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mii_bitbang.c revision 1.10.72.1 
      1 /*	$NetBSD: mii_bitbang.c,v 1.10.72.1 2008/05/18 12:34:13 yamt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
      9  * NASA Ames Research Center.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 /*
     34  * Common module for bit-bang'ing the MII.
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 __KERNEL_RCSID(0, "$NetBSD: mii_bitbang.c,v 1.10.72.1 2008/05/18 12:34:13 yamt Exp $");
     39 
     40 #include <sys/param.h>
     41 #include <sys/device.h>
     42 
     43 #include <dev/mii/mii.h>
     44 #include <dev/mii/mii_bitbang.h>
     45 
     46 #define	WRITE(x)							\
     47 do {									\
     48 	ops->mbo_write(sc, (x));					\
     49 	delay(1);							\
     50 } while (/* CONSTCOND */ 0)
     51 
     52 #define	READ		ops->mbo_read(sc)
     53 
     54 #define	MDO		ops->mbo_bits[MII_BIT_MDO]
     55 #define	MDI		ops->mbo_bits[MII_BIT_MDI]
     56 #define	MDC		ops->mbo_bits[MII_BIT_MDC]
     57 #define	MDIRPHY		ops->mbo_bits[MII_BIT_DIR_HOST_PHY]
     58 #define	MDIRHOST	ops->mbo_bits[MII_BIT_DIR_PHY_HOST]
     59 
     60 /*
     61  * mii_bitbang_sync:
     62  *
     63  *	Synchronize the MII.
     64  */
     65 static void
     66 mii_bitbang_sync(device_t sc, mii_bitbang_ops_t ops)
     67 {
     68 	int i;
     69 	u_int32_t v;
     70 
     71 	v = MDIRPHY | MDO;
     72 
     73 	WRITE(v);
     74 	for (i = 0; i < 32; i++) {
     75 		WRITE(v | MDC);
     76 		WRITE(v);
     77 	}
     78 }
     79 
     80 /*
     81  * mii_bitbang_sendbits:
     82  *
     83  *	Send a series of bits to the MII.
     84  */
     85 static void
     86 mii_bitbang_sendbits(device_t sc, mii_bitbang_ops_t ops, uint32_t data,
     87     int nbits)
     88 {
     89 	int i;
     90 	u_int32_t v;
     91 
     92 	v = MDIRPHY;
     93 	WRITE(v);
     94 
     95 	for (i = 1 << (nbits - 1); i != 0; i >>= 1) {
     96 		if (data & i)
     97 			v |= MDO;
     98 		else
     99 			v &= ~MDO;
    100 		WRITE(v);
    101 		WRITE(v | MDC);
    102 		WRITE(v);
    103 	}
    104 }
    105 
    106 /*
    107  * mii_bitbang_readreg:
    108  *
    109  *	Read a PHY register by bit-bang'ing the MII.
    110  */
    111 int
    112 mii_bitbang_readreg(device_t sc, mii_bitbang_ops_t ops, int phy, int reg)
    113 {
    114 	int val = 0, err = 0, i;
    115 
    116 	mii_bitbang_sync(sc, ops);
    117 
    118 	mii_bitbang_sendbits(sc, ops, MII_COMMAND_START, 2);
    119 	mii_bitbang_sendbits(sc, ops, MII_COMMAND_READ, 2);
    120 	mii_bitbang_sendbits(sc, ops, phy, 5);
    121 	mii_bitbang_sendbits(sc, ops, reg, 5);
    122 
    123 	/* Switch direction to PHY->host, without a clock transition. */
    124 	WRITE(MDIRHOST);
    125 
    126 	/* Turnaround clock. */
    127 	WRITE(MDIRHOST | MDC);
    128 	WRITE(MDIRHOST);
    129 
    130 	/* Check for error. */
    131 	err = READ & MDI;
    132 
    133 	/* Idle clock. */
    134 	WRITE(MDIRHOST | MDC);
    135 	WRITE(MDIRHOST);
    136 
    137 	for (i = 0; i < 16; i++) {
    138 		val <<= 1;
    139 		/* Read data prior to clock low-high transition. */
    140 		if (err == 0 && (READ & MDI) != 0)
    141 			val |= 1;
    142 
    143 		WRITE(MDIRHOST | MDC);
    144 		WRITE(MDIRHOST);
    145 	}
    146 
    147 	/* Set direction to host->PHY, without a clock transition. */
    148 	WRITE(MDIRPHY);
    149 
    150 	return (err ? 0 : val);
    151 }
    152 
    153 /*
    154  * mii_bitbang_writereg:
    155  *
    156  *	Write a PHY register by bit-bang'ing the MII.
    157  */
    158 void
    159 mii_bitbang_writereg(device_t sc, mii_bitbang_ops_t ops, int phy,
    160 	int reg, int val)
    161 {
    162 
    163 	mii_bitbang_sync(sc, ops);
    164 
    165 	mii_bitbang_sendbits(sc, ops, MII_COMMAND_START, 2);
    166 	mii_bitbang_sendbits(sc, ops, MII_COMMAND_WRITE, 2);
    167 	mii_bitbang_sendbits(sc, ops, phy, 5);
    168 	mii_bitbang_sendbits(sc, ops, reg, 5);
    169 	mii_bitbang_sendbits(sc, ops, MII_COMMAND_ACK, 2);
    170 	mii_bitbang_sendbits(sc, ops, val, 16);
    171 
    172 	WRITE(MDIRPHY);
    173 }
    174