drivers/spi/spi-ingenic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SPI bus driver for the Ingenic JZ47xx SoCs
   4  * Copyright (c) 2017-2021 Artur Rojek <contact@artur-rojek.eu>
   5  * Copyright (c) 2017-2021 Paul Cercueil <paul@crapouillou.net>
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/delay.h>
  10 #include <linux/dmaengine.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/iopoll.h>
  13 #include <linux/module.h>
  14 #include <linux/of_device.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regmap.h>
  17 #include <linux/spi/spi.h>
  18
  19 #define REG_SSIDR       0x0
  20 #define REG_SSICR0      0x4
  21 #define REG_SSICR1      0x8
  22 #define REG_SSISR       0xc
  23 #define REG_SSIGR       0x18
  24
  25 #define REG_SSICR0_TENDIAN_LSB          BIT(19)
  26 #define REG_SSICR0_RENDIAN_LSB          BIT(17)
  27 #define REG_SSICR0_SSIE                 BIT(15)
  28 #define REG_SSICR0_LOOP                 BIT(10)
  29 #define REG_SSICR0_EACLRUN              BIT(7)
  30 #define REG_SSICR0_FSEL                 BIT(6)
  31 #define REG_SSICR0_TFLUSH               BIT(2)
  32 #define REG_SSICR0_RFLUSH               BIT(1)
  33
  34 #define REG_SSICR1_FRMHL_MASK           (BIT(31) | BIT(30))
  35 #define REG_SSICR1_FRMHL                BIT(30)
  36 #define REG_SSICR1_LFST                 BIT(25)
  37 #define REG_SSICR1_UNFIN                BIT(23)
  38 #define REG_SSICR1_PHA                  BIT(1)
  39 #define REG_SSICR1_POL                  BIT(0)
  40
  41 #define REG_SSISR_END                   BIT(7)
  42 #define REG_SSISR_BUSY                  BIT(6)
  43 #define REG_SSISR_TFF                   BIT(5)
  44 #define REG_SSISR_RFE                   BIT(4)
  45 #define REG_SSISR_RFHF                  BIT(2)
  46 #define REG_SSISR_UNDR                  BIT(1)
  47 #define REG_SSISR_OVER                  BIT(0)
  48
  49 #define SPI_INGENIC_FIFO_SIZE           128u
  50
  51 struct jz_soc_info {
  52         u32 bits_per_word_mask;
  53         struct reg_field flen_field;
  54         bool has_trendian;
  55 };
  56
  57 struct ingenic_spi {
  58         const struct jz_soc_info *soc_info;
  59         struct clk *clk;
  60         struct resource *mem_res;
  61
  62         struct regmap *map;
  63         struct regmap_field *flen_field;
  64 };
  65
  66 static int spi_ingenic_wait(struct ingenic_spi *priv,
  67                             unsigned long mask,
  68                             bool condition)
  69 {
  70         unsigned int val;
  71
  72         return regmap_read_poll_timeout(priv->map, REG_SSISR, val,
  73                                         !!(val & mask) == condition,
  74                                         100, 10000);
  75 }
  76
  77 static void spi_ingenic_set_cs(struct spi_device *spi, bool disable)
  78 {
  79         struct ingenic_spi *priv = spi_controller_get_devdata(spi->controller);
  80
  81         if (disable) {
  82                 regmap_clear_bits(priv->map, REG_SSICR1, REG_SSICR1_UNFIN);
  83                 regmap_clear_bits(priv->map, REG_SSISR,
  84                                   REG_SSISR_UNDR | REG_SSISR_OVER);
  85
  86                 spi_ingenic_wait(priv, REG_SSISR_END, true);
  87         } else {
  88                 regmap_set_bits(priv->map, REG_SSICR1, REG_SSICR1_UNFIN);
  89         }
  90
  91         regmap_set_bits(priv->map, REG_SSICR0,
  92                         REG_SSICR0_RFLUSH | REG_SSICR0_TFLUSH);
  93 }
  94
  95 static void spi_ingenic_prepare_transfer(struct ingenic_spi *priv,
  96                                          struct spi_device *spi,
  97                                          struct spi_transfer *xfer)
  98 {
  99         unsigned long clk_hz = clk_get_rate(priv->clk);
 100         u32 cdiv, speed_hz = xfer->speed_hz ?: spi->max_speed_hz,
 101             bits_per_word = xfer->bits_per_word ?: spi->bits_per_word;
 102
 103         cdiv = clk_hz / (speed_hz * 2);
 104         cdiv = clamp(cdiv, 1u, 0x100u) - 1;
