diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-cadence.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c index 00f0d1b3a722..31d778e9d255 100644 --- a/drivers/spi/spi-cadence.c +++ b/drivers/spi/spi-cadence.c @@ -93,9 +93,6 @@ #define CDNS_SPI_ER_ENABLE 0x00000001 /* SPI Enable Bit Mask */ #define CDNS_SPI_ER_DISABLE 0x0 /* SPI Disable Bit Mask */ -/* SPI FIFO depth in bytes */ -#define CDNS_SPI_FIFO_DEPTH 128 - /* Default number of chip select lines */ #define CDNS_SPI_DEFAULT_NUM_CS 4 @@ -111,6 +108,7 @@ * @rx_bytes: Number of bytes requested * @dev_busy: Device busy flag * @is_decoded_cs: Flag for decoder property set or not + * @tx_fifo_depth: Depth of the TX FIFO */ struct cdns_spi { void __iomem *regs; @@ -124,6 +122,7 @@ struct cdns_spi { int rx_bytes; u8 dev_busy; u32 is_decoded_cs; + unsigned int tx_fifo_depth; }; /* Macros for the SPI controller read/write */ @@ -305,7 +304,7 @@ static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi) { unsigned long trans_cnt = 0; - while ((trans_cnt < CDNS_SPI_FIFO_DEPTH) && + while ((trans_cnt < xspi->tx_fifo_depth) && (xspi->tx_bytes > 0)) { /* When xspi in busy condition, bytes may send failed, @@ -470,6 +469,24 @@ static int cdns_unprepare_transfer_hardware(struct spi_master *master) } /** + * cdns_spi_detect_fifo_depth - Detect the FIFO depth of the hardware + * @xspi: Pointer to the cdns_spi structure + * + * The depth of the TX FIFO is a synthesis configuration parameter of the SPI + * IP. The FIFO threshold register is sized so that its maximum value can be the + * FIFO size - 1. This is used to detect the size of the FIFO. + */ +static void cdns_spi_detect_fifo_depth(struct cdns_spi *xspi) +{ + /* The MSBs will get truncated giving us the size of the FIFO */ + cdns_spi_write(xspi, CDNS_SPI_THLD, 0xffff); + xspi->tx_fifo_depth = cdns_spi_read(xspi, CDNS_SPI_THLD) + 1; + + /* Reset to default */ + cdns_spi_write(xspi, CDNS_SPI_THLD, 0x1); +} + +/** * cdns_spi_probe - Probe method for the SPI driver * @pdev: Pointer to the platform_device structure * @@ -541,6 +558,8 @@ static int cdns_spi_probe(struct platform_device *pdev) if (ret < 0) xspi->is_decoded_cs = 0; + cdns_spi_detect_fifo_depth(xspi); + /* SPI controller initializations */ cdns_spi_init_hw(xspi); |