drivers/fpga/machxo2-spi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Lattice MachXO2 Slave SPI Driver
   4  *
   5  * Manage Lattice FPGA firmware that is loaded over SPI using
   6  * the slave serial configuration interface.
   7  *
   8  * Copyright (C) 2018 Paolo Pisati <p.pisati@gmail.com>
   9  */
  10
  11 #include <linux/delay.h>
  12 #include <linux/fpga/fpga-mgr.h>
  13 #include <linux/gpio/consumer.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/spi/spi.h>
  17
  18 /* MachXO2 Programming Guide - sysCONFIG Programming Commands */
  19 #define IDCODE_PUB              {0xe0, 0x00, 0x00, 0x00}
  20 #define ISC_ENABLE              {0xc6, 0x08, 0x00, 0x00}
  21 #define ISC_ERASE               {0x0e, 0x04, 0x00, 0x00}
  22 #define ISC_PROGRAMDONE         {0x5e, 0x00, 0x00, 0x00}
  23 #define LSC_INITADDRESS         {0x46, 0x00, 0x00, 0x00}
  24 #define LSC_PROGINCRNV          {0x70, 0x00, 0x00, 0x01}
  25 #define LSC_READ_STATUS         {0x3c, 0x00, 0x00, 0x00}
  26 #define LSC_REFRESH             {0x79, 0x00, 0x00, 0x00}
  27
  28 /*
  29  * Max CCLK in Slave SPI mode according to 'MachXO2 Family Data
  30  * Sheet' sysCONFIG Port Timing Specifications (3-36)
  31  */
  32 #define MACHXO2_MAX_SPEED               66000000
  33
  34 #define MACHXO2_LOW_DELAY_USEC          5
  35 #define MACHXO2_HIGH_DELAY_USEC         200
  36 #define MACHXO2_REFRESH_USEC            4800
  37 #define MACHXO2_MAX_BUSY_LOOP           128
  38 #define MACHXO2_MAX_REFRESH_LOOP        16
  39
  40 #define MACHXO2_PAGE_SIZE               16
  41 #define MACHXO2_BUF_SIZE                (MACHXO2_PAGE_SIZE + 4)
  42
  43 /* Status register bits, errors and error mask */
  44 #define BUSY    12
  45 #define DONE    8
  46 #define DVER    27
  47 #define ENAB    9
  48 #define ERRBITS 23
  49 #define ERRMASK 7
  50 #define FAIL    13
  51
  52 #define ENOERR  0 /* no error */
  53 #define EID     1
  54 #define ECMD    2
  55 #define ECRC    3
  56 #define EPREAM  4 /* preamble error */
  57 #define EABRT   5 /* abort error */
  58 #define EOVERFL 6 /* overflow error */
  59 #define ESDMEOF 7 /* SDM EOF */
  60
  61 static inline u8 get_err(unsigned long *status)
  62 {
  63         return (*status >> ERRBITS) & ERRMASK;
  64 }
  65
  66 static int get_status(struct spi_device *spi, unsigned long *status)
  67 {
  68         struct spi_message msg;
  69         struct spi_transfer rx, tx;
  70         static const u8 cmd[] = LSC_READ_STATUS;
  71         int ret;
  72
  73         memset(&rx, 0, sizeof(rx));
  74         memset(&tx, 0, sizeof(tx));
  75         tx.tx_buf = cmd;
  76         tx.len = sizeof(cmd);
  77         rx.rx_buf = status;
  78         rx.len = 4;
  79         spi_message_init(&msg);
  80         spi_message_add_tail(&tx, &msg);
  81         spi_message_add_tail(&rx, &msg);
  82         ret = spi_sync(spi, &msg);
  83         if (ret)
  84                 return ret;
  85
  86         *status = be32_to_cpu(*status);
  87
  88         return 0;
  89 }
  90
  91 #ifdef DEBUG
  92 static const char *get_err_string(u8 err)
  93 {
  94         switch (err) {
  95         case ENOERR:    return "No Error";
  96         case EID:       return "ID ERR";
  97         case ECMD:      return "CMD ERR";
  98         case ECRC:      return "CRC ERR";
  99         case EPREAM:    return "Preamble ERR";
 100         case EABRT:     return "Abort ERR";
 101         case EOVERFL:   return "Overflow ERR";
 102         case ESDMEOF:   return "SDM EOF";
