drivers/spi/tegra20_sflash.c

   1 /*
   2  * Copyright (c) 2010-2013 NVIDIA Corporation
   3  * With help from the mpc8xxx SPI driver
   4  * With more help from omap3_spi SPI driver
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <dm.h>
  11 #include <errno.h>
  12 #include <asm/io.h>
  13 #include <asm/gpio.h>
  14 #include <asm/arch/clock.h>
  15 #include <asm/arch/pinmux.h>
  16 #include <asm/arch-tegra/clk_rst.h>
  17 #include <spi.h>
  18 #include <fdtdec.h>
  19 #include "tegra_spi.h"
  20
  21 DECLARE_GLOBAL_DATA_PTR;
  22
  23 #define SPI_CMD_GO                      (1 << 30)
  24 #define SPI_CMD_ACTIVE_SCLK_SHIFT       26
  25 #define SPI_CMD_ACTIVE_SCLK_MASK        (3 << SPI_CMD_ACTIVE_SCLK_SHIFT)
  26 #define SPI_CMD_CK_SDA                  (1 << 21)
  27 #define SPI_CMD_ACTIVE_SDA_SHIFT        18
  28 #define SPI_CMD_ACTIVE_SDA_MASK         (3 << SPI_CMD_ACTIVE_SDA_SHIFT)
  29 #define SPI_CMD_CS_POL                  (1 << 16)
  30 #define SPI_CMD_TXEN                    (1 << 15)
  31 #define SPI_CMD_RXEN                    (1 << 14)
  32 #define SPI_CMD_CS_VAL                  (1 << 13)
  33 #define SPI_CMD_CS_SOFT                 (1 << 12)
  34 #define SPI_CMD_CS_DELAY                (1 << 9)
  35 #define SPI_CMD_CS3_EN                  (1 << 8)
  36 #define SPI_CMD_CS2_EN                  (1 << 7)
  37 #define SPI_CMD_CS1_EN                  (1 << 6)
  38 #define SPI_CMD_CS0_EN                  (1 << 5)
  39 #define SPI_CMD_BIT_LENGTH              (1 << 4)
  40 #define SPI_CMD_BIT_LENGTH_MASK         0x0000001F
  41
  42 #define SPI_STAT_BSY                    (1 << 31)
  43 #define SPI_STAT_RDY                    (1 << 30)
  44 #define SPI_STAT_RXF_FLUSH              (1 << 29)
  45 #define SPI_STAT_TXF_FLUSH              (1 << 28)
  46 #define SPI_STAT_RXF_UNR                (1 << 27)
  47 #define SPI_STAT_TXF_OVF                (1 << 26)
  48 #define SPI_STAT_RXF_EMPTY              (1 << 25)
  49 #define SPI_STAT_RXF_FULL               (1 << 24)
  50 #define SPI_STAT_TXF_EMPTY              (1 << 23)
  51 #define SPI_STAT_TXF_FULL               (1 << 22)
  52 #define SPI_STAT_SEL_TXRX_N             (1 << 16)
  53 #define SPI_STAT_CUR_BLKCNT             (1 << 15)
  54
  55 #define SPI_TIMEOUT             1000
  56 #define TEGRA_SPI_MAX_FREQ      52000000
  57
  58 struct spi_regs {
  59         u32 command;    /* SPI_COMMAND_0 register  */
  60         u32 status;     /* SPI_STATUS_0 register */
  61         u32 rx_cmp;     /* SPI_RX_CMP_0 register  */
  62         u32 dma_ctl;    /* SPI_DMA_CTL_0 register */
  63         u32 tx_fifo;    /* SPI_TX_FIFO_0 register */
  64         u32 rsvd[3];    /* offsets 0x14 to 0x1F reserved */
  65         u32 rx_fifo;    /* SPI_RX_FIFO_0 register */
  66 };
  67
  68 struct tegra20_sflash_priv {
  69         struct spi_regs *regs;
  70         unsigned int freq;
  71         unsigned int mode;
  72         int periph_id;
  73         int valid;
  74         int last_transaction_us;
  75 };
  76
  77 int tegra20_sflash_cs_info(struct udevice *bus, unsigned int cs,
  78                            struct spi_cs_info *info)
  79 {
