[mii] Add mii_find()
[ipxe.git] / src / drivers / net / mii.c
1 /*
2 * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 #include <string.h>
27 #include <unistd.h>
28 #include <errno.h>
29 #include <ipxe/mii.h>
30
31 /** @file
32 *
33 * Media Independent Interface
34 *
35 */
36
37 /**
38 * Restart autonegotiation
39 *
40 * @v mii MII device
41 * @ret rc Return status code
42 */
43 int mii_restart ( struct mii_device *mii ) {
44 int bmcr;
45 int rc;
46
47 /* Read BMCR */
48 bmcr = mii_read ( mii, MII_BMCR );
49 if ( bmcr < 0 ) {
50 rc = bmcr;
51 DBGC ( mii, "MII %p could not read BMCR: %s\n",
52 mii, strerror ( rc ) );
53 return rc;
54 }
55
56 /* Enable and restart autonegotiation */
57 bmcr |= ( BMCR_ANENABLE | BMCR_ANRESTART );
58 if ( ( rc = mii_write ( mii, MII_BMCR, bmcr ) ) != 0 ) {
59 DBGC ( mii, "MII %p could not write BMCR: %s\n",
60 mii, strerror ( rc ) );
61 return rc;
62 }
63
64 DBGC ( mii, "MII %p restarted autonegotiation\n", mii );
65 return 0;
66 }
67
68 /**
69 * Reset MII device
70 *
71 * @v mii MII device
72 * @ret rc Return status code
73 */
74 int mii_reset ( struct mii_device *mii ) {
75 unsigned int i;
76 int bmcr;
77 int rc;
78
79 /* Power-up, enable autonegotiation and initiate reset */
80 if ( ( rc = mii_write ( mii, MII_BMCR,
81 ( BMCR_RESET | BMCR_ANENABLE ) ) ) != 0 ) {
82 DBGC ( mii, "MII %p could not write BMCR: %s\n",
83 mii, strerror ( rc ) );
84 return rc;
85 }
86
87 /* Wait for reset to complete */
88 for ( i = 0 ; i < MII_RESET_MAX_WAIT_MS ; i++ ) {
89
90 /* Check if reset has completed */
91 bmcr = mii_read ( mii, MII_BMCR );
92 if ( bmcr < 0 ) {
93 rc = bmcr;
94 DBGC ( mii, "MII %p could not read BMCR: %s\n",
95 mii, strerror ( rc ) );
96 return rc;
97 }
98
99 /* If reset is not complete, delay 1ms and retry */
100 if ( bmcr & BMCR_RESET ) {
101 mdelay ( 1 );
102 continue;
103 }
104
105 /* Force autonegotation on again, in case it was
106 * cleared by the reset.
107 */
108 if ( ( rc = mii_restart ( mii ) ) != 0 )
109 return rc;
110
111 DBGC ( mii, "MII %p reset after %dms\n", mii, i );
112 return 0;
113 }
114
115 DBGC ( mii, "MII %p timed out waiting for reset\n", mii );
116 return -ETIMEDOUT;
117 }
118
119 /**
120 * Update link status via MII
121 *
122 * @v mii MII device
123 * @v netdev Network device
124 * @ret rc Return status code
125 */
126 int mii_check_link ( struct mii_device *mii, struct net_device *netdev ) {
127 int bmsr;
128 int link;
129 int rc;
130
131 /* Read BMSR */
132 bmsr = mii_read ( mii, MII_BMSR );
133 if ( bmsr < 0 ) {
134 rc = bmsr;
135 return rc;
136 }
137
138 /* Report link status */
139 link = ( bmsr & BMSR_LSTATUS );
140 DBGC ( mii, "MII %p link %s (BMSR %#04x)\n",
141 mii, ( link ? "up" : "down" ), bmsr );
142 if ( link ) {
143 netdev_link_up ( netdev );
144 } else {
145 netdev_link_down ( netdev );
146 }
147
148 return 0;
149 }
150
151 /**
152 * Find PHY address
153 *
154 * @v mii MII device
155 * @ret rc Return status code
156 */
157 int mii_find ( struct mii_device *mii ) {
158 unsigned int address;
159 int id;
160
161 /* Try all possible PHY addresses */
162 for ( address = 0 ; address <= MII_MAX_PHY_ADDRESS ; address++ ) {
163 mii->address = address;
164 id = mii_read ( mii, MII_PHYSID1 );
165 if ( ( id > 0x0000 ) && ( id < 0xffff ) ) {
166 DBGC ( mii, "MII %p found PHY at address %d\n",
167 mii, address );
168 return 0;
169 }
170 }
171
172 DBGC ( mii, "MII %p failed to find an address\n", mii );
173 return -ENOENT;
174 }