[PATCH net] net: dpaa: always set a valid mode I/F mode

[Michael Walle <mwalle@kernel.org>]

Before converting to the phylink interface, the init function would have
set the correct mode in the maccfg2. After converting, init will just
set 0 as the mode. According to the "QorIQ Data Path Acceleration
Architecture (DPAA) Reference Manual", this is a reserved value. In
fact, this will prevent the PCS to establish a link to a connected SGMII
PHY. In turn, mac_link_up() is never called. Fix it by setting a
non-reserved mode; mac_link_up() will then set the correct mode later.

Fixes: 5d93cfcf7360 ("net: dpaa: Convert to phylink")
Signed-off-by: Michael Walle <mwalle@kernel.org>
---
FWIW, I've tested this with a Marvell 88E1112 PHY.

 drivers/net/ethernet/freescale/fman/fman_dtsec.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/fman/fman_dtsec.c b/drivers/net/ethernet/freescale/fman/fman_dtsec.c
index fe35703c509e..566921d3a884 100644
--- a/drivers/net/ethernet/freescale/fman/fman_dtsec.c
+++ b/drivers/net/ethernet/freescale/fman/fman_dtsec.c
@@ -402,7 +402,10 @@ static int init(struct dtsec_regs __iomem *regs, struct dtsec_cfg *cfg,
 	tmp |= MACCFG1_TX_FLOW;
 	iowrite32be(tmp, &regs->maccfg1);
 
-	tmp = 0;
+	/* write a non-reserved mode, otherwise the PCS won't establish a link
+	 * and .mac_link_up() is never called.
+	 */
+	tmp = MACCFG2_NIBBLE_MODE;
 
 	tmp |= (cfg->preamble_len << MACCFG2_PREAMBLE_LENGTH_SHIFT) &
 		MACCFG2_PREAMBLE_LENGTH_MASK;
-- 
2.47.3