diff options
| -rw-r--r-- | drivers/spi/spi-fsl-espi.c | 51 | ||||
| -rw-r--r-- | drivers/spi/spi-fsl-lib.h | 1 |
2 files changed, 48 insertions, 4 deletions
diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c index edb524f831a3..9ccbfbc75933 100644 --- a/drivers/spi/spi-fsl-espi.c +++ b/drivers/spi/spi-fsl-espi.c @@ -150,7 +150,8 @@ static void fsl_espi_copy_to_buf(struct spi_message *m, list_for_each_entry(t, &m->transfers, transfer_list) { if (t->tx_buf) fsl_espi_memcpy_swab(buf, t->tx_buf, m, t); - else + /* In RXSKIP mode controller shifts out zeros internally */ + else if (!mspi->rxskip) memset(buf, 0, t->len); buf += t->len; } @@ -203,6 +204,37 @@ static int fsl_espi_check_message(struct spi_message *m) return 0; } +static unsigned int fsl_espi_check_rxskip_mode(struct spi_message *m) +{ + struct spi_transfer *t; + unsigned int i = 0, rxskip = 0; + + /* + * prerequisites for ESPI rxskip mode: + * - message has two transfers + * - first transfer is a write and second is a read + * + * In addition the current low-level transfer mechanism requires + * that the rxskip bytes fit into the TX FIFO. Else the transfer + * would hang because after the first FSL_ESPI_FIFO_SIZE bytes + * the TX FIFO isn't re-filled. + */ + list_for_each_entry(t, &m->transfers, transfer_list) { + if (i == 0) { + if (!t->tx_buf || t->rx_buf || + t->len > FSL_ESPI_FIFO_SIZE) + return 0; + rxskip = t->len; + } else if (i == 1) { + if (t->tx_buf || !t->rx_buf) + return 0; + } + i++; + } + + return i == 2 ? rxskip : 0; +} + static void fsl_espi_fill_tx_fifo(struct mpc8xxx_spi *mspi, u32 events) { u32 tx_fifo_avail; @@ -281,7 +313,7 @@ static void fsl_espi_setup_transfer(struct spi_device *spi, static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) { struct mpc8xxx_spi *mpc8xxx_spi = spi_master_get_devdata(spi->master); - u32 mask; + u32 mask, spcom; int ret; mpc8xxx_spi->rx_len = t->len; @@ -293,8 +325,18 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t) reinit_completion(&mpc8xxx_spi->done); /* Set SPCOM[CS] and SPCOM[TRANLEN] field */ - fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPCOM, - (SPCOM_CS(spi->chip_select) | SPCOM_TRANLEN(t->len - 1))); + spcom = SPCOM_CS(spi->chip_select); + spcom |= SPCOM_TRANLEN(t->len - 1); + + /* configure RXSKIP mode */ + if (mpc8xxx_spi->rxskip) { + spcom |= SPCOM_RXSKIP(mpc8xxx_spi->rxskip); + mpc8xxx_spi->tx_len = mpc8xxx_spi->rxskip; + mpc8xxx_spi->rx_len = t->len - mpc8xxx_spi->rxskip; + mpc8xxx_spi->rx = t->rx_buf + mpc8xxx_spi->rxskip; + } + + fsl_espi_write_reg(mpc8xxx_spi, ESPI_SPCOM, spcom); /* enable interrupts */ mask = SPIM_DON; @@ -326,6 +368,7 @@ static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans) struct spi_device *spi = m->spi; int ret; + mspi->rxskip = fsl_espi_check_rxskip_mode(m); fsl_espi_copy_to_buf(m, mspi); fsl_espi_setup_transfer(spi, trans); diff --git a/drivers/spi/spi-fsl-lib.h b/drivers/spi/spi-fsl-lib.h index 35a7a1730d0c..3951322265d4 100644 --- a/drivers/spi/spi-fsl-lib.h +++ b/drivers/spi/spi-fsl-lib.h @@ -31,6 +31,7 @@ struct mpc8xxx_spi { #if IS_ENABLED(CONFIG_SPI_FSL_ESPI) unsigned int rx_len; unsigned int tx_len; + unsigned int rxskip; u8 *local_buf; spinlock_t lock; #endif |