[U-Boot] [PATCH 05/10] AVR32: macb - Disable 100mbps if clock is slow

[Olav Morken]

For 100mbps operation, the ethernet controller requires a 25 MHz clock
in MII mode, and a 50 MHz clock in RMII mode. If the clock is slower,
disable 100mbps mode.

Signed-off-by: Gunnar Rangoy <gunnar at rangoy.com>
Signed-off-by: Paul Driveklepp <pauldriveklepp at gmail.com>
Signed-off-by: Olav Morken <olavmrk at gmail.com>
---
 drivers/net/macb.c |   23 ++++++++++++++++++++++-
 1 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 08bebf7..4fef374 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -296,8 +296,29 @@ static void macb_phy_reset(struct macb_device *macb)
 	struct eth_device *netdev = &macb->netdev;
 	int i;
 	u16 status, adv;
+	int rmii_mode;
+	unsigned min_hz;
+
+#ifdef CONFIG_RMII
+	rmii_mode = 1;
+	min_hz = 50000000;
+#else
+	rmii_mode = 0;
+	min_hz = 25000000;
+#endif
+
+	adv = ADVERTISE_CSMA | ADVERTISE_ALL ;
+
+	if (get_hsb_clk_rate() < min_hz) {
+		printf("%s: HSB clock < %u MHz in %s mode - "
+		       "disabling 100mbit.\n", netdev->name, min_hz / 1000000,
+		       (rmii_mode ? "RMII" : "MII"));
+
+		adv &= ~ADVERTISE_100FULL;
+		adv &= ~ADVERTISE_100HALF;
+		adv &= ~ADVERTISE_100BASE4;
+	}
 
-	adv = ADVERTISE_CSMA | ADVERTISE_ALL;
 	macb_mdio_write(macb, MII_ADVERTISE, adv);
 	printf("%s: Starting autonegotiation...\n", netdev->name);
 	macb_mdio_write(macb, MII_BMCR, (BMCR_ANENABLE
-- 
1.6.0.2