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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* FPGA Manager Driver for Lattice iCE40.
*
* Copyright (c) 2016 Joel Holdsworth
*
* This driver adds support to the FPGA manager for configuring the SRAM of
* Lattice iCE40 FPGAs through slave SPI.
*/
#include <linux/fpga/fpga-mgr.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/spi/spi.h>
#include <linux/stringify.h>
#define ICE40_SPI_MAX_SPEED 25000000 /* Hz */
#define ICE40_SPI_MIN_SPEED 1000000 /* Hz */
#define ICE40_SPI_RESET_DELAY 1 /* us (>200ns) */
#define ICE40_SPI_HOUSEKEEPING_DELAY 1200 /* us */
#define ICE40_SPI_NUM_ACTIVATION_BYTES DIV_ROUND_UP(49, 8)
struct ice40_fpga_priv {
struct spi_device *dev;
struct gpio_desc *reset;
struct gpio_desc *cdone;
};
static enum fpga_mgr_states ice40_fpga_ops_state(struct fpga_manager *mgr)
{
struct ice40_fpga_priv *priv = mgr->priv;
return gpiod_get_value(priv->cdone) ? FPGA_MGR_STATE_OPERATING :
FPGA_MGR_STATE_UNKNOWN;
}
static int ice40_fpga_ops_write_init(struct fpga_manager *mgr,
struct fpga_image_info *info,
const char *buf, size_t count)
{
struct ice40_fpga_priv *priv = mgr->priv;
struct spi_device *dev = priv->dev;
struct spi_message message;
struct spi_transfer assert_cs_then_reset_delay = {
.cs_change = 1,
.delay = {
.value = ICE40_SPI_RESET_DELAY,
.unit = SPI_DELAY_UNIT_USECS
}
};
struct spi_transfer housekeeping_delay_then_release_cs = {
.delay = {
.value = ICE40_SPI_HOUSEKEEPING_DELAY,
.unit = SPI_DELAY_UNIT_USECS
}
};
int ret;
if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
dev_err(&dev->dev,
"Partial reconfiguration is not supported\n");
return -ENOTSUPP;
}
/* Lock the bus, assert CRESET_B and SS_B and delay >200ns */
spi_bus_lock(dev->master);
gpiod_set_value(priv->reset, 1);
spi_message_init(&message);
spi_message_add_tail(&assert_cs_then_reset_delay, &message);
ret = spi_sync_locked(dev, &message);
/* Come out of reset */
gpiod_set_value(priv->reset, 0);
/* Abort if the chip-select failed */
if (ret)
goto fail;
/* Check CDONE is de-asserted i.e. the FPGA is reset */
if (gpiod_get_value(priv->cdone)) {
dev_err(&dev->dev, "Device reset failed, CDONE is asserted\n");
ret = -EIO;
goto fail;
}
/* Wait for the housekeeping to complete, and release SS_B */
spi_message_init(&message);
spi_message_add_tail(&housekeeping_delay_then_release_cs, &message);
ret = spi_sync_locked(dev, &message);
fail:
spi_bus_unlock(dev->master);
return ret;
}
static int ice40_fpga_ops_write(struct fpga_manager *mgr,
const char *buf, size_t count)
{
struct ice40_fpga_priv *priv = mgr->priv;
return spi_write(priv->dev, buf, count);
}
static int ice40_fpga_ops_write_complete(struct fpga_manager *mgr,
struct fpga_image_info *info)
{
struct ice40_fpga_priv *priv = mgr->priv;
struct spi_device *dev = priv->dev;
const u8 padding[ICE40_SPI_NUM_ACTIVATION_BYTES] = {0};
/* Check CDONE is asserted */
if (!gpiod_get_value(priv->cdone)) {
dev_err(&dev->dev,
"CDONE was not asserted after firmware transfer\n");
return -EIO;
}
/* Send of zero-padding to activate the firmware */
return spi_write(dev, padding, sizeof(padding));
}
static const struct fpga_manager_ops ice40_fpga_ops = {
.state = ice40_fpga_ops_state,
.write_init = ice40_fpga_ops_write_init,
.write = ice40_fpga_ops_write,
.write_complete = ice40_fpga_ops_write_complete,
};
static int ice40_fpga_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
struct ice40_fpga_priv *priv;
struct fpga_manager *mgr;
int ret;
priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->dev = spi;
/* Check board setup data. */
if (spi->max_speed_hz > ICE40_SPI_MAX_SPEED) {
dev_err(dev, "SPI speed is too high, maximum speed is "
__stringify(ICE40_SPI_MAX_SPEED) "\n");
return -EINVAL;
}
if (spi->max_speed_hz < ICE40_SPI_MIN_SPEED) {
dev_err(dev, "SPI speed is too low, minimum speed is "
__stringify(ICE40_SPI_MIN_SPEED) "\n");
return -EINVAL;
}
if (spi->mode & SPI_CPHA) {
dev_err(dev, "Bad SPI mode, CPHA not supported\n");
return -EINVAL;
}
/* Set up the GPIOs */
priv->cdone = devm_gpiod_get(dev, "cdone", GPIOD_IN);
if (IS_ERR(priv->cdone)) {
ret = PTR_ERR(priv->cdone);
dev_err(dev, "Failed to get CDONE GPIO: %d\n", ret);
return ret;
}
priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
if (IS_ERR(priv->reset)) {
ret = PTR_ERR(priv->reset);
dev_err(dev, "Failed to get CRESET_B GPIO: %d\n", ret);
return ret;
}
mgr = devm_fpga_mgr_create(dev, "Lattice iCE40 FPGA Manager",
&ice40_fpga_ops, priv);
if (!mgr)
return -ENOMEM;
spi_set_drvdata(spi, mgr);
return fpga_mgr_register(mgr);
}
static int ice40_fpga_remove(struct spi_device *spi)
{
struct fpga_manager *mgr = spi_get_drvdata(spi);
fpga_mgr_unregister(mgr);
return 0;
}
static const struct of_device_id ice40_fpga_of_match[] = {
{ .compatible = "lattice,ice40-fpga-mgr", },
{},
};
MODULE_DEVICE_TABLE(of, ice40_fpga_of_match);
static struct spi_driver ice40_fpga_driver = {
.probe = ice40_fpga_probe,
.remove = ice40_fpga_remove,
.driver = {
.name = "ice40spi",
.of_match_table = of_match_ptr(ice40_fpga_of_match),
},
};
module_spi_driver(ice40_fpga_driver);
MODULE_AUTHOR("Joel Holdsworth <joel@airwebreathe.org.uk>");
MODULE_DESCRIPTION("Lattice iCE40 FPGA Manager");
MODULE_LICENSE("GPL v2");
|
