nand: Add sandbox driver
Add a sandbox NAND flash driver to facilitate testing. This driver supports
any number of devices, each using a single chip-select. The OOB data is
stored in-band, with the separation enforced through the API.
For now, create two devices to test with. The first is a very small device
with basic ECC. The second is an 8G device (chosen to be larger than 32
bits). It uses ONFI, with the values copied from the datasheet. It also
doesn't need too strong ECC, which speeds things up.
Although the nand subsystem determines the parameters of a chip based on
the ID, the driver itself requires devicetree properties for each
parameter. We do not derive parameters from the ID because parsing the ID
is non-trivial. We do not just use the parameters that the nand subsystem
has calculated since that is something we should be testing. An exception
is made for the ECC layout, since that is difficult to encode in the device
tree and is not a property of the device itself.
Despite using file I/O to access the backing data, we do not support using
external files. In my experience, these are unnecessary for testing since
tests can generally be written to write their expected data beforehand.
Additionally, we would need to store the "programmed" information somewhere
(complicating the format and the programming process) or try to detect
whether block are erased at runtime (degrading probe speeds).
Information about whether each page has been programmed is stored in an
in-memory buffer. To simplify the implementation, we only support a single
program per erase. While this is accurate for many larger flashes, some
smaller flashes (512 byte) support multiple programs and/or subpage
programs. Support for this could be added later as I believe some
filesystems expect this.
To test ECC, we support error-injection. Surprisingly, only ECC bytes in
the OOB area are protected, even though all bytes are equally susceptible
to error. Because of this, we take care to only corrupt ECC bytes.
Similarly, because ECC covers "steps" and not the whole page, we must take
care to corrupt data in the same way.
Signed-off-by: Sean Anderson <seanga2@gmail.com>
diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index 6e9351f..4ab5459 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -447,6 +447,20 @@
This enables the driver for the NAND flash device found on
PXA3xx processors (NFCv1) and also on Armada 370/XP (NFCv2).
+config NAND_SANDBOX
+ bool "Support for NAND in sandbox"
+ depends on SANDBOX
+ select SYS_NAND_SELF_INIT
+ select SYS_NAND_SOFT_ECC
+ select BCH
+ select NAND_ECC_BCH
+ imply CMD_NAND
+ help
+ Enable a dummy NAND driver for sandbox. It simulates any number of
+ arbitrary NAND chips with a RAM buffer. It will also inject errors to
+ test ECC. At the moment, only 8-bit busses and single-chip devices are
+ supported.
+
config NAND_SUNXI
bool "Support for NAND on Allwinner SoCs"
default ARCH_SUNXI
diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
index add2b4c..ddbba89 100644
--- a/drivers/mtd/nand/raw/Makefile
+++ b/drivers/mtd/nand/raw/Makefile
@@ -70,6 +70,7 @@
obj-$(CONFIG_TEGRA_NAND) += tegra_nand.o
obj-$(CONFIG_NAND_OMAP_GPMC) += omap_gpmc.o
obj-$(CONFIG_NAND_OMAP_ELM) += omap_elm.o
+obj-$(CONFIG_NAND_SANDBOX) += sand_nand.o
obj-$(CONFIG_NAND_SUNXI) += sunxi_nand.o
obj-$(CONFIG_NAND_MXIC) += mxic_nand.o
obj-$(CONFIG_NAND_ZYNQ) += zynq_nand.o
diff --git a/drivers/mtd/nand/raw/sand_nand.c b/drivers/mtd/nand/raw/sand_nand.c
new file mode 100644
index 0000000..9b34146
--- /dev/null
+++ b/drivers/mtd/nand/raw/sand_nand.c
@@ -0,0 +1,678 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) Sean Anderson <seanga2@gmail.com>
+ */
+
+#define LOG_CATEGORY UCLASS_MTD
+#include <errno.h>
+#include <hexdump.h>
+#include <log.h>
+#include <nand.h>
+#include <os.h>
+#include <rand.h>
+#include <dm/device_compat.h>
+#include <dm/read.h>
+#include <dm/uclass.h>
+#include <asm/bitops.h>
