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[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>
tags/v1.20.1
Sylvie Barlow 6 jaren geleden
bovenliggende
commit
c239f0bff2
2 gewijzigde bestanden met toevoegingen van 217 en 0 verwijderingen
  1. 162
    0
      src/drivers/bitbash/mii_bit.c
  2. 55
    0
      src/include/ipxe/mii_bit.h

+ 162
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src/drivers/bitbash/mii_bit.c Bestand weergeven

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+/*
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+ * Copyright (C) 2018 Sylvie Barlow <sylvie.c.barlow@gmail.com>.
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License as
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+ * published by the Free Software Foundation; either version 2 of the
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+ * License, or any later version.
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+ *
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+ * This program is distributed in the hope that it will be useful, but
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+ * WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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+ * General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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+ * 02110-1301, USA.
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+ *
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+ * You can also choose to distribute this program under the terms of
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+ * the Unmodified Binary Distribution Licence (as given in the file
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+ * COPYING.UBDL), provided that you have satisfied its requirements.
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+ */
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+
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+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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+
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+#include <stdint.h>
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+#include <unistd.h>
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+#include <ipxe/bitbash.h>
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+#include <ipxe/mii_bit.h>
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+
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+/**
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+ * Transfer bits over MII bit-bashing interface
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+ *
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+ * @v basher		Bit basher
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+ * @v mask		Mask
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+ * @v write		Data to write
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+ * @ret read		Data read
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+ */
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+static uint32_t mii_bit_xfer ( struct bit_basher *basher,
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+			       uint32_t mask, uint32_t write ) {
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+	uint32_t read = 0;
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+	int bit;
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+
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+	for ( ; mask ; mask >>= 1 ) {
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+
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+		/* Delay */
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+		udelay ( 1 );
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+
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+		/* Write bit to basher */
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+		write_bit ( basher, MII_BIT_MDIO, ( write & mask ) );
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+
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+		/* Read bit from basher */
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+		bit = read_bit ( basher, MII_BIT_MDIO );
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+		read <<= 1;
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+		read |= ( bit & 1 );
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+
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+		/* Set clock high */
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+		write_bit ( basher, MII_BIT_MDC, 1 );
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+
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+		/* Delay */
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+		udelay ( 1 );
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+
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+		/* Set clock low */
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+		write_bit ( basher, MII_BIT_MDC, 0 );
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+	}
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+	return read;
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+}
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+
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+/**
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+ * Read or write via MII bit-bashing interface
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+ *
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+ * @v basher		Bit basher
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+ * @v phy		PHY address
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+ * @v reg		Register address
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+ * @v data		Data to write
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+ * @v cmd		Command
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+ * @ret data		Data read
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+ */
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+static unsigned int mii_bit_rw ( struct bit_basher *basher,
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+				 unsigned int phy, unsigned int reg,
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+				 unsigned int data, unsigned int cmd ) {
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+
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+	/* Initiate drive for write */
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+	write_bit ( basher, MII_BIT_DRIVE, 1 );
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+
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+	/* Write start */
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+	mii_bit_xfer ( basher, MII_BIT_START_MASK, MII_BIT_START );
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+
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+	/* Write command */
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+	mii_bit_xfer ( basher, MII_BIT_CMD_MASK, cmd );
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+
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+	/* Write PHY address */
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+	mii_bit_xfer ( basher, MII_BIT_PHY_MASK, phy );
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+
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+	/* Write register address */
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+	mii_bit_xfer ( basher, MII_BIT_REG_MASK, reg );
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+
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+	/* Switch drive to read if applicable */
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+	write_bit ( basher, MII_BIT_DRIVE, ( cmd & MII_BIT_CMD_RW ) );
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+
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+	/* Allow space for turnaround */
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+	mii_bit_xfer ( basher, MII_BIT_SWITCH_MASK, MII_BIT_SWITCH );
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+
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+	/* Read or write data */
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+	data = mii_bit_xfer (basher, MII_BIT_DATA_MASK, data );
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+
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+	/* Initiate drive for read */
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+	write_bit ( basher, MII_BIT_DRIVE, 0 );
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+
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+	return data;
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+}
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+
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+/**
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+ * Read from MII register
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+ *
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+ * @v mdio		MII interface
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+ * @v phy		PHY address
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+ * @v reg		Register address
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+ * @ret data		Data read, or negative error
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+ */
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+static int mii_bit_read ( struct mii_interface *mdio, unsigned int phy,
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+			  unsigned int reg ) {
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+	struct mii_bit_basher *miibit =
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+		container_of ( mdio, struct mii_bit_basher, mdio );
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+	struct bit_basher *basher = &miibit->basher;
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+
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+	return mii_bit_rw ( basher, phy, reg, 0, MII_BIT_CMD_READ );
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+}
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+
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+/**
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+ * Write to MII register
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+ *
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+ * @v mdio		MII interface
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+ * @v phy		PHY address
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+ * @v reg		Register address
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+ * @v data		Data to write
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+ * @ret rc		Return status code
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+ */
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+static int mii_bit_write ( struct mii_interface *mdio, unsigned int phy,
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+			   unsigned int reg, unsigned int data ) {
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+	struct mii_bit_basher *miibit =
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+		container_of ( mdio, struct mii_bit_basher, mdio );
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+	struct bit_basher *basher = &miibit->basher;
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+
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+	mii_bit_rw ( basher, phy, reg, data, MII_BIT_CMD_WRITE );
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+	return 0;
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+}
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+
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+/** MII bit basher operations */
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+static struct mii_operations mii_bit_op = {
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+	.read = mii_bit_read,
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+	.write = mii_bit_write,
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+};
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+
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+/**
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+ * Initialise bit-bashing interface
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+ *
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+ * @v miibit		MII bit basher
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+ */
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+void init_mii_bit_basher ( struct mii_bit_basher *miibit ) {
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+	mdio_init ( &miibit->mdio, &mii_bit_op );
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+};

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- 0
src/include/ipxe/mii_bit.h Bestand weergeven

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

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