[MTD] dataflash OTP support
Now that we can tell when we have one of the newer DataFlash chips,
optionally expose the 128 bytes of OTP memory they provide. Tested
on at45db642 revision B and D chips.
Switch mtdchar over to a generic HAVE_MTD_OTP flag instead of adding
another #ifdef for each type of chip whose driver has OTP support.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Bryan Wu <cooloney@kernel.org>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 14f11f8..a90d50c 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -172,6 +172,11 @@
memory chips, and also use ioctl() to obtain information about
the device, or to erase parts of it.
+config HAVE_MTD_OTP
+ bool
+ help
+ Enable access to OTP regions using MTD_CHAR.
+
config MTD_BLKDEVS
tristate "Common interface to block layer for MTD 'translation layers'"
depends on BLOCK
diff --git a/drivers/mtd/chips/Kconfig b/drivers/mtd/chips/Kconfig
index 479d32b..4c35e5d 100644
--- a/drivers/mtd/chips/Kconfig
+++ b/drivers/mtd/chips/Kconfig
@@ -154,6 +154,7 @@
config MTD_OTP
bool "Protection Registers aka one-time programmable (OTP) bits"
depends on MTD_CFI_ADV_OPTIONS
+ select HAVE_MTD_OTP
default n
help
This enables support for reading, writing and locking so called
diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 9c613f0..88f4df0 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -59,6 +59,17 @@
Sometimes DataFlash chips are packaged inside MMC-format
cards; at this writing, the MMC stack won't handle those.
+config MTD_DATAFLASH_OTP
+ bool "DataFlash OTP support (Security Register)"
+ depends on MTD_DATAFLASH
+ select HAVE_MTD_OTP
+ help
+ Newer DataFlash chips (revisions C and D) support 128 bytes of
+ one-time-programmable (OTP) data. The first half may be written
+ (once) with up to 64 bytes of data, such as a serial number or
+ other key product data. The second half is programmed with a
+ unique-to-each-chip bit pattern at the factory.
+
config MTD_M25P80
tristate "Support most SPI Flash chips (AT26DF, M25P, W25X, ...)"
depends on SPI_MASTER && EXPERIMENTAL
diff --git a/drivers/mtd/devices/mtd_dataflash.c b/drivers/mtd/devices/mtd_dataflash.c
index 8bd0dea..17c9b20 100644
--- a/drivers/mtd/devices/mtd_dataflash.c
+++ b/drivers/mtd/devices/mtd_dataflash.c
@@ -80,7 +80,8 @@
*/
#define OP_READ_ID 0x9F
#define OP_READ_SECURITY 0x77
-#define OP_WRITE_SECURITY 0x9A /* OTP bits */
+#define OP_WRITE_SECURITY_REVC 0x9A
+#define OP_WRITE_SECURITY 0x9B /* revision D */
struct dataflash {
@@ -451,16 +452,192 @@
/* ......................................................................... */
+#ifdef CONFIG_MTD_DATAFLASH_OTP
+
+static int dataflash_get_otp_info(struct mtd_info *mtd,
+ struct otp_info *info, size_t len)
+{
+ /* Report both blocks as identical: bytes 0..64, locked.
+ * Unless the user block changed from all-ones, we can't
+ * tell whether it's still writable; so we assume it isn't.