 103         }
 104
 105         return "Default switch case";
 106 }
 107 #endif
 108
 109 static void dump_status_reg(unsigned long *status)
 110 {
 111 #ifdef DEBUG
 112         pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
 113                  *status, test_bit(DONE, status), test_bit(ENAB, status),
 114                  test_bit(BUSY, status), test_bit(FAIL, status),
 115                  test_bit(DVER, status), get_err_string(get_err(status)));
 116 #endif
 117 }
 118
 119 static int wait_until_not_busy(struct spi_device *spi)
 120 {
 121         unsigned long status;
 122         int ret, loop = 0;
 123
 124         do {
 125                 ret = get_status(spi, &status);
 126                 if (ret)
 127                         return ret;
 128                 if (++loop >= MACHXO2_MAX_BUSY_LOOP)
 129                         return -EBUSY;
 130         } while (test_bit(BUSY, &status));
 131
 132         return 0;
 133 }
 134
 135 static int machxo2_cleanup(struct fpga_manager *mgr)
 136 {
 137         struct spi_device *spi = mgr->priv;
 138         struct spi_message msg;
 139         struct spi_transfer tx[2];
 140         static const u8 erase[] = ISC_ERASE;
 141         static const u8 refresh[] = LSC_REFRESH;
 142         int ret;
 143
 144         memset(tx, 0, sizeof(tx));
 145         spi_message_init(&msg);
 146         tx[0].tx_buf = &erase;
 147         tx[0].len = sizeof(erase);
 148         spi_message_add_tail(&tx[0], &msg);
 149         ret = spi_sync(spi, &msg);
 150         if (ret)
 151                 goto fail;
 152
 153         ret = wait_until_not_busy(spi);
 154         if (ret)
 155                 goto fail;
 156
 157         spi_message_init(&msg);
 158         tx[1].tx_buf = &refresh;
 159         tx[1].len = sizeof(refresh);
 160         tx[1].delay_usecs = MACHXO2_REFRESH_USEC;
 161         spi_message_add_tail(&tx[1], &msg);
 162         ret = spi_sync(spi, &msg);
 163         if (ret)
 164                 goto fail;
 165
 166         return 0;
 167 fail:
 168         dev_err(&mgr->dev, "Cleanup failed\n");
 169
 170         return ret;
 171 }
 172
 173 static enum fpga_mgr_states machxo2_spi_state(struct fpga_manager *mgr)
 174 {
 175         struct spi_device *spi = mgr->priv;
 176         unsigned long status;
 177
 178         get_status(spi, &status);
 179         if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
 180             get_err(&status) == ENOERR)
 181                 return FPGA_MGR_STATE_OPERATING;
 182
 183         return FPGA_MGR_STATE_UNKNOWN;
 184 }
 185
 186 static int machxo2_write_init(struct fpga_manager *mgr,
 187                               struct fpga_image_info *info,
 188                               const char *buf, size_t count)
 189 {
 190         struct spi_device *spi = mgr->priv;
 191         struct spi_message msg;
 192         struct spi_transfer tx[3];
 193         static const u8 enable[] = ISC_ENABLE;
 194         static const u8 erase[] = ISC_ERASE;
 195         static const u8 initaddr[] = LSC_INITADDRESS;
 196         unsigned long status;
 197         int ret;
 198
 199         if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
 200                 dev_err(&mgr->dev,
 201                         "Partial reconfiguration is not supported\n");
 202                 return -ENOTSUPP;
 203         }
 204
 205         get_status(spi, &status);
 206         dump_status_reg(&status);
 207         memset(tx, 0, sizeof(tx));
 208         spi_message_init(&msg);
