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_platform.h>
  19 #include <linux/io.h>
  20
  21 #define FPGA_NAND_CMD_MASK              (0x7 << 28)
  22 #define FPGA_NAND_CMD_COMMAND           (0x0 << 28)
  23 #define FPGA_NAND_CMD_ADDR              (0x1 << 28)
  24 #define FPGA_NAND_CMD_READ              (0x2 << 28)
  25 #define FPGA_NAND_CMD_WRITE             (0x3 << 28)
  26 #define FPGA_NAND_BUSY                  (0x1 << 15)
  27 #define FPGA_NAND_ENABLE                (0x1 << 31)
  28 #define FPGA_NAND_DATA_SHIFT            16
  29
  30 struct socrates_nand_host {
  31         struct nand_chip        nand_chip;
  32         struct mtd_info         mtd;
  33         void __iomem            *io_base;
  34         struct device           *dev;
  35 };
  36
  37 /**
  38  * socrates_nand_write_buf -  write buffer to chip
  39  * @mtd:        MTD device structure
  40  * @buf:        data buffer
  41  * @len:        number of bytes to write
  42  */
  43 static void socrates_nand_write_buf(struct mtd_info *mtd,
  44                 const uint8_t *buf, int len)
  45 {
  46         int i;
  47         struct nand_chip *this = mtd->priv;
  48         struct socrates_nand_host *host = this->priv;
  49
  50         for (i = 0; i < len; i++) {
  51                 out_be32(host->io_base, FPGA_NAND_ENABLE |
  52                                 FPGA_NAND_CMD_WRITE |
  53                                 (buf[i] << FPGA_NAND_DATA_SHIFT));
  54         }
  55 }
  56
  57 /**
  58  * socrates_nand_read_buf -  read chip data into buffer
  59  * @mtd:        MTD device structure
  60  * @buf:        buffer to store date
  61  * @len:        number of bytes to read
  62  */
  63 static void socrates_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
  64 {
  65         int i;
  66         struct nand_chip *this = mtd->priv;
  67         struct socrates_nand_host *host = this->priv;
  68         uint32_t val;
  69
  70         val = FPGA_NAND_ENABLE | FPGA_NAND_CMD_READ;
  71
  72         out_be32(host->io_base, val);
  73         for (i = 0; i < len; i++) {
  74                 buf[i] = (in_be32(host->io_base) >>
  75                                 FPGA_NAND_DATA_SHIFT) & 0xff;
  76         }
  77 }
  78
  79 /**
  80  * socrates_nand_read_byte -  read one byte from the chip
  81  * @mtd:        MTD device structure
  82  */
  83 static uint8_t socrates_nand_read_byte(struct mtd_info *mtd)
  84 {
  85         uint8_t byte;
  86         socrates_nand_read_buf(mtd, &byte, sizeof(byte));
  87         return byte;
  88 }
  89
  90 /**
  91  * socrates_nand_read_word -  read one word from the chip
  92  * @mtd:        MTD device structure
  93  */
  94 static uint16_t socrates_nand_read_word(struct mtd_info *mtd)
  95 {
  96         uint16_t word;
  97         socrates_nand_read_buf(mtd, (uint8_t *)&word, sizeof(word));
  98         return word;
  99 }
 100
 101 /**
 102  * socrates_nand_verify_buf -  Verify chip data against buffer
 103  * @mtd:        MTD device structure
 104  * @buf:        buffer containing the data to compare
 105  * @len:        number of bytes to compare
 106  */
 107 static int socrates_nand_verify_buf(struct mtd_info *mtd, const u8 *buf,
 108                 int len)
 109 {
 110         int i;
 111
 112         for (i = 0; i < len; i++) {
 113                 if (buf[i] != socrates_nand_read_byte(mtd))
 114                         return -EFAULT;
 115         }
 116         return 0;
 117 }
 118
 119 /*
 120  * Hardware specific access to control-lines
 121  */
 122 static void socrates_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
 123                 unsigned int ctrl)
 124 {
 125         struct nand_chip *nand_chip = mtd->priv;
 126         struct socrates_nand_host *host = nand_chip->priv;
 127         uint32_t val;
 128
 129         if (cmd == NAND_CMD_NONE)
 130                 return;
 131
 132         if (ctrl & NAND_CLE)
 133                 val = FPGA_NAND_CMD_COMMAND;
 134         else
 135                 val = FPGA_NAND_CMD_ADDR;
 136
 137         if (ctrl & NAND_NCE)
 138                 val |= FPGA_NAND_ENABLE;
 139
 140         val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT;
 141
 142         out_be32(host->io_base, val);
 143 }
 144
 145 /*
 146  * Read the Device Ready pin.
