drivers/spi/spi-lantiq-ssc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2011-2015 Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
   4  * Copyright (C) 2016 Hauke Mehrtens <hauke@hauke-m.de>
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/of_device.h>
  10 #include <linux/clk.h>
  11 #include <linux/io.h>
  12 #include <linux/delay.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/sched.h>
  15 #include <linux/completion.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/err.h>
  18 #include <linux/pm_runtime.h>
  19 #include <linux/spi/spi.h>
  20
  21 #ifdef CONFIG_LANTIQ
  22 #include <lantiq_soc.h>
  23 #endif
  24
  25 #define LTQ_SPI_RX_IRQ_NAME     "spi_rx"
  26 #define LTQ_SPI_TX_IRQ_NAME     "spi_tx"
  27 #define LTQ_SPI_ERR_IRQ_NAME    "spi_err"
  28 #define LTQ_SPI_FRM_IRQ_NAME    "spi_frm"
  29
  30 #define LTQ_SPI_CLC             0x00
  31 #define LTQ_SPI_PISEL           0x04
  32 #define LTQ_SPI_ID              0x08
  33 #define LTQ_SPI_CON             0x10
  34 #define LTQ_SPI_STAT            0x14
  35 #define LTQ_SPI_WHBSTATE        0x18
  36 #define LTQ_SPI_TB              0x20
  37 #define LTQ_SPI_RB              0x24
  38 #define LTQ_SPI_RXFCON          0x30
  39 #define LTQ_SPI_TXFCON          0x34
  40 #define LTQ_SPI_FSTAT           0x38
  41 #define LTQ_SPI_BRT             0x40
  42 #define LTQ_SPI_BRSTAT          0x44
  43 #define LTQ_SPI_SFCON           0x60
  44 #define LTQ_SPI_SFSTAT          0x64
  45 #define LTQ_SPI_GPOCON          0x70
  46 #define LTQ_SPI_GPOSTAT         0x74
  47 #define LTQ_SPI_FPGO            0x78
  48 #define LTQ_SPI_RXREQ           0x80
  49 #define LTQ_SPI_RXCNT           0x84
  50 #define LTQ_SPI_DMACON          0xec
  51 #define LTQ_SPI_IRNEN           0xf4
  52
  53 #define LTQ_SPI_CLC_SMC_S       16      /* Clock divider for sleep mode */
  54 #define LTQ_SPI_CLC_SMC_M       (0xFF << LTQ_SPI_CLC_SMC_S)
  55 #define LTQ_SPI_CLC_RMC_S       8       /* Clock divider for normal run mode */
  56 #define LTQ_SPI_CLC_RMC_M       (0xFF << LTQ_SPI_CLC_RMC_S)
  57 #define LTQ_SPI_CLC_DISS        BIT(1)  /* Disable status bit */
  58 #define LTQ_SPI_CLC_DISR        BIT(0)  /* Disable request bit */
  59
  60 #define LTQ_SPI_ID_TXFS_S       24      /* Implemented TX FIFO size */
  61 #define LTQ_SPI_ID_RXFS_S       16      /* Implemented RX FIFO size */
  62 #define LTQ_SPI_ID_MOD_S        8       /* Module ID */
  63 #define LTQ_SPI_ID_MOD_M        (0xff << LTQ_SPI_ID_MOD_S)
  64 #define LTQ_SPI_ID_CFG_S        5       /* DMA interface support */
  65 #define LTQ_SPI_ID_CFG_M        (1 << LTQ_SPI_ID_CFG_S)
  66 #define LTQ_SPI_ID_REV_M        0x1F    /* Hardware revision number */
  67
  68 #define LTQ_SPI_CON_BM_S        16      /* Data width selection */
  69 #define LTQ_SPI_CON_BM_M        (0x1F << LTQ_SPI_CON_BM_S)
  70 #define LTQ_SPI_CON_EM          BIT(24) /* Echo mode */
  71 #define LTQ_SPI_CON_IDLE        BIT(23) /* Idle bit value */
  72 #define LTQ_SPI_CON_ENBV        BIT(22) /* Enable byte valid control */
  73 #define LTQ_SPI_CON_RUEN        BIT(12) /* Receive underflow error enable */
  74 #define LTQ_SPI_CON_TUEN        BIT(11) /* Transmit underflow error enable */
  75 #define LTQ_SPI_CON_AEN         BIT(10) /* Abort error enable */
  76 #define LTQ_SPI_CON_REN         BIT(9)  /* Receive overflow error enable */
  77 #define LTQ_SPI_CON_TEN         BIT(8)  /* Transmit overflow error enable */
  78 #define LTQ_SPI_CON_LB          BIT(7)  /* Loopback control */
  79 #define LTQ_SPI_CON_PO          BIT(6)  /* Clock polarity control */
  80 #define LTQ_SPI_CON_PH          BIT(5)  /* Clock phase control */
  81 #define LTQ_SPI_CON_HB          BIT(4)  /* Heading control */
  82 #define LTQ_SPI_CON_RXOFF       BIT(1)  /* Switch receiver off */
  83 #define LTQ_SPI_CON_TXOFF       BIT(0)  /* Switch transmitter off */
  84
  85 #define LTQ_SPI_STAT_RXBV_S     28
  86 #define LTQ_SPI_STAT_RXBV_M     (0x7 << LTQ_SPI_STAT_RXBV_S)
  87 #define LTQ_SPI_STAT_BSY        BIT(13) /* Busy flag */
  88 #define LTQ_SPI_STAT_RUE        BIT(12) /* Receive underflow error flag */
