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Root/trunk/bitbang_spi.c

1/*␊
2 * This file is part of the flashrom project.␊
3 *␊
4 * Copyright (C) 2009, 2010 Carl-Daniel Hailfinger␊
5 *␊
6 * This program is free software; you can redistribute it and/or modify␊
7 * it under the terms of the GNU General Public License as published by␊
8 * the Free Software Foundation; version 2 of the License.␊
9 *␊
10 * This program is distributed in the hope that it will be useful,␊
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of␊
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the␊
13 * GNU General Public License for more details.␊
14 *␊
15 * You should have received a copy of the GNU General Public License␊
16 * along with this program; if not, write to the Free Software␊
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA␊
18 */␊
19␊
20#include <stdio.h>␊
21#include <string.h>␊
22#include <stdlib.h>␊
23#include <ctype.h>␊
24#include "flash.h"␊
25#include "programmer.h"␊
26#include "spi.h"␊
27␊
28/* Note that CS# is active low, so val=0 means the chip is active. */␊
29static void bitbang_spi_set_cs(const const struct bitbang_spi_master *master, int val)␊
30{␊
31␉master->set_cs(val);␊
32}␊
33␊
34static void bitbang_spi_set_sck(const const struct bitbang_spi_master *master, int val)␊
35{␊
36␉master->set_sck(val);␊
37}␊
38␊
39static void bitbang_spi_set_mosi(const const struct bitbang_spi_master *master, int val)␊
40{␊
41␉master->set_mosi(val);␊
42}␊
43␊
44static int bitbang_spi_get_miso(const const struct bitbang_spi_master *master)␊
45{␊
46␉return master->get_miso();␊
47}␊
48␊
49static void bitbang_spi_request_bus(const const struct bitbang_spi_master *master)␊
50{␊
51␉if (master->request_bus)␊
52␉␉master->request_bus();␊
53}␊
54␊
55static void bitbang_spi_release_bus(const const struct bitbang_spi_master *master)␊
56{␊
57␉if (master->release_bus)␊
58␉␉master->release_bus();␊
59}␊
60␊
61static int bitbang_spi_send_command(struct flashctx *flash,␊
62␉␉␉␉ unsigned int writecnt, unsigned int readcnt,␊
63␉␉␉␉ const unsigned char *writearr,␊
64␉␉␉␉ unsigned char *readarr);␊
65␊
66static const struct spi_programmer spi_programmer_bitbang = {␊
67␉.type␉␉= SPI_CONTROLLER_BITBANG,␊
68␉.max_data_read␉= MAX_DATA_READ_UNLIMITED,␊
69␉.max_data_write␉= MAX_DATA_WRITE_UNLIMITED,␊
70␉.command␉= bitbang_spi_send_command,␊
71␉.multicommand␉= default_spi_send_multicommand,␊
72␉.read␉␉= default_spi_read,␊
73␉.write_256␉= default_spi_write_256,␊
74};␊
75␊
76#if 0 // until it is needed␊
77static int bitbang_spi_shutdown(const struct bitbang_spi_master *master)␊
78{␊
79␉/* FIXME: Run bitbang_spi_release_bus here or per command? */␊
80␉return 0;␊
81}␊
82#endif␊
83␊
84int bitbang_spi_init(const struct bitbang_spi_master *master)␊
85{␊
86␉struct spi_programmer pgm = spi_programmer_bitbang;␊
87␉/* BITBANG_SPI_INVALID is 0, so if someone forgot to initialize ->type,␊
88␉ * we catch it here. Same goes for missing initialization of bitbanging␊
89␉ * functions.␊
90␉ */␊
91␉if (!master || master->type == BITBANG_SPI_INVALID || !master->set_cs ||␊
92␉ !master->set_sck || !master->set_mosi || !master->get_miso ||␊
93␉ (master->request_bus && !master->release_bus) ||␊
94␉ (!master->request_bus && master->release_bus)) {␊
95␉␉msg_perr("Incomplete SPI bitbang master setting!\n"␊
96␉␉␉ "Please report a bug at flashrom@flashrom.org\n");␊
97␉␉return ERROR_FLASHROM_BUG;␊
98␉}␊
99␊
100␉pgm.data = master;␊
101␉register_spi_programmer(&pgm);␊
102␊
103␉/* Only mess with the bus if we're sure nobody else uses it. */␊
104␉bitbang_spi_request_bus(master);␊
105␉bitbang_spi_set_cs(master, 1);␊
106␉bitbang_spi_set_sck(master, 0);␊
107␉bitbang_spi_set_mosi(master, 0);␊
108␉/* FIXME: Release SPI bus here and request it again for each command or␊
109␉ * don't release it now and only release it on programmer shutdown?␊
110␉ */␊
111␉bitbang_spi_release_bus(master);␊
112␉return 0;␊
113}␊
114␊
115static uint8_t bitbang_spi_rw_byte(const struct bitbang_spi_master *master,␊
116␉␉␉␉ uint8_t val)␊
117{␊
118␉uint8_t ret = 0;␊
119␉int i;␊
120␊
121␉for (i = 7; i >= 0; i--) {␊
122␉␉bitbang_spi_set_mosi(master, (val >> i) & 1);␊
123␉␉programmer_delay(master->half_period);␊
124␉␉bitbang_spi_set_sck(master, 1);␊
125␉␉ret <<= 1;␊
126␉␉ret |= bitbang_spi_get_miso(master);␊
127␉␉programmer_delay(master->half_period);␊
128␉␉bitbang_spi_set_sck(master, 0);␊
129␉}␊
130␉return ret;␊
131}␊
132␊
133static int bitbang_spi_send_command(struct flashctx *flash,␊
134␉␉␉␉ unsigned int writecnt, unsigned int readcnt,␊
135␉␉␉␉ const unsigned char *writearr,␊
136␉␉␉␉ unsigned char *readarr)␊
137{␊
138␉int i;␊
139␉const struct bitbang_spi_master *master = flash->pgm->spi.data;␊
140␊
141␉/* FIXME: Run bitbang_spi_request_bus here or in programmer init?␊
142␉ * Requesting and releasing the SPI bus is handled in here to allow the␊
143␉ * programmer to use its own SPI engine for native accesses.␊
144␉ */␊
145␉bitbang_spi_request_bus(master);␊
146␉bitbang_spi_set_cs(master, 0);␊
147␉for (i = 0; i < writecnt; i++)␊
148␉␉bitbang_spi_rw_byte(master, writearr[i]);␊
149␉for (i = 0; i < readcnt; i++)␊
150␉␉readarr[i] = bitbang_spi_rw_byte(master, 0);␊
151␊
152␉programmer_delay(master->half_period);␊
153␉bitbang_spi_set_cs(master, 1);␊
154␉programmer_delay(master->half_period);␊
155␉/* FIXME: Run bitbang_spi_release_bus here or in programmer init? */␊
156␉bitbang_spi_release_bus(master);␊
157␊
158␉return 0;␊
159}␊
160

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