Update SPI driver

stm-firmware/include/stm-periph/spi.h

@@ -21,4 +21,42 @@
 #ifndef __SPI_H__
 #define __SPI_H__
 
+#include <stm32/stm32f4xx.h>
+#include <stdbool.h>
+
+enum stm_spi_prescaler {
+	SPI_PRSC_DIV2 = 0,
+	SPI_PRSC_DIV4 = 1,
+	SPI_PRSC_DIV8 = 2,
+	SPI_PRSC_DIV16 = 3,
+	SPI_PRSC_DIV32 = 4,
+	SPI_PRSC_DIV64 = 5,
+	SPI_PRSC_DIV128 = 6,
+	SPI_PRSC_DIV256 = 7,
+};
+
+struct stm_spi_settings {
+	void (*cs_activate)(void);
+	void (*cs_deactivate)(void);
+	bool cpol;
+	bool cpha;
+	bool master;
+	bool msb_first;
+	enum stm_spi_prescaler prescaler;
+};
+
+struct stm_spi_dev {
+	uint32_t magic;
+	SPI_TypeDef *spi_regs;
+	struct stm_spi_settings settings;
+};
+
+typedef void * stm_spi_handle;
+
+stm_spi_handle spi_init(struct stm_spi_dev *spi_dev_struct, SPI_TypeDef *spi_regs, const struct stm_spi_settings *settings);
+
+void spi_deinit(stm_spi_handle handle);
+
+int spi_transfer(stm_spi_handle handle, const uint8_t *tx, uint8_t *rx, uint32_t count, bool handle_cs);
+
 #endif /* __SPI_H__ */

stm-firmware/stm-periph/spi.c

@@ -19,4 +19,146 @@
 */
 
 #include <stm-periph/spi.h>
-#include <stm32/stm32f4xx.h>
+#include <helper-macros/helper-macros.h>
+#include <stm-periph/rcc-manager.h>
+#include <string.h>
+
+#define STM_SPI_DEV_MAGIC 0x5A678F5CUL
+
+struct spi_rcc_lookup_pair {
+	SPI_TypeDef *spi_regs;
+	volatile uint32_t *rcc_reg;
+	uint32_t bit_no;
+};
+
+const struct spi_rcc_lookup_pair rcc_lookup[3] = {
+	{SPI1, &RCC->APB2ENR, BITMASK_TO_BITNO(RCC_APB2ENR_SPI1EN)},
+	{SPI2, &RCC->APB1ENR, BITMASK_TO_BITNO(RCC_APB1ENR_SPI2EN)},
+	{SPI3, &RCC->APB1ENR, BITMASK_TO_BITNO(RCC_APB1ENR_SPI3EN)},
+};
+
+static const struct spi_rcc_lookup_pair *spi_find_rcc_reg_and_bit(SPI_TypeDef *spi_regs)
+{
+	uint32_t i;
+	const struct spi_rcc_lookup_pair *ret = NULL;
+
+	for (i = 0; i < COUNT_OF(rcc_lookup); i++) {
+		if (rcc_lookup[i].spi_regs == spi_regs) {
+			ret = &rcc_lookup[i];
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static struct stm_spi_dev *spi_handle_to_struct(stm_spi_handle handle)
+{
+	struct stm_spi_dev *dev;
+
+	dev = (struct stm_spi_dev *)handle;
+	if (dev == NULL)
+		return NULL;
+	if (dev->magic != STM_SPI_DEV_MAGIC)
+		return NULL;
+
+	return dev;
+}
+
+stm_spi_handle spi_init(struct stm_spi_dev *spi_dev_struct, SPI_TypeDef *spi_regs, const struct stm_spi_settings *settings)
+{
+	stm_spi_handle ret_handle = NULL;
+	uint32_t reg_val;
+	const struct spi_rcc_lookup_pair *rcc_pair;
+
+	if (!spi_dev_struct || !spi_regs || !settings)
+		goto exit;
+	if (!settings->cs_activate || !settings->cs_deactivate)
+		goto exit;
+
+	rcc_pair = spi_find_rcc_reg_and_bit(spi_regs);
+	if (!rcc_pair)
+		goto exit;
+
+	memcpy(&spi_dev_struct->settings, settings, sizeof(struct stm_spi_settings));
+	spi_dev_struct->spi_regs = spi_regs;
+
+	rcc_manager_enable_clock(rcc_pair->rcc_reg, rcc_pair->bit_no);
+
+	reg_val = 0;
+	if (settings->cpha)
+		reg_val |= SPI_CR1_CPHA;
+	if (settings->cpol)
+		reg_val |= SPI_CR1_CPOL;
+	if (settings->master)
+		reg_val |= SPI_CR1_MSTR;
+	reg_val |= (settings->prescaler & 0x7) << 3;
+	reg_val |= SPI_CR1_SPE | SPI_CR1_SSI | SPI_CR1_SSM;
+
+	if (!settings->msb_first)
+		reg_val |= SPI_CR1_LSBFIRST;
+
+	spi_regs->CR2 = 0UL;
+	spi_regs->CR1 = reg_val;
+
+	ret_handle = spi_dev_struct;
+
+	spi_dev_struct->settings.cs_deactivate();
+
+exit:
+	return ret_handle;
+}
+
+void spi_deinit(stm_spi_handle handle)
+{
+	const struct spi_rcc_lookup_pair *rcc_pair;
+	struct stm_spi_dev *dev;
+
+	dev = spi_handle_to_struct(handle);
+	if (!dev)
+		return;
+
+	dev->spi_regs->CR1 = 0;
+	dev->spi_regs->CR2 = 0;
+
+	rcc_pair = spi_find_rcc_reg_and_bit(dev->spi_regs);
+	if (!rcc_pair)
+		rcc_manager_disable_clock(rcc_pair->rcc_reg, rcc_pair->bit_no);
+}
+
+static uint8_t transfer_byte(uint8_t byte, struct stm_spi_dev *dev)
+{
+	while (dev->spi_regs->SR & SPI_SR_BSY);
+	dev->spi_regs->DR = (uint16_t)byte;
+	__DSB();
+	while((dev->spi_regs->SR & SPI_SR_BSY) || !(dev->spi_regs->SR & SPI_SR_TXE));
+
+	return (uint8_t)dev->spi_regs->DR;
+}
+
+int spi_transfer(stm_spi_handle handle, const uint8_t *tx, uint8_t *rx, uint32_t count, bool handle_cs)
+{
+	struct stm_spi_dev *dev;
+	uint8_t tx_byte;
+	uint8_t rx_byte;
+	uint32_t idx;
+
+	dev = spi_handle_to_struct(handle);
+	if (!dev)
+		return -1001;
+
+	if (handle_cs)
+		dev->settings.cs_activate();
+
+	for (idx = 0; idx < count; idx++) {
+		tx_byte = (tx ? tx[idx] : 0U);
+		rx_byte = transfer_byte(tx_byte, dev);
+		if (rx)
+			rx[idx] = rx_byte;
+	}
+
+	if (handle_cs)
+		dev->settings.cs_deactivate();
+
+	return 0;
+}