linux/drivers/spi/spi-tegra20-slink.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * SPI driver for Nvidia's Tegra20/Tegra30 SLINK Controller.
   4 *
   5 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   6 */
   7
   8#include <linux/clk.h>
   9#include <linux/completion.h>
  10#include <linux/delay.h>
  11#include <linux/dmaengine.h>
  12#include <linux/dma-mapping.h>
  13#include <linux/dmapool.h>
  14#include <linux/err.h>
  15#include <linux/interrupt.h>
  16#include <linux/io.h>
  17#include <linux/kernel.h>
  18#include <linux/kthread.h>
  19#include <linux/module.h>
  20#include <linux/platform_device.h>
  21#include <linux/pm_runtime.h>
  22#include <linux/of.h>
  23#include <linux/of_device.h>
  24#include <linux/reset.h>
  25#include <linux/spi/spi.h>
  26
  27#define SLINK_COMMAND                   0x000
  28#define SLINK_BIT_LENGTH(x)             (((x) & 0x1f) << 0)
  29#define SLINK_WORD_SIZE(x)              (((x) & 0x1f) << 5)
  30#define SLINK_BOTH_EN                   (1 << 10)
  31#define SLINK_CS_SW                     (1 << 11)
  32#define SLINK_CS_VALUE                  (1 << 12)
  33#define SLINK_CS_POLARITY               (1 << 13)
  34#define SLINK_IDLE_SDA_DRIVE_LOW        (0 << 16)
  35#define SLINK_IDLE_SDA_DRIVE_HIGH       (1 << 16)
  36#define SLINK_IDLE_SDA_PULL_LOW         (2 << 16)
  37#define SLINK_IDLE_SDA_PULL_HIGH        (3 << 16)
  38#define SLINK_IDLE_SDA_MASK             (3 << 16)
  39#define SLINK_CS_POLARITY1              (1 << 20)
  40#define SLINK_CK_SDA                    (1 << 21)
  41#define SLINK_CS_POLARITY2              (1 << 22)
  42#define SLINK_CS_POLARITY3              (1 << 23)
  43#define SLINK_IDLE_SCLK_DRIVE_LOW       (0 << 24)
  44#define SLINK_IDLE_SCLK_DRIVE_HIGH      (1 << 24)
  45#define SLINK_IDLE_SCLK_PULL_LOW        (2 << 24)
  46#define SLINK_IDLE_SCLK_PULL_HIGH       (3 << 24)
  47#define SLINK_IDLE_SCLK_MASK            (3 << 24)
  48#define SLINK_M_S                       (1 << 28)
  49#define SLINK_WAIT                      (1 << 29)
  50#define SLINK_GO                        (1 << 30)
  51#define SLINK_ENB                       (1 << 31)
  52
  53#define SLINK_MODES                     (SLINK_IDLE_SCLK_MASK | SLINK_CK_SDA)
  54
  55#define SLINK_COMMAND2                  0x004
  56#define SLINK_LSBFE                     (1 << 0)
  57#define SLINK_SSOE                      (1 << 1)
  58#define SLINK_SPIE                      (1 << 4)
  59#define SLINK_BIDIROE                   (1 << 6)
  60#define SLINK_MODFEN                    (1 << 7)
  61#define SLINK_INT_SIZE(x)               (((x) & 0x1f) << 8)
  62#define SLINK_CS_ACTIVE_BETWEEN         (1 << 17)
  63#define SLINK_SS_EN_CS(x)               (((x) & 0x3) << 18)
  64#define SLINK_SS_SETUP(x)               (((x) & 0x3) << 20)
  65#define SLINK_FIFO_REFILLS_0            (0 << 22)
  66#define SLINK_FIFO_REFILLS_1            (1 << 22)
  67#define SLINK_FIFO_REFILLS_2            (2 << 22)
  68#define SLINK_FIFO_REFILLS_3            (3 << 22)
  69#define SLINK_FIFO_REFILLS_MASK         (3 << 22)
  70#define SLINK_WAIT_PACK_INT(x)          (((x) & 0x7) << 26)
  71#define SLINK_SPC0                      (1 << 29)
  72#define SLINK_TXEN                      (1 << 30)
  73#define SLINK_RXEN                      (1 << 31)
  74
  75#define SLINK_STATUS                    0x008
  76#define SLINK_COUNT(val)                (((val) >> 0) & 0x1f)
  77#define SLINK_WORD(val)                 (((val) >> 5) & 0x1f)
  78#define SLINK_BLK_CNT(val)              (((val) >> 0) & 0xffff)
  79#define SLINK_MODF                      (1 << 16)
  80#define SLINK_RX_UNF                    (1 << 18)
  81#define SLINK_TX_OVF                    (1 << 19)
  82#define SLINK_TX_FULL                   (1 << 20)
  83#define SLINK_TX_EMPTY                  (1 << 21)
  84#define SLINK_RX_FULL                   (1 << 22)
  85#define SLINK_RX_EMPTY                  (1 << 23)
  86#define SLINK_TX_UNF                    (1 << 24)
  87#define SLINK_RX_OVF                    (1 << 25)
  88#define SLINK_TX_FLUSH                  (1 << 26)
  89#define SLINK_RX_FLUSH                  (1 << 27)
  90#define SLINK_SCLK                      (1 << 28)
  91#define SLINK_ERR                       (1 << 29)
  92#define SLINK_RDY                       (1 << 30)
  93#define SLINK_BSY                       (1 << 31)
  94#define SLINK_FIFO_ERROR                (SLINK_TX_OVF | SLINK_RX_UNF |  \
  95                                        SLINK_TX_UNF | SLINK_RX_OVF)
  96
  97#define SLINK_FIFO_EMPTY                (SLINK_TX_EMPTY | SLINK_RX_EMPTY)
  98
  99#define SLINK_MAS_DATA                  0x010
 100#define SLINK_SLAVE_DATA                0x014
 101
 102#define SLINK_DMA_CTL                   0x018
 103#define SLINK_DMA_BLOCK_SIZE(x)         (((x) & 0xffff) << 0)
 104#define SLINK_TX_TRIG_1                 (0 << 16)
 105#define SLINK_TX_TRIG_4                 (1 << 16)
 106#define SLINK_TX_TRIG_8                 (2 << 16)
 107#define SLINK_TX_TRIG_16                (3 << 16)
 108#define SLINK_TX_TRIG_MASK              (3 << 16)
 109#define SLINK_RX_TRIG_1                 (0 << 18)
 110#define SLINK_RX_TRIG_4                 (1 << 18)
 111#define SLINK_RX_TRIG_8                 (2 << 18)
 112#define SLINK_RX_TRIG_16                (3 << 18)
 113#define SLINK_RX_TRIG_MASK              (3 << 18)
 114#define SLINK_PACKED                    (1 << 20)
 115#define SLINK_PACK_SIZE_4               (0 << 21)
 116#define SLINK_PACK_SIZE_8               (1 << 21)
 117#define SLINK_PACK_SIZE_16              (2 << 21)
 118#define SLINK_PACK_SIZE_32              (3 << 21)
 119#define SLINK_PACK_SIZE_MASK            (3 << 21)
 120#define SLINK_IE_TXC                    (1 << 26)
 121#define SLINK_IE_RXC                    (1 << 27)
 122#define SLINK_DMA_EN                    (1 << 31)
 123
 124#define SLINK_STATUS2                   0x01c
 125#define SLINK_TX_FIFO_EMPTY_COUNT(val)  (((val) & 0x3f) >> 0)
 126#define SLINK_RX_FIFO_FULL_COUNT(val)   (((val) & 0x3f0000) >> 16)
 127#define SLINK_SS_HOLD_TIME(val)         (((val) & 0xF) << 6)
 128
 129#define SLINK_TX_FIFO                   0x100
