summaryrefslogtreecommitdiffstats
path: root/bitbang_spi.c
blob: b10fc2609b9a7962d02c71700fe171fe2b9bc9bc (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
/*
 * 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"

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

static void bitbang_spi_set_sck(const struct bitbang_spi_master * const master, int val)
{
	master->set_sck(val);
}

static void bitbang_spi_set_mosi(const struct bitbang_spi_master * const master, int val)
{
	master->set_mosi(val);
}

static int bitbang_spi_get_miso(const struct bitbang_spi_master * const master)
{
	return master->get_miso();
}

static void bitbang_spi_request_bus(const struct bitbang_spi_master * const master)
{
	if (master->request_bus)
		master->request_bus();
}

static void bitbang_spi_release_bus(const struct bitbang_spi_master * const master)
{
	if (master->release_bus)
		master->release_bus();
}

static int bitbang_spi_send_command(struct flashctx *flash,
				    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,
	.write_aai	= default_spi_write_aai,
};

#if 0 // until it is needed
static int bitbang_spi_shutdown(const struct bitbang_spi_master *master)
{
	/* FIXME: Run bitbang_spi_release_bus here or per command? */
	return 0;
}
#endif

int bitbang_spi_init(const struct bitbang_spi_master *master)
{
	struct spi_programmer pgm = spi_programmer_bitbang;
	/* 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 ||
	    (master->request_bus && !master->release_bus) ||
	    (!master->request_bus && master->release_bus)) {
		msg_perr("Incomplete SPI bitbang master setting!\n"
			 "Please report a bug at flashrom@flashrom.org\n");
		return ERROR_FLASHROM_BUG;
	}

	pgm.data = master;
	register_spi_programmer(&pgm);

	/* Only mess with the bus if we're sure nobody else uses it. */
	bitbang_spi_request_bus(master);
	bitbang_spi_set_cs(master, 1);
	bitbang_spi_set_sck(master, 0);
	bitbang_spi_set_mosi(master, 0);
	/* FIXME: Release SPI bus here and request it again for each command or
	 * don't release it now and only release it on programmer shutdown?
	 */
	bitbang_spi_release_bus(master);
	return 0;
}

static uint8_t bitbang_spi_rw_byte(const struct bitbang_spi_master *master,
				   uint8_t val)
{
	uint8_t ret = 0;
	int i;

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

static int bitbang_spi_send_command(struct flashctx *flash,
				    unsigned int writecnt, unsigned int readcnt,
				    const unsigned char *writearr,
				    unsigned char *readarr)
{
	int i;
	const struct bitbang_spi_master *master = flash->pgm->spi.data;

	/* 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(master);
	bitbang_spi_set_cs(master, 0);
	for (i = 0; i < writecnt; i++)
		bitbang_spi_rw_byte(master, writearr[i]);
	for (i = 0; i < readcnt; i++)
		readarr[i] = bitbang_spi_rw_byte(master, 0);

	programmer_delay(master->half_period);
	bitbang_spi_set_cs(master, 1);
	programmer_delay(master->half_period);
	/* FIXME: Run bitbang_spi_release_bus here or in programmer init? */
	bitbang_spi_release_bus(master);

	return 0;
}