diff options
Diffstat (limited to 'drivers/mtd/devices/m25p80.c')
| -rw-r--r-- | drivers/mtd/devices/m25p80.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c new file mode 100644 index 00000000000..ed7e0a1bed3 --- /dev/null +++ b/drivers/mtd/devices/m25p80.c @@ -0,0 +1,267 @@ +/* + * MTD SPI driver for ST M25Pxx (and similar) serial flash chips + * + * Author: Mike Lavender, mike@steroidmicros.com + * + * Copyright (c) 2005, Intec Automation Inc. + * + * Some parts are based on lart.c by Abraham Van Der Merwe + * + * Cleaned up and generalized based on mtd_dataflash.c + * + * This code is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/device.h> + +#include <linux/mtd/mtd.h> +#include <linux/mtd/partitions.h> + +#include <linux/spi/spi.h> +#include <linux/spi/flash.h> +#include <linux/mtd/spi-nor.h> + +#define MAX_CMD_SIZE 6 +struct m25p { + struct spi_device *spi; + struct spi_nor spi_nor; + struct mtd_info mtd; + u8 command[MAX_CMD_SIZE]; +}; + +static int m25p80_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len) +{ + struct m25p *flash = nor->priv; + struct spi_device *spi = flash->spi; + int ret; + + ret = spi_write_then_read(spi, &code, 1, val, len); + if (ret < 0) + dev_err(&spi->dev, "error %d reading %x\n", ret, code); + + return ret; +} + +static void m25p_addr2cmd(struct spi_nor *nor, unsigned int addr, u8 *cmd) +{ + /* opcode is in cmd[0] */ + cmd[1] = addr >> (nor->addr_width * 8 - 8); + cmd[2] = addr >> (nor->addr_width * 8 - 16); + cmd[3] = addr >> (nor->addr_width * 8 - 24); + cmd[4] = addr >> (nor->addr_width * 8 - 32); +} + +static int m25p_cmdsz(struct spi_nor *nor) +{ + return 1 + nor->addr_width; +} + +static int m25p80_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len, + int wr_en) +{ + struct m25p *flash = nor->priv; + struct spi_device *spi = flash->spi; + + flash->command[0] = opcode; + if (buf) + memcpy(&flash->command[1], buf, len); + + return spi_write(spi, flash->command, len + 1); +} + +static void m25p80_write(struct spi_nor *nor, loff_t to, size_t len, + size_t *retlen, const u_char *buf) +{ + struct m25p *flash = nor->priv; + struct spi_device *spi = flash->spi; + struct spi_transfer t[2] = {}; + struct spi_message m; + int cmd_sz = m25p_cmdsz(nor); + + spi_message_init(&m); + + if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second) + cmd_sz = 1; + + flash->command[0] = nor->program_opcode; + m25p_addr2cmd(nor, to, flash->command); + + t[0].tx_buf = flash->command; + t[0].len = cmd_sz; + spi_message_add_tail(&t[0], &m); + + t[1].tx_buf = buf; + t[1].len = len; + spi_message_add_tail(&t[1], &m); + + spi_sync(spi, &m); + + *retlen += m.actual_length - cmd_sz; +} + +static inline unsigned int m25p80_rx_nbits(struct spi_nor *nor) +{ + switch (nor->flash_read) { + case SPI_NOR_DUAL: + return 2; + case SPI_NOR_QUAD: + return 4; + default: + return 0; + } +} + +/* + * Read an address range from the nor chip. The address range + * may be any size provided it is within the physical boundaries. + */ +static int m25p80_read(struct spi_nor *nor, loff_t from, size_t len, + size_t *retlen, u_char *buf) +{ + struct m25p *flash = nor->priv; + struct spi_device *spi = flash->spi; + struct spi_transfer t[2]; + struct spi_message m; + int dummy = nor->read_dummy; + int ret; + + /* Wait till previous write/erase is done. */ + ret = nor->wait_till_ready(nor); + if (ret) + return ret; + + spi_message_init(&m); + memset(t, 0, (sizeof t)); + + flash->command[0] = nor->read_opcode; + m25p_addr2cmd(nor, from, flash->command); + + t[0].tx_buf = flash->command; + t[0].len = m25p_cmdsz(nor) + dummy; + spi_message_add_tail(&t[0], &m); + + t[1].rx_buf = buf; + t[1].rx_nbits = m25p80_rx_nbits(nor); + t[1].len = len; + spi_message_add_tail(&t[1], &m); + + spi_sync(spi, &m); + + *retlen = m.actual_length - m25p_cmdsz(nor) - dummy; + return 0; +} + +static int m25p80_erase(struct spi_nor *nor, loff_t offset) +{ + struct m25p *flash = nor->priv; + int ret; + + dev_dbg(nor->dev, "%dKiB at 0x%08x\n", + flash->mtd.erasesize / 1024, (u32)offset); + + /* Wait until finished previous write command. */ + ret = nor->wait_till_ready(nor); + if (ret) + return ret; + + /* Send write enable, then erase commands. */ + ret = nor->write_reg(nor, SPINOR_OP_WREN, NULL, 0, 0); + if (ret) + return ret; + + /* Set up command buffer. */ + flash->command[0] = nor->erase_opcode; + m25p_addr2cmd(nor, offset, flash->command); + + spi_write(flash->spi, flash->command, m25p_cmdsz(nor)); + + return 0; +} + +/* + * board specific setup should have ensured the SPI clock used here + * matches what the READ command supports, at least until this driver + * understands FAST_READ (for clocks over 25 MHz). + */ +static int m25p_probe(struct spi_device *spi) +{ + struct mtd_part_parser_data ppdata; + struct flash_platform_data *data; + struct m25p *flash; + struct spi_nor *nor; + enum read_mode mode = SPI_NOR_NORMAL; + int ret; + + flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL); + if (!flash) + return -ENOMEM; + + nor = &flash->spi_nor; + + /* install the hooks */ + nor->read = m25p80_read; + nor->write = m25p80_write; + nor->erase = m25p80_erase; + nor->write_reg = m25p80_write_reg; + nor->read_reg = m25p80_read_reg; + + nor->dev = &spi->dev; + nor->mtd = &flash->mtd; + nor->priv = flash; + + spi_set_drvdata(spi, flash); + flash->mtd.priv = nor; + flash->spi = spi; + + if (spi->mode & SPI_RX_QUAD) + mode = SPI_NOR_QUAD; + else if (spi->mode & SPI_RX_DUAL) + mode = SPI_NOR_DUAL; + ret = spi_nor_scan(nor, spi_get_device_id(spi), mode); + if (ret) + return ret; + + data = dev_get_platdata(&spi->dev); + ppdata.of_node = spi->dev.of_node; + + return mtd_device_parse_register(&flash->mtd, NULL, &ppdata, + data ? data->parts : NULL, + data ? data->nr_parts : 0); +} + + +static int m25p_remove(struct spi_device *spi) +{ + struct m25p *flash = spi_get_drvdata(spi); + + /* Clean up MTD stuff. */ + return mtd_device_unregister(&flash->mtd); +} + + +static struct spi_driver m25p80_driver = { + .driver = { + .name = "m25p80", + .owner = THIS_MODULE, + }, + .id_table = spi_nor_ids, + .probe = m25p_probe, + .remove = m25p_remove, + + /* REVISIT: many of these chips have deep power-down modes, which + * should clearly be entered on suspend() to minimize power use. + * And also when they're otherwise idle... + */ +}; + +module_spi_driver(m25p80_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Mike Lavender"); +MODULE_DESCRIPTION("MTD SPI driver for ST M25Pxx flash chips"); |