  89 #define LTQ_SPI_STAT_TUE        BIT(11) /* Transmit underflow error flag */
  90 #define LTQ_SPI_STAT_AE         BIT(10) /* Abort error flag */
  91 #define LTQ_SPI_STAT_RE         BIT(9)  /* Receive error flag */
  92 #define LTQ_SPI_STAT_TE         BIT(8)  /* Transmit error flag */
  93 #define LTQ_SPI_STAT_ME         BIT(7)  /* Mode error flag */
  94 #define LTQ_SPI_STAT_MS         BIT(1)  /* Master/slave select bit */
  95 #define LTQ_SPI_STAT_EN         BIT(0)  /* Enable bit */
  96 #define LTQ_SPI_STAT_ERRORS     (LTQ_SPI_STAT_ME | LTQ_SPI_STAT_TE | \
  97                                  LTQ_SPI_STAT_RE | LTQ_SPI_STAT_AE | \
  98                                  LTQ_SPI_STAT_TUE | LTQ_SPI_STAT_RUE)
  99
 100 #define LTQ_SPI_WHBSTATE_SETTUE BIT(15) /* Set transmit underflow error flag */
 101 #define LTQ_SPI_WHBSTATE_SETAE  BIT(14) /* Set abort error flag */
 102 #define LTQ_SPI_WHBSTATE_SETRE  BIT(13) /* Set receive error flag */
 103 #define LTQ_SPI_WHBSTATE_SETTE  BIT(12) /* Set transmit error flag */
 104 #define LTQ_SPI_WHBSTATE_CLRTUE BIT(11) /* Clear transmit underflow error flag */
 105 #define LTQ_SPI_WHBSTATE_CLRAE  BIT(10) /* Clear abort error flag */
 106 #define LTQ_SPI_WHBSTATE_CLRRE  BIT(9)  /* Clear receive error flag */
 107 #define LTQ_SPI_WHBSTATE_CLRTE  BIT(8)  /* Clear transmit error flag */
 108 #define LTQ_SPI_WHBSTATE_SETME  BIT(7)  /* Set mode error flag */
 109 #define LTQ_SPI_WHBSTATE_CLRME  BIT(6)  /* Clear mode error flag */
 110 #define LTQ_SPI_WHBSTATE_SETRUE BIT(5)  /* Set receive underflow error flag */
 111 #define LTQ_SPI_WHBSTATE_CLRRUE BIT(4)  /* Clear receive underflow error flag */
 112 #define LTQ_SPI_WHBSTATE_SETMS  BIT(3)  /* Set master select bit */
 113 #define LTQ_SPI_WHBSTATE_CLRMS  BIT(2)  /* Clear master select bit */
 114 #define LTQ_SPI_WHBSTATE_SETEN  BIT(1)  /* Set enable bit (operational mode) */
 115 #define LTQ_SPI_WHBSTATE_CLREN  BIT(0)  /* Clear enable bit (config mode */
 116 #define LTQ_SPI_WHBSTATE_CLR_ERRORS     (LTQ_SPI_WHBSTATE_CLRRUE | \
 117                                          LTQ_SPI_WHBSTATE_CLRME | \
 118                                          LTQ_SPI_WHBSTATE_CLRTE | \
 119                                          LTQ_SPI_WHBSTATE_CLRRE | \
 120                                          LTQ_SPI_WHBSTATE_CLRAE | \
 121                                          LTQ_SPI_WHBSTATE_CLRTUE)
 122
 123 #define LTQ_SPI_RXFCON_RXFITL_S 8       /* FIFO interrupt trigger level */
 124 #define LTQ_SPI_RXFCON_RXFLU    BIT(1)  /* FIFO flush */
 125 #define LTQ_SPI_RXFCON_RXFEN    BIT(0)  /* FIFO enable */
 126
 127 #define LTQ_SPI_TXFCON_TXFITL_S 8       /* FIFO interrupt trigger level */
 128 #define LTQ_SPI_TXFCON_TXFLU    BIT(1)  /* FIFO flush */
 129 #define LTQ_SPI_TXFCON_TXFEN    BIT(0)  /* FIFO enable */
 130
 131 #define LTQ_SPI_FSTAT_RXFFL_S   0
 132 #define LTQ_SPI_FSTAT_TXFFL_S   8
 133
 134 #define LTQ_SPI_GPOCON_ISCSBN_S 8
 135 #define LTQ_SPI_GPOCON_INVOUTN_S        0
 136
 137 #define LTQ_SPI_FGPO_SETOUTN_S  8
 138 #define LTQ_SPI_FGPO_CLROUTN_S  0
 139
 140 #define LTQ_SPI_RXREQ_RXCNT_M   0xFFFF  /* Receive count value */
 141 #define LTQ_SPI_RXCNT_TODO_M    0xFFFF  /* Recevie to-do value */
 142
 143 #define LTQ_SPI_IRNEN_TFI       BIT(4)  /* TX finished interrupt */
 144 #define LTQ_SPI_IRNEN_F         BIT(3)  /* Frame end interrupt request */
 145 #define LTQ_SPI_IRNEN_E         BIT(2)  /* Error end interrupt request */
 146 #define LTQ_SPI_IRNEN_T_XWAY    BIT(1)  /* Transmit end interrupt request */
 147 #define LTQ_SPI_IRNEN_R_XWAY    BIT(0)  /* Receive end interrupt request */
 148 #define LTQ_SPI_IRNEN_R_XRX     BIT(1)  /* Transmit end interrupt request */
 149 #define LTQ_SPI_IRNEN_T_XRX     BIT(0)  /* Receive end interrupt request */
 150 #define LTQ_SPI_IRNEN_ALL       0x1F
 151
 152 struct lantiq_ssc_spi;
 153
 154 struct lantiq_ssc_hwcfg {
 155         int (*cfg_irq)(struct platform_device *pdev, struct lantiq_ssc_spi *spi);
 156         unsigned int    irnen_r;
 157         unsigned int    irnen_t;
 158         unsigned int    irncr;
 159         unsigned int    irnicr;
 160         bool            irq_ack;
