linux/drivers/spi/spi-meson-spifc.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2//
   3// Driver for Amlogic Meson SPI flash controller (SPIFC)
   4//
   5// Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
   6//
   7
   8#include <linux/clk.h>
   9#include <linux/delay.h>
  10#include <linux/device.h>
  11#include <linux/io.h>
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <linux/of.h>
  15#include <linux/platform_device.h>
  16#include <linux/pm_runtime.h>
  17#include <linux/regmap.h>
  18#include <linux/spi/spi.h>
  19#include <linux/types.h>
  20
  21/* register map */
  22#define REG_CMD                 0x00
  23#define REG_ADDR                0x04
  24#define REG_CTRL                0x08
  25#define REG_CTRL1               0x0c
  26#define REG_STATUS              0x10
  27#define REG_CTRL2               0x14
  28#define REG_CLOCK               0x18
  29#define REG_USER                0x1c
  30#define REG_USER1               0x20
  31#define REG_USER2               0x24
  32#define REG_USER3               0x28
  33#define REG_USER4               0x2c
  34#define REG_SLAVE               0x30
  35#define REG_SLAVE1              0x34
  36#define REG_SLAVE2              0x38
  37#define REG_SLAVE3              0x3c
  38#define REG_C0                  0x40
  39#define REG_B8                  0x60
  40#define REG_MAX                 0x7c
  41
  42/* register fields */
  43#define CMD_USER                BIT(18)
  44#define CTRL_ENABLE_AHB         BIT(17)
  45#define CLOCK_SOURCE            BIT(31)
  46#define CLOCK_DIV_SHIFT         12
  47#define CLOCK_DIV_MASK          (0x3f << CLOCK_DIV_SHIFT)
  48#define CLOCK_CNT_HIGH_SHIFT    6
  49#define CLOCK_CNT_HIGH_MASK     (0x3f << CLOCK_CNT_HIGH_SHIFT)
  50#define CLOCK_CNT_LOW_SHIFT     0
  51#define CLOCK_CNT_LOW_MASK      (0x3f << CLOCK_CNT_LOW_SHIFT)
  52#define USER_DIN_EN_MS          BIT(0)
  53#define USER_CMP_MODE           BIT(2)
  54#define USER_UC_DOUT_SEL        BIT(27)
  55#define USER_UC_DIN_SEL         BIT(28)
  56#define USER_UC_MASK            ((BIT(5) - 1) << 27)
  57#define USER1_BN_UC_DOUT_SHIFT  17
  58#define USER1_BN_UC_DOUT_MASK   (0xff << 16)
  59#define USER1_BN_UC_DIN_SHIFT   8
  60#define USER1_BN_UC_DIN_MASK    (0xff << 8)
  61#define USER4_CS_ACT            BIT(30)
  62#define SLAVE_TRST_DONE         BIT(4)
  63#define SLAVE_OP_MODE           BIT(30)
  64#define SLAVE_SW_RST            BIT(31)
  65
  66#define SPIFC_BUFFER_SIZE       64
  67
  68/**
  69 * struct meson_spifc
  70 * @master:     the SPI master
  71 * @regmap:     regmap for device registers
  72 * @clk:        input clock of the built-in baud rate generator
  73 * @dev:        the device structure
  74 */
  75struct meson_spifc {
  76        struct spi_master *master;
  77        struct regmap *regmap;
  78        struct clk *clk;
  79        struct device *dev;
  80};
  81
  82static const struct regmap_config spifc_regmap_config = {
  83        .reg_bits = 32,
  84        .val_bits = 32,
  85        .reg_stride = 4,
  86        .max_register = REG_MAX,
  87};
  88
  89/**
  90 * meson_spifc_wait_ready() - wait for the current operation to terminate
  91 * @spifc:      the Meson SPI device
  92 * Return:      0 on success, a negative value on error
  93 */
  94static int meson_spifc_wait_ready(struct meson_spifc *spifc)
  95{
  96        unsigned long deadline = jiffies + msecs_to_jiffies(5);
  97        u32 data;
  98
  99        do {
 100                regmap_read(spifc->regmap, REG_SLAVE, &data);
 101                if (data & SLAVE_TRST_DONE)
 102                        return 0;
 103                cond_resched();
 104        } while (!time_after(jiffies, deadline));
 105
 106        return -ETIMEDOUT;
 107}
 108
 109/**
 110 * meson_spifc_drain_buffer() - copy data from device buffer to memory
 111 * @spifc:      the Meson SPI device
 112 * @buf:        the destination buffer
 113 * @len:        number of bytes to copy
 114 */
