drivers/spi/bcm63xx_spi.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
   4  *
   5  * Derived from linux/drivers/spi/spi-bcm63xx.c:
   6  *      Copyright (C) 2009-2012 Florian Fainelli <florian@openwrt.org>
   7  *      Copyright (C) 2010 Tanguy Bouzeloc <tanguy.bouzeloc@efixo.com>
   8  */
   9
  10 #include <common.h>
  11 #include <clk.h>
  12 #include <dm.h>
  13 #include <log.h>
  14 #include <malloc.h>
  15 #include <spi.h>
  16 #include <reset.h>
  17 #include <wait_bit.h>
  18 #include <asm/io.h>
  19
  20 /* BCM6348 SPI core */
  21 #define SPI_6348_CLK                    0x06
  22 #define SPI_6348_CMD                    0x00
  23 #define SPI_6348_CTL                    0x40
  24 #define SPI_6348_CTL_SHIFT              6
  25 #define SPI_6348_FILL                   0x07
  26 #define SPI_6348_IR_MASK                0x04
  27 #define SPI_6348_IR_STAT                0x02
  28 #define SPI_6348_RX                     0x80
  29 #define SPI_6348_RX_SIZE                0x3f
  30 #define SPI_6348_TX                     0x41
  31 #define SPI_6348_TX_SIZE                0x3f
  32
  33 /* BCM6358 SPI core */
  34 #define SPI_6358_CLK                    0x706
  35 #define SPI_6358_CMD                    0x700
  36 #define SPI_6358_CTL                    0x000
  37 #define SPI_6358_CTL_SHIFT              14
  38 #define SPI_6358_FILL                   0x707
  39 #define SPI_6358_IR_MASK                0x702
  40 #define SPI_6358_IR_STAT                0x704
  41 #define SPI_6358_RX                     0x400
  42 #define SPI_6358_RX_SIZE                0x220
  43 #define SPI_6358_TX                     0x002
  44 #define SPI_6358_TX_SIZE                0x21e
  45
  46 /* SPI Clock register */
  47 #define SPI_CLK_SHIFT           0
  48 #define SPI_CLK_20MHZ           (0 << SPI_CLK_SHIFT)
  49 #define SPI_CLK_0_391MHZ        (1 << SPI_CLK_SHIFT)
  50 #define SPI_CLK_0_781MHZ        (2 << SPI_CLK_SHIFT)
  51 #define SPI_CLK_1_563MHZ        (3 << SPI_CLK_SHIFT)
  52 #define SPI_CLK_3_125MHZ        (4 << SPI_CLK_SHIFT)
  53 #define SPI_CLK_6_250MHZ        (5 << SPI_CLK_SHIFT)
  54 #define SPI_CLK_12_50MHZ        (6 << SPI_CLK_SHIFT)
  55 #define SPI_CLK_25MHZ           (7 << SPI_CLK_SHIFT)
  56 #define SPI_CLK_MASK            (7 << SPI_CLK_SHIFT)
  57 #define SPI_CLK_SSOFF_SHIFT     3
  58 #define SPI_CLK_SSOFF_2         (2 << SPI_CLK_SSOFF_SHIFT)
  59 #define SPI_CLK_SSOFF_MASK      (7 << SPI_CLK_SSOFF_SHIFT)
  60 #define SPI_CLK_BSWAP_SHIFT     7
  61 #define SPI_CLK_BSWAP_MASK      (1 << SPI_CLK_BSWAP_SHIFT)
  62
  63 /* SPI Command register */
  64 #define SPI_CMD_OP_SHIFT        0
  65 #define SPI_CMD_OP_START        (0x3 << SPI_CMD_OP_SHIFT)
  66 #define SPI_CMD_SLAVE_SHIFT     4
  67 #define SPI_CMD_SLAVE_MASK      (0xf << SPI_CMD_SLAVE_SHIFT)
  68 #define SPI_CMD_PREPEND_SHIFT   8
  69 #define SPI_CMD_PREPEND_BYTES   0xf
  70 #define SPI_CMD_3WIRE_SHIFT     12
  71 #define SPI_CMD_3WIRE_MASK      (1 << SPI_CMD_3WIRE_SHIFT)
  72
  73 /* SPI Control register */
  74 #define SPI_CTL_TYPE_FD_RW      0
  75 #define SPI_CTL_TYPE_HD_W       1
  76 #define SPI_CTL_TYPE_HD_R       2
  77
  78 /* SPI Interrupt registers */
  79 #define SPI_IR_DONE_SHIFT       0
  80 #define SPI_IR_DONE_MASK        (1 << SPI_IR_DONE_SHIFT)
  81 #define SPI_IR_RXOVER_SHIFT     1
  82 #define SPI_IR_RXOVER_MASK      (1 << SPI_IR_RXOVER_SHIFT)
  83 #define SPI_IR_TXUNDER_SHIFT    2