 161         u32             fifo_size_mask;
 162 };
 163
 164 struct lantiq_ssc_spi {
 165         struct spi_master               *master;
 166         struct device                   *dev;
 167         void __iomem                    *regbase;
 168         struct clk                      *spi_clk;
 169         struct clk                      *fpi_clk;
 170         const struct lantiq_ssc_hwcfg   *hwcfg;
 171
 172         spinlock_t                      lock;
 173         struct workqueue_struct         *wq;
 174         struct work_struct              work;
 175
 176         const u8                        *tx;
 177         u8                              *rx;
 178         unsigned int                    tx_todo;
 179         unsigned int                    rx_todo;
 180         unsigned int                    bits_per_word;
 181         unsigned int                    speed_hz;
 182         unsigned int                    tx_fifo_size;
 183         unsigned int                    rx_fifo_size;
 184         unsigned int                    base_cs;
 185         unsigned int                    fdx_tx_level;
 186 };
 187
 188 static u32 lantiq_ssc_readl(const struct lantiq_ssc_spi *spi, u32 reg)
 189 {
 190         return __raw_readl(spi->regbase + reg);
 191 }
 192
 193 static void lantiq_ssc_writel(const struct lantiq_ssc_spi *spi, u32 val,
 194                               u32 reg)
 195 {
 196         __raw_writel(val, spi->regbase + reg);
 197 }
 198
 199 static void lantiq_ssc_maskl(const struct lantiq_ssc_spi *spi, u32 clr,
 200                              u32 set, u32 reg)
 201 {
 202         u32 val = __raw_readl(spi->regbase + reg);
 203
 204         val &= ~clr;
 205         val |= set;
 206         __raw_writel(val, spi->regbase + reg);
 207 }
 208
 209 static unsigned int tx_fifo_level(const struct lantiq_ssc_spi *spi)
 210 {
 211         const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
 212         u32 fstat = lantiq_ssc_readl(spi, LTQ_SPI_FSTAT);
 213
 214         return (fstat >> LTQ_SPI_FSTAT_TXFFL_S) & hwcfg->fifo_size_mask;
 215 }
 216
 217 static unsigned int rx_fifo_level(const struct lantiq_ssc_spi *spi)
 218 {
 219         const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
 220         u32 fstat = lantiq_ssc_readl(spi, LTQ_SPI_FSTAT);
 221
 222         return (fstat >> LTQ_SPI_FSTAT_RXFFL_S) & hwcfg->fifo_size_mask;
 223 }
 224
 225 static unsigned int tx_fifo_free(const struct lantiq_ssc_spi *spi)
 226 {
 227         return spi->tx_fifo_size - tx_fifo_level(spi);
 228 }
 229
 230 static void rx_fifo_reset(const struct lantiq_ssc_spi *spi)
 231 {
 232         u32 val = spi->rx_fifo_size << LTQ_SPI_RXFCON_RXFITL_S;
 233
 234         val |= LTQ_SPI_RXFCON_RXFEN | LTQ_SPI_RXFCON_RXFLU;
 235         lantiq_ssc_writel(spi, val, LTQ_SPI_RXFCON);
 236 }
 237
 238 static void tx_fifo_reset(const struct lantiq_ssc_spi *spi)
 239 {
 240         u32 val = 1 << LTQ_SPI_TXFCON_TXFITL_S;
 241
 242         val |= LTQ_SPI_TXFCON_TXFEN | LTQ_SPI_TXFCON_TXFLU;
 243         lantiq_ssc_writel(spi, val, LTQ_SPI_TXFCON);
 244 }
 245
 246 static void rx_fifo_flush(const struct lantiq_ssc_spi *spi)
 247 {
 248         lantiq_ssc_maskl(spi, 0, LTQ_SPI_RXFCON_RXFLU, LTQ_SPI_RXFCON);
 249 }
 250
 251 static void tx_fifo_flush(const struct lantiq_ssc_spi *spi)
 252 {
 253         lantiq_ssc_maskl(spi, 0, LTQ_SPI_TXFCON_TXFLU, LTQ_SPI_TXFCON);
 254 }
 255
 256 static void hw_enter_config_mode(const struct lantiq_ssc_spi *spi)
 257 {
 258         lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_CLREN, LTQ_SPI_WHBSTATE);
 259 }
 260
 261 static void hw_enter_active_mode(const struct lantiq_ssc_spi *spi)
 262 {
 263         lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_SETEN, LTQ_SPI_WHBSTATE);
 264 }
 265
 266 static void hw_setup_speed_hz(const struct lantiq_ssc_spi *spi,
 267                               unsigned int max_speed_hz)
 268 {
 269         u32 spi_clk, brt;
 270
 271         /*
 272          * SPI module clock is derived from FPI bus clock dependent on
 273          * divider value in CLC.RMS which is always set to 1.