+ */
+ info->start = 0;
+ info->length = 64;
+ info->locked = 1;
+ return sizeof(*info);
+}
+
+static ssize_t otp_read(struct spi_device *spi, unsigned base,
+ uint8_t *buf, loff_t off, size_t len)
+{
+ struct spi_message m;
+ size_t l;
+ uint8_t *scratch;
+ struct spi_transfer t;
+ int status;
+
+ if (off > 64)
+ return -EINVAL;
+
+ if ((off + len) > 64)
+ len = 64 - off;
+ if (len == 0)
+ return len;
+
+ spi_message_init(&m);
+
+ l = 4 + base + off + len;
+ scratch = kzalloc(l, GFP_KERNEL);
+ if (!scratch)
+ return -ENOMEM;
+
+ /* OUT: OP_READ_SECURITY, 3 don't-care bytes, zeroes
+ * IN: ignore 4 bytes, data bytes 0..N (max 127)
+ */
+ scratch[0] = OP_READ_SECURITY;
+
+ memset(&t, 0, sizeof t);
+ t.tx_buf = scratch;
+ t.rx_buf = scratch;
+ t.len = l;
+ spi_message_add_tail(&t, &m);
+
+ dataflash_waitready(spi);
+
+ status = spi_sync(spi, &m);
+ if (status >= 0) {
+ memcpy(buf, scratch + 4 + base + off, len);
+ status = len;
+ }
+
+ kfree(scratch);
+ return status;
+}
+
+static int dataflash_read_fact_otp(struct mtd_info *mtd,
+ loff_t from, size_t len, size_t *retlen, u_char *buf)
+{
+ struct dataflash *priv = (struct dataflash *)mtd->priv;
+ int status;
+
+ /* 64 bytes, from 0..63 ... start at 64 on-chip */
+ mutex_lock(&priv->lock);
+ status = otp_read(priv->spi, 64, buf, from, len);
+ mutex_unlock(&priv->lock);
+
+ if (status < 0)
+ return status;
+ *retlen = status;
+ return 0;
+}
+
+static int dataflash_read_user_otp(struct mtd_info *mtd,
+ loff_t from, size_t len, size_t *retlen, u_char *buf)
+{
+ struct dataflash *priv = (struct dataflash *)mtd->priv;
+ int status;
+
+ /* 64 bytes, from 0..63 ... start at 0 on-chip */
+ mutex_lock(&priv->lock);
+ status = otp_read(priv->spi, 0, buf, from, len);
+ mutex_unlock(&priv->lock);
+
+ if (status < 0)
+ return status;
+ *retlen = status;
+ return 0;
+}
+
+static int dataflash_write_user_otp(struct mtd_info *mtd,
+ loff_t from, size_t len, size_t *retlen, u_char *buf)
+{
+ struct spi_message m;
+ const size_t l = 4 + 64;
+ uint8_t *scratch;
+ struct spi_transfer t;
+ struct dataflash *priv = (struct dataflash *)mtd->priv;
+ int status;
+
+ if (len > 64)
+ return -EINVAL;
+
+ /* Strictly speaking, we *could* truncate the write ... but
+ * let's not do that for the only write that's ever possible.
+ */
+ if ((from + len) > 64)
+ return -EINVAL;
+
+ /* OUT: OP_WRITE_SECURITY, 3 zeroes, 64 data-or-zero bytes
+ * IN: ignore all
+ */
+ scratch = kzalloc(l, GFP_KERNEL);
+ if (!scratch)
+ return -ENOMEM;
+ scratch[0] = OP_WRITE_SECURITY;
+ memcpy(scratch + 4 + from, buf, len);
+
+ spi_message_init(&m);
+
+ memset(&t, 0, sizeof t);
+ t.tx_buf = scratch;
+ t.len = l;
+ spi_message_add_tail(&t, &m);
+
+ /* Write the OTP bits, if they've not yet been written.
+ * This modifies SRAM buffer1.
+ */
+ mutex_lock(&priv->lock);
+ dataflash_waitready(priv->spi);
+ status = spi_sync(priv->spi, &m);
+ mutex_unlock(&priv->lock);
+
+ kfree(scratch);
+
+ if (status >= 0) {
+ status = 0;
+ *retlen = len;
+ }
+ return status;
+}
+
+static char *otp_setup(struct mtd_info *device, char revision)
+{
+ device->get_fact_prot_info = dataflash_get_otp_info;
+ device->read_fact_prot_reg = dataflash_read_fact_otp;
+ device->get_user_prot_info = dataflash_get_otp_info;
+ device->read_user_prot_reg = dataflash_read_user_otp;
+
+ /* rev c parts (at45db321c and at45db1281 only!) use a
+ * different write procedure; not (yet?) implemented.
