[tcpip] Allow supported address families to be detected at runtime
[ipxe.git] / src / drivers / nvs / threewire.c
1 /*
2 * Copyright (C) 2006 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 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 <stddef.h>
27 #include <string.h>
28 #include <assert.h>
29 #include <unistd.h>
30 #include <ipxe/threewire.h>
31
32 /** @file
33 *
34 * Three-wire serial devices
35 *
36 */
37
38 /**
39 * Read data from three-wire device
40 *
41 * @v nvs NVS device
42 * @v address Address from which to read
43 * @v data Data buffer
44 * @v len Length of data buffer
45 * @ret rc Return status code
46 */
47 int threewire_read ( struct nvs_device *nvs, unsigned int address,
48 void *data, size_t len ) {
49 struct spi_device *device = nvs_to_spi ( nvs );
50 struct spi_bus *bus = device->bus;
51 int rc;
52
53 assert ( bus->mode == SPI_MODE_THREEWIRE );
54
55 DBGC ( device, "3wire %p reading %zd bytes at %04x\n",
56 device, len, address );
57
58 if ( ( rc = bus->rw ( bus, device, THREEWIRE_READ, address,
59 NULL, data, len ) ) != 0 ) {
60 DBGC ( device, "3wire %p could not read: %s\n",
61 device, strerror ( rc ) );
62 return rc;
63 }
64
65 return 0;
66 }
67
68 /**
69 * Write data to three-wire device
70 *
71 * @v nvs NVS device
72 * @v address Address from which to read
73 * @v data Data buffer
74 * @v len Length of data buffer
75 * @ret rc Return status code
76 */
77 int threewire_write ( struct nvs_device *nvs, unsigned int address,
78 const void *data, size_t len ) {
79 struct spi_device *device = nvs_to_spi ( nvs );
80 struct spi_bus *bus = device->bus;
81 int rc;
82
83 assert ( bus->mode == SPI_MODE_THREEWIRE );
84
85 DBGC ( device, "3wire %p writing %zd bytes at %04x\n",
86 device, len, address );
87
88 /* Enable device for writing */
89 if ( ( rc = bus->rw ( bus, device, THREEWIRE_EWEN,
90 THREEWIRE_EWEN_ADDRESS, NULL, NULL, 0 ) ) != 0 ){
91 DBGC ( device, "3wire %p could not enable writing: %s\n",
92 device, strerror ( rc ) );
93 return rc;
94 }
95
96 /* Write data */
97 if ( ( rc = bus->rw ( bus, device, THREEWIRE_WRITE, address,
98 data, NULL, len ) ) != 0 ) {
99 DBGC ( device, "3wire %p could not write: %s\n",
100 device, strerror ( rc ) );
101 return rc;
102 }
103
104 /* Our model of an SPI bus doesn't provide a mechanism for
105 * "assert CS, wait for MISO to become high, so just wait for
106 * long enough to ensure that the write has completed.
107 */
108 mdelay ( THREEWIRE_WRITE_MDELAY );
109
110 return 0;
111 }
112
113 /**
114 * Autodetect device address length
115 *
116 * @v device SPI device
117 * @ret rc Return status code
118 */
119 int threewire_detect_address_len ( struct spi_device *device ) {
120 struct nvs_device *nvs = &device->nvs;
121 int rc;
122
123 DBGC ( device, "3wire %p autodetecting address length\n", device );
124
125 device->address_len = SPI_AUTODETECT_ADDRESS_LEN;
126 if ( ( rc = threewire_read ( nvs, 0, NULL,
127 ( 1 << nvs->word_len_log2 ) ) ) != 0 ) {
128 DBGC ( device, "3wire %p could not autodetect address "
129 "length: %s\n", device, strerror ( rc ) );
130 return rc;
131 }
132
133 DBGC ( device, "3wire %p autodetected address length %d\n",
134 device, device->address_len );
135 return 0;
136 }