 130#define SLINK_RX_FIFO                   0x180
 131
 132#define DATA_DIR_TX                     (1 << 0)
 133#define DATA_DIR_RX                     (1 << 1)
 134
 135#define SLINK_DMA_TIMEOUT               (msecs_to_jiffies(1000))
 136
 137#define DEFAULT_SPI_DMA_BUF_LEN         (16*1024)
 138#define TX_FIFO_EMPTY_COUNT_MAX         SLINK_TX_FIFO_EMPTY_COUNT(0x20)
 139#define RX_FIFO_FULL_COUNT_ZERO         SLINK_RX_FIFO_FULL_COUNT(0)
 140
 141#define SLINK_STATUS2_RESET \
 142        (TX_FIFO_EMPTY_COUNT_MAX | RX_FIFO_FULL_COUNT_ZERO << 16)
 143
 144#define MAX_CHIP_SELECT                 4
 145#define SLINK_FIFO_DEPTH                32
 146
 147struct tegra_slink_chip_data {
 148        bool cs_hold_time;
 149};
 150
 151struct tegra_slink_data {
 152        struct device                           *dev;
 153        struct spi_master                       *master;
 154        const struct tegra_slink_chip_data      *chip_data;
 155        spinlock_t                              lock;
 156
 157        struct clk                              *clk;
 158        struct reset_control                    *rst;
 159        void __iomem                            *base;
 160        phys_addr_t                             phys;
 161        unsigned                                irq;
 162        u32                                     cur_speed;
 163
 164        struct spi_device                       *cur_spi;
 165        unsigned                                cur_pos;
 166        unsigned                                cur_len;
 167        unsigned                                words_per_32bit;
 168        unsigned                                bytes_per_word;
 169        unsigned                                curr_dma_words;
 170        unsigned                                cur_direction;
 171
 172        unsigned                                cur_rx_pos;
 173        unsigned                                cur_tx_pos;
 174
 175        unsigned                                dma_buf_size;
 176        unsigned                                max_buf_size;
 177        bool                                    is_curr_dma_xfer;
 178
 179        struct completion                       rx_dma_complete;
 180        struct completion                       tx_dma_complete;
 181
 182        u32                                     tx_status;
 183        u32                                     rx_status;
 184        u32                                     status_reg;
 185        bool                                    is_packed;
 186        u32                                     packed_size;
 187
 188        u32                                     command_reg;
 189        u32                                     command2_reg;
 190        u32                                     dma_control_reg;
 191        u32                                     def_command_reg;
 192        u32                                     def_command2_reg;
 193
 194        struct completion                       xfer_completion;
 195        struct spi_transfer                     *curr_xfer;
 196        struct dma_chan                         *rx_dma_chan;
 197        u32                                     *rx_dma_buf;
 198        dma_addr_t                              rx_dma_phys;
 199        struct dma_async_tx_descriptor          *rx_dma_desc;
 200
 201        struct dma_chan                         *tx_dma_chan;
 202        u32                                     *tx_dma_buf;
 203        dma_addr_t                              tx_dma_phys;
 204        struct dma_async_tx_descriptor          *tx_dma_desc;
 205};
 206
 207static int tegra_slink_runtime_suspend(struct device *dev);
 208static int tegra_slink_runtime_resume(struct device *dev);
 209
 210static inline u32 tegra_slink_readl(struct tegra_slink_data *tspi,
 211                unsigned long reg)
 212{
 213        return readl(tspi->base + reg);
 214}
 215
 216static inline void tegra_slink_writel(struct tegra_slink_data *tspi,
 217                u32 val, unsigned long reg)
 218{
 219        writel(val, tspi->base + reg);
 220
 221        /* Read back register to make sure that register writes completed */
 222        if (reg != SLINK_TX_FIFO)
 223                readl(tspi->base + SLINK_MAS_DATA);
 224}
 225
 226static void tegra_slink_clear_status(struct tegra_slink_data *tspi)
 227{
 228        u32 val_write;
 229
 230        tegra_slink_readl(tspi, SLINK_STATUS);
 231
 232        /* Write 1 to clear status register */
 233        val_write = SLINK_RDY | SLINK_FIFO_ERROR;
 234        tegra_slink_writel(tspi, val_write, SLINK_STATUS);
 235}
 236
 237static u32 tegra_slink_get_packed_size(struct tegra_slink_data *tspi,
 238                                  struct spi_transfer *t)
 239{
 240        switch (tspi->bytes_per_word) {
 241        case 0:
 242                return SLINK_PACK_SIZE_4;
 243        case 1:
 244                return SLINK_PACK_SIZE_8;
 245        case 2:
 246                return SLINK_PACK_SIZE_16;
 247        case 4:
 248                return SLINK_PACK_SIZE_32;
 249        default:
 250                return 0;
 251        }
 252}
 253
 254static unsigned tegra_slink_calculate_curr_xfer_param(
 255        struct spi_device *spi, struct tegra_slink_data *tspi,
 256        struct spi_transfer *t)
 257{
 258        unsigned remain_len = t->len - tspi->cur_pos;
 259        unsigned max_word;
 260        unsigned bits_per_word;
 261        unsigned max_len;
 262        unsigned total_fifo_words;
 263
 264        bits_per_word = t->bits_per_word;
 265        tspi->bytes_per_word = DIV_ROUND_UP(bits_per_word, 8);
 266
 267        if (bits_per_word == 8 || bits_per_word == 16) {
 268                tspi->is_packed = true;
 269                tspi->words_per_32bit = 32/bits_per_word;
 270        } else {
 271                tspi->is_packed = false;
 272                tspi->words_per_32bit = 1;
 273        }
 274        tspi->packed_size = tegra_slink_get_packed_size(tspi, t);
 275
 276        if (tspi->is_packed) {
 277                max_len = min(remain_len, tspi->max_buf_size);