 105
 106         regmap_write(priv->map, REG_SSIGR, cdiv);
 107
 108         regmap_field_write(priv->flen_field, bits_per_word - 2);
 109 }
 110
 111 static void spi_ingenic_finalize_transfer(void *controller)
 112 {
 113         spi_finalize_current_transfer(controller);
 114 }
 115
 116 static struct dma_async_tx_descriptor *
 117 spi_ingenic_prepare_dma(struct spi_controller *ctlr, struct dma_chan *chan,
 118                         struct sg_table *sg, enum dma_transfer_direction dir,
 119                         unsigned int bits)
 120 {
 121         struct ingenic_spi *priv = spi_controller_get_devdata(ctlr);
 122         struct dma_slave_config cfg = {
 123                 .direction = dir,
 124                 .src_addr = priv->mem_res->start + REG_SSIDR,
 125                 .dst_addr = priv->mem_res->start + REG_SSIDR,
 126         };
 127         struct dma_async_tx_descriptor *desc;
 128         dma_cookie_t cookie;
 129         int ret;
 130
 131         if (bits > 16) {
 132                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 133                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 134                 cfg.src_maxburst = cfg.dst_maxburst = 4;
 135         } else if (bits > 8) {
 136                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 137                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
 138                 cfg.src_maxburst = cfg.dst_maxburst = 2;
 139         } else {
 140                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 141                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 142                 cfg.src_maxburst = cfg.dst_maxburst = 1;
 143         }
 144
 145         ret = dmaengine_slave_config(chan, &cfg);
 146         if (ret)
 147                 return ERR_PTR(ret);
 148
 149         desc = dmaengine_prep_slave_sg(chan, sg->sgl, sg->nents, dir,
 150                                        DMA_PREP_INTERRUPT);
 151         if (!desc)
 152                 return ERR_PTR(-ENOMEM);
 153
 154         if (dir == DMA_DEV_TO_MEM) {
 155                 desc->callback = spi_ingenic_finalize_transfer;
 156                 desc->callback_param = ctlr;
 157         }
 158
 159         cookie = dmaengine_submit(desc);
 160
 161         ret = dma_submit_error(cookie);
 162         if (ret) {
 163                 dmaengine_desc_free(desc);
 164                 return ERR_PTR(ret);
 165         }
 166
 167         return desc;
 168 }
 169
 170 static int spi_ingenic_dma_tx(struct spi_controller *ctlr,
 171                               struct spi_transfer *xfer, unsigned int bits)
 172 {
 173         struct dma_async_tx_descriptor *rx_desc, *tx_desc;
 174
 175         rx_desc = spi_ingenic_prepare_dma(ctlr, ctlr->dma_rx,
 176                                           &xfer->rx_sg, DMA_DEV_TO_MEM, bits);
 177         if (IS_ERR(rx_desc))
 178                 return PTR_ERR(rx_desc);
 179
 180         tx_desc = spi_ingenic_prepare_dma(ctlr, ctlr->dma_tx,
 181                                           &xfer->tx_sg, DMA_MEM_TO_DEV, bits);
 182         if (IS_ERR(tx_desc)) {
 183                 dmaengine_terminate_async(ctlr->dma_rx);
 184                 dmaengine_desc_free(rx_desc);
 185                 return PTR_ERR(tx_desc);
 186         }
 187
 188         dma_async_issue_pending(ctlr->dma_rx);
 189         dma_async_issue_pending(ctlr->dma_tx);
 190
 191         return 1;
 192 }
 193
 194 #define SPI_INGENIC_TX(x)                                                       \
 195 static int spi_ingenic_tx##x(struct ingenic_spi *priv,                          \
 196                              struct spi_transfer *xfer)                         \
 197 {                                                                               \
 198         unsigned int count = xfer->len / (x / 8);                               \
 199         unsigned int prefill = min(count, SPI_INGENIC_FIFO_SIZE);               \
