drivers/mtd/nand/socrates_nand.c

   1 /*
   2  * drivers/mtd/nand/socrates_nand.c
   3  *
   4  *  Copyright © 2008 Ilya Yanok, Emcraft Systems
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #include <linux/slab.h>
  14 #include <linux/module.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/mtd/nand.h>
  17 #include <linux/mtd/partitions.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/io.h>
  21
  22 #define FPGA_NAND_CMD_MASK              (0x7 << 28)
  23 #define FPGA_NAND_CMD_COMMAND           (0x0 << 28)
  24 #define FPGA_NAND_CMD_ADDR              (0x1 << 28)
  25 #define FPGA_NAND_CMD_READ              (0x2 << 28)
  26 #define FPGA_NAND_CMD_WRITE             (0x3 << 28)
  27 #define FPGA_NAND_BUSY                  (0x1 << 15)
  28 #define FPGA_NAND_ENABLE                (0x1 << 31)
  29 #define FPGA_NAND_DATA_SHIFT            16
  30
  31 struct socrates_nand_host {
  32         struct nand_chip        nand_chip;
  33         struct mtd_info         mtd;
  34         void __iomem            *io_base;
  35         struct device           *dev;
  36 };
  37
  38 /**
  39  * socrates_nand_write_buf -  write buffer to chip
  40  * @mtd:        MTD device structure
  41  * @buf:        data buffer
  42  * @len:        number of bytes to write
  43  */
  44 static void socrates_nand_write_buf(struct mtd_info *mtd,
  45                 const uint8_t *buf, int len)
  46 {
  47         int i;
  48         struct nand_chip *this = mtd->priv;
  49         struct socrates_nand_host *host = this->priv;
  50
  51         for (i = 0; i < len; i++) {
  52                 out_be32(host->io_base, FPGA_NAND_ENABLE |
  53                                 FPGA_NAND_CMD_WRITE |
  54                                 (buf[i] << FPGA_NAND_DATA_SHIFT));
  55         }
  56 }
  57
  58 /**
  59  * socrates_nand_read_buf -  read chip data into buffer
  60  * @mtd:        MTD device structure
  61  * @buf:        buffer to store date
  62  * @len:        number of bytes to read
  63  */
  64 static void socrates_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
  65 {
  66         int i;
  67         struct nand_chip *this = mtd->priv;
  68         struct socrates_nand_host *host = this->priv;
  69         uint32_t val;
  70
  71         val = FPGA_NAND_ENABLE | FPGA_NAND_CMD_READ;
  72
  73         out_be32(host->io_base, val);
  74         for (i = 0; i < len; i++) {
  75                 buf[i] = (in_be32(host->io_base) >>
  76                                 FPGA_NAND_DATA_SHIFT) & 0xff;
  77         }
  78 }
  79
  80 /**
  81  * socrates_nand_read_byte -  read one byte from the chip
  82  * @mtd:        MTD device structure
  83  */
  84 static uint8_t socrates_nand_read_byte(struct mtd_info *mtd)
  85 {
  86         uint8_t byte;
  87         socrates_nand_read_buf(mtd, &byte, sizeof(byte));
  88         return byte;
  89 }
  90
  91 /**
  92  * socrates_nand_read_word -  read one word from the chip
  93  * @mtd:        MTD device structure
  94  */
  95 static uint16_t socrates_nand_read_word(struct mtd_info *mtd)
  96 {
  97         uint16_t word;
  98         socrates_nand_read_buf(mtd, (uint8_t *)&word, sizeof(word));
  99         return word;
 100 }
 101
 102 /*
 103  * Hardware specific access to control-lines
 104  */
 105 static void socrates_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
 106                 unsigned int ctrl)
 107 {
 108         struct nand_chip *nand_chip = mtd->priv;
 109         struct socrates_nand_host *host = nand_chip->priv;
 110         uint32_t val;
 111
 112         if (cmd == NAND_CMD_NONE)
 113                 return;
 114
 115         if (ctrl & NAND_CLE)
 116                 val = FPGA_NAND_CMD_COMMAND;
 117         else
 118                 val = FPGA_NAND_CMD_ADDR;
 119
 120         if (ctrl & NAND_NCE)
 121                 val |= FPGA_NAND_ENABLE;
 122
 123         val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT;
 124
 125         out_be32(host->io_base, val);
 126 }
 127
 128 /*
 129  * Read the Device Ready pin.