+#include <linux/bitmap.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/sizes.h>
+
+enum sand_nand_state {
+ STATE_READY,
+ STATE_IDLE,
+ STATE_READ,
+ STATE_READ_ID,
+ STATE_READ_ONFI,
+ STATE_PARAM_ONFI,
+ STATE_STATUS,
+ STATE_PROG,
+ STATE_ERASE,
+};
+
+static const char *const state_name[] = {
+ [STATE_READY] = "READY",
+ [STATE_IDLE] = "IDLE",
+ [STATE_READ] = "READ",
+ [STATE_READ_ID] = "READ_ID",
+ [STATE_READ_ONFI] = "READ_ONFI",
+ [STATE_PARAM_ONFI] = "PARAM_ONFI",
+ [STATE_STATUS] = "STATUS",
+ [STATE_PROG] = "PROG",
+ [STATE_ERASE] = "ERASE",
+};
+
+/**
+ * struct sand_nand_chip - Per-device private data
+ * @nand: The nand chip
+ * @node: The next device in this controller
+ * @programmed: Bitmap of whether sectors are programmed
+ * @id: ID to report for NAND_CMD_READID
+ * @id_len: Length of @id
+ * @onfi: Three copies of ONFI parameter page
+ * @status: Status to report for NAND_CMD_STATUS
+ * @chunksize: Size of one "chunk" (page + oob) in bytes
+ * @pageize: Size of one page in bytes
+ * @pages: Total number of pages
+ * @pages_per_erase: Number of pages per eraseblock
+ * @err_count: Number of errors to inject per @err_step_bits of data
+ * @err_step_bits: Number of data bits per error "step"
+ * @err_steps: Number of err steps in a page
+ * @cs: Chip select for this device
+ * @state: Current state of the device
+ * @column: Column of the most-recent command
+ * @page_addr: Page address of the most-recent command
+ * @fd: File descriptor for the backing data
+ * @fd_page_addr: Page address that @fd is seek'd to
+ * @selected: Whether this device is selected
+ * @tmp: "Cache" buffer used to store transferred data before committing it
+ * @tmp_dirty: Whether @tmp is dirty (modified) or clean (all ones)
+ *
+ * Data is stored with the OOB area in-line. For example, with 512-byte pages
+ * and and 16-byte OOB areas, the first page would start at offset 0, the second
+ * at offset 528, the third at offset 1056, and so on
+ */
+struct sand_nand_chip {
+ struct nand_chip nand;
+ struct list_head node;
+ long *programmed;
+ const u8 *id;
+ u32 chunksize, pagesize, pages, pages_per_erase;
+ u32 err_count, err_step_bits, err_steps, ecc_bits;
+ unsigned int cs;
+ enum sand_nand_state state;
+ int column, page_addr, fd, fd_page_addr;
+ bool selected, tmp_dirty;
+ u8 status;
+ u8 id_len;
+ u8 tmp[NAND_MAX_PAGESIZE + NAND_MAX_OOBSIZE];
+ u8 onfi[sizeof(struct nand_onfi_params) * 3];
+};
+
+#define SAND_DEBUG(chip, fmt, ...) \
+ dev_dbg((chip)->nand.mtd.dev, "%u (%s): " fmt, (chip)->cs, \
+ state_name[(chip)->state], ##__VA_ARGS__)
+
+static inline void to_state(struct sand_nand_chip *chip,
+ enum sand_nand_state new_state)
+{
+ if (new_state != chip->state)
+ SAND_DEBUG(chip, "to state %s\n", state_name[new_state]);
+ chip->state = new_state;
+}
+
+static inline struct sand_nand_chip *to_sand_nand(struct nand_chip *nand)
+{
+ return container_of(nand, struct sand_nand_chip, nand);
+}
+
+struct sand_nand_priv {
+ struct list_head chips;
+};
+
+static int sand_nand_dev_ready(struct mtd_info *mtd)
+{
+ return 1;
+}
+
+static int sand_nand_wait(struct mtd_info *mtd, struct nand_chip *chip)
+{
+ u8 status;
+
+ return nand_status_op(chip, &status) ?: status;
+}
+
+static int sand_nand_seek(struct sand_nand_chip *chip)
+{
+ if (chip->fd_page_addr == chip->page_addr)
+ return 0;
+
+ if (os_lseek(chip->fd, (off_t)chip->page_addr * chip->chunksize,
+ OS_SEEK_SET) < 0) {
+ SAND_DEBUG(chip, "could not seek: %d\n", errno);
+ return -EIO;
+ }
+
+ chip->fd_page_addr = chip->page_addr;
+ return 0;
+}
+
+static void sand_nand_inject_error(struct sand_nand_chip *chip,
+ unsigned int step, unsigned int pos)
+{
+ int byte, index;
+
+ if (pos < chip->err_step_bits) {
+ __change_bit(step * chip->err_step_bits + pos, chip->tmp);
+ return;
+ }
+
+ /*
+ * Only ECC bytes are covered in the OOB area, so
+ * pretend that those are the only bytes which can have
+ * errors.
