--- /dev/null
+/*
+ * Atmel DataFlash driver for Atmel AT91RM9200 (Thunder)
+ * This is a largely modified version of at91_dataflash.c that
+ * supports AT26xxx dataflash chips. The original driver supports
+ * AT45xxx chips.
+ *
+ * Note: This driver was only tested with an AT26F004. It should be
+ * easy to make it work with other AT26xxx dataflash devices, though.
+ *
+ * Copyright (C) 2007 Hans J. Koch <hjk@linutronix.de>
+ * original Copyright (C) SAN People (Pty) Ltd
+ *
+ * This program 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/config.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+
+#include <asm/arch/at91_spi.h>
+
+#define DATAFLASH_MAX_DEVICES 4 /* max number of dataflash devices */
+
+#define MANUFACTURER_ID_ATMEL 0x1F
+
+/* command codes */
+
+#define AT26_OP_READ_STATUS 0x05
+#define AT26_OP_READ_DEV_ID 0x9F
+#define AT26_OP_ERASE_PAGE_4K 0x20
+#define AT26_OP_READ_ARRAY_FAST 0x0B
+#define AT26_OP_SEQUENTIAL_WRITE 0xAF
+#define AT26_OP_WRITE_ENABLE 0x06
+#define AT26_OP_WRITE_DISABLE 0x04
+#define AT26_OP_SECTOR_PROTECT 0x36
+#define AT26_OP_SECTOR_UNPROTECT 0x39
+
+/* status register bits */
+
+#define AT26_STATUS_BUSY 0x01
+#define AT26_STATUS_WRITE_ENABLE 0x02
+
+struct dataflash_local
+{
+ int spi; /* SPI chip-select number */
+ unsigned int page_size; /* number of bytes per page */
+};
+
+
+/* Detected DataFlash devices */
+static struct mtd_info* mtd_devices[DATAFLASH_MAX_DEVICES];
+static int nr_devices = 0;
+
+/* Allocate a single SPI transfer descriptor. We're assuming that if multiple
+ SPI transfers occur at the same time, spi_access_bus() will serialize them.
+ If this is not valid, then either (i) each dataflash 'priv' structure
+ needs it's own transfer descriptor, (ii) we lock this one, or (iii) use
+ another mechanism. */
+static struct spi_transfer_list* spi_transfer_desc;
+
+/*
+ * Perform a SPI transfer to access the DataFlash device.
+ */
+static int do_spi_transfer(int nr, char* tx, int tx_len, char* rx, int rx_len,
+ char* txnext, int txnext_len, char* rxnext, int rxnext_len)
+{
+ struct spi_transfer_list* list = spi_transfer_desc;
+
+ list->tx[0] = tx; list->txlen[0] = tx_len;
+ list->rx[0] = rx; list->rxlen[0] = rx_len;
+
+ list->tx[1] = txnext; list->txlen[1] = txnext_len;
+ list->rx[1] = rxnext; list->rxlen[1] = rxnext_len;
+
+ list->nr_transfers = nr;
+ /* Note: spi_transfer() always returns 0, there are no error checks */
+ return spi_transfer(list);
+}
+
+/*
+ * Return the status of the DataFlash device.
+ */
+static unsigned char at91_dataflash26_status(void)
+{
+ unsigned char command[2];
+
+ command[0] = AT26_OP_READ_STATUS;
+ command[1] = 0;
+
+ do_spi_transfer(1, command, 2, command, 2, NULL, 0, NULL, 0);
+
+ return command[1];
+}
+
+/*
+ * Poll the DataFlash device until it is READY.