 130  */
 131 static int socrates_nand_device_ready(struct mtd_info *mtd)
 132 {
 133         struct nand_chip *nand_chip = mtd->priv;
 134         struct socrates_nand_host *host = nand_chip->priv;
 135
 136         if (in_be32(host->io_base) & FPGA_NAND_BUSY)
 137                 return 0; /* busy */
 138         return 1;
 139 }
 140
 141 /*
 142  * Probe for the NAND device.
 143  */
 144 static int socrates_nand_probe(struct platform_device *ofdev)
 145 {
 146         struct socrates_nand_host *host;
 147         struct mtd_info *mtd;
 148         struct nand_chip *nand_chip;
 149         int res;
 150
 151         /* Allocate memory for the device structure (and zero it) */
 152         host = devm_kzalloc(&ofdev->dev, sizeof(*host), GFP_KERNEL);
 153         if (!host)
 154                 return -ENOMEM;
 155
 156         host->io_base = of_iomap(ofdev->dev.of_node, 0);
 157         if (host->io_base == NULL) {
 158                 dev_err(&ofdev->dev, "ioremap failed\n");
 159                 return -EIO;
 160         }
 161
 162         mtd = &host->mtd;
 163         nand_chip = &host->nand_chip;
 164         host->dev = &ofdev->dev;
 165
 166         nand_chip->priv = host;         /* link the private data structures */
 167         nand_set_flash_node(nand_chip, ofdev->dev.of_node);
 168         mtd->priv = nand_chip;
 169         mtd->name = "socrates_nand";
 170         mtd->dev.parent = &ofdev->dev;
 171
 172         /*should never be accessed directly */
 173         nand_chip->IO_ADDR_R = (void *)0xdeadbeef;
 174         nand_chip->IO_ADDR_W = (void *)0xdeadbeef;
 175
 176         nand_chip->cmd_ctrl = socrates_nand_cmd_ctrl;
 177         nand_chip->read_byte = socrates_nand_read_byte;
 178         nand_chip->read_word = socrates_nand_read_word;
 179         nand_chip->write_buf = socrates_nand_write_buf;
 180         nand_chip->read_buf = socrates_nand_read_buf;
 181         nand_chip->dev_ready = socrates_nand_device_ready;
 182
 183         nand_chip->ecc.mode = NAND_ECC_SOFT;    /* enable ECC */
 184
 185         /* TODO: I have no idea what real delay is. */
 186         nand_chip->chip_delay = 20;             /* 20us command delay time */
 187
 188         dev_set_drvdata(&ofdev->dev, host);
 189
 190         /* first scan to find the device and get the page size */
 191         if (nand_scan_ident(mtd, 1, NULL)) {
 192                 res = -ENXIO;
 193                 goto out;
 194         }
 195
 196         /* second phase scan */
 197         if (nand_scan_tail(mtd)) {
 198                 res = -ENXIO;
 199                 goto out;
 200         }
 201
 202         res = mtd_device_register(mtd, NULL, 0);
 203         if (!res)
 204                 return res;
 205
 206         nand_release(mtd);
 207
 208 out:
 209         iounmap(host->io_base);
 210         return res;
 211 }
 212
 213 /*
 214  * Remove a NAND device.
 215  */
 216 static int socrates_nand_remove(struct platform_device *ofdev)
 217 {
 218         struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev);
 219         struct mtd_info *mtd = &host->mtd;
 220
 221         nand_release(mtd);
 222
 223         iounmap(host->io_base);
 224
 225         return 0;
 226 }
 227
 228 static const struct of_device_id socrates_nand_match[] =
 229 {
 230         {
 231                 .compatible   = "abb,socrates-nand",
 232         },
 233         {},
 234 };
 235
 236 MODULE_DEVICE_TABLE(of, socrates_nand_match);
 237
 238 static struct platform_driver socrates_nand_driver = {
 239         .driver = {
 240                 .name = "socrates_nand",
 241                 .of_match_table = socrates_nand_match,
 242         },
 243         .probe          = socrates_nand_probe,
 244         .remove         = socrates_nand_remove,
 245 };
 246
 247 module_platform_driver(socrates_nand_driver);
 248
 249 MODULE_LICENSE("GPL");
 250 MODULE_AUTHOR("Ilya Yanok");
 251 MODULE_DESCRIPTION("NAND driver for Socrates board");