 278                tspi->curr_dma_words = max_len/tspi->bytes_per_word;
 279                total_fifo_words = max_len/4;
 280        } else {
 281                max_word = (remain_len - 1) / tspi->bytes_per_word + 1;
 282                max_word = min(max_word, tspi->max_buf_size/4);
 283                tspi->curr_dma_words = max_word;
 284                total_fifo_words = max_word;
 285        }
 286        return total_fifo_words;
 287}
 288
 289static unsigned tegra_slink_fill_tx_fifo_from_client_txbuf(
 290        struct tegra_slink_data *tspi, struct spi_transfer *t)
 291{
 292        unsigned nbytes;
 293        unsigned tx_empty_count;
 294        u32 fifo_status;
 295        unsigned max_n_32bit;
 296        unsigned i, count;
 297        unsigned int written_words;
 298        unsigned fifo_words_left;
 299        u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
 300
 301        fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
 302        tx_empty_count = SLINK_TX_FIFO_EMPTY_COUNT(fifo_status);
 303
 304        if (tspi->is_packed) {
 305                fifo_words_left = tx_empty_count * tspi->words_per_32bit;
 306                written_words = min(fifo_words_left, tspi->curr_dma_words);
 307                nbytes = written_words * tspi->bytes_per_word;
 308                max_n_32bit = DIV_ROUND_UP(nbytes, 4);
 309                for (count = 0; count < max_n_32bit; count++) {
 310                        u32 x = 0;
 311                        for (i = 0; (i < 4) && nbytes; i++, nbytes--)
 312                                x |= (u32)(*tx_buf++) << (i * 8);
 313                        tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
 314                }
 315        } else {
 316                max_n_32bit = min(tspi->curr_dma_words,  tx_empty_count);
 317                written_words = max_n_32bit;
 318                nbytes = written_words * tspi->bytes_per_word;
 319                for (count = 0; count < max_n_32bit; count++) {
 320                        u32 x = 0;
 321                        for (i = 0; nbytes && (i < tspi->bytes_per_word);
 322                                                        i++, nbytes--)
 323                                x |= (u32)(*tx_buf++) << (i * 8);
 324                        tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
 325                }
 326        }
 327        tspi->cur_tx_pos += written_words * tspi->bytes_per_word;
 328        return written_words;
 329}
 330
 331static unsigned int tegra_slink_read_rx_fifo_to_client_rxbuf(
 332                struct tegra_slink_data *tspi, struct spi_transfer *t)
 333{
 334        unsigned rx_full_count;
 335        u32 fifo_status;
 336        unsigned i, count;
 337        unsigned int read_words = 0;
 338        unsigned len;
 339        u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_rx_pos;
 340
 341        fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
 342        rx_full_count = SLINK_RX_FIFO_FULL_COUNT(fifo_status);
 343        if (tspi->is_packed) {
 344                len = tspi->curr_dma_words * tspi->bytes_per_word;
 345                for (count = 0; count < rx_full_count; count++) {
 346                        u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
 347                        for (i = 0; len && (i < 4); i++, len--)
 348                                *rx_buf++ = (x >> i*8) & 0xFF;
 349                }
 350                tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
 351                read_words += tspi->curr_dma_words;
 352        } else {
 353                for (count = 0; count < rx_full_count; count++) {
 354                        u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
 355                        for (i = 0; (i < tspi->bytes_per_word); i++)
 356                                *rx_buf++ = (x >> (i*8)) & 0xFF;
 357                }
 358                tspi->cur_rx_pos += rx_full_count * tspi->bytes_per_word;
 359                read_words += rx_full_count;
 360        }
 361        return read_words;
 362}
 363
 364static void tegra_slink_copy_client_txbuf_to_spi_txbuf(
 365                struct tegra_slink_data *tspi, struct spi_transfer *t)
 366{
 367        /* Make the dma buffer to read by cpu */
 368        dma_sync_single_for_cpu(tspi->dev, tspi->tx_dma_phys,
 369                                tspi->dma_buf_size, DMA_TO_DEVICE);
 370
 371        if (tspi->is_packed) {
 372                unsigned len = tspi->curr_dma_words * tspi->bytes_per_word;
 373                memcpy(tspi->tx_dma_buf, t->tx_buf + tspi->cur_pos, len);
 374        } else {
 375                unsigned int i;
 376                unsigned int count;
 377                u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
 378                unsigned consume = tspi->curr_dma_words * tspi->bytes_per_word;
 379
 380                for (count = 0; count < tspi->curr_dma_words; count++) {
 381                        u32 x = 0;
 382                        for (i = 0; consume && (i < tspi->bytes_per_word);
 383                                                        i++, consume--)
 384                                x |= (u32)(*tx_buf++) << (i * 8);
 385                        tspi->tx_dma_buf[count] = x;
 386                }
 387        }
 388        tspi->cur_tx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
 389
 390        /* Make the dma buffer to read by dma */
 391        dma_sync_single_for_device(tspi->dev, tspi->tx_dma_phys,
 392                                tspi->dma_buf_size, DMA_TO_DEVICE);
 393}
 394
 395static void tegra_slink_copy_spi_rxbuf_to_client_rxbuf(
 396                struct tegra_slink_data *tspi, struct spi_transfer *t)
 397{
 398        unsigned len;
 399
 400        /* Make the dma buffer to read by cpu */
 401        dma_sync_single_for_cpu(tspi->dev, tspi->rx_dma_phys,
 402                tspi->dma_buf_size, DMA_FROM_DEVICE);
 403
 404        if (tspi->is_packed) {
 405                len = tspi->curr_dma_words * tspi->bytes_per_word;
 406                memcpy(t->rx_buf + tspi->cur_rx_pos, tspi->rx_dma_buf, len);
 407        } else {
 408                unsigned int i;
