diff options
Diffstat (limited to 'drivers/net/ethernet/freescale/fec_main.c')
| -rw-r--r-- | drivers/net/ethernet/freescale/fec_main.c | 30 |
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(); |