1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Altera Passive Serial SPI Driver
4 *
5 * Copyright (c) 2017 United Western Technologies, Corporation
6 *
7 * Joshua Clayton <stillcompiling@gmail.com>
8 *
9 * Manage Altera FPGA firmware that is loaded over SPI using the passive
10 * serial configuration method.
11 * Firmware must be in binary "rbf" format.
12 * Works on Arria 10, Cyclone V and Stratix V. Should work on Cyclone series.
13 * May work on other Altera FPGAs.
14 */
15
16 #include <linux/bitrev.h>
17 #include <linux/delay.h>
18 #include <linux/fpga/fpga-mgr.h>
19 #include <linux/gpio/consumer.h>
20 #include <linux/module.h>
21 #include <linux/of_gpio.h>
22 #include <linux/of_device.h>
23 #include <linux/spi/spi.h>
24 #include <linux/sizes.h>
25
26 enum altera_ps_devtype {
27 CYCLONE5,
28 ARRIA10,
29 };
30
31 struct altera_ps_data {
32 enum altera_ps_devtype devtype;
33 int status_wait_min_us;
34 int status_wait_max_us;
35 int t_cfg_us;
36 int t_st2ck_us;
37 };
38
39 struct altera_ps_conf {
40 struct gpio_desc *config;
41 struct gpio_desc *confd;
42 struct gpio_desc *status;
43 struct spi_device *spi;
44 const struct altera_ps_data *data;
45 u32 info_flags;
46 char mgr_name[64];
47 };
48
49 /* | Arria 10 | Cyclone5 | Stratix5 |
50 * t_CF2ST0 | [; 600] | [; 600] | [; 600] |ns
51 * t_CFG | [2;] | [2;] | [2;] |µs
52 * t_STATUS | [268; 3000] | [268; 1506] | [268; 1506] |µs
53 * t_CF2ST1 | [; 3000] | [; 1506] | [; 1506] |µs
54 * t_CF2CK | [3010;] | [1506;] | [1506;] |µs
55 * t_ST2CK | [10;] | [2;] | [2;] |µs
56 * t_CD2UM | [175; 830] | [175; 437] | [175; 437] |µs
57 */
58 static struct altera_ps_data c5_data = {
59 /* these values for Cyclone5 are compatible with Stratix5 */
60 .devtype = CYCLONE5,
61 .status_wait_min_us = 268,
62 .status_wait_max_us = 1506,
63 .t_cfg_us = 2,
64 .t_st2ck_us = 2,
65 };
66
67 static struct altera_ps_data a10_data = {
68 .devtype = ARRIA10,
69 .status_wait_min_us = 268, /* min(t_STATUS) */
70 .status_wait_max_us = 3000, /* max(t_CF2ST1) */
71 .t_cfg_us = 2, /* max { min(t_CFG), max(tCF2ST0) } */
72 .t_st2ck_us = 10, /* min(t_ST2CK) */
73 };
74
75 /* Array index is enum altera_ps_devtype */
76 static const struct altera_ps_data *altera_ps_data_map[] = {
77 &c5_data,
78 &a10_data,
79 };
80
81 static const struct of_device_id of_ef_match[] = {
82 { .compatible = "altr,fpga-passive-serial", .data = &c5_data },
83 { .compatible = "altr,fpga-arria10-passive-serial", .data = &a10_data },
84 {}
85 };
86 MODULE_DEVICE_TABLE(of, of_ef_match);
87
altera_ps_state(struct fpga_manager * mgr)88 static enum fpga_mgr_states altera_ps_state(struct fpga_manager *mgr)
89 {
90 struct altera_ps_conf *conf = mgr->priv;
91
92 if (gpiod_get_value_cansleep(conf->status))
93 return FPGA_MGR_STATE_RESET;
94
95 return FPGA_MGR_STATE_UNKNOWN;
96 }
97
altera_ps_delay(int delay_us)98 static inline void altera_ps_delay(int delay_us)
99 {
100 if (delay_us > 10)
101 usleep_range(delay_us, delay_us + 5);
102 else
103 udelay(delay_us);
104 }
105
altera_ps_write_init(struct fpga_manager * mgr,struct fpga_image_info * info,const char * buf,size_t count)106 static int altera_ps_write_init(struct fpga_manager *mgr,
