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* Copyright (c) 2018 SiFive Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
#define LOG_LEVEL CONFIG_SPI_LOG_LEVEL
#include <logging/log.h>
LOG_MODULE_REGISTER(spi_sifive);
#include "spi_sifive.h"
#include <stdbool.h>
/* Helper Functions */
static inline void sys_set_mask(mem_addr_t addr, u32_t mask, u32_t value)
{
u32_t temp = sys_read32(addr);
temp &= ~(mask);
temp |= value;
sys_write32(temp, addr);
}
int spi_config(struct device *dev, u32_t frequency, u16_t operation)
{
u32_t div;
u32_t fmt_len;
if (SPI_OP_MODE_GET(operation) != SPI_OP_MODE_MASTER) {
return -ENOTSUP;
}
if (operation & SPI_MODE_LOOP) {
return -ENOTSUP;
}
/* Set the SPI frequency */
div = (SPI_CFG(dev)->f_sys / (frequency * 2U)) - 1;
sys_write32((SF_SCKDIV_DIV_MASK & div), SPI_REG(dev, REG_SCKDIV));
/* Set the polarity */
if (operation & SPI_MODE_CPOL) {
/* If CPOL is set, then SCK idles at logical 1 */
sys_set_bit(SPI_REG(dev, REG_SCKMODE), SF_SCKMODE_POL);
} else {
/* SCK idles at logical 0 */
sys_clear_bit(SPI_REG(dev, REG_SCKMODE), SF_SCKMODE_POL);
}
/* Set the phase */
if (operation & SPI_MODE_CPHA) {
/*
* If CPHA is set, then data is sampled
* on the trailing SCK edge
*/
sys_set_bit(SPI_REG(dev, REG_SCKMODE), SF_SCKMODE_PHA);
} else {
/* Data is sampled on the leading SCK edge */
sys_clear_bit(SPI_REG(dev, REG_SCKMODE), SF_SCKMODE_PHA);
}
/* Get the frame length */
fmt_len = SPI_WORD_SIZE_GET(operation);
if (fmt_len > SF_FMT_LEN_MASK) {
return -ENOTSUP;
}
/* Set the frame length */
fmt_len = fmt_len << SF_FMT_LEN;
fmt_len &= SF_FMT_LEN_MASK;
sys_set_mask(SPI_REG(dev, REG_FMT), SF_FMT_LEN_MASK, fmt_len);
if ((operation & SPI_LINES_MASK) != SPI_LINES_SINGLE) {
return -ENOTSUP;
}
/* Set single line operation */
sys_set_mask(SPI_REG(dev, REG_FMT),
SF_FMT_PROTO_MASK,
SF_FMT_PROTO_SINGLE);
/* Set the endianness */
if (operation & SPI_TRANSFER_LSB) {
sys_set_bit(SPI_REG(dev, REG_FMT), SF_FMT_ENDIAN);
} else {
sys_clear_bit(SPI_REG(dev, REG_FMT), SF_FMT_ENDIAN);
}
return 0;
}
void spi_sifive_send(struct device *dev, u16_t frame)
{
while (SPI_REG(dev, REG_TXDATA) & SF_TXDATA_FULL) {
}
sys_write32((u32_t) frame, SPI_REG(dev, REG_TXDATA));
}
u16_t spi_sifive_recv(struct device *dev)
{
u32_t val;
while ((val = sys_read32(SPI_REG(dev, REG_RXDATA))) & SF_RXDATA_EMPTY) {
}
return (u16_t) val;
}
void spi_sifive_xfer(struct device *dev, const bool hw_cs_control)
{
struct spi_context *ctx = &SPI_DATA(dev)->ctx;
u32_t send_len = spi_context_longest_current_buf(ctx);
for (u32_t i = 0; i < send_len; i++) {
/* Send a frame */
if (i < ctx->tx_len) {
spi_sifive_send(dev, (u16_t) (ctx->tx_buf)[i]);
} else {
/* Send dummy bytes */
spi_sifive_send(dev, 0);
}
/* Receive a frame */
if (i < ctx->rx_len) {
ctx->rx_buf[i] = (u8_t) spi_sifive_recv(dev);
} else {
/* Discard returned value */
spi_sifive_recv(dev);
}
}
/* Deassert the CS line */
if (!hw_cs_control) {
spi_context_cs_control(&SPI_DATA(dev)->ctx, false);
} else {
sys_write32(SF_CSMODE_OFF, SPI_REG(dev, REG_CSMODE));
}
spi_context_complete(ctx, 0);
}