+ */
+ byte = (pos - chip->err_step_bits + step * chip->ecc_bits) / 8;
+ index = chip->nand.ecc.layout->eccpos[byte];
+ /* Avoid endianness issues by working with bytes */
+ chip->tmp[chip->pagesize + index] ^= BIT(pos & 0x7);
+}
+
+static int sand_nand_read(struct sand_nand_chip *chip)
+{
+ unsigned int i, stop = 0;
+
+ if (chip->column == chip->pagesize)
+ stop = chip->err_step_bits;
+
+ if (test_bit(chip->page_addr, chip->programmed)) {
+ if (sand_nand_seek(chip))
+ return -EIO;
+
+ if (os_read(chip->fd, chip->tmp, chip->chunksize) !=
+ chip->chunksize) {
+ SAND_DEBUG(chip, "could not read: %d\n", errno);
+ return -EIO;
+ }
+ chip->fd_page_addr++;
+ } else if (chip->tmp_dirty) {
+ memset(chip->tmp + chip->column, 0xff,
+ chip->chunksize - chip->column);
+ }
+
+ /*
+ * Inject some errors; this is Method A from "An Efficient Algorithm for
+ * Sequential Random Sampling" (Vitter 87). This is still slow when
+ * generating a lot (dozens) of ECC errors.
+ *
+ * To avoid generating too many errors in any one ECC step, we separate
+ * our error generation by ECC step.
+ */
+ chip->tmp_dirty = true;
+ for (i = 0; i < chip->err_steps; i++) {
+ u32 bit_errors = chip->err_count;
+ unsigned int j = chip->err_step_bits + chip->ecc_bits;
+
+ while (bit_errors) {
+ unsigned int u = rand();
+ float quot = 1ULL << 32;
+
+ do {
+ quot *= j - bit_errors;
+ quot /= j;
+ j--;
+
+ if (j < stop)
+ goto next;
+ } while (u < quot);
+
+ sand_nand_inject_error(chip, i, j);
+ bit_errors--;
+ }
+next:
+ ;
+ }
+
+ return 0;
+}
+
+static void sand_nand_command(struct mtd_info *mtd, unsigned int command,
+ int column, int page_addr)
+{
+ struct nand_chip *nand = mtd_to_nand(mtd);
+ struct sand_nand_chip *chip = to_sand_nand(nand);
+ enum sand_nand_state new_state = chip->state;
+
+ SAND_DEBUG(chip, "command=%02x column=%d page_addr=%d\n", command,
+ column, page_addr);
+
+ if (!chip->selected)
+ return;
+
+ switch (chip->state) {
+ case STATE_READY:
+ if (command == NAND_CMD_RESET)
+ goto reset;
+ break;
+ case STATE_PROG:
+ new_state = STATE_IDLE;
+ if (command != NAND_CMD_PAGEPROG ||
+ test_and_set_bit(chip->page_addr, chip->programmed)) {
+ chip->status |= NAND_STATUS_FAIL;
+ break;
+ }
+
+ if (sand_nand_seek(chip)) {
+ chip->status |= NAND_STATUS_FAIL;
+ break;
+ }
+
+ if (os_write(chip->fd, chip->tmp, chip->chunksize) !=
+ chip->chunksize) {
+ SAND_DEBUG(chip, "could not write: %d\n", errno);
+ chip->status |= NAND_STATUS_FAIL;
+ break;
+ }
+
+ chip->fd_page_addr++;
+ break;
+ case STATE_ERASE:
+ new_state = STATE_IDLE;
+ if (command != NAND_CMD_ERASE2) {
+ chip->status |= NAND_STATUS_FAIL;
+ break;
+ }
+
+ if (chip->page_addr < 0 ||
+ chip->page_addr >= chip->pages ||
+ chip->page_addr % chip->pages_per_erase)
+ chip->status |= NAND_STATUS_FAIL;
+ else
+ bitmap_clear(chip->programmed, chip->page_addr,
+ chip->pages_per_erase);
+ break;
+ default:
+ chip->column = column;
+ chip->page_addr = page_addr;
+ switch (command) {
+ case NAND_CMD_READOOB:
+ if (column >= 0)
+ chip->column += chip->pagesize;