107 struct fpga_image_info *info,
108 const char *buf, size_t count)
109 {
110 struct altera_ps_conf *conf = mgr->priv;
111 int min, max, waits;
112 int i;
113
114 conf->info_flags = info->flags;
115
116 if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
117 dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");
118 return -EINVAL;
119 }
120
121 gpiod_set_value_cansleep(conf->config, 1);
122
123 /* wait min reset pulse time */
124 altera_ps_delay(conf->data->t_cfg_us);
125
126 if (!gpiod_get_value_cansleep(conf->status)) {
127 dev_err(&mgr->dev, "Status pin failed to show a reset\n");
128 return -EIO;
129 }
130
131 gpiod_set_value_cansleep(conf->config, 0);
132
133 min = conf->data->status_wait_min_us;
134 max = conf->data->status_wait_max_us;
135 waits = max / min;
136 if (max % min)
137 waits++;
138
139 /* wait for max { max(t_STATUS), max(t_CF2ST1) } */
140 for (i = 0; i < waits; i++) {
141 usleep_range(min, min + 10);
142 if (!gpiod_get_value_cansleep(conf->status)) {
143 /* wait for min(t_ST2CK)*/
144 altera_ps_delay(conf->data->t_st2ck_us);
145 return 0;
146 }
147 }
148
149 dev_err(&mgr->dev, "Status pin not ready.\n");
150 return -EIO;
151 }
152
rev_buf(char * buf,size_t len)153 static void rev_buf(char *buf, size_t len)
154 {
155 u32 *fw32 = (u32 *)buf;
156 size_t extra_bytes = (len & 0x03);
157 const u32 *fw_end = (u32 *)(buf + len - extra_bytes);
158
159 /* set buffer to lsb first */
160 while (fw32 < fw_end) {
161 *fw32 = bitrev8x4(*fw32);
162 fw32++;
163 }
164
165 if (extra_bytes) {
166 buf = (char *)fw_end;
167 while (extra_bytes) {
168 *buf = bitrev8(*buf);
169 buf++;
170 extra_bytes--;
171 }
172 }
173 }
174
altera_ps_write(struct fpga_manager * mgr,const char * buf,size_t count)175 static int altera_ps_write(struct fpga_manager *mgr, const char *buf,
176 size_t count)
177 {
178 struct altera_ps_conf *conf = mgr->priv;
179 const char *fw_data = buf;
180 const char *fw_data_end = fw_data + count;
181
182 while (fw_data < fw_data_end) {
183 int ret;
184 size_t stride = min_t(size_t, fw_data_end - fw_data, SZ_4K);
185
186 if (!(conf->info_flags & FPGA_MGR_BITSTREAM_LSB_FIRST))
187 rev_buf((char *)fw_data, stride);
188
189 ret = spi_write(conf->spi, fw_data, stride);
190 if (ret) {
191 dev_err(&mgr->dev, "spi error in firmware write: %d\n",
192 ret);
193 return ret;
194 }
195 fw_data += stride;
196 }
197
198 return 0;
199 }
200
altera_ps_write_complete(struct fpga_manager * mgr,struct fpga_image_info * info)201 static int altera_ps_write_complete(struct fpga_manager *mgr,
202 struct fpga_image_info *info)
203 {
204 struct altera_ps_conf *conf = mgr->priv;
205 static const char dummy[] = {0};
206 int ret;
207
208 if (gpiod_get_value_cansleep(conf->status)) {
209 dev_err(&mgr->dev, "Error during configuration.\n");
210 return -EIO;
211 }
212
213 if (conf->confd) {
214 if (!gpiod_get_raw_value_cansleep(conf->confd)) {
215 dev_err(&mgr->dev, "CONF_DONE is inactive!\n");
216 return -EIO;
217 }
218 }
219
220 /*
221 * After CONF_DONE goes high, send two additional falling edges on DCLK
222 * to begin initialization and enter user mode
223 */
224 ret = spi_write(conf->spi, dummy, 1);
225 if (ret) {
226 dev_err(&mgr->dev, "spi error during end sequence: %d\n", ret);
