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From:   Michal Simek <michal.simek@xilinx.com>
To:     linux-kernel@vger.kernel.org, monstr@monstr.eu,
        "Edgar E. Iglesias" <edgari@xilinx.com>
Cc:     "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        u-boot@lists.denx.de, Joe Hershberger <joe.hershberger@ni.com>,
        Nicolas Ferre <nicolas.ferre@microchip.com>
Subject: [PATCH] net: macb: Clean 64b dma addresses if they are not detected
Date:   Wed, 19 Sep 2018 18:08:18 +0200
Message-Id: <0997a0e77b5e5c04c9a4d277d702d93a1a8a7448.1537373294.git.michal.simek@xilinx.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Clear ADDR64 dma bit in DMACFG register in case that HW_DMA_CAP_64B
is not detected on 64bit system.
The issue was observed when bootloader(u-boot) does not check macb
feature at DCFG6 register (DAW64_OFFSET) and enabling 64bit dma support
by default. Then macb driver is reading DMACFG register back and only
adding 64bit dma configuration but not cleaning it out.

This is also align with other features which are also cleared if they are not
present.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

 drivers/net/ethernet/cadence/macb_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 16e4ef7d7185..79707dff3f13 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -2163,6 +2163,8 @@ static void macb_configure_dma(struct macb *bp)
 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
 		if (bp->hw_dma_cap & HW_DMA_CAP_64B)
 			dmacfg |= GEM_BIT(ADDR64);
+		else
+			dmacfg &= ~GEM_BIT(ADDR64);
 #endif
 #ifdef CONFIG_MACB_USE_HWSTAMP
 		if (bp->hw_dma_cap & HW_DMA_CAP_PTP)
-- 
1.9.1