  84 #define SPI_IR_TXUNDER_MASK     (1 << SPI_IR_TXUNDER_SHIFT)
  85 #define SPI_IR_TXOVER_SHIFT     3
  86 #define SPI_IR_TXOVER_MASK      (1 << SPI_IR_TXOVER_SHIFT)
  87 #define SPI_IR_RXUNDER_SHIFT    4
  88 #define SPI_IR_RXUNDER_MASK     (1 << SPI_IR_RXUNDER_SHIFT)
  89 #define SPI_IR_CLEAR_MASK       (SPI_IR_DONE_MASK |\
  90                                  SPI_IR_RXOVER_MASK |\
  91                                  SPI_IR_TXUNDER_MASK |\
  92                                  SPI_IR_TXOVER_MASK |\
  93                                  SPI_IR_RXUNDER_MASK)
  94
  95 enum bcm63xx_regs_spi {
  96         SPI_CLK,
  97         SPI_CMD,
  98         SPI_CTL,
  99         SPI_CTL_SHIFT,
 100         SPI_FILL,
 101         SPI_IR_MASK,
 102         SPI_IR_STAT,
 103         SPI_RX,
 104         SPI_RX_SIZE,
 105         SPI_TX,
 106         SPI_TX_SIZE,
 107 };
 108
 109 struct bcm63xx_spi_priv {
 110         const unsigned long *regs;
 111         void __iomem *base;
 112         size_t tx_bytes;
 113         uint8_t num_cs;
 114 };
 115
 116 #define SPI_CLK_CNT             8
 117 static const unsigned bcm63xx_spi_freq_table[SPI_CLK_CNT][2] = {
 118         { 25000000, SPI_CLK_25MHZ },
 119         { 20000000, SPI_CLK_20MHZ },
 120         { 12500000, SPI_CLK_12_50MHZ },
 121         {  6250000, SPI_CLK_6_250MHZ },
 122         {  3125000, SPI_CLK_3_125MHZ },
 123         {  1563000, SPI_CLK_1_563MHZ },
 124         {   781000, SPI_CLK_0_781MHZ },
 125         {   391000, SPI_CLK_0_391MHZ }
 126 };
 127
 128 static int bcm63xx_spi_cs_info(struct udevice *bus, uint cs,
 129                            struct spi_cs_info *info)
 130 {
 131         struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
 132
 133         if (cs >= priv->num_cs) {
 134                 printf("no cs %u\n", cs);
 135                 return -EINVAL;
 136         }
 137
 138         return 0;
 139 }
 140
 141 static int bcm63xx_spi_set_mode(struct udevice *bus, uint mode)
 142 {
 143         struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
 144         const unsigned long *regs = priv->regs;
 145
 146         if (mode & SPI_LSB_FIRST)
 147                 setbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);
 148         else
 149                 clrbits_8(priv->base + regs[SPI_CLK], SPI_CLK_BSWAP_MASK);
 150
 151         return 0;
 152 }
 153
 154 static int bcm63xx_spi_set_speed(struct udevice *bus, uint speed)
 155 {
 156         struct bcm63xx_spi_priv *priv = dev_get_priv(bus);
 157         const unsigned long *regs = priv->regs;
 158         uint8_t clk_cfg;
 159         int i;
 160
 161         /* default to lowest clock configuration */
 162         clk_cfg = SPI_CLK_0_391MHZ;
 163
 164         /* find the closest clock configuration */
 165         for (i = 0; i < SPI_CLK_CNT; i++) {
 166                 if (speed >= bcm63xx_spi_freq_table[i][0]) {
 167                         clk_cfg = bcm63xx_spi_freq_table[i][1];
 168                         break;
 169                 }
 170         }
 171
 172         /* write clock configuration */
 173         clrsetbits_8(priv->base + regs[SPI_CLK],
 174                      SPI_CLK_SSOFF_MASK | SPI_CLK_MASK,
 175                      clk_cfg | SPI_CLK_SSOFF_2);
 176
 177         return 0;
 178 }
 179
 180 /*
 181  * BCM63xx SPI driver doesn't allow keeping CS active between transfers since
 182  * they are HW controlled.