 209         tx[0].tx_buf = &enable;
 210         tx[0].len = sizeof(enable);
 211         tx[0].delay_usecs = MACHXO2_LOW_DELAY_USEC;
 212         spi_message_add_tail(&tx[0], &msg);
 213
 214         tx[1].tx_buf = &erase;
 215         tx[1].len = sizeof(erase);
 216         spi_message_add_tail(&tx[1], &msg);
 217         ret = spi_sync(spi, &msg);
 218         if (ret)
 219                 goto fail;
 220
 221         ret = wait_until_not_busy(spi);
 222         if (ret)
 223                 goto fail;
 224
 225         get_status(spi, &status);
 226         if (test_bit(FAIL, &status))
 227                 goto fail;
 228         dump_status_reg(&status);
 229
 230         spi_message_init(&msg);
 231         tx[2].tx_buf = &initaddr;
 232         tx[2].len = sizeof(initaddr);
 233         spi_message_add_tail(&tx[2], &msg);
 234         ret = spi_sync(spi, &msg);
 235         if (ret)
 236                 goto fail;
 237
 238         get_status(spi, &status);
 239         dump_status_reg(&status);
 240
 241         return 0;
 242 fail:
 243         dev_err(&mgr->dev, "Error during FPGA init.\n");
 244
 245         return ret;
 246 }
 247
 248 static int machxo2_write(struct fpga_manager *mgr, const char *buf,
 249                          size_t count)
 250 {
 251         struct spi_device *spi = mgr->priv;
 252         struct spi_message msg;
 253         struct spi_transfer tx;
 254         static const u8 progincr[] = LSC_PROGINCRNV;
 255         u8 payload[MACHXO2_BUF_SIZE];
 256         unsigned long status;
 257         int i, ret;
 258
 259         if (count % MACHXO2_PAGE_SIZE != 0) {
 260                 dev_err(&mgr->dev, "Malformed payload.\n");
 261                 return -EINVAL;
 262         }
 263         get_status(spi, &status);
 264         dump_status_reg(&status);
 265         memcpy(payload, &progincr, sizeof(progincr));
 266         for (i = 0; i < count; i += MACHXO2_PAGE_SIZE) {
 267                 memcpy(&payload[sizeof(progincr)], &buf[i], MACHXO2_PAGE_SIZE);
 268                 memset(&tx, 0, sizeof(tx));
 269                 spi_message_init(&msg);
 270                 tx.tx_buf = payload;
 271                 tx.len = MACHXO2_BUF_SIZE;
 272                 tx.delay_usecs = MACHXO2_HIGH_DELAY_USEC;
 273                 spi_message_add_tail(&tx, &msg);
 274                 ret = spi_sync(spi, &msg);
 275                 if (ret) {
 276                         dev_err(&mgr->dev, "Error loading the bitstream.\n");
 277                         return ret;
 278                 }
 279         }
 280         get_status(spi, &status);
 281         dump_status_reg(&status);
 282
 283         return 0;
 284 }
 285
 286 static int machxo2_write_complete(struct fpga_manager *mgr,
 287                                   struct fpga_image_info *info)
 288 {
 289         struct spi_device *spi = mgr->priv;
 290         struct spi_message msg;
 291         struct spi_transfer tx[2];
 292         static const u8 progdone[] = ISC_PROGRAMDONE;
 293         static const u8 refresh[] = LSC_REFRESH;
 294         unsigned long status;
 295         int ret, refreshloop = 0;
 296
 297         memset(tx, 0, sizeof(tx));
 298         spi_message_init(&msg);
 299         tx[0].tx_buf = &progdone;
 300         tx[0].len = sizeof(progdone);
 301         spi_message_add_tail(&tx[0], &msg);
 302         ret = spi_sync(spi, &msg);
 303         if (ret)
 304                 goto fail;
 305         ret = wait_until_not_busy(spi);