+ */
+static unsigned char at91_dataflash26_waitready(void)
+{
+ unsigned char status;
+
+ while (1) {
+ status = at91_dataflash26_status();
+ if (!(status & AT26_STATUS_BUSY))
+ return status;
+ }
+}
+
+/*
+ * Enable/disable write access
+ */
+ static void at91_dataflash26_write_enable(int enable)
+{
+ unsigned char cmd[2];
+
+ DEBUG(MTD_DEBUG_LEVEL3, "write_enable: enable=%i\n", enable);
+
+ if (enable)
+ cmd[0] = AT26_OP_WRITE_ENABLE;
+ else
+ cmd[0] = AT26_OP_WRITE_DISABLE;
+ cmd[1] = 0;
+
+ do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
+}
+
+/*
+ * Protect/unprotect sector
+ */
+ static void at91_dataflash26_sector_protect(loff_t addr, int protect)
+{
+ unsigned char cmd[4];
+
+ DEBUG(MTD_DEBUG_LEVEL3, "sector_protect: addr=0x%06x prot=%d\n",
+ addr, protect);
+
+ if (protect)
+ cmd[0] = AT26_OP_SECTOR_PROTECT;
+ else
+ cmd[0] = AT26_OP_SECTOR_UNPROTECT;
+ cmd[1] = (addr & 0x00FF0000) >> 16;
+ cmd[2] = (addr & 0x0000FF00) >> 8;
+ cmd[3] = (addr & 0x000000FF);
+
+ do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
+}
+
+/*
+ * Erase blocks of flash.
+ */
+static int at91_dataflash26_erase(struct mtd_info *mtd,
+ struct erase_info *instr)
+{
+ struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
+ unsigned char cmd[4];
+
+ DEBUG(MTD_DEBUG_LEVEL1, "dataflash_erase: addr=0x%06x len=%i\n",
+ instr->addr, instr->len);
+
+ /* Sanity checks */
+ if (priv->page_size != 4096)
+ return -EINVAL; /* Can't handle other sizes at the moment */
+
+ if ( ((instr->len % mtd->erasesize) != 0)
+ || ((instr->len % priv->page_size) != 0)
+ || ((instr->addr % priv->page_size) != 0)
+ || ((instr->addr + instr->len) > mtd->size))
+ return -EINVAL;
+
+ spi_access_bus(priv->spi);
+
+ while (instr->len > 0) {
+ at91_dataflash26_write_enable(1);
+ at91_dataflash26_sector_protect(instr->addr, 0);
+ at91_dataflash26_write_enable(1);
+ cmd[0] = AT26_OP_ERASE_PAGE_4K;
+ cmd[1] = (instr->addr & 0x00FF0000) >> 16;
+ cmd[2] = (instr->addr & 0x0000FF00) >> 8;
+ cmd[3] = (instr->addr & 0x000000FF);
+
+ DEBUG(MTD_DEBUG_LEVEL3, "ERASE: (0x%02x) 0x%02x 0x%02x"
+ "0x%02x\n",
+ cmd[0], cmd[1], cmd[2], cmd[3]);
+
+ do_spi_transfer(1, cmd, 4, cmd, 4, NULL, 0, NULL, 0);
+ at91_dataflash26_waitready();
+
+ instr->addr += priv->page_size; /* next page */
+ instr->len -= priv->page_size;
+ }
+
+ at91_dataflash26_write_enable(0);
+ spi_release_bus(priv->spi);
+
+ /* Inform MTD subsystem that erase is complete */
+ instr->state = MTD_ERASE_DONE;
+ if (instr->callback)
+ instr->callback(instr);
+
+ return 0;
+}
+
+/*
+ * Read from the DataFlash device.
+ * from : Start offset in flash device
+ * len : Number of bytes to read
+ * retlen : Number of bytes actually read
+ * buf : Buffer that will receive data
+ */
+static int at91_dataflash26_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
+ unsigned char cmd[5];
+
+ DEBUG(MTD_DEBUG_LEVEL1, "dataflash_read: %lli .. %lli\n",
+ from, from+len);
+
+ *retlen = 0;
+
+ /* Sanity checks */
+ if (!len)
+ return 0;
+ if (from + len > mtd->size)
+ return -EINVAL;
+
+ cmd[0] = AT26_OP_READ_ARRAY_FAST;
+ cmd[1] = (from & 0x00FF0000) >> 16;
+ cmd[2] = (from & 0x0000FF00) >> 8;
+ cmd[3] = (from & 0x000000FF);
+ /* cmd[4] is a "Don't care" byte */
+
+ DEBUG(MTD_DEBUG_LEVEL3, "READ: (0x%02x) 0x%02x 0x%02x 0x%02x\n",
+ cmd[0], cmd[1], cmd[2], cmd[3]);
+
+ spi_access_bus(priv->spi);
+ do_spi_transfer(2, cmd, 5, cmd, 5, buf, len, buf, len);
+ spi_release_bus(priv->spi);
+
+ *retlen = len;
+ return 0;
+}
+
+/*
+ * Write to the DataFlash device.
