drivers/spi/spi-amd.c

   1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2 //
   3 // AMD SPI controller driver
   4 //
   5 // Copyright (c) 2020, Advanced Micro Devices, Inc.
   6 //
   7 // Author: Sanjay R Mehta <sanju.mehta@amd.com>
   8
   9 #include <linux/acpi.h>
  10 #include <linux/init.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/delay.h>
  14 #include <linux/spi/spi.h>
  15
  16 #define AMD_SPI_CTRL0_REG       0x00
  17 #define AMD_SPI_EXEC_CMD        BIT(16)
  18 #define AMD_SPI_FIFO_CLEAR      BIT(20)
  19 #define AMD_SPI_BUSY            BIT(31)
  20
  21 #define AMD_SPI_OPCODE_MASK     0xFF
  22
  23 #define AMD_SPI_ALT_CS_REG      0x1D
  24 #define AMD_SPI_ALT_CS_MASK     0x3
  25
  26 #define AMD_SPI_FIFO_BASE       0x80
  27 #define AMD_SPI_TX_COUNT_REG    0x48
  28 #define AMD_SPI_RX_COUNT_REG    0x4B
  29 #define AMD_SPI_STATUS_REG      0x4C
  30
  31 #define AMD_SPI_MEM_SIZE        200
  32
  33 /* M_CMD OP codes for SPI */
  34 #define AMD_SPI_XFER_TX         1
  35 #define AMD_SPI_XFER_RX         2
  36
  37 struct amd_spi {
  38         void __iomem *io_remap_addr;
  39         unsigned long io_base_addr;
  40         u32 rom_addr;
  41         u8 chip_select;
  42 };
  43
  44 static inline u8 amd_spi_readreg8(struct spi_master *master, int idx)
  45 {
  46         struct amd_spi *amd_spi = spi_master_get_devdata(master);
  47
  48         return ioread8((u8 __iomem *)amd_spi->io_remap_addr + idx);
  49 }
  50
  51 static inline void amd_spi_writereg8(struct spi_master *master, int idx,
  52                                      u8 val)
  53 {
  54         struct amd_spi *amd_spi = spi_master_get_devdata(master);
  55
  56         iowrite8(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
  57 }
  58
  59 static inline void amd_spi_setclear_reg8(struct spi_master *master, int idx,
  60                                          u8 set, u8 clear)
  61 {
  62         u8 tmp = amd_spi_readreg8(master, idx);
  63
  64         tmp = (tmp & ~clear) | set;
  65         amd_spi_writereg8(master, idx, tmp);
  66 }
  67
  68 static inline u32 amd_spi_readreg32(struct spi_master *master, int idx)
  69 {
  70         struct amd_spi *amd_spi = spi_master_get_devdata(master);
  71
  72         return ioread32((u8 __iomem *)amd_spi->io_remap_addr + idx);
  73 }
  74
  75 static inline void amd_spi_writereg32(struct spi_master *master, int idx,
  76                                       u32 val)
  77 {
  78         struct amd_spi *amd_spi = spi_master_get_devdata(master);
  79
  80         iowrite32(val, ((u8 __iomem *)amd_spi->io_remap_addr + idx));
  81 }
  82
  83 static inline void amd_spi_setclear_reg32(struct spi_master *master, int idx,
  84                                           u32 set, u32 clear)
  85 {
  86         u32 tmp = amd_spi_readreg32(master, idx);
  87
  88         tmp = (tmp & ~clear) | set;
  89         amd_spi_writereg32(master, idx, tmp);
  90 }
  91
  92 static void amd_spi_select_chip(struct spi_master *master)
  93 {
  94         struct amd_spi *amd_spi = spi_master_get_devdata(master);
  95         u8 chip_select = amd_spi->chip_select;
  96
  97         amd_spi_setclear_reg8(master, AMD_SPI_ALT_CS_REG, chip_select,
  98                               AMD_SPI_ALT_CS_MASK);
  99 }
 100
 101 static void amd_spi_clear_fifo_ptr(struct spi_master *master)
 102 {
 103         amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, AMD_SPI_FIFO_CLEAR,
 104                                AMD_SPI_FIFO_CLEAR);
 105 }
 106
 107 static void amd_spi_set_opcode(struct spi_master *master, u8 cmd_opcode)
 108 {
 109         amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, cmd_opcode,
 110                                AMD_SPI_OPCODE_MASK);
 111 }
 112
 113 static inline void amd_spi_set_rx_count(struct spi_master *master,