 274          *
 275          *                 f_SPI
 276          * baudrate = --------------
 277          *             2 * (BR + 1)
 278          */
 279         spi_clk = clk_get_rate(spi->fpi_clk) / 2;
 280
 281         if (max_speed_hz > spi_clk)
 282                 brt = 0;
 283         else
 284                 brt = spi_clk / max_speed_hz - 1;
 285
 286         if (brt > 0xFFFF)
 287                 brt = 0xFFFF;
 288
 289         dev_dbg(spi->dev, "spi_clk %u, max_speed_hz %u, brt %u\n",
 290                 spi_clk, max_speed_hz, brt);
 291
 292         lantiq_ssc_writel(spi, brt, LTQ_SPI_BRT);
 293 }
 294
 295 static void hw_setup_bits_per_word(const struct lantiq_ssc_spi *spi,
 296                                    unsigned int bits_per_word)
 297 {
 298         u32 bm;
 299
 300         /* CON.BM value = bits_per_word - 1 */
 301         bm = (bits_per_word - 1) << LTQ_SPI_CON_BM_S;
 302
 303         lantiq_ssc_maskl(spi, LTQ_SPI_CON_BM_M, bm, LTQ_SPI_CON);
 304 }
 305
 306 static void hw_setup_clock_mode(const struct lantiq_ssc_spi *spi,
 307                                 unsigned int mode)
 308 {
 309         u32 con_set = 0, con_clr = 0;
 310
 311         /*
 312          * SPI mode mapping in CON register:
 313          * Mode CPOL CPHA CON.PO CON.PH
 314          *  0    0    0      0      1
 315          *  1    0    1      0      0
 316          *  2    1    0      1      1
 317          *  3    1    1      1      0
 318          */
 319         if (mode & SPI_CPHA)
 320                 con_clr |= LTQ_SPI_CON_PH;
 321         else
 322                 con_set |= LTQ_SPI_CON_PH;
 323
 324         if (mode & SPI_CPOL)
 325                 con_set |= LTQ_SPI_CON_PO | LTQ_SPI_CON_IDLE;
 326         else
 327                 con_clr |= LTQ_SPI_CON_PO | LTQ_SPI_CON_IDLE;
 328
 329         /* Set heading control */
 330         if (mode & SPI_LSB_FIRST)
 331                 con_clr |= LTQ_SPI_CON_HB;
 332         else
 333                 con_set |= LTQ_SPI_CON_HB;
 334
 335         /* Set loopback mode */
 336         if (mode & SPI_LOOP)
 337                 con_set |= LTQ_SPI_CON_LB;
 338         else
 339                 con_clr |= LTQ_SPI_CON_LB;
 340
 341         lantiq_ssc_maskl(spi, con_clr, con_set, LTQ_SPI_CON);
 342 }
 343
 344 static void lantiq_ssc_hw_init(const struct lantiq_ssc_spi *spi)
 345 {
 346         const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
 347
 348         /*
 349          * Set clock divider for run mode to 1 to
 350          * run at same frequency as FPI bus
 351          */
 352         lantiq_ssc_writel(spi, 1 << LTQ_SPI_CLC_RMC_S, LTQ_SPI_CLC);
 353
 354         /* Put controller into config mode */
 355         hw_enter_config_mode(spi);
 356
 357         /* Clear error flags */
 358         lantiq_ssc_maskl(spi, 0, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);
 359
 360         /* Enable error checking, disable TX/RX */
 361         lantiq_ssc_writel(spi, LTQ_SPI_CON_RUEN | LTQ_SPI_CON_AEN |
 362                 LTQ_SPI_CON_TEN | LTQ_SPI_CON_REN | LTQ_SPI_CON_TXOFF |
 363                 LTQ_SPI_CON_RXOFF, LTQ_SPI_CON);
 364
 365         /* Setup default SPI mode */
 366         hw_setup_bits_per_word(spi, spi->bits_per_word);
 367         hw_setup_clock_mode(spi, SPI_MODE_0);
 368
 369         /* Enable master mode and clear error flags */
 370         lantiq_ssc_writel(spi, LTQ_SPI_WHBSTATE_SETMS |
 371                                LTQ_SPI_WHBSTATE_CLR_ERRORS,
 372                                LTQ_SPI_WHBSTATE);
 373
 374         /* Reset GPIO/CS registers */
 375         lantiq_ssc_writel(spi, 0, LTQ_SPI_GPOCON);
 376         lantiq_ssc_writel(spi, 0xFF00, LTQ_SPI_FPGO);
 377
 378         /* Enable and flush FIFOs */
 379         rx_fifo_reset(spi);
 380         tx_fifo_reset(spi);
 381
 382         /* Enable interrupts */
 383         lantiq_ssc_writel(spi, hwcfg->irnen_t | hwcfg->irnen_r |
 384                           LTQ_SPI_IRNEN_E, LTQ_SPI_IRNEN);
 385 }
 386
 387 static int lantiq_ssc_setup(struct spi_device *spidev)
 388 {
 389         struct spi_master *master = spidev->master;
 390         struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
 391         unsigned int cs = spidev->chip_select;
 392         u32 gpocon;
 393
 394         /* GPIOs are used for CS */
 395         if (spidev->cs_gpiod)
 396                 return 0;
 397
 398         dev_dbg(spi->dev, "using internal chipselect %u\n", cs);
 399
 400         if (cs < spi->base_cs) {
 401                 dev_err(spi->dev,
 402                         "chipselect %i too small (min %i)\n", cs, spi->base_cs);
 403                 return -EINVAL;
 404         }
 405
 406         /* set GPO pin to CS mode */
 407         gpocon = 1 << ((cs - spi->base_cs) + LTQ_SPI_GPOCON_ISCSBN_S);
 408
 409         /* invert GPO pin */
 410         if (spidev->mode & SPI_CS_HIGH)
 411                 gpocon |= 1 << (cs - spi->base_cs);
 412
 413         lantiq_ssc_maskl(spi, 0, gpocon, LTQ_SPI_GPOCON);
 414
 415         return 0;
 416 }
 417
 418 static int lantiq_ssc_prepare_message(struct spi_master *master,
 419                                       struct spi_message *message)
 420 {
 421         struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
 422
 423         hw_enter_config_mode(spi);
 424         hw_setup_clock_mode(spi, message->spi->mode);
 425         hw_enter_active_mode(spi);
 426
 427         return 0;
 428 }
 429
 430 static void hw_setup_transfer(struct lantiq_ssc_spi *spi,
 431                               struct spi_device *spidev, struct spi_transfer *t)
 432 {
 433         unsigned int speed_hz = t->speed_hz;
 434         unsigned int bits_per_word = t->bits_per_word;
 435         u32 con;
 436
 437         if (bits_per_word != spi->bits_per_word ||
 438                 speed_hz != spi->speed_hz) {
 439                 hw_enter_config_mode(spi);
 440                 hw_setup_speed_hz(spi, speed_hz);
 441                 hw_setup_bits_per_word(spi, bits_per_word);
 442                 hw_enter_active_mode(spi);
 443
 444                 spi->speed_hz = speed_hz;