+ fallthrough;
+ case NAND_CMD_READ0:
+ new_state = STATE_IDLE;
+ if (page_addr < 0 || page_addr >= chip->pages)
+ break;
+
+ if (chip->column < 0 || chip->column >= chip->chunksize)
+ break;
+
+ if (sand_nand_read(chip))
+ break;
+
+ chip->page_addr = page_addr;
+ new_state = STATE_READ;
+ break;
+ case NAND_CMD_ERASE1:
+ new_state = STATE_ERASE;
+ chip->status = ~NAND_STATUS_FAIL;
+ break;
+ case NAND_CMD_STATUS:
+ new_state = STATE_STATUS;
+ chip->column = 0;
+ break;
+ case NAND_CMD_SEQIN:
+ new_state = STATE_PROG;
+ chip->status = ~NAND_STATUS_FAIL;
+ if (page_addr < 0 || page_addr >= chip->pages ||
+ chip->column < 0 ||
+ chip->column >= chip->chunksize) {
+ chip->status |= NAND_STATUS_FAIL;
+ } else if (chip->tmp_dirty) {
+ memset(chip->tmp, 0xff, chip->chunksize);
+ chip->tmp_dirty = false;
+ }
+ break;
+ case NAND_CMD_READID:
+ if (chip->onfi[0] && column == 0x20)
+ new_state = STATE_READ_ONFI;
+ else
+ new_state = STATE_READ_ID;
+ chip->column = 0;
+ break;
+ case NAND_CMD_PARAM:
+ if (chip->onfi[0] && !column)
+ new_state = STATE_PARAM_ONFI;
+ else
+ new_state = STATE_IDLE;
+ break;
+ case NAND_CMD_RESET:
+reset:
+ new_state = STATE_IDLE;
+ chip->column = -1;
+ chip->page_addr = -1;
+ chip->status = ~NAND_STATUS_FAIL;
+ break;
+ default:
+ new_state = STATE_IDLE;
+ SAND_DEBUG(chip, "Unsupported command %02x\n", command);
+ }
+ }
+
+ to_state(chip, new_state);
+}
+
+static void sand_nand_select_chip(struct mtd_info *mtd, int n)
+{
+ struct nand_chip *nand = mtd_to_nand(mtd);
+ struct sand_nand_chip *chip = to_sand_nand(nand);
+
+ chip->selected = !n;
+}
+
+static void sand_nand_read_buf(struct mtd_info *mtd, u8 *buf, int len)
+{
+ struct nand_chip *nand = mtd_to_nand(mtd);
+ struct sand_nand_chip *chip = to_sand_nand(nand);
+ unsigned int to_copy;
+ int src_len = 0;
+ const u8 *src = NULL;
+
+ if (!chip->selected)
+ goto copy;
+
+ switch (chip->state) {
+ case STATE_READ:
+ src = chip->tmp;
+ src_len = chip->chunksize;
+ break;
+ case STATE_READ_ID:
+ src = chip->id;
+ src_len = chip->id_len;
+ break;
+ case STATE_READ_ONFI:
+ src = "ONFI";
+ src_len = 4;
+ break;
+ case STATE_PARAM_ONFI:
+ src = chip->onfi;
+ src_len = sizeof(chip->onfi);
+ break;
+ case STATE_STATUS:
+ src = &chip->status;
+ src_len = 1;
+ break;
+ default:
+ break;
+ }
+
+copy:
+ if (chip->column >= 0)
+ to_copy = max(min(len, src_len - chip->column), 0);
+ else
+ to_copy = 0;
+ memcpy(buf, src + chip->column, to_copy);
+ memset(buf + to_copy, 0xff, len - to_copy);
+ chip->column += to_copy;
+
+ if (len == 1) {
+ SAND_DEBUG(chip, "read [ %02x ]\n", buf[0]);
+ } else if (src_len) {
+ SAND_DEBUG(chip, "read %d bytes\n", len);
+#ifdef VERBOSE_DEBUG
+ print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, len);
+#endif
+ }
+
+ if (src_len && chip->column == src_len)
+ to_state(chip, STATE_IDLE);
+}
+
+static u8 sand_nand_read_byte(struct mtd_info *mtd)
+{
+ u8 ret;
+
+ sand_nand_read_buf(mtd, &ret, 1);
+ return ret;
+}
+
+static u16 sand_nand_read_word(struct mtd_info *mtd)
+{
