diff options
| -rw-r--r-- | drivers/spi/spi-xilinx.c | 46 |
1 files changed, 33 insertions, 13 deletions
diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c index 416b227eb302..1890af8f8636 100644 --- a/drivers/spi/spi-xilinx.c +++ b/drivers/spi/spi-xilinx.c @@ -88,6 +88,7 @@ struct xilinx_spi { const u8 *tx_ptr; /* pointer in the Rx buffer */ int remaining_bytes; /* the number of bytes left to transfer */ u8 bits_per_word; + int buffer_size; /* buffer size in words */ unsigned int (*read_fn)(void __iomem *); void (*write_fn)(u32, void __iomem *); void (*tx_fn)(struct xilinx_spi *); @@ -221,24 +222,16 @@ static int xilinx_spi_setup_transfer(struct spi_device *spi, return 0; } -static int xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi) +static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi, int n_words) { - u8 sr; - int n_words = 0; + xspi->remaining_bytes -= n_words * xspi->bits_per_word / 8; - /* Fill the Tx FIFO with as many bytes as possible */ - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) { + while (n_words--) if (xspi->tx_ptr) xspi->tx_fn(xspi); else xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); - xspi->remaining_bytes -= xspi->bits_per_word / 8; - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - n_words++; - } - - return n_words; + return; } static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) @@ -265,7 +258,10 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) u16 cr; int n_words; - n_words = xilinx_spi_fill_tx_fifo(xspi); + n_words = (xspi->remaining_bytes * 8) / xspi->bits_per_word; + n_words = min(n_words, xspi->buffer_size); + + xilinx_spi_fill_tx_fifo(xspi, n_words); /* Start the transfer by not inhibiting the transmitter any * longer @@ -322,6 +318,28 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id) return IRQ_HANDLED; } +static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi) +{ + u8 sr; + int n_words = 0; + + /* + * Before the buffer_size detection we reset the core + * to make sure we start with a clean state. + */ + xspi->write_fn(XIPIF_V123B_RESET_MASK, + xspi->regs + XIPIF_V123B_RESETR_OFFSET); + + /* Fill the Tx FIFO with as many words as possible */ + do { + xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); + sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); + n_words++; + } while (!(sr & XSPI_SR_TX_FULL_MASK)); + + return n_words; +} + static const struct of_device_id xilinx_spi_of_match[] = { { .compatible = "xlnx,xps-spi-2.00.a", }, { .compatible = "xlnx,xps-spi-2.00.b", }, @@ -413,6 +431,8 @@ static int xilinx_spi_probe(struct platform_device *pdev) goto put_master; } + xspi->buffer_size = xilinx_spi_find_buffer_size(xspi); + /* SPI controller initializations */ xspi_init_hw(xspi); |