+ * to : Start offset in flash device
+ * len : Number of bytes to write
+ * retlen : Number of bytes actually written
+ * buf : Buffer containing the data
+ */
+static int at91_dataflash26_write(struct mtd_info *mtd, loff_t to, size_t len,
+ size_t *retlen, const u_char *buf)
+{
+ struct dataflash_local *priv = (struct dataflash_local *) mtd->priv;
+ unsigned int addr, buf_index = 0;
+ int ret = -EIO, sector, last_sector;
+ unsigned char status, cmd[5];
+
+ DEBUG(MTD_DEBUG_LEVEL1, "dataflash_write: %lli .. %lli\n", to, to+len);
+
+ *retlen = 0;
+
+ /* Sanity checks */
+ if (!len)
+ return 0;
+ if (to + len > mtd->size)
+ return -EINVAL;
+
+ spi_access_bus(priv->spi);
+
+ addr = to;
+ last_sector = -1;
+
+ while (buf_index < len) {
+ sector = addr / priv->page_size;
+ /* Write first byte if a new sector begins */
+ if (sector != last_sector) {
+ at91_dataflash26_write_enable(1);
+ at91_dataflash26_sector_protect(addr, 0);
+ at91_dataflash26_write_enable(1);
+
+ /* Program first byte of a new sector */
+ cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
+ cmd[1] = (addr & 0x00FF0000) >> 16;
+ cmd[2] = (addr & 0x0000FF00) >> 8;
+ cmd[3] = (addr & 0x000000FF);
+ cmd[4] = buf[buf_index++];
+ do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
+ status = at91_dataflash26_waitready();
+ addr++;
+ /* On write errors, the chip resets the write enable
+ flag. This also happens after the last byte of a
+ sector is successfully programmed. */
+ if ( ( !(status & AT26_STATUS_WRITE_ENABLE))
+ && ((addr % priv->page_size) != 0) ) {
+ DEBUG(MTD_DEBUG_LEVEL1,
+ "write error1: addr=0x%06x, "
+ "status=0x%02x\n", addr, status);
+ goto write_err;
+ }
+ (*retlen)++;
+ last_sector = sector;
+ }
+
+ /* Write subsequent bytes in the same sector */
+ cmd[0] = AT26_OP_SEQUENTIAL_WRITE;
+ cmd[1] = buf[buf_index++];
+ do_spi_transfer(1, cmd, 2, cmd, 2, NULL, 0, NULL, 0);
+ status = at91_dataflash26_waitready();
+ addr++;
+
+ if ( ( !(status & AT26_STATUS_WRITE_ENABLE))
+ && ((addr % priv->page_size) != 0) ) {
+ DEBUG(MTD_DEBUG_LEVEL1, "write error2: addr=0x%06x, "
+ "status=0x%02x\n", addr, status);
+ goto write_err;
+ }
+
+ (*retlen)++;
+ }
+
+ ret = 0;
+ at91_dataflash26_write_enable(0);
+write_err:
+ spi_release_bus(priv->spi);
+ return ret;
+}
+
+/*
+ * Initialize and register DataFlash device with MTD subsystem.
