drivers/spi/apple_spi.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2021 Mark Kettenis <[email protected]>
   4  * Copyright The Asahi Linux Contributors
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <clk.h>
  10 #include <spi.h>
  11 #include <asm/io.h>
  12 #include <linux/bitfield.h>
  13 #include <linux/delay.h>
  14
  15 #define APPLE_SPI_CTRL                  0x000
  16 #define APPLE_SPI_CTRL_RUN              BIT(0)
  17 #define APPLE_SPI_CTRL_TX_RESET         BIT(2)
  18 #define APPLE_SPI_CTRL_RX_RESET         BIT(3)
  19
  20 #define APPLE_SPI_CFG                   0x004
  21 #define APPLE_SPI_CFG_CPHA              BIT(1)
  22 #define APPLE_SPI_CFG_CPOL              BIT(2)
  23 #define APPLE_SPI_CFG_MODE              GENMASK(6, 5)
  24 #define APPLE_SPI_CFG_MODE_POLLED       0
  25 #define APPLE_SPI_CFG_MODE_IRQ          1
  26 #define APPLE_SPI_CFG_MODE_DMA          2
  27 #define APPLE_SPI_CFG_IE_RXCOMPLETE     BIT(7)
  28 #define APPLE_SPI_CFG_IE_TXRXTHRESH     BIT(8)
  29 #define APPLE_SPI_CFG_LSB_FIRST         BIT(13)
  30 #define APPLE_SPI_CFG_WORD_SIZE         GENMASK(16, 15)
  31 #define APPLE_SPI_CFG_WORD_SIZE_8B      0
  32 #define APPLE_SPI_CFG_WORD_SIZE_16B     1
  33 #define APPLE_SPI_CFG_WORD_SIZE_32B     2
  34 #define APPLE_SPI_CFG_FIFO_THRESH       GENMASK(18, 17)
  35 #define APPLE_SPI_CFG_FIFO_THRESH_8B    0
  36 #define APPLE_SPI_CFG_FIFO_THRESH_4B    1
  37 #define APPLE_SPI_CFG_FIFO_THRESH_1B    2
  38 #define APPLE_SPI_CFG_IE_TXCOMPLETE     BIT(21)
  39
  40 #define APPLE_SPI_STATUS                0x008
  41 #define APPLE_SPI_STATUS_RXCOMPLETE     BIT(0)
  42 #define APPLE_SPI_STATUS_TXRXTHRESH     BIT(1)
  43 #define APPLE_SPI_STATUS_TXCOMPLETE     BIT(2)
  44
  45 #define APPLE_SPI_PIN                   0x00c
  46 #define APPLE_SPI_PIN_KEEP_MOSI         BIT(0)
  47 #define APPLE_SPI_PIN_CS                BIT(1)
  48
  49 #define APPLE_SPI_TXDATA                0x010
  50 #define APPLE_SPI_RXDATA                0x020
  51 #define APPLE_SPI_CLKDIV                0x030
  52 #define APPLE_SPI_CLKDIV_MIN            0x002
  53 #define APPLE_SPI_CLKDIV_MAX            0x7ff
  54 #define APPLE_SPI_RXCNT                 0x034
  55 #define APPLE_SPI_WORD_DELAY            0x038
  56 #define APPLE_SPI_TXCNT                 0x04c
  57
  58 #define APPLE_SPI_FIFOSTAT              0x10c
  59 #define APPLE_SPI_FIFOSTAT_TXFULL       BIT(4)
  60 #define APPLE_SPI_FIFOSTAT_LEVEL_TX     GENMASK(15, 8)
  61 #define APPLE_SPI_FIFOSTAT_RXEMPTY      BIT(20)
  62 #define APPLE_SPI_FIFOSTAT_LEVEL_RX     GENMASK(31, 24)
  63
  64 #define APPLE_SPI_IE_XFER               0x130
  65 #define APPLE_SPI_IF_XFER               0x134
  66 #define APPLE_SPI_XFER_RXCOMPLETE       BIT(0)
  67 #define APPLE_SPI_XFER_TXCOMPLETE       BIT(1)
  68
  69 #define APPLE_SPI_IE_FIFO               0x138
  70 #define APPLE_SPI_IF_FIFO               0x13c
  71 #define APPLE_SPI_FIFO_RXTHRESH         BIT(4)
  72 #define APPLE_SPI_FIFO_TXTHRESH         BIT(5)
  73 #define APPLE_SPI_FIFO_RXFULL           BIT(8)
  74 #define APPLE_SPI_FIFO_TXEMPTY          BIT(9)
  75 #define APPLE_SPI_FIFO_RXUNDERRUN       BIT(16)
  76 #define APPLE_SPI_FIFO_TXOVERFLOW       BIT(17)
  77
  78 #define APPLE_SPI_SHIFTCFG              0x150
  79 #define APPLE_SPI_SHIFTCFG_CLK_ENABLE   BIT(0)
  80 #define APPLE_SPI_SHIFTCFG_CS_ENABLE    BIT(1)
  81 #define APPLE_SPI_SHIFTCFG_AND_CLK_DATA BIT(8)
  82 #define APPLE_SPI_SHIFTCFG_CS_AS_DATA   BIT(9)
  83 #define APPLE_SPI_SHIFTCFG_TX_ENABLE    BIT(10)
  84 #define APPLE_SPI_SHIFTCFG_RX_ENABLE    BIT(11)