 445                 spi->bits_per_word = bits_per_word;
 446         }
 447
 448         /* Configure transmitter and receiver */
 449         con = lantiq_ssc_readl(spi, LTQ_SPI_CON);
 450         if (t->tx_buf)
 451                 con &= ~LTQ_SPI_CON_TXOFF;
 452         else
 453                 con |= LTQ_SPI_CON_TXOFF;
 454
 455         if (t->rx_buf)
 456                 con &= ~LTQ_SPI_CON_RXOFF;
 457         else
 458                 con |= LTQ_SPI_CON_RXOFF;
 459
 460         lantiq_ssc_writel(spi, con, LTQ_SPI_CON);
 461 }
 462
 463 static int lantiq_ssc_unprepare_message(struct spi_master *master,
 464                                         struct spi_message *message)
 465 {
 466         struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
 467
 468         flush_workqueue(spi->wq);
 469
 470         /* Disable transmitter and receiver while idle */
 471         lantiq_ssc_maskl(spi, 0, LTQ_SPI_CON_TXOFF | LTQ_SPI_CON_RXOFF,
 472                          LTQ_SPI_CON);
 473
 474         return 0;
 475 }
 476
 477 static void tx_fifo_write(struct lantiq_ssc_spi *spi)
 478 {
 479         const u8 *tx8;
 480         const u16 *tx16;
 481         const u32 *tx32;
 482         u32 data;
 483         unsigned int tx_free = tx_fifo_free(spi);
 484
 485         spi->fdx_tx_level = 0;
 486         while (spi->tx_todo && tx_free) {
 487                 switch (spi->bits_per_word) {
 488                 case 2 ... 8:
 489                         tx8 = spi->tx;
 490                         data = *tx8;
 491                         spi->tx_todo--;
 492                         spi->tx++;
 493                         break;
 494                 case 16:
 495                         tx16 = (u16 *) spi->tx;
 496                         data = *tx16;
 497                         spi->tx_todo -= 2;
 498                         spi->tx += 2;
 499                         break;
 500                 case 32:
 501                         tx32 = (u32 *) spi->tx;
 502                         data = *tx32;
 503                         spi->tx_todo -= 4;
 504                         spi->tx += 4;
 505                         break;
 506                 default:
 507                         WARN_ON(1);
 508                         data = 0;
 509                         break;
 510                 }
 511
 512                 lantiq_ssc_writel(spi, data, LTQ_SPI_TB);
 513                 tx_free--;
 514                 spi->fdx_tx_level++;
 515         }
 516 }
 517
 518 static void rx_fifo_read_full_duplex(struct lantiq_ssc_spi *spi)
 519 {
 520         u8 *rx8;
 521         u16 *rx16;
 522         u32 *rx32;
 523         u32 data;
 524         unsigned int rx_fill = rx_fifo_level(spi);
 525
 526         /*
 527          * Wait until all expected data to be shifted in.
 528          * Otherwise, rx overrun may occur.
 529          */
 530         while (rx_fill != spi->fdx_tx_level)
 531                 rx_fill = rx_fifo_level(spi);
 532
 533         while (rx_fill) {
 534                 data = lantiq_ssc_readl(spi, LTQ_SPI_RB);
 535
 536                 switch (spi->bits_per_word) {
 537                 case 2 ... 8:
 538                         rx8 = spi->rx;
 539                         *rx8 = data;
 540                         spi->rx_todo--;
 541                         spi->rx++;
 542                         break;
 543                 case 16:
 544                         rx16 = (u16 *) spi->rx;
 545                         *rx16 = data;
 546                         spi->rx_todo -= 2;
 547                         spi->rx += 2;
 548                         break;
 549                 case 32:
 550                         rx32 = (u32 *) spi->rx;
 551                         *rx32 = data;
 552                         spi->rx_todo -= 4;
 553                         spi->rx += 4;
 554                         break;
 555                 default:
 556                         WARN_ON(1);
 557                         break;
 558                 }
 559
 560                 rx_fill--;
 561         }
 562 }
 563
 564 static void rx_fifo_read_half_duplex(struct lantiq_ssc_spi *spi)
 565 {
 566         u32 data, *rx32;
 567         u8 *rx8;
 568         unsigned int rxbv, shift;
 569         unsigned int rx_fill = rx_fifo_level(spi);
 570
 571         /*
 572          * In RX-only mode the bits per word value is ignored by HW. A value
 573          * of 32 is used instead. Thus all 4 bytes per FIFO must be read.
 574          * If remaining RX bytes are less than 4, the FIFO must be read
 575          * differently. The amount of received and valid bytes is indicated
 576          * by STAT.RXBV register value.
 577          */
 578         while (rx_fill) {
 579                 if (spi->rx_todo < 4)  {
 580                         rxbv = (lantiq_ssc_readl(spi, LTQ_SPI_STAT) &
 581                                 LTQ_SPI_STAT_RXBV_M) >> LTQ_SPI_STAT_RXBV_S;
 582                         data = lantiq_ssc_readl(spi, LTQ_SPI_RB);
 583
 584                         shift = (rxbv - 1) * 8;
 585                         rx8 = spi->rx;
 586
 587                         while (rxbv) {
 588                                 *rx8++ = (data >> shift) & 0xFF;
 589                                 rxbv--;
 590                                 shift -= 8;
 591                                 spi->rx_todo--;
 592                                 spi->rx++;
 593                         }
 594                 } else {
 595                         data = lantiq_ssc_readl(spi, LTQ_SPI_RB);
 596                         rx32 = (u32 *) spi->rx;
 597
 598                         *rx32++ = data;
 599                         spi->rx_todo -= 4;
 600                         spi->rx += 4;
 601                 }
 602                 rx_fill--;
 603         }
 604 }
 605
 606 static void rx_request(struct lantiq_ssc_spi *spi)
 607 {
 608         unsigned int rxreq, rxreq_max;
 609
 610         /*
 611          * To avoid receive overflows at high clocks it is better to request
 612          * only the amount of bytes that fits into all FIFOs. This value
 613          * depends on the FIFO size implemented in hardware.
