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path: root/drivers/net/ethernet/freescale/fec_main.c
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Diffstat (limited to 'drivers/net/ethernet/freescale/fec_main.c')
-rw-r--r--drivers/net/ethernet/freescale/fec_main.c30
1 files changed, 27 insertions, 3 deletions
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 78e1ce09b1ab..f6a3a7abd468 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1954,6 +1954,7 @@ static int fec_enet_mii_init(struct platform_device *pdev)
struct fec_enet_private *fep = netdev_priv(ndev);
struct device_node *node;
int err = -ENXIO, i;
+ u32 mii_speed, holdtime;
/*
* The i.MX28 dual fec interfaces are not equal.
@@ -1991,10 +1992,33 @@ static int fec_enet_mii_init(struct platform_device *pdev)
* Reference Manual has an error on this, and gets fixed on i.MX6Q
* document.
*/
- fep->phy_speed = DIV_ROUND_UP(clk_get_rate(fep->clk_ipg), 5000000);
+ mii_speed = DIV_ROUND_UP(clk_get_rate(fep->clk_ipg), 5000000);
if (fep->quirks & FEC_QUIRK_ENET_MAC)
- fep->phy_speed--;
- fep->phy_speed <<= 1;
+ mii_speed--;
+ if (mii_speed > 63) {
+ dev_err(&pdev->dev,
+ "fec clock (%lu) to fast to get right mii speed\n",
+ clk_get_rate(fep->clk_ipg));
+ err = -EINVAL;
+ goto err_out;
+ }
+
+ /*
+ * The i.MX28 and i.MX6 types have another filed in the MSCR (aka
+ * MII_SPEED) register that defines the MDIO output hold time. Earlier
+ * versions are RAZ there, so just ignore the difference and write the
+ * register always.
+ * The minimal hold time according to IEE802.3 (clause 22) is 10 ns.
+ * HOLDTIME + 1 is the number of clk cycles the fec is holding the
+ * output.
+ * The HOLDTIME bitfield takes values between 0 and 7 (inclusive).
+ * Given that ceil(clkrate / 5000000) <= 64, the calculation for
+ * holdtime cannot result in a value greater than 3.
+ */
+ holdtime = DIV_ROUND_UP(clk_get_rate(fep->clk_ipg), 100000000) - 1;
+
+ fep->phy_speed = mii_speed << 1 | holdtime << 8;
+
writel(fep->phy_speed, fep->hwp + FEC_MII_SPEED);
fep->mii_bus = mdiobus_alloc();