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gex-core/units/spi/_spi_api.c

103 lines
2.8 KiB

//
// Created by MightyPork on 2018/02/03.
//
#include "platform.h"
#include "unit_base.h"
#include "unit_spi.h"
#define SPI_INTERNAL
#include "_spi_internal.h"
static error_t spi_wait_until_flag(struct priv *priv, uint32_t flag, bool stop_state)
{
uint32_t t_start = HAL_GetTick();
while (((priv->periph->SR & flag) != 0) != stop_state) {
if (HAL_GetTick() - t_start > 10) {
return E_HW_TIMEOUT;
}
}
return E_SUCCESS;
}
/**
* Perform a low level SPI transfer
*
* @param priv - private object of the SPI unit
* @param request - request buffer
* @param response - response buffer
* @param req_len - request len
* @param resp_skip - response skip bytes
* @param resp_len - response len
* @return success
*/
static error_t xfer_do(struct priv *priv, const uint8_t *request,
uint8_t *response,
uint32_t req_len,
uint32_t resp_skip,
uint32_t resp_len)
{
// TODO this is slow, use DMA
if (response == NULL) resp_len = 0;
// avoid skip causing stretch beyond tx window if nothing is to be read back
if (resp_len == 0) resp_skip = 0;
// in tx only mode, return zeros
if (priv->tx_only && resp_len>0) {
memset(response, 0, resp_len);
}
uint8_t tb;
uint32_t end = MAX(req_len, resp_len + resp_skip);
for (uint32_t i = 0; i < end; i++) {
if (i < req_len) tb = *request++;
else tb = 0;
TRY(spi_wait_until_flag(priv, SPI_SR_TXE, true));
LL_SPI_TransmitData8(priv->periph, tb);
if (!priv->tx_only) {
TRY(spi_wait_until_flag(priv, SPI_SR_RXNE, true));
uint8_t rb = LL_SPI_ReceiveData8(priv->periph);
if (resp_skip > 0) resp_skip--;
else if (resp_len > 0) {
resp_len--;
*response++ = rb;
}
}
}
return E_SUCCESS;
}
error_t UU_SPI_Multicast(Unit *unit, uint16_t slaves,
const uint8_t *request, uint32_t req_len)
{
struct priv *priv= unit->data;
uint16_t mask = pinmask_spread(slaves, priv->ssn_pins);
priv->ssn_port->BRR = mask;
{
TRY(xfer_do(priv, request, NULL, req_len, 0, 0));
}
priv->ssn_port->BSRR = mask;
return E_SUCCESS;
}
error_t UU_SPI_Write(Unit *unit, uint8_t slave_num,
const uint8_t *request, uint8_t *response,
uint32_t req_len, uint32_t resp_skip, uint32_t resp_len)
{
struct priv *priv= unit->data;
uint16_t mask = pinmask_spread((uint16_t) (1 << slave_num), priv->ssn_pins);
priv->ssn_port->BRR = mask;
{
TRY(xfer_do(priv, request, response, req_len, resp_len, resp_skip));
}
priv->ssn_port->BSRR = mask;
return E_SUCCESS;
}