+ struct nand_chip *nand = mtd_to_nand(mtd);
+ struct sand_nand_chip *chip = to_sand_nand(nand);
+
+ SAND_DEBUG(chip, "16-bit access unsupported\n");
+ return sand_nand_read_byte(mtd) | 0xff00;
+}
+
+static void sand_nand_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
+{
+ struct nand_chip *nand = mtd_to_nand(mtd);
+ struct sand_nand_chip *chip = to_sand_nand(nand);
+
+ SAND_DEBUG(chip, "write %d bytes\n", len);
+#ifdef VERBOSE_DEBUG
+ print_hex_dump_bytes("", DUMP_PREFIX_OFFSET, buf, len);
+#endif
+
+ if (chip->state != STATE_PROG || chip->status & NAND_STATUS_FAIL)
+ return;
+
+ chip->tmp_dirty = true;
+ len = min((unsigned int)len, chip->chunksize - chip->column);
+ memcpy(chip->tmp + chip->column, buf, len);
+ chip->column += len;
+}
+
+static struct nand_chip *nand_chip;
+
+int sand_nand_remove(struct udevice *dev)
+{
+ struct sand_nand_priv *priv = dev_get_priv(dev);
+ struct sand_nand_chip *chip;
+
+ list_for_each_entry(chip, &priv->chips, node) {
+ struct nand_chip *nand = &chip->nand;
+
+ if (nand_chip == nand)
+ nand_chip = NULL;
+
+ nand_unregister(nand_to_mtd(nand));
+ free(chip->programmed);
+ os_close(chip->fd);
+ free(chip);
+ }
+
+ return 0;
+}
+
+static int sand_nand_probe(struct udevice *dev)
+{
+ struct sand_nand_priv *priv = dev_get_priv(dev);
+ struct sand_nand_chip *chip;
+ int ret, devnum = 0;
+ ofnode np;
+
+ INIT_LIST_HEAD(&priv->chips);
+
+ dev_for_each_subnode(np, dev) {
+ struct nand_chip *nand;
+ struct mtd_info *mtd;
+ u32 erasesize, oobsize, pagesize, pages;
+ u32 err_count, err_step_size;
+ off_t expected_size;
+ char filename[30];
+ fdt_addr_t cs;
+ const u8 *id, *onfi;
+ int id_len, onfi_len;
+
+ cs = ofnode_get_addr_size_index_notrans(np, 0, NULL);
+ if (cs == FDT_ADDR_T_NONE) {
+ dev_dbg(dev, "Invalid cs for chip %s\n",
+ ofnode_get_name(np));
+ ret = -ENOENT;
+ goto err;
+ }
+
+ id = ofnode_read_prop(np, "sandbox,id", &id_len);
+ if (!id) {
+ dev_dbg(dev, "No sandbox,id property for chip %s\n",
+ ofnode_get_name(np));
+ ret = -EINVAL;
+ goto err;
+ }
+
+ onfi = ofnode_read_prop(np, "sandbox,onfi", &onfi_len);
+ if (onfi && onfi_len != sizeof(struct nand_onfi_params)) {
+ dev_dbg(dev, "Invalid length %d for onfi params\n",
+ onfi_len);
+ ret = -EINVAL;
+ goto err;
+ }
+
+ ret = ofnode_read_u32(np, "sandbox,erasesize", &erasesize);
+ if (ret) {
+ dev_dbg(dev, "No sandbox,erasesize property for chip %s",
+ ofnode_get_name(np));
+ goto err;
+ }
+
+ ret = ofnode_read_u32(np, "sandbox,oobsize", &oobsize);
+ if (ret) {
+ dev_dbg(dev, "No sandbox,oobsize property for chip %s",
+ ofnode_get_name(np));
+ goto err;
+ }
+
+ ret = ofnode_read_u32(np, "sandbox,pagesize", &pagesize);
+ if (ret) {
+ dev_dbg(dev, "No sandbox,pagesize property for chip %s",
+ ofnode_get_name(np));
+ goto err;
+ }
+
+ ret = ofnode_read_u32(np, "sandbox,pages", &pages);
+ if (ret) {
+ dev_dbg(dev, "No sandbox,pages property for chip %s",
+ ofnode_get_name(np));
+ goto err;
+ }
+
+ ret = ofnode_read_u32(np, "sandbox,err-count", &err_count);
+ if (ret) {
+ dev_dbg(dev,
