drivers/mtd/nand/raw/socrates_nand.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright © 2008 Ilya Yanok, Emcraft Systems
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/module.h>
   8 #include <linux/mtd/mtd.h>
   9 #include <linux/mtd/rawnand.h>
  10 #include <linux/mtd/partitions.h>
  11 #include <linux/of_address.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/io.h>
  14
  15 #define FPGA_NAND_CMD_MASK              (0x7 << 28)
  16 #define FPGA_NAND_CMD_COMMAND           (0x0 << 28)
  17 #define FPGA_NAND_CMD_ADDR              (0x1 << 28)
  18 #define FPGA_NAND_CMD_READ              (0x2 << 28)
  19 #define FPGA_NAND_CMD_WRITE             (0x3 << 28)
  20 #define FPGA_NAND_BUSY                  (0x1 << 15)
  21 #define FPGA_NAND_ENABLE                (0x1 << 31)
  22 #define FPGA_NAND_DATA_SHIFT            16
  23
  24 struct socrates_nand_host {
  25         struct nand_chip        nand_chip;
  26         void __iomem            *io_base;
  27         struct device           *dev;
  28 };
  29
  30 /**
  31  * socrates_nand_write_buf -  write buffer to chip
  32  * @this:       NAND chip object
  33  * @buf:        data buffer
  34  * @len:        number of bytes to write
  35  */
  36 static void socrates_nand_write_buf(struct nand_chip *this, const uint8_t *buf,
  37                                     int len)
  38 {
  39         int i;
  40         struct socrates_nand_host *host = nand_get_controller_data(this);
  41
  42         for (i = 0; i < len; i++) {
  43                 out_be32(host->io_base, FPGA_NAND_ENABLE |
  44                                 FPGA_NAND_CMD_WRITE |
  45                                 (buf[i] << FPGA_NAND_DATA_SHIFT));
  46         }
  47 }
  48
  49 /**
  50  * socrates_nand_read_buf -  read chip data into buffer
  51  * @this:       NAND chip object
  52  * @buf:        buffer to store date
  53  * @len:        number of bytes to read
  54  */
  55 static void socrates_nand_read_buf(struct nand_chip *this, uint8_t *buf,
  56                                    int len)
  57 {
  58         int i;
  59         struct socrates_nand_host *host = nand_get_controller_data(this);
  60         uint32_t val;
  61
  62         val = FPGA_NAND_ENABLE | FPGA_NAND_CMD_READ;
  63
  64         out_be32(host->io_base, val);
  65         for (i = 0; i < len; i++) {
  66                 buf[i] = (in_be32(host->io_base) >>
  67                                 FPGA_NAND_DATA_SHIFT) & 0xff;
  68         }
  69 }
  70
  71 /**
  72  * socrates_nand_read_byte -  read one byte from the chip
  73  * @mtd:        MTD device structure
  74  */
  75 static uint8_t socrates_nand_read_byte(struct nand_chip *this)
  76 {
  77         uint8_t byte;
  78         socrates_nand_read_buf(this, &byte, sizeof(byte));
  79         return byte;
  80 }
  81
  82 /*
  83  * Hardware specific access to control-lines
  84  */
  85 static void socrates_nand_cmd_ctrl(struct nand_chip *nand_chip, int cmd,
  86                                    unsigned int ctrl)
  87 {
  88         struct socrates_nand_host *host = nand_get_controller_data(nand_chip);
  89         uint32_t val;
  90
  91         if (cmd == NAND_CMD_NONE)
  92                 return;
  93
  94         if (ctrl & NAND_CLE)
  95                 val = FPGA_NAND_CMD_COMMAND;
  96         else
  97                 val = FPGA_NAND_CMD_ADDR;
  98
  99         if (ctrl & NAND_NCE)
 100                 val |= FPGA_NAND_ENABLE;
 101
 102         val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT;
 103
 104         out_be32(host->io_base, val);
 105 }
 106
 107 /*
 108  * Read the Device Ready pin.