+ */
+static int __init add_dataflash(int channel, char *name, int nr_pages,
+ int pagesize)
+{
+ struct mtd_info *device;
+ struct dataflash_local *priv;
+
+ if (nr_devices >= DATAFLASH_MAX_DEVICES) {
+ printk(KERN_ERR "at91_dataflash26: Too many devices "
+ "detected\n");
+ return 0;
+ }
+
+ device = kzalloc(sizeof(struct mtd_info) + strlen(name) + 8,
+ GFP_KERNEL);
+ if (!device)
+ return -ENOMEM;
+
+ device->name = (char *)&device[1];
+ sprintf(device->name, "%s.spi%d", name, channel);
+ device->size = nr_pages * pagesize;
+ device->erasesize = pagesize;
+ device->owner = THIS_MODULE;
+ device->type = MTD_DATAFLASH;
+ device->flags = MTD_CAP_NORFLASH;
+ device->erase = at91_dataflash26_erase;
+ device->read = at91_dataflash26_read;
+ device->write = at91_dataflash26_write;
+
+ priv = (struct dataflash_local *)kzalloc(sizeof(struct dataflash_local),
+ GFP_KERNEL);
+ if (!priv) {
+ kfree(device);
+ return -ENOMEM;
+ }
+
+ priv->spi = channel;
+ priv->page_size = pagesize;
+ device->priv = priv;
+
+ mtd_devices[nr_devices] = device;
+ nr_devices++;
+ printk(KERN_INFO "at91_dataflash26: %s detected [spi%i] (%i bytes)\n",
+ name, channel, device->size);
+
+ return add_mtd_device(device);
+}
+
+/*
+ * Detect and initialize DataFlash device connected to specified SPI channel.
+ *
+ */
+
+struct dataflash26_types {
+ unsigned char id0;
+ unsigned char id1;
+ char *name;
+ int pagesize;
+ int nr_pages;
+};
+
+struct dataflash26_types df26_types[] = {
+ {
+ .id0 = 0x04,
+ .id1 = 0x00,
+ .name = "AT26F004",
+ .pagesize = 4096,
+ .nr_pages = 128,
+ },
+ {
+ .id0 = 0x45,
+ .id1 = 0x01,
+ .name = "AT26DF081A", /* Not tested ! */
+ .pagesize = 4096,
+ .nr_pages = 256,
+ },
+};
+
+static int __init at91_dataflash26_detect(int channel)
+{
+ unsigned char status, cmd[5];
+ int i;
+
+ spi_access_bus(channel);
+ status = at91_dataflash26_status();
+
+ if (status == 0 || status == 0xff) {
+ printk(KERN_ERR "at91_dataflash26_detect: status error %d\n",
+ status);
+ spi_release_bus(channel);
+ return -ENODEV;
+ }
+
+ cmd[0] = AT26_OP_READ_DEV_ID;
+ do_spi_transfer(1, cmd, 5, cmd, 5, NULL, 0, NULL, 0);
+ spi_release_bus(channel);
+
+ if (cmd[1] != MANUFACTURER_ID_ATMEL)
+ return -ENODEV;
+
+ for (i = 0; i < ARRAY_SIZE(df26_types); i++) {
+ if ( cmd[2] == df26_types[i].id0
+ && cmd[3] == df26_types[i].id1)
+ return add_dataflash(channel,
+ df26_types[i].name,
+ df26_types[i].nr_pages,
+ df26_types[i].pagesize);
+ }
+
+ printk(KERN_ERR "at91_dataflash26_detect: Unsupported device "
+ "(0x%02x/0x%02x)\n", cmd[2], cmd[3]);
+ return -ENODEV;
+}
+
+static int __init at91_dataflash26_init(void)
+{
+ spi_transfer_desc = kmalloc(sizeof(struct spi_transfer_list),
+ GFP_KERNEL);
+ if (!spi_transfer_desc)
+ return -ENOMEM;
+
+ /* DataFlash (SPI chip select 0) */
+ at91_dataflash26_detect(0);
+
+#ifdef CONFIG_MTD_AT91_DATAFLASH_CARD
+ /* DataFlash card (SPI chip select 3) */
+ at91_dataflash26_detect(3);
+#endif
+ return 0;
+}
+
+static void __exit at91_dataflash26_exit(void)
+{
+ int i;
+
+ for (i = 0; i < DATAFLASH_MAX_DEVICES; i++) {
+ if (mtd_devices[i]) {
+ del_mtd_device(mtd_devices[i]);
+ kfree(mtd_devices[i]->priv);
+ kfree(mtd_devices[i]);
+ }
+ }
+ nr_devices = 0;
+ kfree(spi_transfer_desc);
+}
+
+module_init(at91_dataflash26_init);
+module_exit(at91_dataflash26_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Hans J. Koch");
+MODULE_DESCRIPTION("DataFlash AT26xxx driver for Atmel AT91RM9200");
git.openpandora.org / pandora-kernel.git / commitdiff