[RFC PATCHv4 4/4] drivers/otp: convert bfin otp to generic OTP

From: Jamie Iles
Date: Tue Mar 29 2011 - 08:08:30 EST

Convert the blackfin OTP driver to the generic OTP layer.

Changes since v3:
- Use the lock_word device operation to allow OTP are locking
through the OTP_LOCK_AREA ioctl().
- Convert read_word/write_word to device operations.

Changes since v2:
- Convert bfin-otp to a platform_driver.
- Hide the ECC and control bits from the character device
interface.

Cc: Mike Frysinger <vapier@xxxxxxxxx>
Signed-off-by: Jamie Iles <jamie@xxxxxxxxxxxxx>
---
drivers/char/Kconfig | 28 ----
drivers/char/Makefile | 1 -
drivers/otp/Kconfig | 16 +++
drivers/otp/Makefile | 1 +
drivers/{char => otp}/bfin-otp.c | 261 ++++++++++++++++++--------------------
5 files changed, 138 insertions(+), 169 deletions(-)
rename drivers/{char => otp}/bfin-otp.c (44%)

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index ad59b4e..a078362 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -81,34 +81,6 @@ config BRIQ_PANEL

It's safe to say N here.

-config BFIN_OTP
- tristate "Blackfin On-Chip OTP Memory Support"
- depends on BLACKFIN && (BF51x || BF52x || BF54x)
- default y
- help
- If you say Y here, you will get support for a character device
- interface into the One Time Programmable memory pages that are
- stored on the Blackfin processor. This will not get you access
- to the secure memory pages however. You will need to write your
- own secure code and reader for that.
-
- To compile this driver as a module, choose M here: the module
- will be called bfin-otp.
-
- If unsure, it is safe to say Y.
-
-config BFIN_OTP_WRITE_ENABLE
- bool "Enable writing support of OTP pages"
- depends on BFIN_OTP
- default n
- help
- If you say Y here, you will enable support for writing of the
- OTP pages. This is dangerous by nature as you can only program
- the pages once, so only enable this option when you actually
- need it so as to not inadvertently clobber data.
-
- If unsure, say N.
-
config PRINTER
tristate "Parallel printer support"
depends on PARPORT
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 7a00672..bc436a6 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -17,7 +17,6 @@ obj-$(CONFIG_VIOTAPE) += viotape.o
obj-$(CONFIG_IBM_BSR) += bsr.o
obj-$(CONFIG_SGI_MBCS) += mbcs.o
obj-$(CONFIG_BRIQ_PANEL) += briq_panel.o
-obj-$(CONFIG_BFIN_OTP) += bfin-otp.o

obj-$(CONFIG_PRINTER) += lp.o

diff --git a/drivers/otp/Kconfig b/drivers/otp/Kconfig
index edac4d5..feee010 100644
--- a/drivers/otp/Kconfig
+++ b/drivers/otp/Kconfig
@@ -32,4 +32,20 @@ config OTP_PC3X3
Say Y or M here to allow support for the OTP found in PC3X3 devices.
If you say M then the module will be called otp_pc3x3.

+config BFIN_OTP
+ tristate "Blackfin On-Chip OTP Memory Support"
+ depends on BLACKFIN && (BF51x || BF52x || BF54x)
+ default y
+ help
+ If you say Y here, you will get support for a character device
+ interface into the One Time Programmable memory pages that are
+ stored on the Blackfin processor. This will not get you access
+ to the secure memory pages however. You will need to write your
+ own secure code and reader for that.
+
+ To compile this driver as a module, choose M here: the module
+ will be called bfin-otp.
+
+ If unsure, it is safe to say Y.
+
endif
diff --git a/drivers/otp/Makefile b/drivers/otp/Makefile
index c710ec4..db79667 100644
--- a/drivers/otp/Makefile
+++ b/drivers/otp/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_OTP) += otp.o
obj-$(CONFIG_OTP_PC3X3) += otp_pc3x3.o
+obj-$(CONFIG_BFIN_OTP) += bfin-otp.o
diff --git a/drivers/char/bfin-otp.c b/drivers/otp/bfin-otp.c
similarity index 44%
rename from drivers/char/bfin-otp.c
rename to drivers/otp/bfin-otp.c
index 44660f1..ecff490 100644
--- a/drivers/char/bfin-otp.c
+++ b/drivers/otp/bfin-otp.c
@@ -9,12 +9,14 @@
*/

#include <linux/device.h>
+#include <linux/err.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
-#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/otp.h>
#include <linux/types.h>
#include <mtd/mtd-abi.h>

@@ -28,58 +30,41 @@

#define DRIVER_NAME "bfin-otp"
#define PFX DRIVER_NAME ": "
+#define BFIN_OTP_SIZE (8 * 1024)
+#define BFIN_PAGE_SIZE 16
+#define BFIN_OTP_WORDS_PER_PAGE 2

-static DEFINE_MUTEX(bfin_otp_lock);
+static struct otp_device *bfin_otp;