 614          */
 615         rxreq = spi->rx_todo;
 616         rxreq_max = spi->rx_fifo_size * 4;
 617         if (rxreq > rxreq_max)
 618                 rxreq = rxreq_max;
 619
 620         lantiq_ssc_writel(spi, rxreq, LTQ_SPI_RXREQ);
 621 }
 622
 623 static irqreturn_t lantiq_ssc_xmit_interrupt(int irq, void *data)
 624 {
 625         struct lantiq_ssc_spi *spi = data;
 626         const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
 627         u32 val = lantiq_ssc_readl(spi, hwcfg->irncr);
 628
 629         spin_lock(&spi->lock);
 630         if (hwcfg->irq_ack)
 631                 lantiq_ssc_writel(spi, val, hwcfg->irncr);
 632
 633         if (spi->tx) {
 634                 if (spi->rx && spi->rx_todo)
 635                         rx_fifo_read_full_duplex(spi);
 636
 637                 if (spi->tx_todo)
 638                         tx_fifo_write(spi);
 639                 else if (!tx_fifo_level(spi))
 640                         goto completed;
 641         } else if (spi->rx) {
 642                 if (spi->rx_todo) {
 643                         rx_fifo_read_half_duplex(spi);
 644
 645                         if (spi->rx_todo)
 646                                 rx_request(spi);
 647                         else
 648                                 goto completed;
 649                 } else {
 650                         goto completed;
 651                 }
 652         }
 653
 654         spin_unlock(&spi->lock);
 655         return IRQ_HANDLED;
 656
 657 completed:
 658         queue_work(spi->wq, &spi->work);
 659         spin_unlock(&spi->lock);
 660
 661         return IRQ_HANDLED;
 662 }
 663
 664 static irqreturn_t lantiq_ssc_err_interrupt(int irq, void *data)
 665 {
 666         struct lantiq_ssc_spi *spi = data;
 667         const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
 668         u32 stat = lantiq_ssc_readl(spi, LTQ_SPI_STAT);
 669         u32 val = lantiq_ssc_readl(spi, hwcfg->irncr);
 670
 671         if (!(stat & LTQ_SPI_STAT_ERRORS))
 672                 return IRQ_NONE;
 673
 674         spin_lock(&spi->lock);
 675         if (hwcfg->irq_ack)
 676                 lantiq_ssc_writel(spi, val, hwcfg->irncr);
 677
 678         if (stat & LTQ_SPI_STAT_RUE)
 679                 dev_err(spi->dev, "receive underflow error\n");
 680         if (stat & LTQ_SPI_STAT_TUE)
 681                 dev_err(spi->dev, "transmit underflow error\n");
 682         if (stat & LTQ_SPI_STAT_AE)
 683                 dev_err(spi->dev, "abort error\n");
 684         if (stat & LTQ_SPI_STAT_RE)
 685                 dev_err(spi->dev, "receive overflow error\n");
 686         if (stat & LTQ_SPI_STAT_TE)
 687                 dev_err(spi->dev, "transmit overflow error\n");
 688         if (stat & LTQ_SPI_STAT_ME)
 689                 dev_err(spi->dev, "mode error\n");
 690
 691         /* Clear error flags */
 692         lantiq_ssc_maskl(spi, 0, LTQ_SPI_WHBSTATE_CLR_ERRORS, LTQ_SPI_WHBSTATE);
 693
 694         /* set bad status so it can be retried */
 695         if (spi->master->cur_msg)
 696                 spi->master->cur_msg->status = -EIO;
 697         queue_work(spi->wq, &spi->work);
 698         spin_unlock(&spi->lock);
 699
 700         return IRQ_HANDLED;
 701 }
 702
 703 static irqreturn_t intel_lgm_ssc_isr(int irq, void *data)
 704 {
 705         struct lantiq_ssc_spi *spi = data;
 706         const struct lantiq_ssc_hwcfg *hwcfg = spi->hwcfg;
 707         u32 val = lantiq_ssc_readl(spi, hwcfg->irncr);
 708
 709         if (!(val & LTQ_SPI_IRNEN_ALL))
 710                 return IRQ_NONE;
 711
 712         if (val & LTQ_SPI_IRNEN_E)
 713                 return lantiq_ssc_err_interrupt(irq, data);
 714
 715         if ((val & hwcfg->irnen_t) || (val & hwcfg->irnen_r))
 716                 return lantiq_ssc_xmit_interrupt(irq, data);
 717
 718         return IRQ_HANDLED;
 719 }
 720
 721 static int transfer_start(struct lantiq_ssc_spi *spi, struct spi_device *spidev,
 722                           struct spi_transfer *t)
 723 {
 724         unsigned long flags;
 725
 726         spin_lock_irqsave(&spi->lock, flags);
 727
 728         spi->tx = t->tx_buf;
 729         spi->rx = t->rx_buf;
 730
 731         if (t->tx_buf) {
 732                 spi->tx_todo = t->len;
 733
 734                 /* initially fill TX FIFO */
 735                 tx_fifo_write(spi);
 736         }
 737
 738         if (spi->rx) {
 739                 spi->rx_todo = t->len;
 740
 741                 /* start shift clock in RX-only mode */
 742                 if (!spi->tx)
 743                         rx_request(spi);
 744         }
 745
 746         spin_unlock_irqrestore(&spi->lock, flags);
 747
 748         return t->len;
 749 }
 750
 751 /*
 752  * The driver only gets an interrupt when the FIFO is empty, but there
 753  * is an additional shift register from which the data is written to
 754  * the wire. We get the last interrupt when the controller starts to
 755  * write the last word to the wire, not when it is finished. Do busy
 756  * waiting till it finishes.