/* API Functions */
int spi_sifive_init(struct device *dev)
{
/* Disable SPI Flash mode */
sys_clear_bit(SPI_REG(dev, REG_FCTRL), SF_FCTRL_EN);
/* Make sure the context is unlocked */
spi_context_unlock_unconditionally(&SPI_DATA(dev)->ctx);
return 0;
}
int spi_sifive_transceive(struct device *dev,
const struct spi_config *config,
const struct spi_buf_set *tx_bufs,
const struct spi_buf_set *rx_bufs)
{
int rc = 0;
bool hw_cs_control = false;
/* Lock the SPI Context */
spi_context_lock(&SPI_DATA(dev)->ctx, false, NULL);
/* Configure the SPI bus */
SPI_DATA(dev)->ctx.config = config;
/*
* If the chip select configuration is not present, we'll ask the
* SPI peripheral itself to control the CS line
*/
if (config->cs == NULL) {
hw_cs_control = true;
}
if (!hw_cs_control) {
/*
* If the user has requested manual GPIO control, ask the
* context for control and disable HW control
*/
spi_context_cs_configure(&SPI_DATA(dev)->ctx);
sys_write32(SF_CSMODE_OFF, SPI_REG(dev, REG_CSMODE));
} else {
/*
* Tell the hardware to control the requested CS pin.
* NOTE:
* For the SPI peripheral, the pin number is not the
* GPIO pin, but the index into the list of available
* CS lines for the SPI peripheral.
*/
sys_write32(config->slave, SPI_REG(dev, REG_CSID));
sys_write32(SF_CSMODE_OFF, SPI_REG(dev, REG_CSMODE));
}
rc = spi_config(dev, config->frequency, config->operation);
if (rc < 0) {
spi_context_release(&SPI_DATA(dev)->ctx, rc);
return rc;
}
spi_context_buffers_setup(&SPI_DATA(dev)->ctx, tx_bufs, rx_bufs, 1);
/* Assert the CS line */
if (!hw_cs_control) {
spi_context_cs_control(&SPI_DATA(dev)->ctx, true);
} else {
sys_write32(SF_CSMODE_HOLD, SPI_REG(dev, REG_CSMODE));
}
/* Perform transfer */
spi_sifive_xfer(dev, hw_cs_control);
rc = spi_context_wait_for_completion(&SPI_DATA(dev)->ctx);
spi_context_release(&SPI_DATA(dev)->ctx, rc);
return rc;
}
int spi_sifive_release(struct device *dev, const struct spi_config *config)
{
spi_context_unlock_unconditionally(&SPI_DATA(dev)->ctx);
return 0;
}
/* Device Instantiation */
static struct spi_driver_api spi_sifive_api = {
.transceive = spi_sifive_transceive,
.release = spi_sifive_release,
};
#define SPI_INIT(n) \
static struct spi_sifive_data spi_sifive_data_##n = { \
SPI_CONTEXT_INIT_LOCK(spi_sifive_data_##n, ctx), \
SPI_CONTEXT_INIT_SYNC(spi_sifive_data_##n, ctx), \
}; \
static struct spi_sifive_cfg spi_sifive_cfg_##n = { \
.base = DT_INST_##n##_SIFIVE_SPI0_CONTROL_BASE_ADDRESS, \
.f_sys = DT_INST_##n##_SIFIVE_SPI0_CLOCK_FREQUENCY, \
}; \
DEVICE_AND_API_INIT(spi_##n, \
DT_INST_##n##_SIFIVE_SPI0_LABEL, \
spi_sifive_init, \
&spi_sifive_data_##n, \
&spi_sifive_cfg_##n, \
POST_KERNEL, \
CONFIG_SPI_INIT_PRIORITY, \
&spi_sifive_api)
#ifndef CONFIG_SIFIVE_SPI_0_ROM
#ifdef DT_INST_0_SIFIVE_SPI0_LABEL
SPI_INIT(0);
#endif /* DT_INST_0_SIFIVE_SPI0_LABEL */
#endif /* !DT_SIFIVE_SPI0_0_ROM */
#ifdef DT_INST_1_SIFIVE_SPI0_LABEL
SPI_INIT(1);
#endif /* DT_INST_1_SIFIVE_SPI0_LABEL */
#ifdef DT_INST_2_SIFIVE_SPI0_LABEL
SPI_INIT(2);
#endif /* DT_INST_2_SIFIVE_SPI0_LABEL */
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