227 return ret;
228 }
229
230 return 0;
231 }
232
233 static const struct fpga_manager_ops altera_ps_ops = {
234 .state = altera_ps_state,
235 .write_init = altera_ps_write_init,
236 .write = altera_ps_write,
237 .write_complete = altera_ps_write_complete,
238 };
239
id_to_data(const struct spi_device_id * id)240 static const struct altera_ps_data *id_to_data(const struct spi_device_id *id)
241 {
242 kernel_ulong_t devtype = id->driver_data;
243 const struct altera_ps_data *data;
244
245 /* someone added a altera_ps_devtype without adding to the map array */
246 if (devtype >= ARRAY_SIZE(altera_ps_data_map))
247 return NULL;
248
249 data = altera_ps_data_map[devtype];
250 if (!data || data->devtype != devtype)
251 return NULL;
252
253 return data;
254 }
255
altera_ps_probe(struct spi_device * spi)256 static int altera_ps_probe(struct spi_device *spi)
257 {
258 struct altera_ps_conf *conf;
259 const struct of_device_id *of_id;
260 struct fpga_manager *mgr;
261
262 conf = devm_kzalloc(&spi->dev, sizeof(*conf), GFP_KERNEL);
263 if (!conf)
264 return -ENOMEM;
265
266 if (spi->dev.of_node) {
267 of_id = of_match_device(of_ef_match, &spi->dev);
268 if (!of_id)
269 return -ENODEV;
270 conf->data = of_id->data;
271 } else {
272 conf->data = id_to_data(spi_get_device_id(spi));
273 if (!conf->data)
274 return -ENODEV;
275 }
276
277 conf->spi = spi;
278 conf->config = devm_gpiod_get(&spi->dev, "nconfig", GPIOD_OUT_LOW);
279 if (IS_ERR(conf->config)) {
280 dev_err(&spi->dev, "Failed to get config gpio: %ld\n",
281 PTR_ERR(conf->config));
282 return PTR_ERR(conf->config);
283 }
284
285 conf->status = devm_gpiod_get(&spi->dev, "nstat", GPIOD_IN);
286 if (IS_ERR(conf->status)) {
287 dev_err(&spi->dev, "Failed to get status gpio: %ld\n",
288 PTR_ERR(conf->status));
289 return PTR_ERR(conf->status);
290 }
291
292 conf->confd = devm_gpiod_get_optional(&spi->dev, "confd", GPIOD_IN);
293 if (IS_ERR(conf->confd)) {
294 dev_err(&spi->dev, "Failed to get confd gpio: %ld\n",
295 PTR_ERR(conf->confd));
296 return PTR_ERR(conf->confd);
297 } else if (!conf->confd) {
298 dev_warn(&spi->dev, "Not using confd gpio");
299 }
300
301 /* Register manager with unique name */
302 snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s %s",
303 dev_driver_string(&spi->dev), dev_name(&spi->dev));
304
305 mgr = devm_fpga_mgr_register(&spi->dev, conf->mgr_name,
306 &altera_ps_ops, conf);
307 return PTR_ERR_OR_ZERO(mgr);
308 }
309
310 static const struct spi_device_id altera_ps_spi_ids[] = {
311 { "cyclone-ps-spi", CYCLONE5 },
312 { "fpga-passive-serial", CYCLONE5 },
313 { "fpga-arria10-passive-serial", ARRIA10 },
314 {}
315 };
316 MODULE_DEVICE_TABLE(spi, altera_ps_spi_ids);
317
318 static struct spi_driver altera_ps_driver = {
319 .driver = {
320 .name = "altera-ps-spi",
321 .owner = THIS_MODULE,
322 .of_match_table = of_match_ptr(of_ef_match),
323 },
324 .id_table = altera_ps_spi_ids,
325 .probe = altera_ps_probe,
326 };
327
328 module_spi_driver(altera_ps_driver)
329
330 MODULE_LICENSE("GPL v2");
331 MODULE_AUTHOR("Joshua Clayton <stillcompiling@gmail.com>");
332 MODULE_DESCRIPTION("Module to load Altera FPGA firmware over SPI");
333