diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/spi/spi-dw-core.c | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c index 3bb8aa3cba2b..4a45610c85f1 100644 --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -189,17 +189,30 @@ static irqreturn_t interrupt_transfer(struct dw_spi *dws) return IRQ_HANDLED; } + /* + * Read data from the Rx FIFO every time we've got a chance executing + * this method. If there is nothing left to receive, terminate the + * procedure. Otherwise adjust the Rx FIFO Threshold level if it's a + * final stage of the transfer. By doing so we'll get the next IRQ + * right when the leftover incoming data is received. + */ dw_reader(dws); if (!dws->rx_len) { spi_mask_intr(dws, 0xff); spi_finalize_current_transfer(dws->master); - return IRQ_HANDLED; + } else if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR)) { + dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1); } + + /* + * Send data out if Tx FIFO Empty IRQ is received. The IRQ will be + * disabled after the data transmission is finished so not to + * have the TXE IRQ flood at the final stage of the transfer. + */ if (irq_status & SPI_INT_TXEI) { - spi_mask_intr(dws, SPI_INT_TXEI); dw_writer(dws); - /* Enable TX irq always, it will be disabled when RX finished */ - spi_umask_intr(dws, SPI_INT_TXEI); + if (!dws->tx_len) + spi_mask_intr(dws, SPI_INT_TXEI); } return IRQ_HANDLED; @@ -338,10 +351,6 @@ static int dw_spi_transfer_one(struct spi_controller *master, /* For poll mode just disable all interrupts */ spi_mask_intr(dws, 0xff); - /* - * Interrupt mode - * we only need set the TXEI IRQ, as TX/RX always happen syncronizely - */ if (dws->dma_mapped) { ret = dws->dma_ops->dma_setup(dws, transfer); if (ret < 0) { @@ -349,12 +358,18 @@ static int dw_spi_transfer_one(struct spi_controller *master, return ret; } } else { + /* + * Originally Tx and Rx data lengths match. Rx FIFO Threshold level + * will be adjusted at the final stage of the IRQ-based SPI transfer + * execution so not to lose the leftover of the incoming data. + */ txlevel = min_t(u16, dws->fifo_len / 2, dws->tx_len); dw_writel(dws, DW_SPI_TXFTLR, txlevel); + dw_writel(dws, DW_SPI_RXFTLR, txlevel - 1); /* Set the interrupt mask */ imask |= SPI_INT_TXEI | SPI_INT_TXOI | - SPI_INT_RXUI | SPI_INT_RXOI; + SPI_INT_RXUI | SPI_INT_RXOI | SPI_INT_RXFI; spi_umask_intr(dws, imask); dws->transfer_handler = interrupt_transfer; |