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xtensa/esp32: Improve SPI polling to use the entire HW buffer

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This commit is contained in:
Gustavo Henrique Nihei 2021-03-26 21:27:06 -03:00 committed by Xiang Xiao
parent a41d37cffd
commit 4d4250fcca
1 changed files with 98 additions and 28 deletions
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126
arch/xtensa/src/esp32/esp32_spi.c
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@ -28,14 +28,9 @@
#include <sys/types.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <stdlib.h>
#include <time.h>
#include <nuttx/arch.h>
@ -86,6 +81,14 @@
#define VALUE_MASK(_val, _field) ((_val & (_field##_V)) << (_field##_S))
/* SPI Maximum buffer size in bytes */
#define SPI_MAX_BUF_SIZE (64)
#ifndef MIN
# define MIN(a, b) (((a) < (b)) ? (a) : (b))
#endif
/****************************************************************************
* Private Types
****************************************************************************/
@ -1021,38 +1024,105 @@ static void esp32_spi_poll_exchange(FAR struct esp32_spi_priv_s *priv,
FAR void *rxbuffer,
size_t nwords)
{
int i;
const uintptr_t spi_user_reg = SPI_USER_REG(priv->config->id);
const uintptr_t spi_w0_reg = SPI_W0_REG(priv->config->id);
const uintptr_t spi_cmd_reg = SPI_CMD_REG(priv->config->id);
const uintptr_t spi_miso_dlen_reg = SPI_MISO_DLEN_REG(priv->config->id);
const uintptr_t spi_mosi_dlen_reg = SPI_MOSI_DLEN_REG(priv->config->id);
const uint32_t total_bytes = nwords * (priv->nbits / 8);
uintptr_t bytes_remaining = total_bytes;
uint8_t *tp = (uint8_t *)txbuffer;
uint8_t *rp = (uint8_t *)rxbuffer;
for (i = 0 ; i < nwords; i++)
while (bytes_remaining != 0)
{
uint32_t w_wd = 0xffff;
uint32_t r_wd;
/* Initialize data_buf_reg with the address of the first data buffer
* register (W0).
*/
if (txbuffer != NULL)
uintptr_t data_buf_reg = spi_w0_reg;
uint32_t transfer_size = MIN(SPI_MAX_BUF_SIZE, bytes_remaining);
/* Write data words to data buffer registers.
* SPI peripheral contains 16 registers (W0 - W15).
*/
for (int i = 0 ; i < transfer_size; i += sizeof(uint32_t))
{
if (priv->nbits == 8)
uint32_t w_wd = UINT32_MAX;
if (tp != NULL)
{
w_wd = ((uint8_t *)txbuffer)[i];
memcpy(&w_wd, tp, sizeof(uint32_t));
tp += sizeof(uintptr_t);
}
else
putreg32(w_wd, data_buf_reg);
spiinfo("send=0x%" PRIx32 " data_reg=0x%" PRIx32 "\n",
w_wd, data_buf_reg);
/* Update data_buf_reg to point to the next data buffer register. */
data_buf_reg += sizeof(uintptr_t);
}
esp32_spi_set_regbits(spi_user_reg, SPI_USR_MOSI_M);
if (rp == NULL)
{
esp32_spi_reset_regbits(spi_user_reg, SPI_USR_MISO_M);
}
else
{
esp32_spi_set_regbits(spi_user_reg, SPI_USR_MISO_M);
}
putreg32((transfer_size * 8) - 1, spi_mosi_dlen_reg);
putreg32((transfer_size * 8) - 1, spi_miso_dlen_reg);
/* Trigger start of user-defined transaction for master. */
esp32_spi_set_regbits(spi_cmd_reg, SPI_USR_M);
/* Wait for the user-defined transaction to finish. */
while ((getreg32(spi_cmd_reg) & SPI_USR_M) != 0)
{
;
}
if (rp != NULL)
{
/* Set data_buf_reg with the address of the first data buffer
* register (W0).
*/
data_buf_reg = spi_w0_reg;
/* Read received data words from SPI data buffer registers. */
for (int i = 0 ; i < transfer_size; i += sizeof(uint32_t))
{
w_wd = ((uint16_t *)txbuffer)[i];
uint32_t r_wd = getreg32(data_buf_reg);
spiinfo("recv=0x%" PRIx32 " data_reg=0x%" PRIx32 "\n",
r_wd, data_buf_reg);
memcpy(rp, &r_wd, sizeof(uint32_t));
rp += sizeof(uintptr_t);
/* Update data_buf_reg to point to the next data buffer
* register.
*/
data_buf_reg += sizeof(uintptr_t);
}
}
r_wd = esp32_spi_poll_send(priv, w_wd);
if (rxbuffer != NULL)
{
if (priv->nbits == 8)
{
((uint8_t *)rxbuffer)[i] = r_wd;
}
else
{
((uint16_t *)rxbuffer)[i] = r_wd;
}
}
bytes_remaining -= transfer_size;
}
}