From: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Date: Sat, 30 Jul 2016 21:28:24 +0000 (+0100)
Subject: spi: zynq_spi: Fix infinite looping while xfer
X-Git-Tag: v2016.11-rc1~112^2~11
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=d2998286fc58e3ac6c75ed4d3a1e77b618bbf2ae;p=oweals%2Fu-boot.git

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 09ae1be7e9..dd3de2792d 100644
--- 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;