 306         if (ret)
 307                 goto fail;
 308
 309         get_status(spi, &status);
 310         dump_status_reg(&status);
 311         if (!test_bit(DONE, &status)) {
 312                 machxo2_cleanup(mgr);
 313                 goto fail;
 314         }
 315
 316         do {
 317                 spi_message_init(&msg);
 318                 tx[1].tx_buf = &refresh;
 319                 tx[1].len = sizeof(refresh);
 320                 tx[1].delay_usecs = MACHXO2_REFRESH_USEC;
 321                 spi_message_add_tail(&tx[1], &msg);
 322                 ret = spi_sync(spi, &msg);
 323                 if (ret)
 324                         goto fail;
 325
 326                 /* check refresh status */
 327                 get_status(spi, &status);
 328                 dump_status_reg(&status);
 329                 if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
 330                     get_err(&status) == ENOERR)
 331                         break;
 332                 if (++refreshloop == MACHXO2_MAX_REFRESH_LOOP) {
 333                         machxo2_cleanup(mgr);
 334                         goto fail;
 335                 }
 336         } while (1);
 337
 338         get_status(spi, &status);
 339         dump_status_reg(&status);
 340
 341         return 0;
 342 fail:
 343         dev_err(&mgr->dev, "Refresh failed.\n");
 344
 345         return ret;
 346 }
 347
 348 static const struct fpga_manager_ops machxo2_ops = {
 349         .state = machxo2_spi_state,
 350         .write_init = machxo2_write_init,
 351         .write = machxo2_write,
 352         .write_complete = machxo2_write_complete,
 353 };
 354
 355 static int machxo2_spi_probe(struct spi_device *spi)
 356 {
 357         struct device *dev = &spi->dev;
 358         struct fpga_manager *mgr;
 359         int ret;
 360
 361         if (spi->max_speed_hz > MACHXO2_MAX_SPEED) {
 362                 dev_err(dev, "Speed is too high\n");
 363                 return -EINVAL;
 364         }
 365
 366         mgr = fpga_mgr_create(dev, "Lattice MachXO2 SPI FPGA Manager",
 367                               &machxo2_ops, spi);
 368         if (!mgr)
 369                 return -ENOMEM;
 370
 371         spi_set_drvdata(spi, mgr);
 372
 373         ret = fpga_mgr_register(mgr);
 374         if (ret)
 375                 fpga_mgr_free(mgr);
 376
 377         return ret;
 378 }
 379
 380 static int machxo2_spi_remove(struct spi_device *spi)
 381 {
 382         struct fpga_manager *mgr = spi_get_drvdata(spi);
 383
 384         fpga_mgr_unregister(mgr);
 385
 386         return 0;
 387 }
 388
 389 static const struct of_device_id of_match[] = {
 390         { .compatible = "lattice,machxo2-slave-spi", },
 391         {}
 392 };
 393 MODULE_DEVICE_TABLE(of, of_match);
 394
 395 static const struct spi_device_id lattice_ids[] = {
 396         { "machxo2-slave-spi", 0 },
 397         { },
 398 };
 399 MODULE_DEVICE_TABLE(spi, lattice_ids);
 400
 401 static struct spi_driver machxo2_spi_driver = {
 402         .driver = {
 403                 .name = "machxo2-slave-spi",
 404                 .of_match_table = of_match_ptr(of_match),
 405         },
 406         .probe = machxo2_spi_probe,
 407         .remove = machxo2_spi_remove,
 408         .id_table = lattice_ids,
 409 };
 410
 411 module_spi_driver(machxo2_spi_driver)
 412
 413 MODULE_AUTHOR("Paolo Pisati <p.pisati@gmail.com>");
 414 MODULE_DESCRIPTION("Load Lattice FPGA firmware over SPI");
 415 MODULE_LICENSE("GPL v2");