 183  * However, it provides a mechanism to prepend write transfers prior to read
 184  * transfers (with a maximum prepend of 15 bytes), which is usually enough for
 185  * SPI-connected flashes since reading requires prepending a write transfer of
 186  * 5 bytes.
 187  *
 188  * This implementation takes advantage of the prepend mechanism and combines
 189  * multiple transfers into a single one where possible (single/multiple write
 190  * transfer(s) followed by a final read/write transfer).
 191  * However, it's not possible to buffer reads, which means that read transfers
 192  * should always be done as the final ones.
 193  * On the other hand, take into account that combining write transfers into
 194  * a single one is just buffering and doesn't require prepend mechanism.
 195  */
 196 static int bcm63xx_spi_xfer(struct udevice *dev, unsigned int bitlen,
 197                 const void *dout, void *din, unsigned long flags)
 198 {
 199         struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
 200         const unsigned long *regs = priv->regs;
 201         size_t data_bytes = bitlen / 8;
 202
 203         if (flags & SPI_XFER_BEGIN) {
 204                 /* clear prepends */
 205                 priv->tx_bytes = 0;
 206
 207                 /* initialize hardware */
 208                 writeb_be(0, priv->base + regs[SPI_IR_MASK]);
 209         }
 210
 211         if (din) {
 212                 /* buffering reads not possible since cs is hw controlled */
 213                 if (!(flags & SPI_XFER_END)) {
 214                         printf("unable to buffer reads\n");
 215                         return -EINVAL;
 216                 }
 217
 218                 /* check rx size */
 219                  if (data_bytes > regs[SPI_RX_SIZE]) {
 220                         printf("max rx bytes exceeded\n");
 221                         return -EMSGSIZE;
 222                 }
 223         }
 224
 225         if (dout) {
 226                 /* check tx size */
 227                 if (priv->tx_bytes + data_bytes > regs[SPI_TX_SIZE]) {
 228                         printf("max tx bytes exceeded\n");
 229                         return -EMSGSIZE;
 230                 }
 231
 232                 /* copy tx data */
 233                 memcpy_toio(priv->base + regs[SPI_TX] + priv->tx_bytes,
 234                             dout, data_bytes);
 235                 priv->tx_bytes += data_bytes;
 236         }
 237
 238         if (flags & SPI_XFER_END) {
 239                 struct dm_spi_slave_plat *plat =
 240                         dev_get_parent_plat(dev);
 241                 uint16_t val, cmd;
 242                 int ret;
 243
 244                 /* determine control config */
 245                 if (dout && !din) {
 246                         /* buffered write transfers */
 247                         val = priv->tx_bytes;
 248                         val |= (SPI_CTL_TYPE_HD_W << regs[SPI_CTL_SHIFT]);
 249                         priv->tx_bytes = 0;
 250                 } else {
 251                         if (dout && din && (flags & SPI_XFER_ONCE)) {
 252                                 /* full duplex read/write */
 253                                 val = data_bytes;
