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From:   Yan Markman <ymarkman@marvell.com>
To:     Antoine Tenart <antoine.tenart@bootlin.com>,
        "davem@davemloft.net" <davem@davemloft.net>,
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CC:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
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        "thomas.petazzoni@bootlin.com" <thomas.petazzoni@bootlin.com>,
        "maxime.chevallier@bootlin.com" <maxime.chevallier@bootlin.com>,
        "miquel.raynal@bootlin.com" <miquel.raynal@bootlin.com>,
        Nadav Haklai <nadavh@marvell.com>,
        Stefan Chulski <stefanc@marvell.com>,
        Yelena Krivosheev <yelena@marvell.com>
Subject: [PATCH net] net: mvneta: fix the Rx desc DMA address in the Rx path
Thread-Topic: [PATCH net] net: mvneta: fix the Rx desc DMA address in the Rx
 path
Thread-Index: AdQKZzflqC7AXW+7SbCthpO/KC9fcQ==
Date:   Fri, 22 Jun 2018 20:26:47 +0000
Message-ID: <93287208519f4364afbb299dd9961a27@IL-EXCH01.marvell.com>
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YANM: adding Yelena-K
--------------------------------
When using s/w buffer management, buffers are allocated and DMA mapped.
When doing so on an arm64 platform, an offset correction is applied on the DMA address, before storing it in an Rx descriptor. The issue is this DMA address is then used later in the Rx path without removing the offset correction. Thus the DMA address is wrong, which can led to various issues.

This patch fixes this by removing the offset correction from the DMA address retrieved from the Rx descriptor before using it in the Rx path.

Fixes: 8d5047cf9ca2 ("net: mvneta: Convert to be 64 bits compatible")
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
---
 drivers/net/ethernet/marvell/mvneta.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 17a904cc6a5e..0ad2f3f7da85 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -1932,7 +1932,7 @@ static int mvneta_rx_swbm(struct mvneta_port *pp, int rx_todo,
 		rx_bytes = rx_desc->data_size - (ETH_FCS_LEN + MVNETA_MH_SIZE);
 		index = rx_desc - rxq->descs;
 		data = rxq->buf_virt_addr[index];
-		phys_addr = rx_desc->buf_phys_addr;
+		phys_addr = rx_desc->buf_phys_addr - pp->rx_offset_correction;
 
 		if (!mvneta_rxq_desc_is_first_last(rx_status) ||
 		    (rx_status & MVNETA_RXD_ERR_SUMMARY)) {
--
2.17.1