 147  */
 148 static int socrates_nand_device_ready(struct mtd_info *mtd)
 149 {
 150         struct nand_chip *nand_chip = mtd->priv;
 151         struct socrates_nand_host *host = nand_chip->priv;
 152
 153         if (in_be32(host->io_base) & FPGA_NAND_BUSY)
 154                 return 0; /* busy */
 155         return 1;
 156 }
 157
 158 /*
 159  * Probe for the NAND device.
 160  */
 161 static int __devinit socrates_nand_probe(struct platform_device *ofdev)
 162 {
 163         struct socrates_nand_host *host;
 164         struct mtd_info *mtd;
 165         struct nand_chip *nand_chip;
 166         int res;
 167         struct mtd_part_parser_data ppdata;
 168
 169         /* Allocate memory for the device structure (and zero it) */
 170         host = kzalloc(sizeof(struct socrates_nand_host), GFP_KERNEL);
 171         if (!host) {
 172                 printk(KERN_ERR
 173                        "socrates_nand: failed to allocate device structure.\n");
 174                 return -ENOMEM;
 175         }
 176
 177         host->io_base = of_iomap(ofdev->dev.of_node, 0);
 178         if (host->io_base == NULL) {
 179                 printk(KERN_ERR "socrates_nand: ioremap failed\n");
 180                 kfree(host);
 181                 return -EIO;
 182         }
 183
 184         mtd = &host->mtd;
 185         nand_chip = &host->nand_chip;
 186         host->dev = &ofdev->dev;
 187
 188         nand_chip->priv = host;         /* link the private data structures */
 189         mtd->priv = nand_chip;
 190         mtd->name = "socrates_nand";
 191         mtd->owner = THIS_MODULE;
 192         mtd->dev.parent = &ofdev->dev;
 193         ppdata.of_node = ofdev->dev.of_node;
 194
 195         /*should never be accessed directly */
 196         nand_chip->IO_ADDR_R = (void *)0xdeadbeef;
 197         nand_chip->IO_ADDR_W = (void *)0xdeadbeef;
 198
 199         nand_chip->cmd_ctrl = socrates_nand_cmd_ctrl;
 200         nand_chip->read_byte = socrates_nand_read_byte;
 201         nand_chip->read_word = socrates_nand_read_word;
 202         nand_chip->write_buf = socrates_nand_write_buf;
 203         nand_chip->read_buf = socrates_nand_read_buf;
 204         nand_chip->verify_buf = socrates_nand_verify_buf;
 205         nand_chip->dev_ready = socrates_nand_device_ready;
 206
 207         nand_chip->ecc.mode = NAND_ECC_SOFT;    /* enable ECC */
 208
 209         /* TODO: I have no idea what real delay is. */
 210         nand_chip->chip_delay = 20;             /* 20us command delay time */
 211
 212         dev_set_drvdata(&ofdev->dev, host);
 213
 214         /* first scan to find the device and get the page size */
 215         if (nand_scan_ident(mtd, 1, NULL)) {
 216                 res = -ENXIO;
 217                 goto out;
 218         }
 219
 220         /* second phase scan */
 221         if (nand_scan_tail(mtd)) {
 222                 res = -ENXIO;
 223                 goto out;
 224         }
 225
 226         res = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
 227         if (!res)
 228                 return res;
 229
 230         nand_release(mtd);
 231
 232 out:
 233         dev_set_drvdata(&ofdev->dev, NULL);
 234         iounmap(host->io_base);
 235         kfree(host);
 236         return res;
 237 }
 238
 239 /*
 240  * Remove a NAND device.
 241  */
 242 static int __devexit socrates_nand_remove(struct platform_device *ofdev)
 243 {
 244         struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev);
 245         struct mtd_info *mtd = &host->mtd;
 246
 247         nand_release(mtd);
 248
 249         dev_set_drvdata(&ofdev->dev, NULL);
 250         iounmap(host->io_base);
 251         kfree(host);
 252
 253         return 0;
 254 }
 255
 256 static const struct of_device_id socrates_nand_match[] =
 257 {
 258         {
 259                 .compatible   = "abb,socrates-nand",
 260         },
 261         {},
 262 };
 263
 264 MODULE_DEVICE_TABLE(of, socrates_nand_match);
 265
 266 static struct platform_driver socrates_nand_driver = {
 267         .driver = {
 268                 .name = "socrates_nand",
 269                 .owner = THIS_MODULE,
 270                 .of_match_table = socrates_nand_match,
 271         },
 272         .probe          = socrates_nand_probe,
 273         .remove         = __devexit_p(socrates_nand_remove),
 274 };
 275
 276 module_platform_driver(socrates_nand_driver);
 277
 278 MODULE_LICENSE("GPL");
 279 MODULE_AUTHOR("Ilya Yanok");
 280 MODULE_DESCRIPTION("NAND driver for Socrates board");