  85 #define APPLE_SPI_SHIFTCFG_BITS         GENMASK(21, 16)
  86 #define APPLE_SPI_SHIFTCFG_OVERRIDE_CS  BIT(24)
  87
  88 #define APPLE_SPI_PINCFG                0x154
  89 #define APPLE_SPI_PINCFG_KEEP_CLK       BIT(0)
  90 #define APPLE_SPI_PINCFG_KEEP_CS        BIT(1)
  91 #define APPLE_SPI_PINCFG_KEEP_MOSI      BIT(2)
  92 #define APPLE_SPI_PINCFG_CLK_IDLE_VAL   BIT(8)
  93 #define APPLE_SPI_PINCFG_CS_IDLE_VAL    BIT(9)
  94 #define APPLE_SPI_PINCFG_MOSI_IDLE_VAL  BIT(10)
  95
  96 #define APPLE_SPI_DELAY_PRE             0x160
  97 #define APPLE_SPI_DELAY_POST            0x168
  98 #define APPLE_SPI_DELAY_ENABLE          BIT(0)
  99 #define APPLE_SPI_DELAY_NO_INTERBYTE    BIT(1)
 100 #define APPLE_SPI_DELAY_SET_SCK         BIT(4)
 101 #define APPLE_SPI_DELAY_SET_MOSI        BIT(6)
 102 #define APPLE_SPI_DELAY_SCK_VAL         BIT(8)
 103 #define APPLE_SPI_DELAY_MOSI_VAL        BIT(12)
 104
 105 #define APPLE_SPI_FIFO_DEPTH            16
 106
 107 #define APPLE_SPI_TIMEOUT_MS            200
 108
 109 struct apple_spi_priv {
 110         void *base;
 111         u32 clkfreq;            /* Input clock frequency */
 112 };
 113
 114 static void apple_spi_set_cs(struct apple_spi_priv *priv, int on)
 115 {
 116         writel(on ? 0 : APPLE_SPI_PIN_CS, priv->base + APPLE_SPI_PIN);
 117 }
 118
 119 /* Fill Tx FIFO. */
 120 static void apple_spi_tx(struct apple_spi_priv *priv, uint *len,
 121                          const void **dout)
 122 {
 123         const u8 *out = *dout;
 124         u32 data, fifostat;
 125         uint count;
 126
 127         fifostat = readl(priv->base + APPLE_SPI_FIFOSTAT);
 128         count = APPLE_SPI_FIFO_DEPTH -
 129                 FIELD_GET(APPLE_SPI_FIFOSTAT_LEVEL_TX, fifostat);
 130         while (*len > 0 && count > 0) {
 131                 data = out ? *out++ : 0;
 132                 writel(data, priv->base + APPLE_SPI_TXDATA);
 133                 (*len)--;
 134                 count--;
 135         }
 136
 137         *dout = out;
 138 }
 139
 140 /* Empty Rx FIFO. */
 141 static void apple_spi_rx(struct apple_spi_priv *priv, uint *len,
 142                          void **din)
 143 {
 144         u8 *in = *din;
 145         u32 data, fifostat;
 146         uint count;
 147
 148         fifostat = readl(priv->base + APPLE_SPI_FIFOSTAT);
 149         count = FIELD_GET(APPLE_SPI_FIFOSTAT_LEVEL_RX, fifostat);
 150         while (*len > 0 && count > 0) {
 151                 data = readl(priv->base + APPLE_SPI_RXDATA);
 152                 if (in)
 153                         *in++ = data;
 154                 (*len)--;
 155                 count--;
 156         }
 157
 158         *din = in;
 159 }
 160
 161 static int apple_spi_xfer(struct udevice *dev, unsigned int bitlen,
 162                           const void *dout, void *din, unsigned long flags)
 163 {
 164         struct apple_spi_priv *priv = dev_get_priv(dev->parent);
 165         unsigned long start = get_timer(0);
 166         uint txlen, rxlen;
 167         int ret = 0;
 168
 169         if ((bitlen % 8) != 0)
 170                 return -EINVAL;
 171         txlen = rxlen = bitlen / 8;
 172
 173         if (flags & SPI_XFER_BEGIN)
 174                 apple_spi_set_cs(priv, 1);
 175
 176         if (txlen > 0) {
 177                 /* Reset FIFOs */
 178                 writel(APPLE_SPI_CTRL_RX_RESET | APPLE_SPI_CTRL_TX_RESET,
 179                        priv->base + APPLE_SPI_CTRL);
 180
 181                 /* Set the transfer length */
 182                 writel(txlen, priv->base + APPLE_SPI_TXCNT);
 183                 writel(rxlen, priv->base + APPLE_SPI_RXCNT);
 184
