summaryrefslogtreecommitdiff
path: root/src/drivers/spi/spi-generic.c
blob: 84a42d1c9c19a7e24b04a7752e9b57d366b3faf1 (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
/*
 * This file is part of the coreboot project.
 *
 * Copyright 2016 Google Inc.
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 */

#include <assert.h>
#include <spi-generic.h>
#include <string.h>

int spi_claim_bus(const struct spi_slave *slave)
{
	const struct spi_ctrlr *ctrlr = slave->ctrlr;
	if (ctrlr && ctrlr->claim_bus)
		return ctrlr->claim_bus(slave);
	return 0;
}

void spi_release_bus(const struct spi_slave *slave)
{
	const struct spi_ctrlr *ctrlr = slave->ctrlr;
	if (ctrlr && ctrlr->release_bus)
		ctrlr->release_bus(slave);
}

static int spi_xfer_single_op(const struct spi_slave *slave,
			struct spi_op *op)
{
	const struct spi_ctrlr *ctrlr = slave->ctrlr;
	int ret;

	if (!ctrlr || !ctrlr->xfer)
		return -1;

	ret = ctrlr->xfer(slave, op->dout, op->bytesout, op->din, op->bytesin);
	if (ret)
		op->status = SPI_OP_FAILURE;
	else
		op->status = SPI_OP_SUCCESS;

	return ret;
}

static int spi_xfer_vector_default(const struct spi_slave *slave,
				struct spi_op vectors[], size_t count)
{
	size_t i;
	int ret;

	for (i = 0; i < count; i++) {
		ret = spi_xfer_single_op(slave, &vectors[i]);
		if (ret)
			return ret;
	}

	return 0;
}

int spi_xfer_vector(const struct spi_slave *slave,
		struct spi_op vectors[], size_t count)
{
	const struct spi_ctrlr *ctrlr = slave->ctrlr;

	if (ctrlr && ctrlr->xfer_vector)
		return ctrlr->xfer_vector(slave, vectors, count);

	return spi_xfer_vector_default(slave, vectors, count);
}

int spi_xfer(const struct spi_slave *slave, const void *dout, size_t bytesout,
	     void *din, size_t bytesin)
{
	const struct spi_ctrlr *ctrlr = slave->ctrlr;

	if (ctrlr && ctrlr->xfer)
		return ctrlr->xfer(slave, dout, bytesout, din, bytesin);

	return -1;
}

unsigned int spi_crop_chunk(const struct spi_slave *slave, unsigned int cmd_len,
			unsigned int buf_len)
{
	const struct spi_ctrlr *ctrlr = slave->ctrlr;
	unsigned int ctrlr_max;
	bool deduct_cmd_len;
	bool deduct_opcode_len;

	if (!ctrlr)
		return 0;

	deduct_cmd_len = !!(ctrlr->flags & SPI_CNTRLR_DEDUCT_CMD_LEN);
	deduct_opcode_len = !!(ctrlr->flags & SPI_CNTRLR_DEDUCT_OPCODE_LEN);
	ctrlr_max = ctrlr->max_xfer_size;

	assert (ctrlr_max != 0);

	/* Assume opcode is always one byte and deduct it from the cmd_len
	   as the hardware has a separate register for the opcode. */
	if (deduct_opcode_len)
		cmd_len--;

	if (deduct_cmd_len && (ctrlr_max > cmd_len))
		ctrlr_max -= cmd_len;

	return min(ctrlr_max, buf_len);
}

void __weak spi_init(void)
{
	/* Default weak implementation - do nothing. */
}

int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)
{
	size_t i;

	memset(slave, 0, sizeof(*slave));

	for (i = 0; i < spi_ctrlr_bus_map_count; i++) {
		if ((spi_ctrlr_bus_map[i].bus_start <= bus) &&
		    (spi_ctrlr_bus_map[i].bus_end >= bus)) {
			slave->ctrlr = spi_ctrlr_bus_map[i].ctrlr;
			break;
		}
	}

	if (slave->ctrlr == NULL)
		return -1;

	slave->bus = bus;
	slave->cs = cs;

	if (slave->ctrlr->setup)
		return slave->ctrlr->setup(slave);

	return 0;
}