summaryrefslogtreecommitdiffstats
path: root/bitbang_spi.c
blob: 391fd324662788b3d1475d1e717d04e3a8be90db (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
/*
 * This file is part of the flashrom project.
 *
 * Copyright (C) 2009, 2010 Carl-Daniel Hailfinger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include "flash.h"
#include "programmer.h"
#include "spi.h"

/* Length of half a clock period in usecs. */
static int bitbang_spi_half_period;

static const struct bitbang_spi_master *bitbang_spi_master = NULL;

/* Note that CS# is active low, so val=0 means the chip is active. */
static void bitbang_spi_set_cs(int val)
{
	bitbang_spi_master->set_cs(val);
}

static void bitbang_spi_set_sck(int val)
{
	bitbang_spi_master->set_sck(val);
}

static void bitbang_spi_set_mosi(int val)
{
	bitbang_spi_master->set_mosi(val);
}

static int bitbang_spi_get_miso(void)
{
	return bitbang_spi_master->get_miso();
}

static void bitbang_spi_request_bus(void)
{
	if (bitbang_spi_master->request_bus)
		bitbang_spi_master->request_bus();
}

static void bitbang_spi_release_bus(void)
{
	if (bitbang_spi_master->release_bus)
		bitbang_spi_master->release_bus();
}

static int bitbang_spi_send_command(unsigned int writecnt, unsigned int readcnt,
		const unsigned char *writearr, unsigned char *readarr);

static const struct spi_programmer spi_programmer_bitbang = {
	.type		= SPI_CONTROLLER_BITBANG,
	.max_data_read	= MAX_DATA_READ_UNLIMITED,
	.max_data_write	= MAX_DATA_WRITE_UNLIMITED,
	.command	= bitbang_spi_send_command,
	.multicommand	= default_spi_send_multicommand,
	.read		= default_spi_read,
	.write_256	= default_spi_write_256,
};

int bitbang_spi_init(const struct bitbang_spi_master *master, int halfperiod)
{
	/* BITBANG_SPI_INVALID is 0, so if someone forgot to initialize ->type,
	 * we catch it here. Same goes for missing initialization of bitbanging
	 * functions.
	 */
	if (!master || master->type == BITBANG_SPI_INVALID || !master->set_cs ||
	    !master->set_sck || !master->set_mosi || !master->get_miso) {
		msg_perr("Incomplete SPI bitbang master setting!\n"
			 "Please report a bug at flashrom@flashrom.org\n");
		return 1;
	}
	if (bitbang_spi_master) {
		msg_perr("SPI bitbang master already initialized!\n"
			 "Please report a bug at flashrom@flashrom.org\n");
		return 1;
	}

	bitbang_spi_master = master;
	bitbang_spi_half_period = halfperiod;

	register_spi_programmer(&spi_programmer_bitbang);

	/* FIXME: Run bitbang_spi_request_bus here or in programmer init? */
	bitbang_spi_set_cs(1);
	bitbang_spi_set_sck(0);
	bitbang_spi_set_mosi(0);
	return 0;
}

int bitbang_spi_shutdown(const struct bitbang_spi_master *master)
{
	if (!bitbang_spi_master) {
		msg_perr("Shutting down an uninitialized SPI bitbang master!\n"
			 "Please report a bug at flashrom@flashrom.org\n");
		return 1;
	}
	if (master != bitbang_spi_master) {
		msg_perr("Shutting down a mismatched SPI bitbang master!\n"
			 "Please report a bug at flashrom@flashrom.org\n");
		return 1;
	}

	/* FIXME: Run bitbang_spi_release_bus here or per command? */
	bitbang_spi_master = NULL;
	return 0;
}

static uint8_t bitbang_spi_readwrite_byte(uint8_t val)
{
	uint8_t ret = 0;
	int i;

	for (i = 7; i >= 0; i--) {
		bitbang_spi_set_mosi((val >> i) & 1);
		programmer_delay(bitbang_spi_half_period);
		bitbang_spi_set_sck(1);
		ret <<= 1;
		ret |= bitbang_spi_get_miso();
		programmer_delay(bitbang_spi_half_period);
		bitbang_spi_set_sck(0);
	}
	return ret;
}

static int bitbang_spi_send_command(unsigned int writecnt, unsigned int readcnt,
		const unsigned char *writearr, unsigned char *readarr)
{
	int i;

	/* FIXME: Run bitbang_spi_request_bus here or in programmer init?
	 * Requesting and releasing the SPI bus is handled in here to allow the
	 * programmer to use its own SPI engine for native accesses.
	 */
	bitbang_spi_request_bus();
	bitbang_spi_set_cs(0);
	for (i = 0; i < writecnt; i++)
		bitbang_spi_readwrite_byte(writearr[i]);
	for (i = 0; i < readcnt; i++)
		readarr[i] = bitbang_spi_readwrite_byte(0);

	programmer_delay(bitbang_spi_half_period);
	bitbang_spi_set_cs(1);
	programmer_delay(bitbang_spi_half_period);
	/* FIXME: Run bitbang_spi_release_bus here or in programmer init? */
	bitbang_spi_release_bus();

	return 0;
}