2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
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.
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.
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
20 FILE_LICENCE ( GPL2_OR_LATER );
26 #include <ipxe/threewire.h>
30 * Three-wire serial devices
35 * Read data from three-wire device
38 * @v address Address from which to read
40 * @v len Length of data buffer
41 * @ret rc Return status code
43 int threewire_read ( struct nvs_device *nvs, unsigned int address,
44 void *data, size_t len ) {
45 struct spi_device *device = nvs_to_spi ( nvs );
46 struct spi_bus *bus = device->bus;
49 assert ( bus->mode == SPI_MODE_THREEWIRE );
51 DBGC ( device, "3wire %p reading %zd bytes at %04x\n",
52 device, len, address );
54 if ( ( rc = bus->rw ( bus, device, THREEWIRE_READ, address,
55 NULL, data, len ) ) != 0 ) {
56 DBGC ( device, "3wire %p could not read: %s\n",
57 device, strerror ( rc ) );
65 * Write data to three-wire device
68 * @v address Address from which to read
70 * @v len Length of data buffer
71 * @ret rc Return status code
73 int threewire_write ( struct nvs_device *nvs, unsigned int address,
74 const void *data, size_t len ) {
75 struct spi_device *device = nvs_to_spi ( nvs );
76 struct spi_bus *bus = device->bus;
79 assert ( bus->mode == SPI_MODE_THREEWIRE );
81 DBGC ( device, "3wire %p writing %zd bytes at %04x\n",
82 device, len, address );
84 /* Enable device for writing */
85 if ( ( rc = bus->rw ( bus, device, THREEWIRE_EWEN,
86 THREEWIRE_EWEN_ADDRESS, NULL, NULL, 0 ) ) != 0 ){
87 DBGC ( device, "3wire %p could not enable writing: %s\n",
88 device, strerror ( rc ) );
93 if ( ( rc = bus->rw ( bus, device, THREEWIRE_WRITE, address,
94 data, NULL, len ) ) != 0 ) {
95 DBGC ( device, "3wire %p could not write: %s\n",
96 device, strerror ( rc ) );
100 /* Our model of an SPI bus doesn't provide a mechanism for
101 * "assert CS, wait for MISO to become high, so just wait for
102 * long enough to ensure that the write has completed.
104 mdelay ( THREEWIRE_WRITE_MDELAY );
110 * Autodetect device address length
112 * @v device SPI device
113 * @ret rc Return status code
115 int threewire_detect_address_len ( struct spi_device *device ) {
116 struct nvs_device *nvs = &device->nvs;
119 DBGC ( device, "3wire %p autodetecting address length\n", device );
121 device->address_len = SPI_AUTODETECT_ADDRESS_LEN;
122 if ( ( rc = threewire_read ( nvs, 0, NULL,
123 ( 1 << nvs->word_len_log2 ) ) ) != 0 ) {
124 DBGC ( device, "3wire %p could not autodetect address "
125 "length: %s\n", device, strerror ( rc ) );
129 DBGC ( device, "3wire %p autodetected address length %d\n",
130 device, device->address_len );