  80         /* Tegra20 SPI-Flash - only 1 device ('bus/cs') */
  81         if (cs != 0)
  82                 return -ENODEV;
  83         else
  84                 return 0;
  85 }
  86
  87 static int tegra20_sflash_ofdata_to_platdata(struct udevice *bus)
  88 {
  89         struct tegra_spi_platdata *plat = bus->platdata;
  90         const void *blob = gd->fdt_blob;
  91         int node = bus->of_offset;
  92
  93         plat->base = fdtdec_get_addr(blob, node, "reg");
  94         plat->periph_id = clock_decode_periph_id(blob, node);
  95
  96         if (plat->periph_id == PERIPH_ID_NONE) {
  97                 debug("%s: could not decode periph id %d\n", __func__,
  98                       plat->periph_id);
  99                 return -FDT_ERR_NOTFOUND;
 100         }
 101
 102         /* Use 500KHz as a suitable default */
 103         plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
 104                                         500000);
 105         plat->deactivate_delay_us = fdtdec_get_int(blob, node,
 106                                         "spi-deactivate-delay", 0);
 107         debug("%s: base=%#08lx, periph_id=%d, max-frequency=%d, deactivate_delay=%d\n",
 108               __func__, plat->base, plat->periph_id, plat->frequency,
 109               plat->deactivate_delay_us);
 110
 111         return 0;
 112 }
 113
 114 static int tegra20_sflash_probe(struct udevice *bus)
 115 {
 116         struct tegra_spi_platdata *plat = dev_get_platdata(bus);
 117         struct tegra20_sflash_priv *priv = dev_get_priv(bus);
 118
 119         priv->regs = (struct spi_regs *)plat->base;
 120
 121         priv->last_transaction_us = timer_get_us();
 122         priv->freq = plat->frequency;
 123         priv->periph_id = plat->periph_id;
 124
 125         return 0;
 126 }
 127
 128 static int tegra20_sflash_claim_bus(struct udevice *dev)
 129 {
 130         struct udevice *bus = dev->parent;
 131         struct tegra20_sflash_priv *priv = dev_get_priv(bus);
 132         struct spi_regs *regs = priv->regs;
 133         u32 reg;
 134
 135         /* Change SPI clock to correct frequency, PLLP_OUT0 source */
 136         clock_start_periph_pll(priv->periph_id, CLOCK_ID_PERIPH,
 137                                priv->freq);
 138
 139         /* Clear stale status here */
 140         reg = SPI_STAT_RDY | SPI_STAT_RXF_FLUSH | SPI_STAT_TXF_FLUSH | \
 141                 SPI_STAT_RXF_UNR | SPI_STAT_TXF_OVF;
 142         writel(reg, &regs->status);
 143         debug("%s: STATUS = %08x\n", __func__, readl(&regs->status));
 144
 145         /*
 146          * Use sw-controlled CS, so we can clock in data after ReadID, etc.
 147          */
 148         reg = (priv->mode & 1) << SPI_CMD_ACTIVE_SDA_SHIFT;
 149         if (priv->mode & 2)
 150                 reg |= 1 << SPI_CMD_ACTIVE_SCLK_SHIFT;
 151         clrsetbits_le32(&regs->command, SPI_CMD_ACTIVE_SCLK_MASK |
 152                 SPI_CMD_ACTIVE_SDA_MASK, SPI_CMD_CS_SOFT | reg);
 153         debug("%s: COMMAND = %08x\n", __func__, readl(&regs->command));
 154
 155         /*
 156          * SPI pins on Tegra20 are muxed - change pinmux later due to UART
 157          * issue.