 200         const u##x *tx_buf = xfer->tx_buf;                                      \
 201         u##x *rx_buf = xfer->rx_buf;                                            \
 202         unsigned int i, val;                                                    \
 203         int err;                                                                \
 204                                                                                 \
 205         /* Fill up the TX fifo */                                               \
 206         for (i = 0; i < prefill; i++) {                                         \
 207                 val = tx_buf ? tx_buf[i] : 0;                                   \
 208                                                                                 \
 209                 regmap_write(priv->map, REG_SSIDR, val);                        \
 210         }                                                                       \
 211                                                                                 \
 212         for (i = 0; i < count; i++) {                                           \
 213                 err = spi_ingenic_wait(priv, REG_SSISR_RFE, false);             \
 214                 if (err)                                                        \
 215                         return err;                                             \
 216                                                                                 \
 217                 regmap_read(priv->map, REG_SSIDR, &val);                        \
 218                 if (rx_buf)                                                     \
 219                         rx_buf[i] = val;                                        \
 220                                                                                 \
 221                 if (i < count - prefill) {                                      \
 222                         val = tx_buf ? tx_buf[i + prefill] : 0;                 \
 223                                                                                 \
 224                         regmap_write(priv->map, REG_SSIDR, val);                \
 225                 }                                                               \
 226         }                                                                       \
 227                                                                                 \
 228         return 0;                                                               \
 229 }
 230 SPI_INGENIC_TX(8)
 231 SPI_INGENIC_TX(16)
 232 SPI_INGENIC_TX(32)
 233 #undef SPI_INGENIC_TX
 234
 235 static int spi_ingenic_transfer_one(struct spi_controller *ctlr,
 236                                     struct spi_device *spi,
 237                                     struct spi_transfer *xfer)
 238 {
 239         struct ingenic_spi *priv = spi_controller_get_devdata(ctlr);
 240         unsigned int bits = xfer->bits_per_word ?: spi->bits_per_word;
 241         bool can_dma = ctlr->can_dma && ctlr->can_dma(ctlr, spi, xfer);
 242
 243         spi_ingenic_prepare_transfer(priv, spi, xfer);
 244
 245         if (ctlr->cur_msg_mapped && can_dma)
 246                 return spi_ingenic_dma_tx(ctlr, xfer, bits);
 247
 248         if (bits > 16)
 249                 return spi_ingenic_tx32(priv, xfer);
 250
 251         if (bits > 8)
 252                 return spi_ingenic_tx16(priv, xfer);
 253
 254         return spi_ingenic_tx8(priv, xfer);
 255 }
 256
 257 static int spi_ingenic_prepare_message(struct spi_controller *ctlr,
 258                                        struct spi_message *message)
 259 {
 260         struct ingenic_spi *priv = spi_controller_get_devdata(ctlr);
 261         struct spi_device *spi = message->spi;
 262         unsigned int cs = REG_SSICR1_FRMHL << spi->chip_select;
 263         unsigned int ssicr0_mask = REG_SSICR0_LOOP | REG_SSICR0_FSEL;
 264         unsigned int ssicr1_mask = REG_SSICR1_PHA | REG_SSICR1_POL | cs;
 265         unsigned int ssicr0 = 0, ssicr1 = 0;
