commit 636ef59fb51f4b9e0fa6939697e144e04a99eb71
author Lad, Prabhakar <prabhakar.csengg@gmail.com> Sat Jul 30 22:28:24 2016 +0100
committer Jagan Teki <jagannadh.teki@gmail.com> Thu Sep 22 00:58:26 2016 +0530
tree 182a4b7b709ca147fb85d8dfa239171d66a47b51
parent 75794f994ab4120238cb47304cb711f045f77c8a

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>

drivers/spi/zynq_spi.c

diff --git a/drivers/spi/zynq_spi.c b/drivers/spi/zynq_spi.c
index 09ae1be..dd3de27 100644
--- a/drivers/spi/zynq_spi.c
+++ b/drivers/spi/zynq_spi.c
@@ -230,7 +230,7 @@
 
 		/* 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;