 115static void meson_spifc_drain_buffer(struct meson_spifc *spifc, u8 *buf,
 116                                     int len)
 117{
 118        u32 data;
 119        int i = 0;
 120
 121        while (i < len) {
 122                regmap_read(spifc->regmap, REG_C0 + i, &data);
 123
 124                if (len - i >= 4) {
 125                        *((u32 *)buf) = data;
 126                        buf += 4;
 127                } else {
 128                        memcpy(buf, &data, len - i);
 129                        break;
 130                }
 131                i += 4;
 132        }
 133}
 134
 135/**
 136 * meson_spifc_fill_buffer() - copy data from memory to device buffer
 137 * @spifc:      the Meson SPI device
 138 * @buf:        the source buffer
 139 * @len:        number of bytes to copy
 140 */
 141static void meson_spifc_fill_buffer(struct meson_spifc *spifc, const u8 *buf,
 142                                    int len)
 143{
 144        u32 data;
 145        int i = 0;
 146
 147        while (i < len) {
 148                if (len - i >= 4)
 149                        data = *(u32 *)buf;
 150                else
 151                        memcpy(&data, buf, len - i);
 152
 153                regmap_write(spifc->regmap, REG_C0 + i, data);
 154
 155                buf += 4;
 156                i += 4;
 157        }
 158}
 159
 160/**
 161 * meson_spifc_setup_speed() - program the clock divider
 162 * @spifc:      the Meson SPI device
 163 * @speed:      desired speed in Hz
 164 */
 165static void meson_spifc_setup_speed(struct meson_spifc *spifc, u32 speed)
 166{
 167        unsigned long parent, value;
 168        int n;
 169
 170        parent = clk_get_rate(spifc->clk);
 171        n = max_t(int, parent / speed - 1, 1);
 172
 173        dev_dbg(spifc->dev, "parent %lu, speed %u, n %d\n", parent,
 174                speed, n);
 175
 176        value = (n << CLOCK_DIV_SHIFT) & CLOCK_DIV_MASK;
 177        value |= (n << CLOCK_CNT_LOW_SHIFT) & CLOCK_CNT_LOW_MASK;
 178        value |= (((n + 1) / 2 - 1) << CLOCK_CNT_HIGH_SHIFT) &
 179                CLOCK_CNT_HIGH_MASK;
 180
 181        regmap_write(spifc->regmap, REG_CLOCK, value);
 182}
 183
 184/**
 185 * meson_spifc_txrx() - transfer a chunk of data
 186 * @spifc:      the Meson SPI device
 187 * @xfer:       the current SPI transfer
 188 * @offset:     offset of the data to transfer
 189 * @len:        length of the data to transfer
 190 * @last_xfer:  whether this is the last transfer of the message
 191 * @last_chunk: whether this is the last chunk of the transfer
 192 * Return:      0 on success, a negative value on error
 193 */
 194static int meson_spifc_txrx(struct meson_spifc *spifc,
 195                            struct spi_transfer *xfer,
 196                            int offset, int len, bool last_xfer,
 197                            bool last_chunk)
 198{
 199        bool keep_cs = true;
 200        int ret;
 201
 202        if (xfer->tx_buf)
 203                meson_spifc_fill_buffer(spifc, xfer->tx_buf + offset, len);
 204
 205        /* enable DOUT stage */
 206        regmap_update_bits(spifc->regmap, REG_USER, USER_UC_MASK,
 207                           USER_UC_DOUT_SEL);
 208        regmap_write(spifc->regmap, REG_USER1,
 209                     (8 * len - 1) << USER1_BN_UC_DOUT_SHIFT);
 210
 211        /* enable data input during DOUT */
 212        regmap_update_bits(spifc->regmap, REG_USER, USER_DIN_EN_MS,
 213                           USER_DIN_EN_MS);
 214
 215        if (last_chunk) {
 216                if (last_xfer)
 217                        keep_cs = xfer->cs_change;
 218                else
 219                        keep_cs = !xfer->cs_change;
 220        }
 221
 222        regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_ACT,
 223                           keep_cs ? USER4_CS_ACT : 0);
 224
 225        /* clear transition done bit */
 226        regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_TRST_DONE, 0);