 266
 267         if (priv->soc_info->has_trendian) {
 268                 ssicr0_mask |= REG_SSICR0_RENDIAN_LSB | REG_SSICR0_TENDIAN_LSB;
 269
 270                 if (spi->mode & SPI_LSB_FIRST)
 271                         ssicr0 |= REG_SSICR0_RENDIAN_LSB | REG_SSICR0_TENDIAN_LSB;
 272         } else {
 273                 ssicr1_mask |= REG_SSICR1_LFST;
 274
 275                 if (spi->mode & SPI_LSB_FIRST)
 276                         ssicr1 |= REG_SSICR1_LFST;
 277         }
 278
 279         if (spi->mode & SPI_LOOP)
 280                 ssicr0 |= REG_SSICR0_LOOP;
 281         if (spi->chip_select)
 282                 ssicr0 |= REG_SSICR0_FSEL;
 283
 284         if (spi->mode & SPI_CPHA)
 285                 ssicr1 |= REG_SSICR1_PHA;
 286         if (spi->mode & SPI_CPOL)
 287                 ssicr1 |= REG_SSICR1_POL;
 288         if (spi->mode & SPI_CS_HIGH)
 289                 ssicr1 |= cs;
 290
 291         regmap_update_bits(priv->map, REG_SSICR0, ssicr0_mask, ssicr0);
 292         regmap_update_bits(priv->map, REG_SSICR1, ssicr1_mask, ssicr1);
 293
 294         return 0;
 295 }
 296
 297 static int spi_ingenic_prepare_hardware(struct spi_controller *ctlr)
 298 {
 299         struct ingenic_spi *priv = spi_controller_get_devdata(ctlr);
 300         int ret;
 301
 302         ret = clk_prepare_enable(priv->clk);
 303         if (ret)
 304                 return ret;
 305
 306         regmap_write(priv->map, REG_SSICR0, REG_SSICR0_EACLRUN);
 307         regmap_write(priv->map, REG_SSICR1, 0);
 308         regmap_write(priv->map, REG_SSISR, 0);
 309         regmap_set_bits(priv->map, REG_SSICR0, REG_SSICR0_SSIE);
 310
 311         return 0;
 312 }
 313
 314 static int spi_ingenic_unprepare_hardware(struct spi_controller *ctlr)
 315 {
 316         struct ingenic_spi *priv = spi_controller_get_devdata(ctlr);
 317
 318         regmap_clear_bits(priv->map, REG_SSICR0, REG_SSICR0_SSIE);
 319
 320         clk_disable_unprepare(priv->clk);
 321
 322         return 0;
 323 }
 324
 325 static bool spi_ingenic_can_dma(struct spi_controller *ctlr,
 326                                 struct spi_device *spi,
 327                                 struct spi_transfer *xfer)
 328 {
 329         struct dma_slave_caps caps;
 330         int ret;
 331
 332         ret = dma_get_slave_caps(ctlr->dma_tx, &caps);
 333         if (ret) {
 334                 dev_err(&spi->dev, "Unable to get slave caps: %d\n", ret);
 335                 return false;
 336         }
 337
 338         return !caps.max_sg_burst ||
 339                 xfer->len <= caps.max_sg_burst * SPI_INGENIC_FIFO_SIZE;
 340 }
 341
 342 static int spi_ingenic_request_dma(struct spi_controller *ctlr,
 343                                    struct device *dev)
 344 {
 345         ctlr->dma_tx = dma_request_slave_channel(dev, "tx");
 346         if (!ctlr->dma_tx)
 347                 return -ENODEV;
 348
 349         ctlr->dma_rx = dma_request_slave_channel(dev, "rx");
 350
 351         if (!ctlr->dma_rx)
 352                 return -ENODEV;
 353
 354         ctlr->can_dma = spi_ingenic_can_dma;
 355
 356         return 0;
 357 }
 358
 359 static void spi_ingenic_release_dma(void *data)
 360 {
 361         struct spi_controller *ctlr = data;
 362
 363         if (ctlr->dma_tx)
 364                 dma_release_channel(ctlr->dma_tx);
 365         if (ctlr->dma_rx)
 366                 dma_release_channel(ctlr->dma_rx);
 367 }
 368
 369 static const struct regmap_config spi_ingenic_regmap_config = {
 370         .reg_bits = 32,
 371         .val_bits = 32,
 372         .reg_stride = 4,
 373         .max_register = REG_SSIGR,
 374 };
 375
 376 static int spi_ingenic_probe(struct platform_device *pdev)
 377 {
 378         const struct jz_soc_info *pdata;
 379         struct device *dev = &pdev->dev;
 380         struct spi_controller *ctlr;
 381         struct ingenic_spi *priv;
 382         void __iomem *base;
 383         int ret;
 384
 385         pdata = of_device_get_match_data(dev);
