spi: zynq_spi: Fix infinite looping while xfer

During spi transfer, for example:
sspi 1:1.0 8 ff

the rx_len values will  be:
rx_len = 0
rx_len = 4294967295

This caused a busy looping during xfer, this patch fixes it
by adding a check while reading the rx fifo

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>

diff --git a/drivers/spi/zynq_spi.c b/drivers/spi/zynq_spi.c
index 09ae1be7e9875ed4d6acd2d7d0eae810561fefdb..dd3de2792d462ed32f91b3246a0f83e61c89f8bd 100644 (file)
--- a/drivers/spi/zynq_spi.c
+++ b/drivers/spi/zynq_spi.c
@@ -230,7 +230,7 @@ static int zynq_spi_xfer(struct udevice *dev, unsigned int bitlen,
 
                /* Read the data from RX FIFO */
                status = readl(&regs->isr);
-               while (status & ZYNQ_SPI_IXR_RXNEMPTY_MASK) {
+               while ((status & ZYNQ_SPI_IXR_RXNEMPTY_MASK) && rx_len) {
                        buf = readl(&regs->rxdr);
                        if (rx_buf)
                                *rx_buf++ = buf;