Instead of checking the TX_FULL flag for every transaction, find out the
size of the buffer at probe time and use it.
Signed-off-by: Ricardo Ribalda Delgado <ricardo.riba...@gmail.com>
---
drivers/spi/spi-xilinx.c | 39 ++++++++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 13 deletions(-)
diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 416b227..17480a2 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 +318,21 @@ 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;
+
+ /* 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 +424,8 @@ 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);
--
2.1.4
--
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