 109  */
 110 static int socrates_nand_device_ready(struct nand_chip *nand_chip)
 111 {
 112         struct socrates_nand_host *host = nand_get_controller_data(nand_chip);
 113
 114         if (in_be32(host->io_base) & FPGA_NAND_BUSY)
 115                 return 0; /* busy */
 116         return 1;
 117 }
 118
 119 /*
 120  * Probe for the NAND device.
 121  */
 122 static int socrates_nand_probe(struct platform_device *ofdev)
 123 {
 124         struct socrates_nand_host *host;
 125         struct mtd_info *mtd;
 126         struct nand_chip *nand_chip;
 127         int res;
 128
 129         /* Allocate memory for the device structure (and zero it) */
 130         host = devm_kzalloc(&ofdev->dev, sizeof(*host), GFP_KERNEL);
 131         if (!host)
 132                 return -ENOMEM;
 133
 134         host->io_base = of_iomap(ofdev->dev.of_node, 0);
 135         if (host->io_base == NULL) {
 136                 dev_err(&ofdev->dev, "ioremap failed\n");
 137                 return -EIO;
 138         }
 139
 140         nand_chip = &host->nand_chip;
 141         mtd = nand_to_mtd(nand_chip);
 142         host->dev = &ofdev->dev;
 143
 144         /* link the private data structures */
 145         nand_set_controller_data(nand_chip, host);
 146         nand_set_flash_node(nand_chip, ofdev->dev.of_node);
 147         mtd->name = "socrates_nand";
 148         mtd->dev.parent = &ofdev->dev;
 149
 150         nand_chip->legacy.cmd_ctrl = socrates_nand_cmd_ctrl;
 151         nand_chip->legacy.read_byte = socrates_nand_read_byte;
 152         nand_chip->legacy.write_buf = socrates_nand_write_buf;
 153         nand_chip->legacy.read_buf = socrates_nand_read_buf;
 154         nand_chip->legacy.dev_ready = socrates_nand_device_ready;
 155
 156         nand_chip->ecc.mode = NAND_ECC_SOFT;    /* enable ECC */
 157         nand_chip->ecc.algo = NAND_ECC_HAMMING;
 158
 159         /* TODO: I have no idea what real delay is. */
 160         nand_chip->legacy.chip_delay = 20;      /* 20us command delay time */
 161
 162         dev_set_drvdata(&ofdev->dev, host);
 163
 164         res = nand_scan(nand_chip, 1);
 165         if (res)
 166                 goto out;
 167
 168         res = mtd_device_register(mtd, NULL, 0);
 169         if (!res)
 170                 return res;
 171
 172         nand_release(nand_chip);
 173
 174 out:
 175         iounmap(host->io_base);
 176         return res;
 177 }
 178
 179 /*
 180  * Remove a NAND device.
 181  */
 182 static int socrates_nand_remove(struct platform_device *ofdev)
 183 {
 184         struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev);
 185
 186         nand_release(&host->nand_chip);
 187
 188         iounmap(host->io_base);
 189
 190         return 0;
 191 }
 192
 193 static const struct of_device_id socrates_nand_match[] =
 194 {
 195         {
 196                 .compatible   = "abb,socrates-nand",
 197         },
 198         {},
 199 };
 200
 201 MODULE_DEVICE_TABLE(of, socrates_nand_match);
 202
 203 static struct platform_driver socrates_nand_driver = {
 204         .driver = {
 205                 .name = "socrates_nand",
 206                 .of_match_table = socrates_nand_match,
 207         },
 208         .probe          = socrates_nand_probe,
 209         .remove         = socrates_nand_remove,
 210 };
 211
 212 module_platform_driver(socrates_nand_driver);
 213
 214 MODULE_LICENSE("GPL");
 215 MODULE_AUTHOR("Ilya Yanok");
 216 MODULE_DESCRIPTION("NAND driver for Socrates board");