 409                unsigned int count;
 410                unsigned char *rx_buf = t->rx_buf + tspi->cur_rx_pos;
 411                u32 rx_mask = ((u32)1 << t->bits_per_word) - 1;
 412
 413                for (count = 0; count < tspi->curr_dma_words; count++) {
 414                        u32 x = tspi->rx_dma_buf[count] & rx_mask;
 415                        for (i = 0; (i < tspi->bytes_per_word); i++)
 416                                *rx_buf++ = (x >> (i*8)) & 0xFF;
 417                }
 418        }
 419        tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
 420
 421        /* Make the dma buffer to read by dma */
 422        dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
 423                tspi->dma_buf_size, DMA_FROM_DEVICE);
 424}
 425
 426static void tegra_slink_dma_complete(void *args)
 427{
 428        struct completion *dma_complete = args;
 429
 430        complete(dma_complete);
 431}
 432
 433static int tegra_slink_start_tx_dma(struct tegra_slink_data *tspi, int len)
 434{
 435        reinit_completion(&tspi->tx_dma_complete);
 436        tspi->tx_dma_desc = dmaengine_prep_slave_single(tspi->tx_dma_chan,
 437                                tspi->tx_dma_phys, len, DMA_MEM_TO_DEV,
 438                                DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
 439        if (!tspi->tx_dma_desc) {
 440                dev_err(tspi->dev, "Not able to get desc for Tx\n");
 441                return -EIO;
 442        }
 443
 444        tspi->tx_dma_desc->callback = tegra_slink_dma_complete;
 445        tspi->tx_dma_desc->callback_param = &tspi->tx_dma_complete;
 446
 447        dmaengine_submit(tspi->tx_dma_desc);
 448        dma_async_issue_pending(tspi->tx_dma_chan);
 449        return 0;
 450}
 451
 452static int tegra_slink_start_rx_dma(struct tegra_slink_data *tspi, int len)
 453{
 454        reinit_completion(&tspi->rx_dma_complete);
 455        tspi->rx_dma_desc = dmaengine_prep_slave_single(tspi->rx_dma_chan,
 456                                tspi->rx_dma_phys, len, DMA_DEV_TO_MEM,
 457                                DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
 458        if (!tspi->rx_dma_desc) {
 459                dev_err(tspi->dev, "Not able to get desc for Rx\n");
 460                return -EIO;
 461        }
 462
 463        tspi->rx_dma_desc->callback = tegra_slink_dma_complete;
 464        tspi->rx_dma_desc->callback_param = &tspi->rx_dma_complete;
 465
 466        dmaengine_submit(tspi->rx_dma_desc);
 467        dma_async_issue_pending(tspi->rx_dma_chan);
 468        return 0;
 469}
 470
 471static int tegra_slink_start_dma_based_transfer(
 472                struct tegra_slink_data *tspi, struct spi_transfer *t)
 473{
 474        u32 val;
 475        unsigned int len;
 476        int ret = 0;
 477        u32 status;
 478
 479        /* Make sure that Rx and Tx fifo are empty */
 480        status = tegra_slink_readl(tspi, SLINK_STATUS);
 481        if ((status & SLINK_FIFO_EMPTY) != SLINK_FIFO_EMPTY) {
 482                dev_err(tspi->dev, "Rx/Tx fifo are not empty status 0x%08x\n",
 483                        (unsigned)status);
 484                return -EIO;
 485        }
 486
 487        val = SLINK_DMA_BLOCK_SIZE(tspi->curr_dma_words - 1);
 488        val |= tspi->packed_size;
 489        if (tspi->is_packed)
 490                len = DIV_ROUND_UP(tspi->curr_dma_words * tspi->bytes_per_word,
 491                                        4) * 4;
 492        else
 493                len = tspi->curr_dma_words * 4;
 494
 495        /* Set attention level based on length of transfer */
 496        if (len & 0xF)
 497                val |= SLINK_TX_TRIG_1 | SLINK_RX_TRIG_1;
 498        else if (((len) >> 4) & 0x1)
 499                val |= SLINK_TX_TRIG_4 | SLINK_RX_TRIG_4;
 500        else
 501                val |= SLINK_TX_TRIG_8 | SLINK_RX_TRIG_8;
 502
 503        if (tspi->cur_direction & DATA_DIR_TX)
 504                val |= SLINK_IE_TXC;
 505
 506        if (tspi->cur_direction & DATA_DIR_RX)
 507                val |= SLINK_IE_RXC;
 508
 509        tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
 510        tspi->dma_control_reg = val;
 511
 512        if (tspi->cur_direction & DATA_DIR_TX) {
 513                tegra_slink_copy_client_txbuf_to_spi_txbuf(tspi, t);
 514                wmb();
 515                ret = tegra_slink_start_tx_dma(tspi, len);
 516                if (ret < 0) {
 517                        dev_err(tspi->dev,
 518                                "Starting tx dma failed, err %d\n", ret);
 519                        return ret;
 520                }
 521
 522                /* Wait for tx fifo to be fill before starting slink */
 523                status = tegra_slink_readl(tspi, SLINK_STATUS);
 524                while (!(status & SLINK_TX_FULL))
 525                        status = tegra_slink_readl(tspi, SLINK_STATUS);
 526        }
 527
 528        if (tspi->cur_direction & DATA_DIR_RX) {
 529                /* Make the dma buffer to read by dma */
 530                dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
 531                                tspi->dma_buf_size, DMA_FROM_DEVICE);
 532
 533                ret = tegra_slink_start_rx_dma(tspi, len);
 534                if (ret < 0) {
 535                        dev_err(tspi->dev,
 536                                "Starting rx dma failed, err %d\n", ret);
 537                        if (tspi->cur_direction & DATA_DIR_TX)
 538                                dmaengine_terminate_all(tspi->tx_dma_chan);
 539                        return ret;
 540                }
 541        }
 542        tspi->is_curr_dma_xfer = true;
 543        if (tspi->is_packed) {
 544                val |= SLINK_PACKED;
 545                tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
 546                /* HW need small delay after settign Packed mode */
 547                udelay(1);
 548        }
 549        tspi->dma_control_reg = val;
 550
 551        val |= SLINK_DMA_EN;
 552        tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
 553        return ret;
 554}
 555