 254                                 val |= (SPI_CTL_TYPE_FD_RW <<
 255                                         regs[SPI_CTL_SHIFT]);
 256                                 priv->tx_bytes = 0;
 257                         } else {
 258                                 /* prepended write transfer */
 259                                 val = data_bytes;
 260                                 val |= (SPI_CTL_TYPE_HD_R <<
 261                                         regs[SPI_CTL_SHIFT]);
 262                                 if (priv->tx_bytes > SPI_CMD_PREPEND_BYTES) {
 263                                         printf("max prepend bytes exceeded\n");
 264                                         return -EMSGSIZE;
 265                                 }
 266                         }
 267                 }
 268
 269                 if (regs[SPI_CTL_SHIFT] >= 8)
 270                         writew_be(val, priv->base + regs[SPI_CTL]);
 271                 else
 272                         writeb_be(val, priv->base + regs[SPI_CTL]);
 273
 274                 /* clear interrupts */
 275                 writeb_be(SPI_IR_CLEAR_MASK, priv->base + regs[SPI_IR_STAT]);
 276
 277                 /* issue the transfer */
 278                 cmd = SPI_CMD_OP_START;
 279                 cmd |= (plat->cs << SPI_CMD_SLAVE_SHIFT) & SPI_CMD_SLAVE_MASK;
 280                 cmd |= (priv->tx_bytes << SPI_CMD_PREPEND_SHIFT);
 281                 if (plat->mode & SPI_3WIRE)
 282                         cmd |= SPI_CMD_3WIRE_MASK;
 283                 writew_be(cmd, priv->base + regs[SPI_CMD]);
 284
 285                 /* enable interrupts */
 286                 writeb_be(SPI_IR_DONE_MASK, priv->base + regs[SPI_IR_MASK]);
 287
 288                 ret = wait_for_bit_8(priv->base + regs[SPI_IR_STAT],
 289                                      SPI_IR_DONE_MASK, true, 1000, false);
 290                 if (ret) {
 291                         printf("interrupt timeout\n");
 292                         return ret;
 293                 }
 294
 295                 /* copy rx data */
 296                 if (din)
 297                         memcpy_fromio(din, priv->base + regs[SPI_RX],
 298                                       data_bytes);
 299         }
 300
 301         return 0;
 302 }
 303
 304 static const struct dm_spi_ops bcm63xx_spi_ops = {
 305         .cs_info = bcm63xx_spi_cs_info,
 306         .set_mode = bcm63xx_spi_set_mode,
 307         .set_speed = bcm63xx_spi_set_speed,
 308         .xfer = bcm63xx_spi_xfer,
 309 };
 310
 311 static const unsigned long bcm6348_spi_regs[] = {
 312         [SPI_CLK] = SPI_6348_CLK,
 313         [SPI_CMD] = SPI_6348_CMD,
 314         [SPI_CTL] = SPI_6348_CTL,
 315         [SPI_CTL_SHIFT] = SPI_6348_CTL_SHIFT,
 316         [SPI_FILL] = SPI_6348_FILL,
 317         [SPI_IR_MASK] = SPI_6348_IR_MASK,
 318         [SPI_IR_STAT] = SPI_6348_IR_STAT,
 319         [SPI_RX] = SPI_6348_RX,
 320         [SPI_RX_SIZE] = SPI_6348_RX_SIZE,
 321         [SPI_TX] = SPI_6348_TX,
 322         [SPI_TX_SIZE] = SPI_6348_TX_SIZE,
 323 };
 324
 325 static const unsigned long bcm6358_spi_regs[] = {
 326         [SPI_CLK] = SPI_6358_CLK,
 327         [SPI_CMD] = SPI_6358_CMD,
 328         [SPI_CTL] = SPI_6358_CTL,
