1 files changed, 275 insertions, 0 deletions
diff --git a/drivers/char/bfin-otp.c b/drivers/char/bfin-otp.c
new file mode 100644
index 000000000..44660f1c4
--- /dev/null
+++ b/drivers/char/bfin-otp.c
@@ -0,0 +1,275 @@
+/*
+ * Blackfin On-Chip OTP Memory Interface
+ *
+ * Copyright 2007-2009 Analog Devices Inc.
+ *
+ * Enter bugs at http://blackfin.uclinux.org/
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/device.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/types.h>
+#include <mtd/mtd-abi.h>
+
+#include <asm/blackfin.h>
+#include <asm/bfrom.h>
+#include <asm/uaccess.h>
+
+#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
+#define stampit() stamp("here i am")
+#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
+
+#define DRIVER_NAME "bfin-otp"
+#define PFX DRIVER_NAME ": "
+
+static DEFINE_MUTEX(bfin_otp_lock);
+
+/**
+ *	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)
+{
+	ssize_t bytes_done;
+	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;
+}
+
+#ifdef CONFIG_BFIN_OTP_WRITE_ENABLE
+static bool allow_writes;
+
+/**
+ *	bfin_otp_init_timing - setup OTP timing parameters
+ *
+ *	Required before doing any write operation.  Algorithms from HRM.
+ */
+static u32 bfin_otp_init_timing(void)
+{
+	u32 tp1, tp2, tp3, timing;
+
+	tp1 = get_sclk() / 1000000;
+	tp2 = (2 * get_sclk() / 10000000) << 8;
+	tp3 = (0x1401) << 15;
+	timing = tp1 | tp2 | tp3;
+	if (bfrom_OtpCommand(OTP_INIT, timing))
+		return 0;
+
+	return timing;
+}
+
+/**
+ *	bfin_otp_deinit_timing - set timings to only allow reads
+ *
+ *	Should be called after all writes are done.
+ */
+static void bfin_otp_deinit_timing(u32 timing)
+{
+	/* mask bits [31:15] so that any attempts to write fail */
+	bfrom_OtpCommand(OTP_CLOSE, 0);
+	bfrom_OtpCommand(OTP_INIT, timing & ~(-1 << 15));
+	bfrom_OtpCommand(OTP_CLOSE, 0);
+}
+
+/**
+ *	bfin_otp_write - write OTP pages
+ *
+ *	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)
+{
+	ssize_t bytes_done;
+	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);
+		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);
+	}
+
+	bfin_otp_deinit_timing(timing);
+
+	mutex_unlock(&bfin_otp_lock);
+
+	return bytes_done;
+}
+
+static long bfin_otp_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
+{
+	stampit();
+
+	switch (cmd) {
+	case OTPLOCK: {
+		u32 timing;
+		int ret = -EIO;
+
+		if (!allow_writes)
+			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);
+			stamp("locking page %lu resulted in 0x%x", arg, otp_result);
+			if (!(otp_result & OTP_MASTER_ERROR))
+				ret = 0;
+
+			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,
+};
+
+static struct miscdevice bfin_otp_misc_device = {
+	.minor    = MISC_DYNAMIC_MINOR,
+	.name     = DRIVER_NAME,
+	.fops     = &bfin_otp_fops,
+};
+
+/**
+ *	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)
+{
+	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;
+}
+
+/**
+ *	bfin_otp_exit - Deinitialize module
+ *
+ *	Unregisters the device and notifier handler. Actual device
+ *	deinitialization is handled by bfin_otp_close().
+ */
+static void __exit bfin_otp_exit(void)
+{
+	stampit();
+
+	misc_deregister(&bfin_otp_misc_device);
+}
+
+module_init(bfin_otp_init);
+module_exit(bfin_otp_exit);
+
+MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
+MODULE_DESCRIPTION("Blackfin OTP Memory Interface");
+MODULE_LICENSE("GPL");