 158          */
 159         pinmux_set_func(PMUX_PINGRP_GMD, PMUX_FUNC_SFLASH);
 160         pinmux_tristate_disable(PMUX_PINGRP_LSPI);
 161         pinmux_set_func(PMUX_PINGRP_GMC, PMUX_FUNC_SFLASH);
 162
 163         return 0;
 164 }
 165
 166 static void spi_cs_activate(struct udevice *dev)
 167 {
 168         struct udevice *bus = dev->parent;
 169         struct tegra_spi_platdata *pdata = dev_get_platdata(bus);
 170         struct tegra20_sflash_priv *priv = dev_get_priv(bus);
 171
 172         /* If it's too soon to do another transaction, wait */
 173         if (pdata->deactivate_delay_us &&
 174             priv->last_transaction_us) {
 175                 ulong delay_us;         /* The delay completed so far */
 176                 delay_us = timer_get_us() - priv->last_transaction_us;
 177                 if (delay_us < pdata->deactivate_delay_us)
 178                         udelay(pdata->deactivate_delay_us - delay_us);
 179         }
 180
 181         /* CS is negated on Tegra, so drive a 1 to get a 0 */
 182         setbits_le32(&priv->regs->command, SPI_CMD_CS_VAL);
 183 }
 184
 185 static void spi_cs_deactivate(struct udevice *dev)
 186 {
 187         struct udevice *bus = dev->parent;
 188         struct tegra_spi_platdata *pdata = dev_get_platdata(bus);
 189         struct tegra20_sflash_priv *priv = dev_get_priv(bus);
 190
 191         /* CS is negated on Tegra, so drive a 0 to get a 1 */
 192         clrbits_le32(&priv->regs->command, SPI_CMD_CS_VAL);
 193
 194         /* Remember time of this transaction so we can honour the bus delay */
 195         if (pdata->deactivate_delay_us)
 196                 priv->last_transaction_us = timer_get_us();
 197 }
 198
 199 static int tegra20_sflash_xfer(struct udevice *dev, unsigned int bitlen,
 200                              const void *data_out, void *data_in,
 201                              unsigned long flags)
 202 {
 203         struct udevice *bus = dev->parent;
 204         struct tegra20_sflash_priv *priv = dev_get_priv(bus);
 205         struct spi_regs *regs = priv->regs;
 206         u32 reg, tmpdout, tmpdin = 0;
 207         const u8 *dout = data_out;
 208         u8 *din = data_in;
 209         int num_bytes;
 210         int ret;
 211
 212         debug("%s: slave %u:%u dout %p din %p bitlen %u\n",
 213               __func__, bus->seq, spi_chip_select(dev), dout, din, bitlen);
 214         if (bitlen % 8)
 215                 return -1;
 216         num_bytes = bitlen / 8;
 217
 218         ret = 0;
 219
 220         reg = readl(&regs->status);
 221         writel(reg, &regs->status);     /* Clear all SPI events via R/W */
 222         debug("spi_xfer entry: STATUS = %08x\n", reg);
 223
 224         reg = readl(&regs->command);
 225         reg |= SPI_CMD_TXEN | SPI_CMD_RXEN;
 226         writel(reg, &regs->command);
 227         debug("spi_xfer: COMMAND = %08x\n", readl(&regs->command));
 228
 229         if (flags & SPI_XFER_BEGIN)
 230                 spi_cs_activate(dev);
 231
 232         /* handle data in 32-bit chunks */
 233         while (num_bytes > 0) {
 234                 int bytes;
 235                 int is_read = 0;
 236                 int tm, i;
 237
 238                 tmpdout = 0;
 239                 bytes = (num_bytes > 4) ?  4 : num_bytes;
 240
 241                 if (dout != NULL) {
 242                         for (i = 0; i < bytes; ++i)
 243                                 tmpdout = (tmpdout << 8) | dout[i];
 244                 }
 245
 246                 num_bytes -= bytes;
 247                 if (dout)
 248                         dout += bytes;
 249
 250                 clrsetbits_le32(&regs->command, SPI_CMD_BIT_LENGTH_MASK,
 251                                 bytes * 8 - 1);
 252                 writel(tmpdout, &regs->tx_fifo);
 253                 setbits_le32(&regs->command, SPI_CMD_GO);
 254
 255                 /*
 256                  * Wait for SPI transmit FIFO to empty, or to time out.
