summaryrefslogtreecommitdiff
path: root/src/soc/nvidia/tegra/i2c.c
blob: 8c8a3727989e9809760b4e25024467549af0683d (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
168
169
170
171
172
173
174
175
176
177
/*
 * This file is part of the coreboot project.
 *
 * Copyright 2013 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; 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 <arch/io.h>
#include <console/console.h>
#include <device/i2c.h>
#include <stdlib.h>
#include <string.h>
#include <soc/addressmap.h>

#include "i2c.h"

static int tegra_i2c_send_recv(int bus, int read,
			       uint32_t *headers, int header_words,
			       uint8_t *data, int data_len)
{
	struct tegra_i2c_bus_info *info = &tegra_i2c_info[bus];
	struct tegra_i2c_regs * const regs = info->base;

	while (data_len) {
		uint32_t status = read32(&regs->fifo_status);
		int tx_empty = status & I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT_MASK;
		tx_empty >>= I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT_SHIFT;
		int rx_full = status & I2C_FIFO_STATUS_RX_FIFO_FULL_CNT_MASK;
		rx_full >>= I2C_FIFO_STATUS_RX_FIFO_FULL_CNT_SHIFT;

		while (header_words && tx_empty) {
			write32(*headers++, &regs->tx_packet_fifo);
			header_words--;
			tx_empty--;
		}

		if (!header_words) {
			if (read) {
				while (data_len && rx_full) {
					uint32_t word = read32(&regs->rx_fifo);
					int todo = MIN(data_len, sizeof(word));

					memcpy(data, &word, todo);
					data_len -= todo;
					data += sizeof(word);
					rx_full--;
				}
			} else {
				while (data_len && tx_empty) {
					uint32_t word;
					int todo = MIN(data_len, sizeof(word));

					memcpy(&word, data, todo);
					write32(word, &regs->tx_packet_fifo);
					data_len -= todo;
					data += sizeof(word);
					tx_empty--;
				}
			}
		}

		uint32_t transfer_status =
			read32(&regs->packet_transfer_status);

		if (transfer_status & I2C_PKT_STATUS_NOACK_ADDR) {
			printk(BIOS_ERR,
			       "%s: The address was not acknowledged.\n",
			       __func__);
			info->reset_func(info->reset_bit);
			return -1;
		} else if (transfer_status & I2C_PKT_STATUS_NOACK_DATA) {
			printk(BIOS_ERR,
			       "%s: The data was not acknowledged.\n",
			       __func__);
			info->reset_func(info->reset_bit);
			return -1;
		} else if (transfer_status & I2C_PKT_STATUS_ARB_LOST) {
			printk(BIOS_ERR,
			       "%s: Lost arbitration.\n",
			       __func__);
			info->reset_func(info->reset_bit);
			return -1;
		}
	}

	return 0;
}

static int tegra_i2c_request(int bus, unsigned chip, int cont, int restart,
			     int read, void *data, int data_len)
{
	uint32_t headers[3];

	if (restart && cont) {
		printk(BIOS_ERR, "%s: Repeat start and continue xfer are "
			"mutually exclusive.\n", __func__);
		return -1;
	}

	headers[0] = (0 << IOHEADER_PROTHDRSZ_SHIFT) |
		     (1 << IOHEADER_PKTID_SHIFT) |
		     (bus << IOHEADER_CONTROLLER_ID_SHIFT) |
		     IOHEADER_PROTOCOL_I2C | IOHEADER_PKTTYPE_REQUEST;

	headers[1] = (data_len - 1) << IOHEADER_PAYLOADSIZE_SHIFT;

	uint32_t slave_addr = (chip << 1) | (read ? 1 : 0);
	headers[2] = IOHEADER_I2C_REQ_ADDR_MODE_7BIT |
		     (slave_addr << IOHEADER_I2C_REQ_SLAVE_ADDR_SHIFT);
	if (read)
		headers[2] |= IOHEADER_I2C_REQ_READ;
	if (restart)
		headers[2] |= IOHEADER_I2C_REQ_REPEAT_START;
	if (cont)
		headers[2] |= IOHEADER_I2C_REQ_CONTINUE_XFER;

	return tegra_i2c_send_recv(bus, read, headers, ARRAY_SIZE(headers),
				   data, data_len);
}

static int i2c_readwrite(unsigned bus, unsigned chip, unsigned addr,
			 unsigned alen, uint8_t *buf, unsigned len, int read)
{
	const uint32_t max_payload =
		(IOHEADER_PAYLOADSIZE_MASK + 1) >> IOHEADER_PAYLOADSIZE_SHIFT;
	uint8_t abuf[sizeof(addr)];

	int i;
	for (i = 0; i < alen; i++)
		abuf[i] = addr >> ((alen - i - 1) * 8);

	if (tegra_i2c_request(bus, chip, !read, 0, 0, abuf, alen))
		return -1;

	while (len) {
		int todo = MIN(len, max_payload);
		int cont = (todo < len);
		if (tegra_i2c_request(bus, chip, cont, 0, read, buf, todo)) {
			// We should reset the controller here.
			return -1;
		}
		len -= todo;
		buf += todo;
	}
	return 0;
}

int i2c_read(unsigned bus, unsigned chip, unsigned addr,
		unsigned alen, uint8_t *buf, unsigned len)
{
	return i2c_readwrite(bus, chip, addr, alen, buf, len, 1);
}

int i2c_write(unsigned bus, unsigned chip, unsigned addr,
		unsigned alen, const uint8_t *buf, unsigned len)
{
	return i2c_readwrite(bus, chip, addr, alen, (void *)buf, len, 0);
}

void i2c_init(unsigned bus)
{
	struct tegra_i2c_regs * const regs = tegra_i2c_info[bus].base;

	write32(I2C_CNFG_PACKET_MODE_EN, &regs->cnfg);
}