[U-Boot] [PATCH v5] zynq-gem: Use appropriate cache flush/invalidate for RX and TX

[Stefan Theil]

The cache was only flushed before *transmitting* packets, but not
when receiving them, leading to an issue where new packets were
handed to the receive handler with old contents in cache. This
only happens when a lot of packets are received without sending
packages every now and then. Also flushing the receive buffers
in the transmit function makes no sense and can be removed.

Signed-off-by: Stefan Theil <stefan.theil at mixed-mode.de>

---
Changes for v2:
	- Use invalidate_dcache_range instead of
	  flush_dcache_range
Changes for v3:
	- Remove unnecessary flushing of all RX
	  buffers in zynq_gem_send
Changes for v4:
	- Invalidate receive buffers after allocating
	  them in zynq_gem_probe
Changes for v5:
	- Clear and flush receive buffers in
	  zynq_gem_probe instead of invalidating the
	  cache
---
 drivers/net/zynq_gem.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c
index 9bd79b198a..3bd0093b7a 100644
--- a/drivers/net/zynq_gem.c
+++ b/drivers/net/zynq_gem.c
@@ -570,11 +570,6 @@ static int zynq_gem_send(struct udevice *dev, void *ptr, int len)
 	addr &= ~(ARCH_DMA_MINALIGN - 1);
 	size = roundup(len, ARCH_DMA_MINALIGN);
 	flush_dcache_range(addr, addr + size);
-
-	addr = (ulong)priv->rxbuffers;
-	addr &= ~(ARCH_DMA_MINALIGN - 1);
-	size = roundup((RX_BUF * PKTSIZE_ALIGN), ARCH_DMA_MINALIGN);
-	flush_dcache_range(addr, addr + size);
 	barrier();
 
 	/* Start transmit */
@@ -621,6 +616,9 @@ static int zynq_gem_recv(struct udevice *dev, int flags, uchar **packetp)
 
 	*packetp = (uchar *)(uintptr_t)addr;
 
+	invalidate_dcache_range(addr, addr + roundup(PKTSIZE_ALIGN, ARCH_DMA_MINALIGN));
+	barrier();
+
 	return frame_len;
 }
 
@@ -706,6 +704,9 @@ static int zynq_gem_probe(struct udevice *dev)
 		return -ENOMEM;
 
 	memset(priv->rxbuffers, 0, RX_BUF * PKTSIZE_ALIGN);
+	u32 addr = (ulong)priv->rxbuffers;
+	flush_dcache_range(addr, addr + roundup(RX_BUF * PKTSIZE_ALIGN, ARCH_DMA_MINALIGN));
+	barrier();
 
 	/* Align bd_space to MMU_SECTION_SHIFT */
 	bd_space = memalign(1 << MMU_SECTION_SHIFT, BD_SPACE);
-- 
2.17.1