 556static int tegra_slink_start_cpu_based_transfer(
 557                struct tegra_slink_data *tspi, struct spi_transfer *t)
 558{
 559        u32 val;
 560        unsigned cur_words;
 561
 562        val = tspi->packed_size;
 563        if (tspi->cur_direction & DATA_DIR_TX)
 564                val |= SLINK_IE_TXC;
 565
 566        if (tspi->cur_direction & DATA_DIR_RX)
 567                val |= SLINK_IE_RXC;
 568
 569        tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
 570        tspi->dma_control_reg = val;
 571
 572        if (tspi->cur_direction & DATA_DIR_TX)
 573                cur_words = tegra_slink_fill_tx_fifo_from_client_txbuf(tspi, t);
 574        else
 575                cur_words = tspi->curr_dma_words;
 576        val |= SLINK_DMA_BLOCK_SIZE(cur_words - 1);
 577        tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
 578        tspi->dma_control_reg = val;
 579
 580        tspi->is_curr_dma_xfer = false;
 581        if (tspi->is_packed) {
 582                val |= SLINK_PACKED;
 583                tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
 584                udelay(1);
 585                wmb();
 586        }
 587        tspi->dma_control_reg = val;
 588        val |= SLINK_DMA_EN;
 589        tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
 590        return 0;
 591}
 592
 593static int tegra_slink_init_dma_param(struct tegra_slink_data *tspi,
 594                        bool dma_to_memory)
 595{
 596        struct dma_chan *dma_chan;
 597        u32 *dma_buf;
 598        dma_addr_t dma_phys;
 599        int ret;
 600        struct dma_slave_config dma_sconfig;
 601
 602        dma_chan = dma_request_slave_channel_reason(tspi->dev,
 603                                                dma_to_memory ? "rx" : "tx");
 604        if (IS_ERR(dma_chan)) {
 605                ret = PTR_ERR(dma_chan);
 606                if (ret != -EPROBE_DEFER)
 607                        dev_err(tspi->dev,
 608                                "Dma channel is not available: %d\n", ret);
 609                return ret;
 610        }
 611
 612        dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
 613                                &dma_phys, GFP_KERNEL);
 614        if (!dma_buf) {
 615                dev_err(tspi->dev, " Not able to allocate the dma buffer\n");
 616                dma_release_channel(dma_chan);
 617                return -ENOMEM;
 618        }
 619
 620        if (dma_to_memory) {
 621                dma_sconfig.src_addr = tspi->phys + SLINK_RX_FIFO;
 622                dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 623                dma_sconfig.src_maxburst = 0;
 624        } else {
 625                dma_sconfig.dst_addr = tspi->phys + SLINK_TX_FIFO;
 626                dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 627                dma_sconfig.dst_maxburst = 0;
 628        }
 629
 630        ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
 631        if (ret)
 632                goto scrub;
 633        if (dma_to_memory) {
 634                tspi->rx_dma_chan = dma_chan;
 635                tspi->rx_dma_buf = dma_buf;
 636                tspi->rx_dma_phys = dma_phys;
 637        } else {
 638                tspi->tx_dma_chan = dma_chan;
 639                tspi->tx_dma_buf = dma_buf;
 640                tspi->tx_dma_phys = dma_phys;
 641        }
 642        return 0;
 643
 644scrub:
 645        dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
 646        dma_release_channel(dma_chan);
 647        return ret;
 648}
 649
 650static void tegra_slink_deinit_dma_param(struct tegra_slink_data *tspi,
 651        bool dma_to_memory)
 652{
 653        u32 *dma_buf;
 654        dma_addr_t dma_phys;
 655        struct dma_chan *dma_chan;
 656
 657        if (dma_to_memory) {
 658                dma_buf = tspi->rx_dma_buf;
 659                dma_chan = tspi->rx_dma_chan;
 660                dma_phys = tspi->rx_dma_phys;
 661                tspi->rx_dma_chan = NULL;
 662                tspi->rx_dma_buf = NULL;
 663        } else {
 664                dma_buf = tspi->tx_dma_buf;
 665                dma_chan = tspi->tx_dma_chan;
 666                dma_phys = tspi->tx_dma_phys;
 667                tspi->tx_dma_buf = NULL;
 668                tspi->tx_dma_chan = NULL;
 669        }
 670        if (!dma_chan)
 671                return;
 672
 673        dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
 674        dma_release_channel(dma_chan);
 675}
 676
 677static int tegra_slink_start_transfer_one(struct spi_device *spi,
 678                struct spi_transfer *t)
 679{
 680        struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
 681        u32 speed;
 682        u8 bits_per_word;
 683        unsigned total_fifo_words;
 684        int ret;
 685        u32 command;
 686        u32 command2;
 687
 688        bits_per_word = t->bits_per_word;
 689        speed = t->speed_hz;
 690        if (speed != tspi->cur_speed) {
 691                clk_set_rate(tspi->clk, speed * 4);
 692                tspi->cur_speed = speed;
 693        }
 694
 695        tspi->cur_spi = spi;
 696        tspi->cur_pos = 0;
 697        tspi->cur_rx_pos = 0;
 698        tspi->cur_tx_pos = 0;
 699        tspi->curr_xfer = t;
 700        total_fifo_words = tegra_slink_calculate_curr_xfer_param(spi, tspi, t);
 701
 702        command = tspi->command_reg;
 703        command &= ~SLINK_BIT_LENGTH(~0);
 704        command |= SLINK_BIT_LENGTH(bits_per_word - 1);
 705
 706        command2 = tspi->command2_reg;
 707        command2 &= ~(SLINK_RXEN | SLINK_TXEN);
 708
 709        tspi->cur_direction = 0;
 710        if (t->rx_buf) {
 711                command2 |= SLINK_RXEN;
 712                tspi->cur_direction |= DATA_DIR_RX;
 713        }
 714        if (t->tx_buf) {
 715                command2 |= SLINK_TXEN;
 716                tspi->cur_direction |= DATA_DIR_TX;
 717        }
 718
 719        /*
 720         * Writing to the command2 register bevore the command register prevents
 721         * a spike in chip_select line 0. This selects the chip_select line
 722         * before changing the chip_select value.
