Thread (5 messages) 5 messages, 3 authors, 2019-06-04

[PATCH] net: macb: dma_sync_* receive buffers

From: Ladislav Michl <hidden>
Date: 2018-11-15 00:38:22
Subsystem: networking drivers, the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds

Receive buffers are properly synchronized only if Cadence is
GEM. Fix it for MACB as well.

Fixes: 86dc5259e25d (net: macb: no need for coherent memory for receive buffer)
Signed-off-by: Ladislav Michl <redacted>
---
 Hi Sascha,

 I'm unsure this is proper fix, but works for me (as well as
 reverting 86dc5259e25d)

 drivers/net/macb.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 1c5752d10..2bd5b62a4 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -216,9 +216,11 @@ static int macb_recv(struct eth_device *edev)
 	dev_dbg(macb->dev, "%s\n", __func__);
 
 	for (;;) {
+		barrier();
 		if (!(macb->rx_ring[rx_tail].addr & MACB_BIT(RX_USED)))
 			return -1;
 
+		barrier();
 		status = macb->rx_ring[rx_tail].ctrl;
 		if (status & MACB_BIT(RX_SOF)) {
 			if (rx_tail != macb->rx_tail)
@@ -229,6 +231,8 @@ static int macb_recv(struct eth_device *edev)
 		if (status & MACB_BIT(RX_EOF)) {
 			buffer = macb->rx_buffer + macb->rx_buffer_size * macb->rx_tail;
 			length = MACB_BFEXT(RX_FRMLEN, status);
+			dma_sync_single_for_cpu((unsigned long)buffer, length,
+						DMA_FROM_DEVICE);
 			if (wrapped) {
 				unsigned int headlen, taillen;
 
@@ -237,12 +241,17 @@ static int macb_recv(struct eth_device *edev)
 				taillen = length - headlen;
 				memcpy((void *)NetRxPackets[0],
 				       buffer, headlen);
+				dma_sync_single_for_cpu((unsigned long)macb->rx_buffer,
+							taillen, DMA_FROM_DEVICE);
 				memcpy((void *)NetRxPackets[0] + headlen,
 				       macb->rx_buffer, taillen);
 				buffer = (void *)NetRxPackets[0];
 			}
 
 			net_receive(edev, buffer, length);
+			dma_sync_single_for_device((unsigned long)buffer, length,
+						   DMA_FROM_DEVICE);
+			barrier();
 			if (++rx_tail >= macb->rx_ring_size)
 				rx_tail = 0;
 			reclaim_rx_buffers(macb, rx_tail);
@@ -252,7 +261,6 @@ static int macb_recv(struct eth_device *edev)
 				rx_tail = 0;
 			}
 		}
-		barrier();
 	}
 
 	return 0;
-- 
2.19.1


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