 386         if (!pdata) {
 387                 dev_err(dev, "Missing platform data.\n");
 388                 return -EINVAL;
 389         }
 390
 391         ctlr = devm_spi_alloc_master(dev, sizeof(*priv));
 392         if (!ctlr) {
 393                 dev_err(dev, "Unable to allocate SPI controller.\n");
 394                 return -ENOMEM;
 395         }
 396
 397         priv = spi_controller_get_devdata(ctlr);
 398         priv->soc_info = pdata;
 399
 400         priv->clk = devm_clk_get(dev, NULL);
 401         if (IS_ERR(priv->clk)) {
 402                 return dev_err_probe(dev, PTR_ERR(priv->clk),
 403                                      "Unable to get clock.\n");
 404         }
 405
 406         base = devm_platform_get_and_ioremap_resource(pdev, 0, &priv->mem_res);
 407         if (IS_ERR(base))
 408                 return PTR_ERR(base);
 409
 410         priv->map = devm_regmap_init_mmio(dev, base, &spi_ingenic_regmap_config);
 411         if (IS_ERR(priv->map))
 412                 return PTR_ERR(priv->map);
 413
 414         priv->flen_field = devm_regmap_field_alloc(dev, priv->map,
 415                                                    pdata->flen_field);
 416         if (IS_ERR(priv->flen_field))
 417                 return PTR_ERR(priv->flen_field);
 418
 419         platform_set_drvdata(pdev, ctlr);
 420
 421         ctlr->prepare_transfer_hardware = spi_ingenic_prepare_hardware;
 422         ctlr->unprepare_transfer_hardware = spi_ingenic_unprepare_hardware;
 423         ctlr->prepare_message = spi_ingenic_prepare_message;
 424         ctlr->set_cs = spi_ingenic_set_cs;
 425         ctlr->transfer_one = spi_ingenic_transfer_one;
 426         ctlr->mode_bits = SPI_MODE_3 | SPI_LSB_FIRST | SPI_LOOP | SPI_CS_HIGH;
 427         ctlr->flags = SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX;
 428         ctlr->max_dma_len = SPI_INGENIC_FIFO_SIZE;
 429         ctlr->bits_per_word_mask = pdata->bits_per_word_mask;
 430         ctlr->min_speed_hz = 7200;
 431         ctlr->max_speed_hz = 54000000;
 432         ctlr->num_chipselect = 2;
 433         ctlr->dev.of_node = pdev->dev.of_node;
 434
 435         if (spi_ingenic_request_dma(ctlr, dev))
 436                 dev_warn(dev, "DMA not available.\n");
 437
 438         ret = devm_add_action_or_reset(dev, spi_ingenic_release_dma, ctlr);
 439         if (ret) {
 440                 dev_err(dev, "Unable to add action.\n");
 441                 return ret;
 442         }
 443
 444         ret = devm_spi_register_controller(dev, ctlr);
 445         if (ret)
 446                 dev_err(dev, "Unable to register SPI controller.\n");
 447
 448         return ret;
 449 }
 450
 451 static const struct jz_soc_info jz4750_soc_info = {
 452         .bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 17),
 453         .flen_field = REG_FIELD(REG_SSICR1, 4, 7),
 454         .has_trendian = false,
 455 };
 456
 457 static const struct jz_soc_info jz4780_soc_info = {
 458         .bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 32),
 459         .flen_field = REG_FIELD(REG_SSICR1, 3, 7),
 460         .has_trendian = true,
 461 };
 462
 463 static const struct of_device_id spi_ingenic_of_match[] = {
 464         { .compatible = "ingenic,jz4750-spi", .data = &jz4750_soc_info },
 465         { .compatible = "ingenic,jz4780-spi", .data = &jz4780_soc_info },
 466         {}
 467 };
 468 MODULE_DEVICE_TABLE(of, spi_ingenic_of_match);
 469
 470 static struct platform_driver spi_ingenic_driver = {
 471         .driver = {
 472                 .name = "spi-ingenic",
 473                 .of_match_table = spi_ingenic_of_match,
 474         },
 475         .probe = spi_ingenic_probe,
 476 };
 477
 478 module_platform_driver(spi_ingenic_driver);
 479 MODULE_DESCRIPTION("SPI bus driver for the Ingenic JZ47xx SoCs");
 480 MODULE_AUTHOR("Artur Rojek <contact@artur-rojek.eu>");
 481 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
 482 MODULE_LICENSE("GPL");