 723         */
 724        tegra_slink_writel(tspi, command2, SLINK_COMMAND2);
 725        tspi->command2_reg = command2;
 726
 727        tegra_slink_writel(tspi, command, SLINK_COMMAND);
 728        tspi->command_reg = command;
 729
 730        if (total_fifo_words > SLINK_FIFO_DEPTH)
 731                ret = tegra_slink_start_dma_based_transfer(tspi, t);
 732        else
 733                ret = tegra_slink_start_cpu_based_transfer(tspi, t);
 734        return ret;
 735}
 736
 737static int tegra_slink_setup(struct spi_device *spi)
 738{
 739        static const u32 cs_pol_bit[MAX_CHIP_SELECT] = {
 740                        SLINK_CS_POLARITY,
 741                        SLINK_CS_POLARITY1,
 742                        SLINK_CS_POLARITY2,
 743                        SLINK_CS_POLARITY3,
 744        };
 745
 746        struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
 747        u32 val;
 748        unsigned long flags;
 749        int ret;
 750
 751        dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
 752                spi->bits_per_word,
 753                spi->mode & SPI_CPOL ? "" : "~",
 754                spi->mode & SPI_CPHA ? "" : "~",
 755                spi->max_speed_hz);
 756
 757        ret = pm_runtime_get_sync(tspi->dev);
 758        if (ret < 0) {
 759                dev_err(tspi->dev, "pm runtime failed, e = %d\n", ret);
 760                return ret;
 761        }
 762
 763        spin_lock_irqsave(&tspi->lock, flags);
 764        val = tspi->def_command_reg;
 765        if (spi->mode & SPI_CS_HIGH)
 766                val |= cs_pol_bit[spi->chip_select];
 767        else
 768                val &= ~cs_pol_bit[spi->chip_select];
 769        tspi->def_command_reg = val;
 770        tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
 771        spin_unlock_irqrestore(&tspi->lock, flags);
 772
 773        pm_runtime_put(tspi->dev);
 774        return 0;
 775}
 776
 777static int tegra_slink_prepare_message(struct spi_master *master,
 778                                       struct spi_message *msg)
 779{
 780        struct tegra_slink_data *tspi = spi_master_get_devdata(master);
 781        struct spi_device *spi = msg->spi;
 782
 783        tegra_slink_clear_status(tspi);
 784
 785        tspi->command_reg = tspi->def_command_reg;
 786        tspi->command_reg |= SLINK_CS_SW | SLINK_CS_VALUE;
 787
 788        tspi->command2_reg = tspi->def_command2_reg;
 789        tspi->command2_reg |= SLINK_SS_EN_CS(spi->chip_select);
 790
 791        tspi->command_reg &= ~SLINK_MODES;
 792        if (spi->mode & SPI_CPHA)
 793                tspi->command_reg |= SLINK_CK_SDA;
 794
 795        if (spi->mode & SPI_CPOL)
 796                tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_HIGH;
 797        else
 798                tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_LOW;
 799
 800        return 0;
 801}
 802
 803static int tegra_slink_transfer_one(struct spi_master *master,
 804                                    struct spi_device *spi,
 805                                    struct spi_transfer *xfer)
 806{
 807        struct tegra_slink_data *tspi = spi_master_get_devdata(master);
 808        int ret;
 809
 810        reinit_completion(&tspi->xfer_completion);
 811        ret = tegra_slink_start_transfer_one(spi, xfer);
 812        if (ret < 0) {
 813                dev_err(tspi->dev,
 814                        "spi can not start transfer, err %d\n", ret);
 815                return ret;
 816        }
 817
 818        ret = wait_for_completion_timeout(&tspi->xfer_completion,
 819                                          SLINK_DMA_TIMEOUT);
 820        if (WARN_ON(ret == 0)) {
 821                dev_err(tspi->dev,
 822                        "spi transfer timeout, err %d\n", ret);
 823                return -EIO;
 824        }
 825
 826        if (tspi->tx_status)
 827                return tspi->tx_status;
 828        if (tspi->rx_status)
 829                return tspi->rx_status;
 830
 831        return 0;
 832}
 833
 834static int tegra_slink_unprepare_message(struct spi_master *master,
 835                                         struct spi_message *msg)
 836{
 837        struct tegra_slink_data *tspi = spi_master_get_devdata(master);
 838
 839        tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
 840        tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
 841
 842        return 0;
 843}
 844
 845static irqreturn_t handle_cpu_based_xfer(struct tegra_slink_data *tspi)
 846{
 847        struct spi_transfer *t = tspi->curr_xfer;
 848        unsigned long flags;
 849
 850        spin_lock_irqsave(&tspi->lock, flags);
 851        if (tspi->tx_status ||  tspi->rx_status ||
 852                                (tspi->status_reg & SLINK_BSY)) {
 853                dev_err(tspi->dev,
 854                        "CpuXfer ERROR bit set 0x%x\n", tspi->status_reg);
 855                dev_err(tspi->dev,
 856                        "CpuXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
 857                                tspi->command2_reg, tspi->dma_control_reg);
 858                reset_control_assert(tspi->rst);
 859                udelay(2);
 860                reset_control_deassert(tspi->rst);
 861                complete(&tspi->xfer_completion);
 862                goto exit;
 863        }
 864
 865        if (tspi->cur_direction & DATA_DIR_RX)
 866                tegra_slink_read_rx_fifo_to_client_rxbuf(tspi, t);
 867
 868        if (tspi->cur_direction & DATA_DIR_TX)
 869                tspi->cur_pos = tspi->cur_tx_pos;
 870        else
 871                tspi->cur_pos = tspi->cur_rx_pos;
 872
 873        if (tspi->cur_pos == t->len) {
 874                complete(&tspi->xfer_completion);
 875                goto exit;
 876        }
 877
 878        tegra_slink_calculate_curr_xfer_param(tspi->cur_spi, tspi, t);
 879        tegra_slink_start_cpu_based_transfer(tspi, t);
 880exit:
 881        spin_unlock_irqrestore(&tspi->lock, flags);
 882        return IRQ_HANDLED;
 883}
 884
 885static irqreturn_t handle_dma_based_xfer(struct tegra_slink_data *tspi)
 886{
 887        struct spi_transfer *t = tspi->curr_xfer;
 888        long wait_status;
 889        int err = 0;
 890        unsigned total_fifo_words;
 891        unsigned long flags;
 892
 893        /* Abort dmas if any error */
 894        if (tspi->cur_direction & DATA_DIR_TX) {
 895                if (tspi->tx_status) {
 896                        dmaengine_terminate_all(tspi->tx_dma_chan);
 897                        err += 1;
 898                } else {
 899                        wait_status = wait_for_completion_interruptible_timeout(
 900                                &tspi->tx_dma_complete, SLINK_DMA_TIMEOUT);