 329         [SPI_CTL_SHIFT] = SPI_6358_CTL_SHIFT,
 330         [SPI_FILL] = SPI_6358_FILL,
 331         [SPI_IR_MASK] = SPI_6358_IR_MASK,
 332         [SPI_IR_STAT] = SPI_6358_IR_STAT,
 333         [SPI_RX] = SPI_6358_RX,
 334         [SPI_RX_SIZE] = SPI_6358_RX_SIZE,
 335         [SPI_TX] = SPI_6358_TX,
 336         [SPI_TX_SIZE] = SPI_6358_TX_SIZE,
 337 };
 338
 339 static const struct udevice_id bcm63xx_spi_ids[] = {
 340         {
 341                 .compatible = "brcm,bcm6348-spi",
 342                 .data = (ulong)&bcm6348_spi_regs,
 343         }, {
 344                 .compatible = "brcm,bcm6358-spi",
 345                 .data = (ulong)&bcm6358_spi_regs,
 346         }, { /* sentinel */ }
 347 };
 348
 349 static int bcm63xx_spi_child_pre_probe(struct udevice *dev)
 350 {
 351         struct bcm63xx_spi_priv *priv = dev_get_priv(dev->parent);
 352         const unsigned long *regs = priv->regs;
 353         struct spi_slave *slave = dev_get_parent_priv(dev);
 354         struct dm_spi_slave_plat *plat = dev_get_parent_plat(dev);
 355
 356         /* check cs */
 357         if (plat->cs >= priv->num_cs) {
 358                 printf("no cs %u\n", plat->cs);
 359                 return -ENODEV;
 360         }
 361
 362         /* max read/write sizes */
 363         slave->max_read_size = regs[SPI_RX_SIZE];
 364         slave->max_write_size = regs[SPI_TX_SIZE];
 365
 366         return 0;
 367 }
 368
 369 static int bcm63xx_spi_probe(struct udevice *dev)
 370 {
 371         struct bcm63xx_spi_priv *priv = dev_get_priv(dev);
 372         const unsigned long *regs =
 373                 (const unsigned long *)dev_get_driver_data(dev);
 374         struct reset_ctl rst_ctl;
 375         struct clk clk;
 376         int ret;
 377
 378         priv->base = dev_remap_addr(dev);
 379         if (!priv->base)
 380                 return -EINVAL;
 381
 382         priv->regs = regs;
 383         priv->num_cs = dev_read_u32_default(dev, "num-cs", 8);
 384
 385         /* enable clock */
 386         ret = clk_get_by_index(dev, 0, &clk);
 387         if (ret < 0)
 388                 return ret;
 389
 390         ret = clk_enable(&clk);
 391         if (ret < 0)
 392                 return ret;
 393
 394         clk_free(&clk);
 395
 396         /* perform reset */
 397         ret = reset_get_by_index(dev, 0, &rst_ctl);
 398         if (ret < 0)
 399                 return ret;
 400
 401         ret = reset_deassert(&rst_ctl);
 402         if (ret < 0)
 403                 return ret;
 404
 405         ret = reset_free(&rst_ctl);
 406         if (ret < 0)
 407                 return ret;
 408
 409         /* initialize hardware */
 410         writeb_be(0, priv->base + regs[SPI_IR_MASK]);
 411
 412         /* set fill register */
 413         writeb_be(0xff, priv->base + regs[SPI_FILL]);
 414
 415         return 0;
 416 }
 417
 418 U_BOOT_DRIVER(bcm63xx_spi) = {
 419         .name = "bcm63xx_spi",
 420         .id = UCLASS_SPI,
 421         .of_match = bcm63xx_spi_ids,
 422         .ops = &bcm63xx_spi_ops,
 423         .priv_auto      = sizeof(struct bcm63xx_spi_priv),
 424         .child_pre_probe = bcm63xx_spi_child_pre_probe,
 425         .probe = bcm63xx_spi_probe,
 426 };