[RFC PATCHv3 3/4] drivers/otp: convert bfin otp to generic OTP
From: Jamie Iles
Date: Fri Mar 25 2011 - 13:15:11 EST
Convert the blackfin OTP driver to the generic OTP layer.
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 | 275 ++++++++++++++++++++-----------------
5 files changed, 166 insertions(+), 155 deletions(-)
rename drivers/{char => otp}/bfin-otp.c (40%)
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 c1a3f5e..74c1f92 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 40%
rename from drivers/char/bfin-otp.c
rename to drivers/otp/bfin-otp.c
index 44660f1..2edf6ae 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 +30,62 @@
#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;
+
+/*
+ * Given the data storage address in a region, find the real address in the
+ * OTP. This takes into account the control bit storage at the start of the
+ * first region and the ECC pages.
+ */
+static inline unsigned long bfin_region_to_raw_addr(unsigned long region_addr)
+{
+ unsigned long raw_addr;
+ unsigned control_words = BFIN_OTP_WORDS_PER_PAGE * 4;
+
+ /*
+ * Skip the control pages then if we would run into the ECC area skip
+ * past to the next data region.
+ */
+ raw_addr = region_addr + control_words;
+ if (raw_addr > 0x80 * BFIN_OTP_WORDS_PER_PAGE)
+ raw_addr += 0x20 * BFIN_OTP_WORDS_PER_PAGE;
+
+ return raw_addr;
+}
/**
* 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_region_read_word(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;
+ addr = bfin_region_to_raw_addr(addr);
+ 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
*
@@ -117,62 +123,39 @@ 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_region_write_word(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();
-
+ addr = bfin_region_to_raw_addr(region->region_nr, addr);
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_region_ioctl(struct otp_region *region, unsigned cmd,
+ unsigned long arg)
{
+ struct otp_device *otp_dev = to_otp_device(region->dev.parent);
stampit();
switch (cmd) {
@@ -180,12 +163,9 @@ static long bfin_otp_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
u32 timing;
int ret = -EIO;
- if (!allow_writes)
+ if (!otp_write_enabled(otp_dev))
return -EACCES;
- if (mutex_lock_interruptible(&bfin_otp_lock))
- return -ERESTARTSYS;
-
timing = bfin_otp_init_timing();
if (timing) {
u32 otp_result = bfrom_OtpWrite(arg, OTP_LOCK, NULL);
@@ -196,64 +176,109 @@ static long bfin_otp_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
bfin_otp_deinit_timing(timing);
}
- mutex_unlock(&bfin_otp_lock);
-
return ret;
}
-
- case MEMLOCK:
- allow_writes = false;
- return 0;
-
- case MEMUNLOCK:
- allow_writes = true;
- return 0;
}
return -EINVAL;
}
-#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,
-};
+#else /* CONFIG_OTP_WRITE_ENABLE */
+static int bfin_region_write_word(struct otp_region *region, unsigned long addr,
+ u64 content)
+{
+ return -EACCES;
+}
+#define bfin_region_ioctl NULL
+#endif /* CONFIG_OTP_WRITE_ENABLE */
-static struct miscdevice bfin_otp_misc_device = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = DRIVER_NAME,
- .fops = &bfin_otp_fops,
+static int bfin_otp_get_nr_regions(struct otp_device *dev)
+{
+ return 1;
+}
+
+static const struct otp_device_ops bfin_otp_ops = {
+ .name = "BFIN",
+ .owner = THIS_MODULE,
+ .get_nr_regions = bfin_otp_get_nr_regions,
};
-/**
- * bfin_otp_init - Initialize module
- *
- * Registers the device and notifier handler. Actual device
- * initialization is handled by bfin_otp_open().
+/*
+ * Blackfin has 0x200 pages, each of 128 bits giving 4KB of storage. This is
+ * further split into two regions of 0x100 pages where the top 0x20 pages are
+ * used for ECC correction automatically by the ROM. The first region also
+ * has 4 pages reserved as control bits for preventing futher writes to a
+ * page. To make it easier for the user we make this look like a single
+ * contiguous region that doesn't include the control or ECC bits. The ECC
+ * bits are written and checked by the lower layers and the control bits can
+ * be set by using the OTPLOCK ioctl().
*/
-static int __init bfin_otp_init(void)
+static ssize_t bfin_region_get_size(struct otp_region *region)
+{
+ return (2 * 0x80 * BFIN_PAGE_SIZE) - (4 * BFIN_PAGE_SIZE);
+}
+
+static enum otp_redundancy_fmt bfin_region_get_fmt(struct otp_region *region)
+{
+ return OTP_REDUNDANCY_FMT_ECC;
+}
+
+static const struct otp_region_ops bfin_region_ops = {
+ .read_word = bfin_region_read_word,
+ .write_word = bfin_region_write_word,
+ .get_size = bfin_region_get_size,
+ .get_fmt = bfin_region_get_fmt,
+ .ioctl = bfin_region_ioctl,
+};
+
+static int __devinit bfin_otp_probe(struct platform_device *pdev)
{
- int ret;
+ struct otp_region *region;
stampit();
- ret = misc_register(&bfin_otp_misc_device);
- if (ret) {
- pr_init(KERN_ERR PFX "unable to register a misc device\n");
- return ret;
+ bfin_otp = otp_device_alloc(&pdev->dev, &bfin_otp_ops, BFIN_OTP_SIZE,
+ 8, 2, OTP_DEVICE_FNO_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);
+ if (IS_ERR(region)) {
+ otp_device_unregister(bfin_otp);
+ return PTR_ERR(region);
+ }
pr_init(KERN_INFO PFX "initialized\n");
return 0;
}
+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",
+};
+
+/**
+ * bfin_otp_init - Initialize module
+ *
+ * Registers the device and notifier handler. Actual device
+ * initialization is handled by bfin_otp_open().
+ */
+static int __init bfin_otp_init(void)
+{
+ return platform_driver_register(&bfin_otp_driver);
+}
+
/**
* bfin_otp_exit - Deinitialize module
*
@@ -262,9 +287,7 @@ 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/