 757  */
 758 static void lantiq_ssc_bussy_work(struct work_struct *work)
 759 {
 760         struct lantiq_ssc_spi *spi;
 761         unsigned long long timeout = 8LL * 1000LL;
 762         unsigned long end;
 763
 764         spi = container_of(work, typeof(*spi), work);
 765
 766         do_div(timeout, spi->speed_hz);
 767         timeout += timeout + 100; /* some tolerance */
 768
 769         end = jiffies + msecs_to_jiffies(timeout);
 770         do {
 771                 u32 stat = lantiq_ssc_readl(spi, LTQ_SPI_STAT);
 772
 773                 if (!(stat & LTQ_SPI_STAT_BSY)) {
 774                         spi_finalize_current_transfer(spi->master);
 775                         return;
 776                 }
 777
 778                 cond_resched();
 779         } while (!time_after_eq(jiffies, end));
 780
 781         if (spi->master->cur_msg)
 782                 spi->master->cur_msg->status = -EIO;
 783         spi_finalize_current_transfer(spi->master);
 784 }
 785
 786 static void lantiq_ssc_handle_err(struct spi_master *master,
 787                                   struct spi_message *message)
 788 {
 789         struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
 790
 791         /* flush FIFOs on timeout */
 792         rx_fifo_flush(spi);
 793         tx_fifo_flush(spi);
 794 }
 795
 796 static void lantiq_ssc_set_cs(struct spi_device *spidev, bool enable)
 797 {
 798         struct lantiq_ssc_spi *spi = spi_master_get_devdata(spidev->master);
 799         unsigned int cs = spidev->chip_select;
 800         u32 fgpo;
 801
 802         if (!!(spidev->mode & SPI_CS_HIGH) == enable)
 803                 fgpo = (1 << (cs - spi->base_cs));
 804         else
 805                 fgpo = (1 << (cs - spi->base_cs + LTQ_SPI_FGPO_SETOUTN_S));
 806
 807         lantiq_ssc_writel(spi, fgpo, LTQ_SPI_FPGO);
 808 }
 809
 810 static int lantiq_ssc_transfer_one(struct spi_master *master,
 811                                    struct spi_device *spidev,
 812                                    struct spi_transfer *t)
 813 {
 814         struct lantiq_ssc_spi *spi = spi_master_get_devdata(master);
 815
 816         hw_setup_transfer(spi, spidev, t);
 817
 818         return transfer_start(spi, spidev, t);
 819 }
 820
 821 static int intel_lgm_cfg_irq(struct platform_device *pdev, struct lantiq_ssc_spi *spi)
 822 {
 823         int irq;
 824
 825         irq = platform_get_irq(pdev, 0);
 826         if (irq < 0)
 827                 return irq;
 828
 829         return devm_request_irq(&pdev->dev, irq, intel_lgm_ssc_isr, 0, "spi", spi);
 830 }
 831
 832 static int lantiq_cfg_irq(struct platform_device *pdev, struct lantiq_ssc_spi *spi)
 833 {
 834         int irq, err;
 835
 836         irq = platform_get_irq_byname(pdev, LTQ_SPI_RX_IRQ_NAME);
 837         if (irq < 0)
 838                 return irq;
 839
 840         err = devm_request_irq(&pdev->dev, irq, lantiq_ssc_xmit_interrupt,
 841                                0, LTQ_SPI_RX_IRQ_NAME, spi);
 842         if (err)
 843                 return err;
 844
 845         irq = platform_get_irq_byname(pdev, LTQ_SPI_TX_IRQ_NAME);
 846         if (irq < 0)
 847                 return irq;
 848
 849         err = devm_request_irq(&pdev->dev, irq, lantiq_ssc_xmit_interrupt,
 850                                0, LTQ_SPI_TX_IRQ_NAME, spi);
 851
 852         if (err)
 853                 return err;
 854
 855         irq = platform_get_irq_byname(pdev, LTQ_SPI_ERR_IRQ_NAME);
 856         if (irq < 0)
 857                 return irq;
 858
 859         err = devm_request_irq(&pdev->dev, irq, lantiq_ssc_err_interrupt,
 860                                0, LTQ_SPI_ERR_IRQ_NAME, spi);
 861         return err;
 862 }
 863
 864 static const struct lantiq_ssc_hwcfg lantiq_ssc_xway = {
 865         .cfg_irq        = lantiq_cfg_irq,
 866         .irnen_r        = LTQ_SPI_IRNEN_R_XWAY,
 867         .irnen_t        = LTQ_SPI_IRNEN_T_XWAY,
 868         .irnicr         = 0xF8,
 869         .irncr          = 0xFC,
 870         .fifo_size_mask = GENMASK(5, 0),
 871         .irq_ack        = false,
 872 };
 873
 874 static const struct lantiq_ssc_hwcfg lantiq_ssc_xrx = {
 875         .cfg_irq        = lantiq_cfg_irq,
 876         .irnen_r        = LTQ_SPI_IRNEN_R_XRX,
 877         .irnen_t        = LTQ_SPI_IRNEN_T_XRX,
 878         .irnicr         = 0xF8,
 879         .irncr          = 0xFC,
 880         .fifo_size_mask = GENMASK(5, 0),
 881         .irq_ack        = false,
 882 };
 883
 884 static const struct lantiq_ssc_hwcfg intel_ssc_lgm = {
 885         .cfg_irq        = intel_lgm_cfg_irq,
 886         .irnen_r        = LTQ_SPI_IRNEN_R_XRX,
 887         .irnen_t        = LTQ_SPI_IRNEN_T_XRX,
 888         .irnicr         = 0xFC,
 889         .irncr          = 0xF8,
 890         .fifo_size_mask = GENMASK(7, 0),
 891         .irq_ack        = true,
 892 };
 893
 894 static const struct of_device_id lantiq_ssc_match[] = {
 895         { .compatible = "lantiq,ase-spi", .data = &lantiq_ssc_xway, },
 896         { .compatible = "lantiq,falcon-spi", .data = &lantiq_ssc_xrx, },
 897         { .compatible = "lantiq,xrx100-spi", .data = &lantiq_ssc_xrx, },
 898         { .compatible = "intel,lgm-spi", .data = &intel_ssc_lgm, },
 899         {},
 900 };
 901 MODULE_DEVICE_TABLE(of, lantiq_ssc_match);
 902
 903 static int lantiq_ssc_probe(struct platform_device *pdev)
 904 {
 905         struct device *dev = &pdev->dev;
 906         struct spi_master *master;
 907         struct lantiq_ssc_spi *spi;
 908         const struct lantiq_ssc_hwcfg *hwcfg;
 909         const struct of_device_id *match;
 910         u32 id, supports_dma, revision;
 911         unsigned int num_cs;
 912         int err;
 913
 914         match = of_match_device(lantiq_ssc_match, dev);
 915         if (!match) {
 916                 dev_err(dev, "no device match\n");
 917                 return -EINVAL;
 918         }
 919         hwcfg = match->data;
 920
 921         master = spi_alloc_master(dev, sizeof(struct lantiq_ssc_spi));
 922         if (!master)
 923                 return -ENOMEM;
 924
 925         spi = spi_master_get_devdata(master);
 926         spi->master = master;
 927         spi->dev = dev;
 928         spi->hwcfg = hwcfg;
 929         platform_set_drvdata(pdev, spi);
 930         spi->regbase = devm_platform_ioremap_resource(pdev, 0);
 931         if (IS_ERR(spi->regbase)) {
 932                 err = PTR_ERR(spi->regbase);
 933                 goto err_master_put;
 934         }
 935
 936         err = hwcfg->cfg_irq(pdev, spi);
 937         if (err)
 938                 goto err_master_put;
 939
 940         spi->spi_clk = devm_clk_get(dev, "gate");
 941         if (IS_ERR(spi->spi_clk)) {
 942                 err = PTR_ERR(spi->spi_clk);
 943                 goto err_master_put;
 944         }
 945         err = clk_prepare_enable(spi->spi_clk);
 946         if (err)
 947                 goto err_master_put;
 948
 949         /*
 950          * Use the old clk_get_fpi() function on Lantiq platform, till it
 951          * supports common clk.