 114                                         u8 rx_count)
 115 {
 116         amd_spi_setclear_reg8(master, AMD_SPI_RX_COUNT_REG, rx_count, 0xff);
 117 }
 118
 119 static inline void amd_spi_set_tx_count(struct spi_master *master,
 120                                         u8 tx_count)
 121 {
 122         amd_spi_setclear_reg8(master, AMD_SPI_TX_COUNT_REG, tx_count, 0xff);
 123 }
 124
 125 static inline int amd_spi_busy_wait(struct amd_spi *amd_spi)
 126 {
 127         bool spi_busy;
 128         int timeout = 100000;
 129
 130         /* poll for SPI bus to become idle */
 131         spi_busy = (ioread32((u8 __iomem *)amd_spi->io_remap_addr +
 132                     AMD_SPI_CTRL0_REG) & AMD_SPI_BUSY) == AMD_SPI_BUSY;
 133         while (spi_busy) {
 134                 usleep_range(10, 20);
 135                 if (timeout-- < 0)
 136                         return -ETIMEDOUT;
 137
 138                 spi_busy = (ioread32((u8 __iomem *)amd_spi->io_remap_addr +
 139                             AMD_SPI_CTRL0_REG) & AMD_SPI_BUSY) == AMD_SPI_BUSY;
 140         }
 141
 142         return 0;
 143 }
 144
 145 static void amd_spi_execute_opcode(struct spi_master *master)
 146 {
 147         struct amd_spi *amd_spi = spi_master_get_devdata(master);
 148
 149         /* Set ExecuteOpCode bit in the CTRL0 register */
 150         amd_spi_setclear_reg32(master, AMD_SPI_CTRL0_REG, AMD_SPI_EXEC_CMD,
 151                                AMD_SPI_EXEC_CMD);
 152
 153         amd_spi_busy_wait(amd_spi);
 154 }
 155
 156 static int amd_spi_master_setup(struct spi_device *spi)
 157 {
 158         struct spi_master *master = spi->master;
 159
 160         amd_spi_clear_fifo_ptr(master);
 161
 162         return 0;
 163 }
 164
 165 static inline int amd_spi_fifo_xfer(struct amd_spi *amd_spi,
 166                                     struct spi_master *master,
 167                                     struct spi_message *message)
 168 {
 169         struct spi_transfer *xfer = NULL;
 170         u8 cmd_opcode;
 171         u8 *buf = NULL;
 172         u32 m_cmd = 0;
 173         u32 i = 0;
 174         u32 tx_len = 0, rx_len = 0;
 175
 176         list_for_each_entry(xfer, &message->transfers,
 177                             transfer_list) {
 178                 if (xfer->rx_buf)
 179                         m_cmd = AMD_SPI_XFER_RX;
 180                 if (xfer->tx_buf)
 181                         m_cmd = AMD_SPI_XFER_TX;
 182
 183                 if (m_cmd & AMD_SPI_XFER_TX) {
 184                         buf = (u8 *)xfer->tx_buf;
 185                         tx_len = xfer->len - 1;
 186                         cmd_opcode = *(u8 *)xfer->tx_buf;
 187                         buf++;
 188                         amd_spi_set_opcode(master, cmd_opcode);
 189
 190                         /* Write data into the FIFO. */
 191                         for (i = 0; i < tx_len; i++) {
 192                                 iowrite8(buf[i],
 193                                          ((u8 __iomem *)amd_spi->io_remap_addr +
 194                                          AMD_SPI_FIFO_BASE + i));
 195                         }
 196
 197                         amd_spi_set_tx_count(master, tx_len);
 198                         amd_spi_clear_fifo_ptr(master);
 199                         /* Execute command */
 200                         amd_spi_execute_opcode(master);
 201                 }
 202                 if (m_cmd & AMD_SPI_XFER_RX) {
 203                         /*
 204                          * Store no. of bytes to be received from
 205                          * FIFO
 206                          */
 207                         rx_len = xfer->len;
 208                         buf = (u8 *)xfer->rx_buf;
 209                         amd_spi_set_rx_count(master, rx_len);
 210                         amd_spi_clear_fifo_ptr(master);