/**
* bfin_otp_read - Read OTP pages
*
* All reads must be in half page chunks (half page == 64 bits).
*/
-static ssize_t bfin_otp_read(struct file *file, char __user *buff, size_t count, loff_t *pos)
+static int bfin_read_word(struct otp_device *otp_dev,
+ struct otp_region *region, unsigned long addr,
+ u64 *word)
{
- ssize_t bytes_done;
+ int err;
u32 page, flags, ret;
- u64 content;

stampit();
-
- if (count % sizeof(u64))
- return -EMSGSIZE;
-
- if (mutex_lock_interruptible(&bfin_otp_lock))
- return -ERESTARTSYS;
-
- bytes_done = 0;
- page = *pos / (sizeof(u64) * 2);
- while (bytes_done < count) {
- flags = (*pos % (sizeof(u64) * 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF);
- stamp("processing page %i (0x%x:%s)", page, flags,
- (flags & OTP_UPPER_HALF ? "upper" : "lower"));
- ret = bfrom_OtpRead(page, flags, &content);
- if (ret & OTP_MASTER_ERROR) {
- stamp("error from otp: 0x%x", ret);
- bytes_done = -EIO;
- break;
- }
- if (copy_to_user(buff + bytes_done, &content, sizeof(content))) {
- bytes_done = -EFAULT;
- break;
- }
- if (flags & OTP_UPPER_HALF)
- ++page;
- bytes_done += sizeof(content);
- *pos += sizeof(content);
- }
-
- mutex_unlock(&bfin_otp_lock);
-
- return bytes_done;
+ page = addr / 2;
+ flags = (addr & 0x1) ? OTP_UPPER_HALF : OTP_LOWER_HALF;
+ stamp("processing page %i (0x%x:%s)", page, flags,
+ (flags & OTP_UPPER_HALF ? "upper" : "lower"));
+
+ err = bfrom_OtpRead(page, flags, word);
+ if (err & OTP_MASTER_ERROR) {
+ stamp("error from otp: 0x%x", ret);
+ err = -EIO;
+ } else
+ err = 0;
+
+ return err;
}

-#ifdef CONFIG_BFIN_OTP_WRITE_ENABLE
-static bool allow_writes;
-
+#ifdef CONFIG_OTP_WRITE_ENABLE
/**
* bfin_otp_init_timing - setup OTP timing parameters
*
@@ -117,118 +102,128 @@ static void bfin_otp_deinit_timing(u32 timing)
*
* All writes must be in half page chunks (half page == 64 bits).
*/
-static ssize_t bfin_otp_write(struct file *filp, const char __user *buff, size_t count, loff_t *pos)
+static int bfin_write_word(struct otp_device *otp_dev,
+ struct otp_region *region, unsigned long addr,
+ u64 content)
{
- ssize_t bytes_done;
+ int err;
u32 timing, page, base_flags, flags, ret;
- u64 content;
-
- if (!allow_writes)
- return -EACCES;
-
- if (count % sizeof(u64))
- return -EMSGSIZE;
-
- if (mutex_lock_interruptible(&bfin_otp_lock))
- return -ERESTARTSYS;

stampit();
-
timing = bfin_otp_init_timing();
- if (timing == 0) {
- mutex_unlock(&bfin_otp_lock);
+ if (timing == 0)
return -EIO;
- }
-
base_flags = OTP_CHECK_FOR_PREV_WRITE;

- bytes_done = 0;
- page = *pos / (sizeof(u64) * 2);
- while (bytes_done < count) {
- flags = base_flags | (*pos % (sizeof(u64) * 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF);
- stamp("processing page %i (0x%x:%s) from %p", page, flags,
- (flags & OTP_UPPER_HALF ? "upper" : "lower"), buff + bytes_done);
- if (copy_from_user(&content, buff + bytes_done, sizeof(content))) {
- bytes_done = -EFAULT;
- break;
- }
- ret = bfrom_OtpWrite(page, flags, &content);
- if (ret & OTP_MASTER_ERROR) {
- stamp("error from otp: 0x%x", ret);
- bytes_done = -EIO;
- break;
- }
- if (flags & OTP_UPPER_HALF)
- ++page;
- bytes_done += sizeof(content);
- *pos += sizeof(content);
- }
+ page = addr / 2;
+ flags = base_flags | (addr & 0x1) ? OTP_UPPER_HALF : OTP_LOWER_HALF;
+ stamp("processing page %i (0x%x:%s)", page, flags,
+ (flags & OTP_UPPER_HALF ? "upper" : "lower"));
+ ret = bfrom_OtpWrite(page, flags, &content);
+ if (ret & OTP_MASTER_ERROR) {
+ stamp("error from otp: 0x%x", ret);
+ err = -EIO;
+ } else
+ err = 0;

bfin_otp_deinit_timing(timing);

- mutex_unlock(&bfin_otp_lock);
-
- return bytes_done;
+ return err;
}

-static long bfin_otp_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
+static long bfin_lock_word(struct otp_device *otp_dev,
+ struct otp_region *region, unsigned long addr)
{
+ u32 timing;
+ int ret = -EIO;
+
stampit();