+ */
+ if (revision > 'c')
+ device->write_user_prot_reg = dataflash_write_user_otp;
+
+ return ", OTP";
+}
+
+#else
+
+static char *otp_setup(struct mtd_info *device)
+{
+ return " (OTP)";
+}
+
+#endif
+
+/* ......................................................................... */
+
/*
* Register DataFlash device with MTD subsystem.
*/
static int __devinit
-add_dataflash(struct spi_device *spi, char *name,
- int nr_pages, int pagesize, int pageoffset)
+add_dataflash_otp(struct spi_device *spi, char *name,
+ int nr_pages, int pagesize, int pageoffset, char revision)
{
struct dataflash *priv;
struct mtd_info *device;
struct flash_platform_data *pdata = spi->dev.platform_data;
+ char *otp_tag = "";
priv = kzalloc(sizeof *priv, GFP_KERNEL);
if (!priv)
@@ -489,8 +666,12 @@
device->write = dataflash_write;
device->priv = priv;
- dev_info(&spi->dev, "%s (%d KBytes) pagesize %d bytes\n",
- name, DIV_ROUND_UP(device->size, 1024), pagesize);
+ if (revision >= 'c')
+ otp_tag = otp_setup(device, revision);
+
+ dev_info(&spi->dev, "%s (%d KBytes) pagesize %d bytes%s\n",
+ name, DIV_ROUND_UP(device->size, 1024),
+ pagesize, otp_tag);
dev_set_drvdata(&spi->dev, priv);
if (mtd_has_partitions()) {
@@ -519,6 +700,14 @@
return add_mtd_device(device) == 1 ? -ENODEV : 0;
}
+static inline int __devinit
+add_dataflash(struct spi_device *spi, char *name,
+ int nr_pages, int pagesize, int pageoffset)
+{
+ return add_dataflash_otp(spi, name, nr_pages, pagesize,
+ pageoffset, 0);
+}
+
struct flash_info {
char *name;
@@ -664,13 +853,16 @@
* Try to detect dataflash by JEDEC ID.
* If it succeeds we know we have either a C or D part.
* D will support power of 2 pagesize option.
+ * Both support the security register, though with different
+ * write procedures.
*/
info = jedec_probe(spi);
if (IS_ERR(info))
return PTR_ERR(info);
if (info != NULL)
- return add_dataflash(spi, info->name, info->nr_pages,
- info->pagesize, info->pageoffset);
+ return add_dataflash_otp(spi, info->name, info->nr_pages,
+ info->pagesize, info->pageoffset,
+ (info->flags & SUP_POW2PS) ? 'd' : 'c');
/*
* Older chips support only legacy commands, identifing
diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index d2f3318..13cc67a 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -350,7 +350,7 @@
wake_up((wait_queue_head_t *)instr->priv);
}
-#if defined(CONFIG_MTD_OTP) || defined(CONFIG_MTD_ONENAND_OTP)
+#ifdef CONFIG_HAVE_MTD_OTP
static int otp_select_filemode(struct mtd_file_info *mfi, int mode)
{
struct mtd_info *mtd = mfi->mtd;
@@ -663,7 +663,7 @@
break;
}
-#if defined(CONFIG_MTD_OTP) || defined(CONFIG_MTD_ONENAND_OTP)
+#ifdef CONFIG_HAVE_MTD_OTP
case OTPSELECT:
{
int mode;
diff --git a/drivers/mtd/onenand/Kconfig b/drivers/mtd/onenand/Kconfig
index cb41cbc..b94a61b 100644
--- a/drivers/mtd/onenand/Kconfig
+++ b/drivers/mtd/onenand/Kconfig
@@ -29,6 +29,7 @@
config MTD_ONENAND_OTP
bool "OneNAND OTP Support"
+ select HAVE_MTD_OTP
help
One Block of the NAND Flash Array memory is reserved as
a One-Time Programmable Block memory area.