 257                  * The RX FIFO status will be read and cleared last
 258                  */
 259                 for (tm = 0, is_read = 0; tm < SPI_TIMEOUT; ++tm) {
 260                         u32 status;
 261
 262                         status = readl(&regs->status);
 263
 264                         /* We can exit when we've had both RX and TX activity */
 265                         if (is_read && (status & SPI_STAT_TXF_EMPTY))
 266                                 break;
 267
 268                         if ((status & (SPI_STAT_BSY | SPI_STAT_RDY)) !=
 269                                         SPI_STAT_RDY)
 270                                 tm++;
 271
 272                         else if (!(status & SPI_STAT_RXF_EMPTY)) {
 273                                 tmpdin = readl(&regs->rx_fifo);
 274                                 is_read = 1;
 275
 276                                 /* swap bytes read in */
 277                                 if (din != NULL) {
 278                                         for (i = bytes - 1; i >= 0; --i) {
 279                                                 din[i] = tmpdin & 0xff;
 280                                                 tmpdin >>= 8;
 281                                         }
 282                                         din += bytes;
 283                                 }
 284                         }
 285                 }
 286
 287                 if (tm >= SPI_TIMEOUT)
 288                         ret = tm;
 289
 290                 /* clear ACK RDY, etc. bits */
 291                 writel(readl(&regs->status), &regs->status);
 292         }
 293
 294         if (flags & SPI_XFER_END)
 295                 spi_cs_deactivate(dev);
 296
 297         debug("spi_xfer: transfer ended. Value=%08x, status = %08x\n",
 298                 tmpdin, readl(&regs->status));
 299
 300         if (ret) {
 301                 printf("spi_xfer: timeout during SPI transfer, tm %d\n", ret);
 302                 return -1;
 303         }
 304
 305         return 0;
 306 }
 307
 308 static int tegra20_sflash_set_speed(struct udevice *bus, uint speed)
 309 {
 310         struct tegra_spi_platdata *plat = bus->platdata;
 311         struct tegra20_sflash_priv *priv = dev_get_priv(bus);
 312
 313         if (speed > plat->frequency)
 314                 speed = plat->frequency;
 315         priv->freq = speed;
 316         debug("%s: regs=%p, speed=%d\n", __func__, priv->regs, priv->freq);
 317
 318         return 0;
 319 }
 320
 321 static int tegra20_sflash_set_mode(struct udevice *bus, uint mode)
 322 {
 323         struct tegra20_sflash_priv *priv = dev_get_priv(bus);
 324
 325         priv->mode = mode;
 326         debug("%s: regs=%p, mode=%d\n", __func__, priv->regs, priv->mode);
 327
 328         return 0;
 329 }
 330
 331 static const struct dm_spi_ops tegra20_sflash_ops = {
 332         .claim_bus      = tegra20_sflash_claim_bus,
 333         .xfer           = tegra20_sflash_xfer,
 334         .set_speed      = tegra20_sflash_set_speed,
 335         .set_mode       = tegra20_sflash_set_mode,
 336         .cs_info        = tegra20_sflash_cs_info,
 337 };
 338
 339 static const struct udevice_id tegra20_sflash_ids[] = {
 340         { .compatible = "nvidia,tegra20-sflash" },
 341         { }
 342 };
 343
 344 U_BOOT_DRIVER(tegra20_sflash) = {
 345         .name   = "tegra20_sflash",
 346         .id     = UCLASS_SPI,
 347         .of_match = tegra20_sflash_ids,
 348         .ops    = &tegra20_sflash_ops,
 349         .ofdata_to_platdata = tegra20_sflash_ofdata_to_platdata,
 350         .platdata_auto_alloc_size = sizeof(struct tegra_spi_platdata),
 351         .priv_auto_alloc_size = sizeof(struct tegra20_sflash_priv),
 352         .probe  = tegra20_sflash_probe,
 353 };