/**
* cdns_spi_irq - Interrupt service routine of the SPI controller
* @irq: IRQ number
* @dev_id: Pointer to the xspi structure
*
* This function handles TX empty and Mode Fault interrupts only.
* On TX empty interrupt this function reads the received data from RX FIFO and
* fills the TX FIFO if there is any data remaining to be transferred.
* On Mode Fault interrupt this function indicates that transfer is completed,
* the SPI subsystem will identify the error as the remaining bytes to be
* transferred is non-zero.
*
* Return: IRQ_HANDLED when handled; IRQ_NONE otherwise.
*/
static irqreturn_t cdns_spi_irq(int irq, void *dev_id)
{
struct spi_master *master = dev_id;
struct cdns_spi *xspi = spi_master_get_devdata(master);
u32 intr_status, status;
status = IRQ_NONE;
intr_status = cdns_spi_read(xspi, CDNS_SPI_ISR_OFFSET);
cdns_spi_write(xspi, CDNS_SPI_ISR_OFFSET, intr_status);
if (intr_status & CDNS_SPI_IXR_MODF_MASK) {
/* Indicate that transfer is completed, the SPI subsystem will
* identify the error as the remaining bytes to be
* transferred is non-zero
*/
cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET,
CDNS_SPI_IXR_DEFAULT_MASK);
spi_finalize_current_transfer(master);
status = IRQ_HANDLED;
} else if (intr_status & CDNS_SPI_IXR_TXOW_MASK) {
unsigned long trans_cnt;
trans_cnt = xspi->rx_bytes - xspi->tx_bytes;
/* Read out the data from the RX FIFO */
while (trans_cnt) {
u8 data;
data = cdns_spi_read(xspi, CDNS_SPI_RXD_OFFSET);
if (xspi->rxbuf)
*xspi->rxbuf++ = data;
xspi->rx_bytes--;
trans_cnt--;
}
if (xspi->tx_bytes) {
/* There is more data to send */
cdns_spi_fill_tx_fifo(xspi);
} else {
/* Transfer is completed */
cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET,
CDNS_SPI_IXR_DEFAULT_MASK);
spi_finalize_current_transfer(master);
}
status = IRQ_HANDLED;
}
return status;
}
/**
* cdns_transfer_one - Initiates the SPI transfer
* @master: Pointer to spi_master structure
* @spi: Pointer to the spi_device structure
* @transfer: Pointer to the spi_transfer structure which provides
* information about next transfer parameters
*
* This function fills the TX FIFO, starts the SPI transfer and
* returns a positive transfer count so that core will wait for completion.
*
* Return: Number of bytes transferred in the last transfer
*/
static int cdns_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *transfer)
{
struct cdns_spi *xspi = spi_master_get_devdata(master);
xspi->txbuf = transfer->tx_buf;
xspi->rxbuf = transfer->rx_buf;
xspi->tx_bytes = transfer->len;
xspi->rx_bytes = transfer->len;
cdns_spi_setup_transfer(spi, transfer);
cdns_spi_fill_tx_fifo(xspi);
cdns_spi_write(xspi, CDNS_SPI_IER, CDNS_SPI_IXR_DEFAULT);
return transfer->len;
}