 901                        if (wait_status <= 0) {
 902                                dmaengine_terminate_all(tspi->tx_dma_chan);
 903                                dev_err(tspi->dev, "TxDma Xfer failed\n");
 904                                err += 1;
 905                        }
 906                }
 907        }
 908
 909        if (tspi->cur_direction & DATA_DIR_RX) {
 910                if (tspi->rx_status) {
 911                        dmaengine_terminate_all(tspi->rx_dma_chan);
 912                        err += 2;
 913                } else {
 914                        wait_status = wait_for_completion_interruptible_timeout(
 915                                &tspi->rx_dma_complete, SLINK_DMA_TIMEOUT);
 916                        if (wait_status <= 0) {
 917                                dmaengine_terminate_all(tspi->rx_dma_chan);
 918                                dev_err(tspi->dev, "RxDma Xfer failed\n");
 919                                err += 2;
 920                        }
 921                }
 922        }
 923
 924        spin_lock_irqsave(&tspi->lock, flags);
 925        if (err) {
 926                dev_err(tspi->dev,
 927                        "DmaXfer: ERROR bit set 0x%x\n", tspi->status_reg);
 928                dev_err(tspi->dev,
 929                        "DmaXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
 930                                tspi->command2_reg, tspi->dma_control_reg);
 931                reset_control_assert(tspi->rst);
 932                udelay(2);
 933                reset_control_assert(tspi->rst);
 934                complete(&tspi->xfer_completion);
 935                spin_unlock_irqrestore(&tspi->lock, flags);
 936                return IRQ_HANDLED;
 937        }
 938
 939        if (tspi->cur_direction & DATA_DIR_RX)
 940                tegra_slink_copy_spi_rxbuf_to_client_rxbuf(tspi, t);
 941
 942        if (tspi->cur_direction & DATA_DIR_TX)
 943                tspi->cur_pos = tspi->cur_tx_pos;
 944        else
 945                tspi->cur_pos = tspi->cur_rx_pos;
 946
 947        if (tspi->cur_pos == t->len) {
 948                complete(&tspi->xfer_completion);
 949                goto exit;
 950        }
 951
 952        /* Continue transfer in current message */
 953        total_fifo_words = tegra_slink_calculate_curr_xfer_param(tspi->cur_spi,
 954                                                        tspi, t);
 955        if (total_fifo_words > SLINK_FIFO_DEPTH)
 956                err = tegra_slink_start_dma_based_transfer(tspi, t);
 957        else
 958                err = tegra_slink_start_cpu_based_transfer(tspi, t);
 959
 960exit:
 961        spin_unlock_irqrestore(&tspi->lock, flags);
 962        return IRQ_HANDLED;
 963}
 964
 965static irqreturn_t tegra_slink_isr_thread(int irq, void *context_data)
 966{
 967        struct tegra_slink_data *tspi = context_data;
 968
 969        if (!tspi->is_curr_dma_xfer)
 970                return handle_cpu_based_xfer(tspi);
 971        return handle_dma_based_xfer(tspi);
 972}
 973
 974static irqreturn_t tegra_slink_isr(int irq, void *context_data)
 975{
 976        struct tegra_slink_data *tspi = context_data;
 977
 978        tspi->status_reg = tegra_slink_readl(tspi, SLINK_STATUS);
 979        if (tspi->cur_direction & DATA_DIR_TX)
 980                tspi->tx_status = tspi->status_reg &
 981                                        (SLINK_TX_OVF | SLINK_TX_UNF);
 982
 983        if (tspi->cur_direction & DATA_DIR_RX)
 984                tspi->rx_status = tspi->status_reg &
 985                                        (SLINK_RX_OVF | SLINK_RX_UNF);
 986        tegra_slink_clear_status(tspi);
 987
 988        return IRQ_WAKE_THREAD;
 989}
 990
 991static const struct tegra_slink_chip_data tegra30_spi_cdata = {
 992        .cs_hold_time = true,
 993};
 994
 995static const struct tegra_slink_chip_data tegra20_spi_cdata = {
 996        .cs_hold_time = false,
 997};
 998
 999static const struct of_device_id tegra_slink_of_match[] = {
1000        { .compatible = "nvidia,tegra30-slink", .data = &tegra30_spi_cdata, },
1001        { .compatible = "nvidia,tegra20-slink", .data = &tegra20_spi_cdata, },
1002        {}
1003};
1004MODULE_DEVICE_TABLE(of, tegra_slink_of_match);
1005
1006static int tegra_slink_probe(struct platform_device *pdev)
1007{
1008        struct spi_master       *master;
1009        struct tegra_slink_data *tspi;
1010        struct resource         *r;
1011        int ret, spi_irq;
1012        const struct tegra_slink_chip_data *cdata = NULL;
1013        const struct of_device_id *match;
1014
1015        match = of_match_device(tegra_slink_of_match, &pdev->dev);
1016        if (!match) {
1017                dev_err(&pdev->dev, "Error: No device match found\n");
1018                return -ENODEV;
1019        }
1020        cdata = match->data;
1021
1022        master = spi_alloc_master(&pdev->dev, sizeof(*tspi));
1023        if (!master) {
1024                dev_err(&pdev->dev, "master allocation failed\n");
1025                return -ENOMEM;
1026        }
1027
1028        /* the spi->mode bits understood by this driver: */
1029        master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1030        master->setup = tegra_slink_setup;
1031        master->prepare_message = tegra_slink_prepare_message;
1032        master->transfer_one = tegra_slink_transfer_one;
1033        master->unprepare_message = tegra_slink_unprepare_message;
1034        master->auto_runtime_pm = true;
1035        master->num_chipselect = MAX_CHIP_SELECT;
1036
1037        platform_set_drvdata(pdev, master);
1038        tspi = spi_master_get_devdata(master);
1039        tspi->master = master;
1040        tspi->dev = &pdev->dev;
1041        tspi->chip_data = cdata;
1042        spin_lock_init(&tspi->lock);
1043
1044        if (of_property_read_u32(tspi->dev->of_node, "spi-max-frequency",
1045                                 &master->max_speed_hz))
1046                master->max_speed_hz = 25000000; /* 25MHz */
1047
1048        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1049        if (!r) {
1050                dev_err(&pdev->dev, "No IO memory resource\n");
1051                ret = -ENODEV;
1052                goto exit_free_master;
1053        }
1054        tspi->phys = r->start;
1055        tspi->base = devm_ioremap_resource(&pdev->dev, r);
1056        if (IS_ERR(tspi->base)) {
1057                ret = PTR_ERR(tspi->base);
1058                goto exit_free_master;
1059        }
1060
1061        /* disabled clock may cause interrupt storm upon request */
1062        tspi->clk = devm_clk_get(&pdev->dev, NULL);
1063        if (IS_ERR(tspi->clk)) {
1064                ret = PTR_ERR(tspi->clk);
1065                dev_err(&pdev->dev, "Can not get clock %d\n", ret);
