drivers/mtd/devices/m25p80.c

   1 /*
   2  * MTD SPI driver for ST M25Pxx (and similar) serial flash chips
   3  *
   4  * Author: Mike Lavender, mike@steroidmicros.com
   5  *
   6  * Copyright (c) 2005, Intec Automation Inc.
   7  *
   8  * Some parts are based on lart.c by Abraham Van Der Merwe
   9  *
  10  * Cleaned up and generalized based on mtd_dataflash.c
  11  *
  12  * This code is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  *
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/errno.h>
  20 #include <linux/module.h>
  21 #include <linux/device.h>
  22
  23 #include <linux/mtd/mtd.h>
  24 #include <linux/mtd/partitions.h>
  25
  26 #include <linux/spi/spi.h>
  27 #include <linux/spi/flash.h>
  28 #include <linux/mtd/spi-nor.h>
  29
  30 #define MAX_CMD_SIZE            6
  31 struct m25p {
  32         struct spi_device       *spi;
  33         struct spi_nor          spi_nor;
  34         struct mtd_info         mtd;
  35         u8                      command[MAX_CMD_SIZE];
  36 };
  37
  38 static int m25p80_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len)
  39 {
  40         struct m25p *flash = nor->priv;
  41         struct spi_device *spi = flash->spi;
  42         int ret;
  43
  44         ret = spi_write_then_read(spi, &code, 1, val, len);
  45         if (ret < 0)
  46                 dev_err(&spi->dev, "error %d reading %x\n", ret, code);
  47
  48         return ret;
  49 }
  50
  51 static void m25p_addr2cmd(struct spi_nor *nor, unsigned int addr, u8 *cmd)
  52 {
  53         /* opcode is in cmd[0] */
  54         cmd[1] = addr >> (nor->addr_width * 8 -  8);
  55         cmd[2] = addr >> (nor->addr_width * 8 - 16);
  56         cmd[3] = addr >> (nor->addr_width * 8 - 24);
  57         cmd[4] = addr >> (nor->addr_width * 8 - 32);
  58 }
  59
  60 static int m25p_cmdsz(struct spi_nor *nor)
  61 {
  62         return 1 + nor->addr_width;
  63 }
  64
  65 static int m25p80_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len,
  66                         int wr_en)
  67 {
  68         struct m25p *flash = nor->priv;
  69         struct spi_device *spi = flash->spi;
  70
  71         flash->command[0] = opcode;
  72         if (buf)
  73                 memcpy(&flash->command[1], buf, len);
  74
  75         return spi_write(spi, flash->command, len + 1);
  76 }
  77
  78 static void m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
  79                         size_t *retlen, const u_char *buf)
  80 {
  81         struct m25p *flash = nor->priv;
  82         struct spi_device *spi = flash->spi;
  83         struct spi_transfer t[2] = {};
  84         struct spi_message m;
  85         int cmd_sz = m25p_cmdsz(nor);
  86
  87         spi_message_init(&m);
  88
  89         if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
  90                 cmd_sz = 1;
  91
  92         flash->command[0] = nor->program_opcode;
  93         m25p_addr2cmd(nor, to, flash->command);
  94
  95         t[0].tx_buf = flash->command;
  96         t[0].len = cmd_sz;
  97         spi_message_add_tail(&t[0], &m);
  98
  99         t[1].tx_buf = buf;
 100         t[1].len = len;
 101         spi_message_add_tail(&t[1], &m);
 102
 103         spi_sync(spi, &m);
 104
 105         *retlen += m.actual_length - cmd_sz;
 106 }
 107
 108 static inline unsigned int m25p80_rx_nbits(struct spi_nor *nor)
 109 {
 110         switch (nor->flash_read) {
 111         case SPI_NOR_DUAL:
 112                 return 2;
 113         case SPI_NOR_QUAD:
 114                 return 4;
 115         default:
 116                 return 0;
 117         }
 118 }
 119
 120 /*
 121  * Read an address range from the nor chip.  The address range
 122  * may be any size provided it is within the physical boundaries.
