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