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  * Hardware specific access to control-lines
 103  */
 104 static void socrates_nand_cmd_ctrl(struct mtd_info *mtd, int cmd,
 105                 unsigned int ctrl)
 106 {
 107         struct nand_chip *nand_chip = mtd->priv;
 108         struct socrates_nand_host *host = nand_chip->priv;
 109         uint32_t val;
 110
 111         if (cmd == NAND_CMD_NONE)
 112                 return;
 113
 114         if (ctrl & NAND_CLE)
 115                 val = FPGA_NAND_CMD_COMMAND;
 116         else
 117                 val = FPGA_NAND_CMD_ADDR;
 118
 119         if (ctrl & NAND_NCE)
 120                 val |= FPGA_NAND_ENABLE;
 121
 122         val |= (cmd & 0xff) << FPGA_NAND_DATA_SHIFT;
 123
 124         out_be32(host->io_base, val);
 125 }
 126
 127 /*
 128  * Read the Device Ready pin.
 129  */
 130 static int socrates_nand_device_ready(struct mtd_info *mtd)
 131 {
 132         struct nand_chip *nand_chip = mtd->priv;
 133         struct socrates_nand_host *host = nand_chip->priv;
 134
 135         if (in_be32(host->io_base) & FPGA_NAND_BUSY)
 136                 return 0; /* busy */
 137         return 1;
 138 }
 139
 140 /*
 141  * Probe for the NAND device.
 142  */
 143 static int socrates_nand_probe(struct platform_device *ofdev)
 144 {
 145         struct socrates_nand_host *host;
 146         struct mtd_info *mtd;
 147         struct nand_chip *nand_chip;
 148         int res;
 149         struct mtd_part_parser_data ppdata;
 150
 151         /* Allocate memory for the device structure (and zero it) */
 152         host = kzalloc(sizeof(struct socrates_nand_host), GFP_KERNEL);
 153         if (!host) {
 154                 printk(KERN_ERR
 155                        "socrates_nand: failed to allocate device structure.\n");
 156                 return -ENOMEM;
 157         }
 158
 159         host->io_base = of_iomap(ofdev->dev.of_node, 0);
 160         if (host->io_base == NULL) {
 161                 printk(KERN_ERR "socrates_nand: ioremap failed\n");
 162                 kfree(host);
 163                 return -EIO;
 164         }
 165
 166         mtd = &host->mtd;
 167         nand_chip = &host->nand_chip;
 168         host->dev = &ofdev->dev;
 169
 170         nand_chip->priv = host;         /* link the private data structures */
 171         mtd->priv = nand_chip;
 172         mtd->name = "socrates_nand";
 173         mtd->owner = THIS_MODULE;
 174         mtd->dev.parent = &ofdev->dev;
 175         ppdata.of_node = ofdev->dev.of_node;
 176
 177         /*should never be accessed directly */
 178         nand_chip->IO_ADDR_R = (void *)0xdeadbeef;
 179         nand_chip->IO_ADDR_W = (void *)0xdeadbeef;
 180
 181         nand_chip->cmd_ctrl = socrates_nand_cmd_ctrl;
 182         nand_chip->read_byte = socrates_nand_read_byte;
 183         nand_chip->read_word = socrates_nand_read_word;
 184         nand_chip->write_buf = socrates_nand_write_buf;
 185         nand_chip->read_buf = socrates_nand_read_buf;
 186         nand_chip->dev_ready = socrates_nand_device_ready;
 187
 188         nand_chip->ecc.mode = NAND_ECC_SOFT;    /* enable ECC */
 189
 190         /* TODO: I have no idea what real delay is. */
 191         nand_chip->chip_delay = 20;             /* 20us command delay time */
 192
 193         dev_set_drvdata(&ofdev->dev, host);
 194
 195         /* first scan to find the device and get the page size */
 196         if (nand_scan_ident(mtd, 1, NULL)) {
 197                 res = -ENXIO;
 198                 goto out;
 199         }
 200
 201         /* second phase scan */
 202         if (nand_scan_tail(mtd)) {
 203                 res = -ENXIO;
 204                 goto out;
 205         }
 206
 207         res = mtd_device_parse_register(mtd, NULL, &ppdata, NULL, 0);
 208         if (!res)
 209                 return res;
 210
 211         nand_release(mtd);
 212
 213 out:
 214         dev_set_drvdata(&ofdev->dev, NULL);
 215         iounmap(host->io_base);
 216         kfree(host);
 217         return res;
 218 }
 219
 220 /*
 221  * Remove a NAND device.
 222  */
 223 static int socrates_nand_remove(struct platform_device *ofdev)
 224 {
 225         struct socrates_nand_host *host = dev_get_drvdata(&ofdev->dev);
 226         struct mtd_info *mtd = &host->mtd;
 227
 228         nand_release(mtd);
 229
 230         dev_set_drvdata(&ofdev->dev, NULL);
 231         iounmap(host->io_base);
 232         kfree(host);
 233
 234         return 0;
 235 }
 236
 237 static const struct of_device_id socrates_nand_match[] =
 238 {
 239         {
 240                 .compatible   = "abb,socrates-nand",
 241         },
 242         {},
 243 };
 244
 245 MODULE_DEVICE_TABLE(of, socrates_nand_match);
 246
 247 static struct platform_driver socrates_nand_driver = {
 248         .driver = {
 249                 .name = "socrates_nand",
 250                 .owner = THIS_MODULE,
 251                 .of_match_table = socrates_nand_match,
 252         },
 253         .probe          = socrates_nand_probe,
 254         .remove         = socrates_nand_remove,
 255 };
 256
 257 module_platform_driver(socrates_nand_driver);
 258
 259 MODULE_LICENSE("GPL");
 260 MODULE_AUTHOR("Ilya Yanok");
 261 MODULE_DESCRIPTION("NAND driver for Socrates board");