+ "No sandbox,err-count property for chip %s",
+ ofnode_get_name(np));
+ goto err;
+ }
+
+ ret = ofnode_read_u32(np, "sandbox,err-step-size",
+ &err_step_size);
+ if (ret) {
+ dev_dbg(dev,
+ "No sandbox,err-step-size property for chip %s",
+ ofnode_get_name(np));
+ goto err;
+ }
+
+ chip = calloc(sizeof(*chip), 1);
+ if (!chip) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ chip->cs = cs;
+ chip->id = id;
+ chip->id_len = id_len;
+ chip->chunksize = pagesize + oobsize;
+ chip->pagesize = pagesize;
+ chip->pages = pages;
+ chip->pages_per_erase = erasesize / pagesize;
+ memset(chip->tmp, 0xff, chip->chunksize);
+
+ chip->err_count = err_count;
+ chip->err_step_bits = err_step_size * 8;
+ chip->err_steps = pagesize / err_step_size;
+
+ expected_size = (off_t)pages * chip->chunksize;
+ snprintf(filename, sizeof(filename),
+ "/tmp/u-boot.nand%d.XXXXXX", devnum);
+ chip->fd = os_mktemp(filename, expected_size);
+ if (chip->fd < 0) {
+ dev_dbg(dev, "Could not create temp file %s\n",
+ filename);
+ ret = chip->fd;
+ goto err_chip;
+ }
+
+ chip->programmed = calloc(sizeof(long),
+ BITS_TO_LONGS(pages));
+ if (!chip->programmed) {
+ ret = -ENOMEM;
+ goto err_fd;
+ }
+
+ if (onfi) {
+ memcpy(chip->onfi, onfi, onfi_len);
+ memcpy(chip->onfi + onfi_len, onfi, onfi_len);
+ memcpy(chip->onfi + 2 * onfi_len, onfi, onfi_len);
+ }
+
+ nand = &chip->nand;
+ nand->flash_node = np;
+ nand->dev_ready = sand_nand_dev_ready;
+ nand->cmdfunc = sand_nand_command;
+ nand->waitfunc = sand_nand_wait;
+ nand->select_chip = sand_nand_select_chip;
+ nand->read_byte = sand_nand_read_byte;
+ nand->read_word = sand_nand_read_word;
+ nand->read_buf = sand_nand_read_buf;
+ nand->write_buf = sand_nand_write_buf;
+ nand->ecc.options = NAND_ECC_GENERIC_ERASED_CHECK;
+
+ mtd = nand_to_mtd(nand);
+ mtd->dev = dev;
+
+ ret = nand_scan(mtd, CONFIG_SYS_NAND_MAX_CHIPS);
+ if (ret) {
+ dev_dbg(dev, "Could not scan chip %s: %d\n",
+ ofnode_get_name(np), ret);
+ goto err_prog;
+ }
+ chip->ecc_bits = nand->ecc.layout->eccbytes * 8 /
+ chip->err_steps;
+
+ ret = nand_register(devnum, mtd);
+ if (ret) {
+ dev_dbg(dev, "Could not register nand %d: %d\n", devnum,
+ ret);
+ goto err_prog;
+ }
+
+ if (!nand_chip)
+ nand_chip = nand;
+
+ list_add_tail(&chip->node, &priv->chips);
+ devnum++;
+ continue;
+
+err_prog:
+ free(chip->programmed);
+err_fd:
+ os_close(chip->fd);
+err_chip:
+ free(chip);
+ goto err;
+ }
+
+ return 0;
+
+err:
+ sand_nand_remove(dev);
+ return ret;
+}
+
+static const struct udevice_id sand_nand_ids[] = {
+ { .compatible = "sandbox,nand" },
+ { }
+};
+
+U_BOOT_DRIVER(sand_nand) = {
+ .name = "sand-nand",
+ .id = UCLASS_MTD,
+ .of_match = sand_nand_ids,
+ .probe = sand_nand_probe,
+ .remove = sand_nand_remove,
+ .priv_auto = sizeof(struct sand_nand_priv),
+};
+
+void board_nand_init(void)
+{
+ struct udevice *dev;
+ int err;
+
+ err = uclass_get_device_by_driver(UCLASS_MTD, DM_DRIVER_REF(sand_nand),
+ &dev);
+ if (err && err != -ENODEV)
+ log_info("Failed to get sandbox NAND: %d\n", err);
+}