 227        /* start transfer */
 228        regmap_update_bits(spifc->regmap, REG_CMD, CMD_USER, CMD_USER);
 229
 230        ret = meson_spifc_wait_ready(spifc);
 231
 232        if (!ret && xfer->rx_buf)
 233                meson_spifc_drain_buffer(spifc, xfer->rx_buf + offset, len);
 234
 235        return ret;
 236}
 237
 238/**
 239 * meson_spifc_transfer_one() - perform a single transfer
 240 * @master:     the SPI master
 241 * @spi:        the SPI device
 242 * @xfer:       the current SPI transfer
 243 * Return:      0 on success, a negative value on error
 244 */
 245static int meson_spifc_transfer_one(struct spi_master *master,
 246                                    struct spi_device *spi,
 247                                    struct spi_transfer *xfer)
 248{
 249        struct meson_spifc *spifc = spi_master_get_devdata(master);
 250        int len, done = 0, ret = 0;
 251
 252        meson_spifc_setup_speed(spifc, xfer->speed_hz);
 253
 254        regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB, 0);
 255
 256        while (done < xfer->len && !ret) {
 257                len = min_t(int, xfer->len - done, SPIFC_BUFFER_SIZE);
 258                ret = meson_spifc_txrx(spifc, xfer, done, len,
 259                                       spi_transfer_is_last(master, xfer),
 260                                       done + len >= xfer->len);
 261                done += len;
 262        }
 263
 264        regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB,
 265                           CTRL_ENABLE_AHB);
 266
 267        return ret;
 268}
 269
 270/**
 271 * meson_spifc_hw_init() - reset and initialize the SPI controller
 272 * @spifc:      the Meson SPI device
 273 */
 274static void meson_spifc_hw_init(struct meson_spifc *spifc)
 275{
 276        /* reset device */
 277        regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_SW_RST,
 278                           SLAVE_SW_RST);
 279        /* disable compatible mode */
 280        regmap_update_bits(spifc->regmap, REG_USER, USER_CMP_MODE, 0);
 281        /* set master mode */
 282        regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_OP_MODE, 0);
 283}
 284
 285static int meson_spifc_probe(struct platform_device *pdev)
 286{
 287        struct spi_master *master;
 288        struct meson_spifc *spifc;
 289        void __iomem *base;
 290        unsigned int rate;
 291        int ret = 0;
 292
 293        master = spi_alloc_master(&pdev->dev, sizeof(struct meson_spifc));
 294        if (!master)
 295                return -ENOMEM;
 296
 297        platform_set_drvdata(pdev, master);
 298
 299        spifc = spi_master_get_devdata(master);
 300        spifc->dev = &pdev->dev;
 301
 302        base = devm_platform_ioremap_resource(pdev, 0);
 303        if (IS_ERR(base)) {
 304                ret = PTR_ERR(base);
 305                goto out_err;
 306        }
 307
 308        spifc->regmap = devm_regmap_init_mmio(spifc->dev, base,
 309                                              &spifc_regmap_config);
 310        if (IS_ERR(spifc->regmap)) {
 311                ret = PTR_ERR(spifc->regmap);
 312                goto out_err;
 313        }
 314
 315        spifc->clk = devm_clk_get(spifc->dev, NULL);
 316        if (IS_ERR(spifc->clk)) {
 317                dev_err(spifc->dev, "missing clock\n");
 318                ret = PTR_ERR(spifc->clk);
 319                goto out_err;
 320        }
 321
 322        ret = clk_prepare_enable(spifc->clk);
 323        if (ret) {
 324                dev_err(spifc->dev, "can't prepare clock\n");
 325                goto out_err;
 326        }
 327
 328        rate = clk_get_rate(spifc->clk);
 329
 330        master->num_chipselect = 1;
 331        master->dev.of_node = pdev->dev.of_node;
 332        master->bits_per_word_mask = SPI_BPW_MASK(8);
 333        master->auto_runtime_pm = true;
 334        master->transfer_one = meson_spifc_transfer_one;
