Small transfers generally can be accomplished faster in polling mode. This patch select the transfer which size is bellow the buffer size to be done on polling mode
Suggested-by: Mark Brown <[email protected]> Signed-off-by: Ricardo Ribalda Delgado <[email protected]> --- drivers/spi/spi-xilinx.c | 43 +++++++++++++++++++++++++------------------ 1 file changed, 25 insertions(+), 18 deletions(-) diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c index 134d8cd..c6b0a6e 100644 --- a/drivers/spi/spi-xilinx.c +++ b/drivers/spi/spi-xilinx.c @@ -130,7 +130,6 @@ static void xilinx_spi_rx(struct xilinx_spi *xspi) static void xspi_init_hw(struct xilinx_spi *xspi) { void __iomem *regs_base = xspi->regs; - u32 inhibit; /* Reset the SPI device */ xspi->write_fn(XIPIF_V123B_RESET_MASK, @@ -140,22 +139,15 @@ static void xspi_init_hw(struct xilinx_spi *xspi) */ xspi->write_fn(XSPI_INTR_TX_EMPTY, regs_base + XIPIF_V123B_IIER_OFFSET); - /* Enable the global IPIF interrupt */ - if (xspi->irq >= 0) { - xspi->write_fn(XIPIF_V123B_GINTR_ENABLE, - regs_base + XIPIF_V123B_DGIER_OFFSET); - inhibit = XSPI_CR_TRANS_INHIBIT; - } else { - xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET); - inhibit = 0; - } + /* Disable the global IPIF interrupt */ + xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET); /* Deselect the slave on the SPI bus */ xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET); /* Disable the transmitter, enable Manual Slave Select Assertion, * put SPI controller into master mode, and enable it */ - xspi->write_fn(inhibit | XSPI_CR_MANUAL_SSELECT | - XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | - XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET); + xspi->write_fn(XSPI_CR_MANUAL_SSELECT | XSPI_CR_MASTER_MODE | + XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | XSPI_CR_RXFIFO_RESET, + regs_base + XSPI_CR_OFFSET); } static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) @@ -214,6 +206,8 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) { struct xilinx_spi *xspi = spi_master_get_devdata(spi->master); int remaining_words; /* the number of words left to transfer */ + bool use_irq = false; + u16 cr = 0; /* We get here with transmitter inhibited */ @@ -222,8 +216,20 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) remaining_words = t->len / xspi->bytes_per_word; reinit_completion(&xspi->done); + if (xspi->irq >= 0 && remaining_words > xspi->buffer_size) { + use_irq = true; + xspi->write_fn(XSPI_INTR_TX_EMPTY, + xspi->regs + XIPIF_V123B_IISR_OFFSET); + /* Enable the global IPIF interrupt */ + xspi->write_fn(XIPIF_V123B_GINTR_ENABLE, + xspi->regs + XIPIF_V123B_DGIER_OFFSET); + /* Inhibit irq to avoid spurious irqs on tx_empty*/ + cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET); + xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT, + xspi->regs + XSPI_CR_OFFSET); + } + while (remaining_words) { - u16 cr = 0; int n_words, tx_words, rx_words; n_words = min(remaining_words, xspi->buffer_size); @@ -236,9 +242,7 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) * longer */ - if (xspi->irq >= 0) { - cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) & - ~XSPI_CR_TRANS_INHIBIT; + if (use_irq) { xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET); wait_for_completion(&xspi->done); } else @@ -251,7 +255,7 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) * transmitter while the Isr refills the transmit register/FIFO, * or make sure it is stopped if we're done. */ - if (xspi->irq >= 0) + if (use_irq) xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT, xspi->regs + XSPI_CR_OFFSET); @@ -263,6 +267,9 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) remaining_words -= n_words; } + if (use_irq) + xspi->write_fn(0, xspi->regs + XIPIF_V123B_DGIER_OFFSET); + return t->len; } -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