 123  */
 124 static int m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
 125                         size_t *retlen, u_char *buf)
 126 {
 127         struct m25p *flash = nor->priv;
 128         struct spi_device *spi = flash->spi;
 129         struct spi_transfer t[2];
 130         struct spi_message m;
 131         int dummy = nor->read_dummy;
 132         int ret;
 133
 134         /* Wait till previous write/erase is done. */
 135         ret = nor->wait_till_ready(nor);
 136         if (ret)
 137                 return ret;
 138
 139         spi_message_init(&m);
 140         memset(t, 0, (sizeof t));
 141
 142         flash->command[0] = nor->read_opcode;
 143         m25p_addr2cmd(nor, from, flash->command);
 144
 145         t[0].tx_buf = flash->command;
 146         t[0].len = m25p_cmdsz(nor) + dummy;
 147         spi_message_add_tail(&t[0], &m);
 148
 149         t[1].rx_buf = buf;
 150         t[1].rx_nbits = m25p80_rx_nbits(nor);
 151         t[1].len = len;
 152         spi_message_add_tail(&t[1], &m);
 153
 154         spi_sync(spi, &m);
 155
 156         *retlen = m.actual_length - m25p_cmdsz(nor) - dummy;
 157         return 0;
 158 }
 159
 160 static int m25p80_erase(struct spi_nor *nor, loff_t offset)
 161 {
 162         struct m25p *flash = nor->priv;
 163         int ret;
 164
 165         dev_dbg(nor->dev, "%dKiB at 0x%08x\n",
 166                 flash->mtd.erasesize / 1024, (u32)offset);
 167
 168         /* Wait until finished previous write command. */
 169         ret = nor->wait_till_ready(nor);
 170         if (ret)
 171                 return ret;
 172
 173         /* Send write enable, then erase commands. */
 174         ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0, 0);
 175         if (ret)
 176                 return ret;
 177
 178         /* Set up command buffer. */
 179         flash->command[0] = nor->erase_opcode;
 180         m25p_addr2cmd(nor, offset, flash->command);
 181
 182         spi_write(flash->spi, flash->command, m25p_cmdsz(nor));
 183
 184         return 0;
 185 }
 186
 187 /*
 188  * board specific setup should have ensured the SPI clock used here
 189  * matches what the READ command supports, at least until this driver
 190  * understands FAST_READ (for clocks over 25 MHz).
 191  */
 192 static int m25p_probe(struct spi_device *spi)
 193 {
 194         struct mtd_part_parser_data     ppdata;
 195         struct flash_platform_data      *data;
 196         struct m25p *flash;
 197         struct spi_nor *nor;
 198         enum read_mode mode = SPI_NOR_NORMAL;
 199         int ret;
 200
 201         flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
 202         if (!flash)
 203                 return -ENOMEM;
 204
 205         nor = &flash->spi_nor;
 206
 207         /* install the hooks */
 208         nor->read = m25p80_read;
 209         nor->write = m25p80_write;
 210         nor->erase = m25p80_erase;
 211         nor->write_reg = m25p80_write_reg;
 212         nor->read_reg = m25p80_read_reg;
 213
 214         nor->dev = &spi->dev;
 215         nor->mtd = &flash->mtd;
 216         nor->priv = flash;
 217
 218         spi_set_drvdata(spi, flash);
 219         flash->mtd.priv = nor;
 220         flash->spi = spi;
 221
 222         if (spi->mode & SPI_RX_QUAD)
 223                 mode = SPI_NOR_QUAD;
 224         else if (spi->mode & SPI_RX_DUAL)
 225                 mode = SPI_NOR_DUAL;
 226         ret = spi_nor_scan(nor, spi_get_device_id(spi), mode);
 227         if (ret)
 228                 return ret;
 229
 230         data = dev_get_platdata(&spi->dev);
 231         ppdata.of_node = spi->dev.of_node;
 232
 233         return mtd_device_parse_register(&flash->mtd, NULL, &ppdata,
 234                         data ? data->parts : NULL,
 235                         data ? data->nr_parts : 0);
 236 }
 237
 238
 239 static int m25p_remove(struct spi_device *spi)
 240 {
 241         struct m25p     *flash = spi_get_drvdata(spi);
 242
 243         /* Clean up MTD stuff. */
 244         return mtd_device_unregister(&flash->mtd);
 245 }
 246
 247
 248 static struct spi_driver m25p80_driver = {
 249         .driver = {
 250                 .name   = "m25p80",
 251                 .owner  = THIS_MODULE,
 252         },
 253         .id_table       = spi_nor_ids,
 254         .probe  = m25p_probe,
 255         .remove = m25p_remove,
 256
 257         /* REVISIT: many of these chips have deep power-down modes, which
 258          * should clearly be entered on suspend() to minimize power use.
 259          * And also when they're otherwise idle...
 260          */
 261 };
 262
 263 module_spi_driver(m25p80_driver);
 264
 265 MODULE_LICENSE("GPL");
 266 MODULE_AUTHOR("Mike Lavender");
 267 MODULE_DESCRIPTION("MTD SPI driver for ST M25Pxx flash chips");