- switch (cmd) {
- case OTPLOCK: {
- u32 timing;
- int ret = -EIO;
+ if (!otp_write_enabled(otp_dev))
+ return -EACCES;

- if (!allow_writes)
- return -EACCES;
+ timing = bfin_otp_init_timing();
+ if (timing) {
+ u32 otp_result = bfrom_OtpWrite(addr, OTP_LOCK, NULL);
+ stamp("locking page %lu resulted in 0x%x", addr, otp_result);
+ if (!(otp_result & OTP_MASTER_ERROR))
+ ret = 0;

- if (mutex_lock_interruptible(&bfin_otp_lock))
- return -ERESTARTSYS;
+ bfin_otp_deinit_timing(timing);
+ }

- timing = bfin_otp_init_timing();
- if (timing) {
- u32 otp_result = bfrom_OtpWrite(arg, OTP_LOCK, NULL);
- stamp("locking page %lu resulted in 0x%x", arg, otp_result);
- if (!(otp_result & OTP_MASTER_ERROR))
- ret = 0;
+ return ret;
+}
+#else /* CONFIG_OTP_WRITE_ENABLE */
+#define bfin_write_word NULL
+#define bfin_lock_word NULL
+#endif /* CONFIG_OTP_WRITE_ENABLE */

- bfin_otp_deinit_timing(timing);
- }
+static ssize_t bfin_otp_get_nr_regions(struct otp_device *dev)
+{
+ return 1;
+}

- mutex_unlock(&bfin_otp_lock);
+static const struct otp_device_ops bfin_otp_ops = {
+ .name = "bfin-otp",
+ .owner = THIS_MODULE,
+ .get_nr_regions = bfin_otp_get_nr_regions,
+ .read_word = bfin_read_word,
+ .write_word = bfin_write_word,
+ .lock_word = bfin_lock_word,
+};

- return ret;
- }
+static ssize_t bfin_region_get_size(struct otp_region *region)
+{
+ return BFIN_OTP_SIZE;
+}

- case MEMLOCK:
- allow_writes = false;
- return 0;
+static enum otp_redundancy_fmt bfin_region_get_fmt(struct otp_region *region)
+{
+ return OTP_REDUNDANCY_FMT_ECC;
+}

- case MEMUNLOCK:
- allow_writes = true;
- return 0;
+static const struct otp_region_ops bfin_region_ops = {
+ .get_size = bfin_region_get_size,
+ .get_fmt = bfin_region_get_fmt,
+};
+
+static int __devinit bfin_otp_probe(struct platform_device *pdev)
+{
+ struct otp_region *region;
+
+ stampit();
+
+ bfin_otp = otp_device_alloc(&pdev->dev, &bfin_otp_ops, BFIN_OTP_SIZE,
+ 8, 1, OTP_CAPS_NO_SUBWORD_WRITE);
+ if (IS_ERR(bfin_otp)) {
+ pr_init(KERN_ERR PFX "failed to create OTP device\n");
+ return PTR_ERR(bfin_otp);
+ }
+
+ region = otp_region_alloc(bfin_otp, &bfin_region_ops, 1, "region1");
+ if (IS_ERR(region)) {
+ otp_device_unregister(bfin_otp);
+ return PTR_ERR(region);
}
+ pr_init(KERN_INFO PFX "initialized\n");

- return -EINVAL;
+ return 0;
}
-#else
-# define bfin_otp_write NULL
-# define bfin_otp_ioctl NULL
-#endif
-
-static const struct file_operations bfin_otp_fops = {
- .owner = THIS_MODULE,
- .unlocked_ioctl = bfin_otp_ioctl,
- .read = bfin_otp_read,
- .write = bfin_otp_write,
- .llseek = default_llseek,
-};

-static struct miscdevice bfin_otp_misc_device = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = DRIVER_NAME,
- .fops = &bfin_otp_fops,
+static int __devexit bfin_otp_remove(struct platform_device *pdev)
+{
+ stampit();
+
+ otp_device_unregister(bfin_otp);
+
+ return 0;
+}
+
+static struct platform_driver bfin_otp_driver = {
+ .probe = bfin_otp_probe,
+ .remove = __devexit_p(bfin_otp_remove),
+ .driver.name = "bfin-otp",
};

/**
@@ -239,19 +234,7 @@ static struct miscdevice bfin_otp_misc_device = {
*/
static int __init bfin_otp_init(void)
{
- int ret;
-
- stampit();
-
- ret = misc_register(&bfin_otp_misc_device);
- if (ret) {
- pr_init(KERN_ERR PFX "unable to register a misc device\n");
- return ret;
- }
-
- pr_init(KERN_INFO PFX "initialized\n");
-
- return 0;
+ return platform_driver_register(&bfin_otp_driver);
}

/**
@@ -262,9 +245,7 @@ static int __init bfin_otp_init(void)
*/
static void __exit bfin_otp_exit(void)
{
- stampit();
-
- misc_deregister(&bfin_otp_misc_device);
+ platform_driver_unregister(&bfin_otp_driver);
}

module_init(bfin_otp_init);
--
1.7.4

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