_ENUMERATION("spi_bus", "spi2", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi2", "PB14,PB15,PB13");
DECL_ENUMERATION("spi_bus", "spi1", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi1", "PA6,PA7,PA5");
DECL_ENUMERATION("spi_bus", "spi1a", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi1a", "PB4,PB5,PB3");
#if !CONFIG_MACH_STM32F1
DECL_ENUMERATION("spi_bus", "spi2a", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi2a", "PC2,PC3,PB10");
#endif
#ifdef SPI3
DECL_ENUMERATION("spi_bus", "spi3a", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi3a", "PC11,PC12,PC10");
#endif
#ifdef SPI4
DECL_ENUMERATION("spi_bus", "spi4", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi4", "PE13,PE14,PE12");
#endif
#ifdef GPIOI
DECL_ENUMERATION("spi_bus", "spi2b", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi2b", "PI2,PI3,PI1");
#endif
#ifdef SPI5
DECL_ENUMERATION("spi_bus", "spi5", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi5", "PF8,PF9,PF7");
DECL_ENUMERATION("spi_bus", "spi5a", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi5a", "PH7,PF11,PH6");
#endif
#ifdef SPI6
DECL_ENUMERATION("spi_bus", "spi6", __COUNTER__);
DECL_CONSTANT_STR("BUS_PINS_spi6", "PG12,PG14,PG13");
#endif
static const struct spi_info spi_bus[] = {
{ SPI2, GPIO('B', 14), GPIO('B', 15), GPIO('B', 13), GPIO_FUNCTION(5) },
{ SPI1, GPIO('A', 6), GPIO('A', 7), GPIO('A', 5), GPIO_FUNCTION(5) },
{ SPI1, GPIO('B', 4), GPIO('B', 5), GPIO('B', 3), GPIO_FUNCTION(5) },
#if !CONFIG_MACH_STM32F1
{ SPI2, GPIO('C', 2), GPIO('C', 3), GPIO('B', 10), GPIO_FUNCTION(5) },
#endif
#ifdef SPI3
{ SPI3, GPIO('C', 11), GPIO('C', 12), GPIO('C', 10), GPIO_FUNCTION(6) },
#endif
#ifdef SPI4
{ SPI4, GPIO('E', 13), GPIO('E', 14), GPIO('E', 12), GPIO_FUNCTION(5) },
#endif
{ SPI2, GPIO('I', 2), GPIO('I', 3), GPIO('I', 1), GPIO_FUNCTION(5) },
#ifdef SPI5
{ SPI5, GPIO('F', 8), GPIO('F', 9), GPIO('F', 7), GPIO_FUNCTION(5) },
{ SPI5, GPIO('H', 7), GPIO('F', 11), GPIO('H', 6), GPIO_FUNCTION(5) },
#endif
#ifdef SPI6
{ SPI6, GPIO('G', 12), GPIO('G', 14), GPIO('G', 13), GPIO_FUNCTION(5)},
#endif
};
struct spi_config
spi_setup(uint32_t bus, uint8_t mode, uint32_t rate)
{
if (bus >= ARRAY_SIZE(spi_bus))
shutdown("Invalid spi bus");
// Enable SPI
SPI_TypeDef *spi = spi_bus[bus].spi;
if (!is_enabled_pclock((uint32_t)spi)) {
enable_pclock((uint32_t)spi);
gpio_peripheral(spi_bus[bus].miso_pin, spi_bus[bus].function, 1);
gpio_peripheral(spi_bus[bus].mosi_pin, spi_bus[bus].function, 0);
gpio_peripheral(spi_bus[bus].sck_pin, spi_bus[bus].function, 0);
}
// Calculate CR1 register
uint32_t pclk = get_pclock_frequency((uint32_t)spi);
uint32_t div = 0;
while ((pclk >> (div + 1)) > rate && div < 7)
div++;
return (struct spi_config){ .spi = spi, .div = div, .mode = mode };
}
void
spi_prepare(struct spi_config config)
{
uint32_t div = config.div;
uint32_t mode = config.mode;
SPI_TypeDef *spi = config.spi;
// Load frequency
spi->CFG1 = (div << SPI_CFG1_MBR_Pos) | (7 << SPI_CFG1_DSIZE_Pos);
// Load mode
uint32_t cfg2 = ((mode << SPI_CFG2_CPHA_Pos) | SPI_CFG2_MASTER
| SPI_CFG2_SSM | SPI_CFG2_AFCNTR | SPI_CFG2_SSOE);
uint32_t diff = spi->CFG2 ^ cfg2;
spi->CFG2 = cfg2;
uint32_t end = timer_read_time() + timer_from_us(1);
if (diff & SPI_CFG2_CPOL_Msk)
while (timer_is_before(timer_read_time(), end))
;
}
void
spi_transfer(struct spi_config config, uint8_t receive_data,
uint8_t len, uint8_t *data)
{
uint8_t rdata = 0;
uint8_t* wptr = data;
uint8_t* end = data + len;
SPI_TypeDef *spi = config.spi;
spi->CR2 = len << SPI_CR2_TSIZE_Pos;
// Enable SPI and start transfer, these MUST be set in this sequence
spi->CR1 = SPI_CR1_SSI | SPI_CR1_SPE;
spi->CR1 = SPI_CR1_SSI | SPI_CR1_CSTART | SPI_CR1_SPE;
while (data < end) {
uint32_t sr = spi->SR & (SPI_SR_TXP | SPI_SR_RXP);
if ((sr == SPI_SR_TXP) && wptr < end)
writeb((void*)&spi->TXDR, *wptr++);
if (!(sr & SPI_SR_RXP))
continue;
rdata = readb((void *)&spi->RXDR);
if (receive_data) {
*data = rdata;
}
data++;
}
while ((spi->SR & SPI_SR_EOT) == 0)
;
// Clear flags and disable SPI
spi->IFCR = 0xFFFFFFFF;
spi->CR1 = SPI_CR1_SSI;
}
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