Blackfin: bf518f-ezbrd: handle different PHYs dynamically

The original BF518F-EZBRD's have a Micrel KSZ8893 DSA on them, but newer
ones only have a National PHY (which lack a RX Error interrupt line).  So
in the board eth init code, dynamically detect what is hooked up to the MAC
and handle each accordingly.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/board/bf518f-ezbrd/bf518f-ezbrd.c b/board/bf518f-ezbrd/bf518f-ezbrd.c
index 85b350f..c2ab598 100644
--- a/board/bf518f-ezbrd/bf518f-ezbrd.c
+++ b/board/bf518f-ezbrd/bf518f-ezbrd.c
@@ -61,6 +61,7 @@
 #define KSZ_WRITE     0x02
 #define KSZ_READ      0x03
 
+#define KSZ_REG_CHID  0x00	/* Register 0: Chip ID0 */
 #define KSZ_REG_STPID 0x01	/* Register 1: Chip ID1 / Start Switch */
 #define KSZ_REG_GC9   0x0b	/* Register 11: Global Control 9 */
 #define KSZ_REG_P3C0  0x30	/* Register 48: Port 3 Control 0 */
@@ -78,15 +79,17 @@
 	return ksz8893m_transfer(slave, KSZ_WRITE, reg, data, din);
 }
 
+static int ksz8893m_reg_read(struct spi_slave *slave, uchar reg)
+{
+	int ret;
+	unsigned char din[3];
+	ret = ksz8893m_transfer(slave, KSZ_READ, reg, 0, din);
+	return ret ? ret : din[2];
+}
+
 static int ksz8893m_reg_clear(struct spi_slave *slave, uchar reg, uchar mask)
 {
-	int ret = 0;
-	unsigned char din[3];
-
-	ret |= ksz8893m_transfer(slave, KSZ_READ, reg, 0, din);
-	ret |= ksz8893m_reg_set(slave, reg, din[2] & mask);
-
-	return ret;
+	return ksz8893m_reg_set(slave, reg, ksz8893m_reg_read(slave, reg) & mask);
 }
 
 static int ksz8893m_reset(struct spi_slave *slave)
@@ -107,16 +110,16 @@
 
 int board_eth_init(bd_t *bis)
 {
-	static bool switch_is_alive = false;
+	static bool switch_is_alive = false, phy_is_ksz = true;
 	int ret;
 
 	if (!switch_is_alive) {
 		struct spi_slave *slave = spi_setup_slave(0, 1, KSZ_MAX_HZ, SPI_MODE_3);
 		if (slave) {
 			if (!spi_claim_bus(slave)) {
-				ret = ksz8893m_reset(slave);
-				if (!ret)
-					switch_is_alive = true;
+				phy_is_ksz = (ksz8893m_reg_read(slave, KSZ_REG_CHID) == 0x88);
+				ret = phy_is_ksz ? ksz8893m_reset(slave) : 0;
+				switch_is_alive = (ret == 0);
 				spi_release_bus(slave);
 			}
 			spi_free_slave(slave);