 952          */
 953 #if defined(CONFIG_LANTIQ) && !defined(CONFIG_COMMON_CLK)
 954         spi->fpi_clk = clk_get_fpi();
 955 #else
 956         spi->fpi_clk = clk_get(dev, "freq");
 957 #endif
 958         if (IS_ERR(spi->fpi_clk)) {
 959                 err = PTR_ERR(spi->fpi_clk);
 960                 goto err_clk_disable;
 961         }
 962
 963         num_cs = 8;
 964         of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
 965
 966         spi->base_cs = 1;
 967         of_property_read_u32(pdev->dev.of_node, "base-cs", &spi->base_cs);
 968
 969         spin_lock_init(&spi->lock);
 970         spi->bits_per_word = 8;
 971         spi->speed_hz = 0;
 972
 973         master->dev.of_node = pdev->dev.of_node;
 974         master->num_chipselect = num_cs;
 975         master->use_gpio_descriptors = true;
 976         master->setup = lantiq_ssc_setup;
 977         master->set_cs = lantiq_ssc_set_cs;
 978         master->handle_err = lantiq_ssc_handle_err;
 979         master->prepare_message = lantiq_ssc_prepare_message;
 980         master->unprepare_message = lantiq_ssc_unprepare_message;
 981         master->transfer_one = lantiq_ssc_transfer_one;
 982         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_CS_HIGH |
 983                                 SPI_LOOP;
 984         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(2, 8) |
 985                                      SPI_BPW_MASK(16) | SPI_BPW_MASK(32);
 986
 987         spi->wq = alloc_ordered_workqueue(dev_name(dev), WQ_MEM_RECLAIM);
 988         if (!spi->wq) {
 989                 err = -ENOMEM;
 990                 goto err_clk_put;
 991         }
 992         INIT_WORK(&spi->work, lantiq_ssc_bussy_work);
 993
 994         id = lantiq_ssc_readl(spi, LTQ_SPI_ID);
 995         spi->tx_fifo_size = (id >> LTQ_SPI_ID_TXFS_S) & hwcfg->fifo_size_mask;
 996         spi->rx_fifo_size = (id >> LTQ_SPI_ID_RXFS_S) & hwcfg->fifo_size_mask;
 997         supports_dma = (id & LTQ_SPI_ID_CFG_M) >> LTQ_SPI_ID_CFG_S;
 998         revision = id & LTQ_SPI_ID_REV_M;
 999
1000         lantiq_ssc_hw_init(spi);
1001
1002         dev_info(dev,
1003                 "Lantiq SSC SPI controller (Rev %i, TXFS %u, RXFS %u, DMA %u)\n",
1004                 revision, spi->tx_fifo_size, spi->rx_fifo_size, supports_dma);
1005
1006         err = devm_spi_register_master(dev, master);
1007         if (err) {
1008                 dev_err(dev, "failed to register spi_master\n");
1009                 goto err_wq_destroy;
1010         }
1011
1012         return 0;
1013
1014 err_wq_destroy:
1015         destroy_workqueue(spi->wq);
1016 err_clk_put:
1017         clk_put(spi->fpi_clk);
1018 err_clk_disable:
1019         clk_disable_unprepare(spi->spi_clk);
1020 err_master_put:
1021         spi_master_put(master);
1022
1023         return err;
1024 }
1025
1026 static int lantiq_ssc_remove(struct platform_device *pdev)
1027 {
1028         struct lantiq_ssc_spi *spi = platform_get_drvdata(pdev);
1029
1030         lantiq_ssc_writel(spi, 0, LTQ_SPI_IRNEN);
1031         lantiq_ssc_writel(spi, 0, LTQ_SPI_CLC);
1032         rx_fifo_flush(spi);
1033         tx_fifo_flush(spi);
1034         hw_enter_config_mode(spi);
1035
1036         destroy_workqueue(spi->wq);
1037         clk_disable_unprepare(spi->spi_clk);
1038         clk_put(spi->fpi_clk);
1039
1040         return 0;
1041 }
1042
1043 static struct platform_driver lantiq_ssc_driver = {
1044         .probe = lantiq_ssc_probe,
1045         .remove = lantiq_ssc_remove,
1046         .driver = {
1047                 .name = "spi-lantiq-ssc",
1048                 .of_match_table = lantiq_ssc_match,
1049         },
1050 };
1051 module_platform_driver(lantiq_ssc_driver);
1052
1053 MODULE_DESCRIPTION("Lantiq SSC SPI controller driver");
1054 MODULE_AUTHOR("Daniel Schwierzeck <daniel.schwierzeck@gmail.com>");
1055 MODULE_AUTHOR("Hauke Mehrtens <hauke@hauke-m.de>");
1056 MODULE_LICENSE("GPL");
1057 MODULE_ALIAS("platform:spi-lantiq-ssc");