1066                goto exit_free_master;
1067        }
1068        ret = clk_prepare(tspi->clk);
1069        if (ret < 0) {
1070                dev_err(&pdev->dev, "Clock prepare failed %d\n", ret);
1071                goto exit_free_master;
1072        }
1073        ret = clk_enable(tspi->clk);
1074        if (ret < 0) {
1075                dev_err(&pdev->dev, "Clock enable failed %d\n", ret);
1076                goto exit_free_master;
1077        }
1078
1079        spi_irq = platform_get_irq(pdev, 0);
1080        tspi->irq = spi_irq;
1081        ret = request_threaded_irq(tspi->irq, tegra_slink_isr,
1082                        tegra_slink_isr_thread, IRQF_ONESHOT,
1083                        dev_name(&pdev->dev), tspi);
1084        if (ret < 0) {
1085                dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
1086                                        tspi->irq);
1087                goto exit_clk_disable;
1088        }
1089
1090        tspi->rst = devm_reset_control_get_exclusive(&pdev->dev, "spi");
1091        if (IS_ERR(tspi->rst)) {
1092                dev_err(&pdev->dev, "can not get reset\n");
1093                ret = PTR_ERR(tspi->rst);
1094                goto exit_free_irq;
1095        }
1096
1097        tspi->max_buf_size = SLINK_FIFO_DEPTH << 2;
1098        tspi->dma_buf_size = DEFAULT_SPI_DMA_BUF_LEN;
1099
1100        ret = tegra_slink_init_dma_param(tspi, true);
1101        if (ret < 0)
1102                goto exit_free_irq;
1103        ret = tegra_slink_init_dma_param(tspi, false);
1104        if (ret < 0)
1105                goto exit_rx_dma_free;
1106        tspi->max_buf_size = tspi->dma_buf_size;
1107        init_completion(&tspi->tx_dma_complete);
1108        init_completion(&tspi->rx_dma_complete);
1109
1110        init_completion(&tspi->xfer_completion);
1111
1112        pm_runtime_enable(&pdev->dev);
1113        if (!pm_runtime_enabled(&pdev->dev)) {
1114                ret = tegra_slink_runtime_resume(&pdev->dev);
1115                if (ret)
1116                        goto exit_pm_disable;
1117        }
1118
1119        ret = pm_runtime_get_sync(&pdev->dev);
1120        if (ret < 0) {
1121                dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
1122                goto exit_pm_disable;
1123        }
1124        tspi->def_command_reg  = SLINK_M_S;
1125        tspi->def_command2_reg = SLINK_CS_ACTIVE_BETWEEN;
1126        tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
1127        tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
1128        pm_runtime_put(&pdev->dev);
1129
1130        master->dev.of_node = pdev->dev.of_node;
1131        ret = devm_spi_register_master(&pdev->dev, master);
1132        if (ret < 0) {
1133                dev_err(&pdev->dev, "can not register to master err %d\n", ret);
1134                goto exit_pm_disable;
1135        }
1136        return ret;
1137
1138exit_pm_disable:
1139        pm_runtime_disable(&pdev->dev);
1140        if (!pm_runtime_status_suspended(&pdev->dev))
1141                tegra_slink_runtime_suspend(&pdev->dev);
1142        tegra_slink_deinit_dma_param(tspi, false);
1143exit_rx_dma_free:
1144        tegra_slink_deinit_dma_param(tspi, true);
1145exit_free_irq:
1146        free_irq(spi_irq, tspi);
1147exit_clk_disable:
1148        clk_disable(tspi->clk);
1149exit_free_master:
1150        spi_master_put(master);
1151        return ret;
1152}
1153
1154static int tegra_slink_remove(struct platform_device *pdev)
1155{
1156        struct spi_master *master = platform_get_drvdata(pdev);
1157        struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1158
1159        free_irq(tspi->irq, tspi);
1160
1161        clk_disable(tspi->clk);
1162
1163        if (tspi->tx_dma_chan)
1164                tegra_slink_deinit_dma_param(tspi, false);
1165
1166        if (tspi->rx_dma_chan)
1167                tegra_slink_deinit_dma_param(tspi, true);
1168
1169        pm_runtime_disable(&pdev->dev);
1170        if (!pm_runtime_status_suspended(&pdev->dev))
1171                tegra_slink_runtime_suspend(&pdev->dev);
1172
1173        return 0;
1174}
1175
1176#ifdef CONFIG_PM_SLEEP
1177static int tegra_slink_suspend(struct device *dev)
1178{
1179        struct spi_master *master = dev_get_drvdata(dev);
1180
1181        return spi_master_suspend(master);
1182}
1183
1184static int tegra_slink_resume(struct device *dev)
1185{
1186        struct spi_master *master = dev_get_drvdata(dev);
1187        struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1188        int ret;
1189
1190        ret = pm_runtime_get_sync(dev);
1191        if (ret < 0) {
1192                dev_err(dev, "pm runtime failed, e = %d\n", ret);
1193                return ret;
1194        }
1195        tegra_slink_writel(tspi, tspi->command_reg, SLINK_COMMAND);
1196        tegra_slink_writel(tspi, tspi->command2_reg, SLINK_COMMAND2);
1197        pm_runtime_put(dev);
1198
1199        return spi_master_resume(master);
1200}
1201#endif
1202
1203static int tegra_slink_runtime_suspend(struct device *dev)
1204{
1205        struct spi_master *master = dev_get_drvdata(dev);
1206        struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1207
1208        /* Flush all write which are in PPSB queue by reading back */
1209        tegra_slink_readl(tspi, SLINK_MAS_DATA);
1210
1211        clk_disable_unprepare(tspi->clk);
1212        return 0;
1213}
1214
1215static int tegra_slink_runtime_resume(struct device *dev)
1216{
1217        struct spi_master *master = dev_get_drvdata(dev);
1218        struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1219        int ret;
1220
1221        ret = clk_prepare_enable(tspi->clk);
1222        if (ret < 0) {
1223                dev_err(tspi->dev, "clk_prepare failed: %d\n", ret);
1224                return ret;
1225        }
1226        return 0;
1227}
1228
1229static const struct dev_pm_ops slink_pm_ops = {
1230        SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,
1231                tegra_slink_runtime_resume, NULL)
1232        SET_SYSTEM_SLEEP_PM_OPS(tegra_slink_suspend, tegra_slink_resume)
1233};
1234static struct platform_driver tegra_slink_driver = {
1235        .driver = {
1236                .name           = "spi-tegra-slink",
1237                .pm             = &slink_pm_ops,
1238                .of_match_table = tegra_slink_of_match,
1239        },
1240        .probe =        tegra_slink_probe,
1241        .remove =       tegra_slink_remove,
1242};
1243module_platform_driver(tegra_slink_driver);
1244
1245MODULE_ALIAS("platform:spi-tegra-slink");
1246MODULE_DESCRIPTION("NVIDIA Tegra20/Tegra30 SLINK Controller Driver");
1247MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1248MODULE_LICENSE("GPL v2");
1249