 335        master->min_speed_hz = rate >> 6;
 336        master->max_speed_hz = rate >> 1;
 337
 338        meson_spifc_hw_init(spifc);
 339
 340        pm_runtime_set_active(spifc->dev);
 341        pm_runtime_enable(spifc->dev);
 342
 343        ret = devm_spi_register_master(spifc->dev, master);
 344        if (ret) {
 345                dev_err(spifc->dev, "failed to register spi master\n");
 346                goto out_clk;
 347        }
 348
 349        return 0;
 350out_clk:
 351        clk_disable_unprepare(spifc->clk);
 352out_err:
 353        spi_master_put(master);
 354        return ret;
 355}
 356
 357static int meson_spifc_remove(struct platform_device *pdev)
 358{
 359        struct spi_master *master = platform_get_drvdata(pdev);
 360        struct meson_spifc *spifc = spi_master_get_devdata(master);
 361
 362        pm_runtime_get_sync(&pdev->dev);
 363        clk_disable_unprepare(spifc->clk);
 364        pm_runtime_disable(&pdev->dev);
 365
 366        return 0;
 367}
 368
 369#ifdef CONFIG_PM_SLEEP
 370static int meson_spifc_suspend(struct device *dev)
 371{
 372        struct spi_master *master = dev_get_drvdata(dev);
 373        struct meson_spifc *spifc = spi_master_get_devdata(master);
 374        int ret;
 375
 376        ret = spi_master_suspend(master);
 377        if (ret)
 378                return ret;
 379
 380        if (!pm_runtime_suspended(dev))
 381                clk_disable_unprepare(spifc->clk);
 382
 383        return 0;
 384}
 385
 386static int meson_spifc_resume(struct device *dev)
 387{
 388        struct spi_master *master = dev_get_drvdata(dev);
 389        struct meson_spifc *spifc = spi_master_get_devdata(master);
 390        int ret;
 391
 392        if (!pm_runtime_suspended(dev)) {
 393                ret = clk_prepare_enable(spifc->clk);
 394                if (ret)
 395                        return ret;
 396        }
 397
 398        meson_spifc_hw_init(spifc);
 399
 400        ret = spi_master_resume(master);
 401        if (ret)
 402                clk_disable_unprepare(spifc->clk);
 403
 404        return ret;
 405}
 406#endif /* CONFIG_PM_SLEEP */
 407
 408#ifdef CONFIG_PM
 409static int meson_spifc_runtime_suspend(struct device *dev)
 410{
 411        struct spi_master *master = dev_get_drvdata(dev);
 412        struct meson_spifc *spifc = spi_master_get_devdata(master);
 413
 414        clk_disable_unprepare(spifc->clk);
 415
 416        return 0;
 417}
 418
 419static int meson_spifc_runtime_resume(struct device *dev)
 420{
 421        struct spi_master *master = dev_get_drvdata(dev);
 422        struct meson_spifc *spifc = spi_master_get_devdata(master);
 423
 424        return clk_prepare_enable(spifc->clk);
 425}
 426#endif /* CONFIG_PM */
 427
 428static const struct dev_pm_ops meson_spifc_pm_ops = {
 429        SET_SYSTEM_SLEEP_PM_OPS(meson_spifc_suspend, meson_spifc_resume)
 430        SET_RUNTIME_PM_OPS(meson_spifc_runtime_suspend,
 431                           meson_spifc_runtime_resume,
 432                           NULL)
 433};
 434
 435static const struct of_device_id meson_spifc_dt_match[] = {
 436        { .compatible = "amlogic,meson6-spifc", },
 437        { .compatible = "amlogic,meson-gxbb-spifc", },
 438        { },
 439};
 440MODULE_DEVICE_TABLE(of, meson_spifc_dt_match);
 441
 442static struct platform_driver meson_spifc_driver = {
 443        .probe  = meson_spifc_probe,
 444        .remove = meson_spifc_remove,
 445        .driver = {
 446                .name           = "meson-spifc",
 447                .of_match_table = of_match_ptr(meson_spifc_dt_match),
 448                .pm             = &meson_spifc_pm_ops,
 449        },
 450};
 451
 452module_platform_driver(meson_spifc_driver);
 453
 454MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
 455MODULE_DESCRIPTION("Amlogic Meson SPIFC driver");
 456MODULE_LICENSE("GPL v2");
 457
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