 211                         /* Execute command */
 212                         amd_spi_execute_opcode(master);
 213                         /* Read data from FIFO to receive buffer  */
 214                         for (i = 0; i < rx_len; i++)
 215                                 buf[i] = amd_spi_readreg8(master,
 216                                                           AMD_SPI_FIFO_BASE +
 217                                                           tx_len + i);
 218                 }
 219         }
 220
 221         /* Update statistics */
 222         message->actual_length = tx_len + rx_len + 1;
 223         /* complete the transaction */
 224         message->status = 0;
 225         spi_finalize_current_message(master);
 226
 227         return 0;
 228 }
 229
 230 static int amd_spi_master_transfer(struct spi_master *master,
 231                                    struct spi_message *msg)
 232 {
 233         struct amd_spi *amd_spi = spi_master_get_devdata(master);
 234         struct spi_device *spi = msg->spi;
 235
 236         amd_spi->chip_select = spi->chip_select;
 237         amd_spi_select_chip(master);
 238
 239         /*
 240          * Extract spi_transfers from the spi message and
 241          * program the controller.
 242          */
 243         amd_spi_fifo_xfer(amd_spi, master, msg);
 244
 245         return 0;
 246 }
 247
 248 static int amd_spi_probe(struct platform_device *pdev)
 249 {
 250         struct device *dev = &pdev->dev;
 251         struct spi_master *master;
 252         struct amd_spi *amd_spi;
 253         struct resource *res;
 254         int err = 0;
 255
 256         /* Allocate storage for spi_master and driver private data */
 257         master = spi_alloc_master(dev, sizeof(struct amd_spi));
 258         if (!master) {
 259                 dev_err(dev, "Error allocating SPI master\n");
 260                 return -ENOMEM;
 261         }
 262
 263         amd_spi = spi_master_get_devdata(master);
 264
 265         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 266         amd_spi->io_remap_addr = devm_ioremap_resource(&pdev->dev, res);
 267         if (IS_ERR(amd_spi->io_remap_addr)) {
 268                 err = PTR_ERR(amd_spi->io_remap_addr);
 269                 dev_err(dev, "error %d ioremap of SPI registers failed\n", err);
 270                 goto err_free_master;
 271         }
 272         dev_dbg(dev, "io_remap_address: %p\n", amd_spi->io_remap_addr);
 273
 274         /* Initialize the spi_master fields */
 275         master->bus_num = 0;
 276         master->num_chipselect = 4;
 277         master->mode_bits = 0;
 278         master->flags = SPI_MASTER_HALF_DUPLEX;
 279         master->setup = amd_spi_master_setup;
 280         master->transfer_one_message = amd_spi_master_transfer;
 281
 282         /* Register the controller with SPI framework */
 283         err = devm_spi_register_master(dev, master);
 284         if (err) {
 285                 dev_err(dev, "error %d registering SPI controller\n", err);
 286                 goto err_free_master;
 287         }
 288
 289         return 0;
 290
 291 err_free_master:
 292         spi_master_put(master);
 293
 294         return err;
 295 }
 296
 297 static const struct acpi_device_id spi_acpi_match[] = {
 298         { "AMDI0061", 0 },
 299         {},
 300 };
 301 MODULE_DEVICE_TABLE(acpi, spi_acpi_match);
 302
 303 static struct platform_driver amd_spi_driver = {
 304         .driver = {
 305                 .name = "amd_spi",
 306                 .acpi_match_table = ACPI_PTR(spi_acpi_match),
 307         },
 308         .probe = amd_spi_probe,
 309 };
 310
 311 module_platform_driver(amd_spi_driver);
 312
 313 MODULE_LICENSE("Dual BSD/GPL");
 314 MODULE_AUTHOR("Sanjay Mehta <sanju.mehta@amd.com>");
 315 MODULE_DESCRIPTION("AMD SPI Master Controller Driver");