[mii] Add bit-bashing interface

Signed-off-by: Sylvie Barlow <sylvie.c.barlow@gmail.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/mii_bit.h

@@ -0,0 +1,55 @@
+#ifndef _IPXE_MII_BIT_H
+#define _IPXE_MII_BIT_H
+
+/** @file
+ *
+ * MII bit-bashing interface
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <ipxe/mii.h>
+#include <ipxe/bitbash.h>
+
+#define MII_BIT_START		0xffffffff	/**< Start */
+#define MII_BIT_START_MASK	0x80000000	/**< Start mask */
+
+#define MII_BIT_CMD_MASK	0x00000008	/**< Command mask */
+#define MII_BIT_CMD_READ	0x00000006	/**< Command read */
+#define MII_BIT_CMD_WRITE	0x00000005	/**< Command write */
+#define MII_BIT_CMD_RW		0x00000001	/**< Command read or write */
+
+#define MII_BIT_PHY_MASK	0x00000010	/**< PHY mask */
+
+#define MII_BIT_REG_MASK	0x00000010	/**< Register mask */
+
+#define MII_BIT_SWITCH		0x00000002	/**< Switch */
+#define MII_BIT_SWITCH_MASK	0x00000002	/**< Switch mask */
+
+#define MII_BIT_DATA_MASK	0x00008000	/**< Data mask */
+
+/** A bit-bashing MII interface */
+struct mii_bit_basher {
+	/** MII interface */
+	struct mii_interface mdio;
+	/** Bit-bashing interface */
+	struct bit_basher basher;
+};
+
+/** Bit indices used for MII bit-bashing interface */
+enum {
+	/** MII clock */
+	MII_BIT_MDC = 0,
+	/** MII data */
+	MII_BIT_MDIO,
+	/** MII data direction */
+	MII_BIT_DRIVE,
+};
+
+/** Delay between MDC transitions */
+#define MII_BIT_UDELAY 1
+
+extern void init_mii_bit_basher ( struct mii_bit_basher *miibit );
+
+#endif /* _IPXE_MII_BIT_H */