 185                 /* Prime transmit FIFO */
 186                 apple_spi_tx(priv, &txlen, &dout);
 187
 188                 /* Start transfer */
 189                 writel(APPLE_SPI_CTRL_RUN, priv->base + APPLE_SPI_CTRL);
 190
 191                 while ((txlen > 0 || rxlen > 0)) {
 192                         apple_spi_rx(priv, &rxlen, &din);
 193                         apple_spi_tx(priv, &txlen, &dout);
 194
 195                         if (get_timer(start) > APPLE_SPI_TIMEOUT_MS) {
 196                                 ret = -ETIMEDOUT;
 197                                 break;
 198                         }
 199                 }
 200
 201                 /* Stop transfer. */
 202                 writel(0, priv->base + APPLE_SPI_CTRL);
 203         }
 204
 205         if (flags & SPI_XFER_END)
 206                 apple_spi_set_cs(priv, 0);
 207
 208         return ret;
 209 }
 210
 211 static int apple_spi_set_speed(struct udevice *dev, uint speed)
 212 {
 213         struct apple_spi_priv *priv = dev_get_priv(dev);
 214         u32 div;
 215
 216         div = DIV_ROUND_UP(priv->clkfreq, speed);
 217         if (div < APPLE_SPI_CLKDIV_MIN)
 218                 div = APPLE_SPI_CLKDIV_MIN;
 219         if (div > APPLE_SPI_CLKDIV_MAX)
 220                 div = APPLE_SPI_CLKDIV_MAX;
 221
 222         writel(div, priv->base + APPLE_SPI_CLKDIV);
 223
 224         return 0;
 225 }
 226
 227 static int apple_spi_set_mode(struct udevice *bus, uint mode)
 228 {
 229         return 0;
 230 }
 231
 232 struct dm_spi_ops apple_spi_ops = {
 233         .xfer = apple_spi_xfer,
 234         .set_speed = apple_spi_set_speed,
 235         .set_mode = apple_spi_set_mode,
 236 };
 237
 238 static int apple_spi_probe(struct udevice *dev)
 239 {
 240         struct apple_spi_priv *priv = dev_get_priv(dev);
 241         struct clk clkdev;
 242         int ret;
 243
 244         priv->base = dev_read_addr_ptr(dev);
 245         if (!priv->base)
 246                 return -EINVAL;
 247
 248         ret = clk_get_by_index(dev, 0, &clkdev);
 249         if (ret)
 250                 return ret;
 251         priv->clkfreq = clk_get_rate(&clkdev);
 252
 253         /* Set CS high (inactive) and disable override and auto-CS */
 254         writel(APPLE_SPI_PIN_CS, priv->base + APPLE_SPI_PIN);
 255         writel(readl(priv->base + APPLE_SPI_SHIFTCFG) & ~APPLE_SPI_SHIFTCFG_OVERRIDE_CS,
 256                priv->base + APPLE_SPI_SHIFTCFG);
 257         writel((readl(priv->base + APPLE_SPI_PINCFG) & ~APPLE_SPI_PINCFG_CS_IDLE_VAL) |
 258                APPLE_SPI_PINCFG_KEEP_CS, priv->base + APPLE_SPI_PINCFG);
 259
 260         /* Reset FIFOs */
 261         writel(APPLE_SPI_CTRL_RX_RESET | APPLE_SPI_CTRL_TX_RESET,
 262                priv->base + APPLE_SPI_CTRL);
 263
 264         /* Configure defaults */
 265         writel(FIELD_PREP(APPLE_SPI_CFG_MODE, APPLE_SPI_CFG_MODE_IRQ) |
 266                FIELD_PREP(APPLE_SPI_CFG_WORD_SIZE, APPLE_SPI_CFG_WORD_SIZE_8B) |
 267                FIELD_PREP(APPLE_SPI_CFG_FIFO_THRESH, APPLE_SPI_CFG_FIFO_THRESH_8B),
 268                priv->base + APPLE_SPI_CFG);
 269
 270         return 0;
 271 }
 272
 273 static const struct udevice_id apple_spi_of_match[] = {
 274         { .compatible = "apple,spi" },
 275         { /* sentinel */ }
 276 };
 277
 278 U_BOOT_DRIVER(apple_spi) = {
 279         .name = "apple_spi",
 280         .id = UCLASS_SPI,
 281         .of_match = apple_spi_of_match,
 282         .probe = apple_spi_probe,
 283         .priv_auto = sizeof(struct apple_spi_priv),
 284         .ops = &apple_spi_ops,
 285 };