This patch adds error checking and prevents clobbering unrelated bits
(reserved bits or the DIS_PREAMBLE bit) when writing the MII_SPEED
register on MPC52xx systems.
Signed-off-by: Wolfgang Denk <w...@denx.de>
Cc: Grant Likely <grant.lik...@secretlab.ca>
Cc: Kumar Gala <ga...@kernel.crashing.org>
Cc: <net...@vger.kernel.org>
---
v3: - use maximum divider in case MPC512x IPS clock is unknown
drivers/net/fec_mpc52xx.c | 2 +-
drivers/net/fec_mpc52xx_phy.c | 23 ++++++++++++++++++++---
2 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/drivers/net/fec_mpc52xx.c b/drivers/net/fec_mpc52xx.c
index cc78633..b69d440 100644
--- a/drivers/net/fec_mpc52xx.c
+++ b/drivers/net/fec_mpc52xx.c
@@ -639,7 +639,7 @@ static void mpc52xx_fec_hw_init(struct net_device *dev)
/* set phy speed.
* this can't be done in phy driver, since it needs to be called
* before fec stuff (even on resume) */
- out_be32(&fec->mii_speed, priv->mdio_speed);
+ clrsetbits_be32(&fec->mii_speed, 0x7E, priv->mdio_speed);
}
/**
diff --git a/drivers/net/fec_mpc52xx_phy.c b/drivers/net/fec_mpc52xx_phy.c
index 31e6d62..d3537e1 100644
--- a/drivers/net/fec_mpc52xx_phy.c
+++ b/drivers/net/fec_mpc52xx_phy.c
@@ -70,7 +70,7 @@ static int mpc52xx_fec_mdio_probe(struct of_device *of,
struct mpc52xx_fec_mdio_priv *priv;
struct resource res = {};
int err;
- int i;
+ int i, clock, speed;
bus = mdiobus_alloc();
if (bus == NULL)
@@ -105,8 +105,25 @@ static int mpc52xx_fec_mdio_probe(struct of_device *of,
dev_set_drvdata(dev, bus);
/* set MII speed */
- out_be32(&priv->regs->mii_speed,
- ((mpc5xxx_get_bus_frequency(of->node) >> 20) / 5) << 1);
+ clock = mpc5xxx_get_bus_frequency(of->node);
+ if (!clock) {
+ /* Use maximum divider if clock is unknown */
+ dev_err(&of->dev, "could not determine IPB clock\n");
+ clock = 0x3F * 5000000;
+ }
+
+ /*
+ * Scale for a MII clock <= 2.5 MHz
+ * Note that only 6 bits (25:30) are available for MII speed.
+ */
+ speed = (clock + 4999999) / 5000000;
+ if (speed > 0x3F) {
+ speed = 0x3F;
+ dev_err(&of->dev, "MII clock (%d Hz) exceeds max (2.5 MHz)\n",
+ clock / speed);
+ }
+
+ clrsetbits_be32(&priv->regs->mii_speed, 0x7E, speed << 1);
err = of_mdiobus_register(bus, np);
if (err)
--
1.6.0.6
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