[linux-2.6-block.git] / drivers / char / bfin-otp.c

/*
 * 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");
Commit	Line	Data
2dc63a84 MF	1	/*
2dc63a84 MF	2	* Blackfin On-Chip OTP Memory Interface
2dc63a84	3	*
156dd635	4	* Copyright 2007-2009 Analog Devices Inc.
2dc63a84 MF	5	*
	6	* Enter bugs at http://blackfin.uclinux.org/
	7	*
	8	* Licensed under the GPL-2 or later.
	9	*/
	10
	11	#include <linux/device.h>
	12	#include <linux/errno.h>
	13	#include <linux/fs.h>
	14	#include <linux/init.h>
	15	#include <linux/miscdevice.h>
	16	#include <linux/module.h>
	17	#include <linux/mutex.h>
	18	#include <linux/types.h>
156dd635	19	#include <mtd/mtd-abi.h>
2dc63a84 MF	20
2dc63a84 MF	21	#include <asm/blackfin.h>
156dd635	22	#include <asm/bfrom.h>
2dc63a84 MF	23	#include <asm/uaccess.h>
	24
	25	#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
	26	#define stampit() stamp("here i am")
	27	#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
	28
	29	#define DRIVER_NAME "bfin-otp"
	30	#define PFX DRIVER_NAME ": "
	31
	32	static DEFINE_MUTEX(bfin_otp_lock);
	33
2dc63a84 MF	34	/**
	35	* bfin_otp_read - Read OTP pages
	36	*
	37	* All reads must be in half page chunks (half page == 64 bits).
	38	*/
	39	static ssize_t bfin_otp_read(struct file file, char __user buff, size_t count, loff_t *pos)
	40	{
	41	ssize_t bytes_done;
	42	u32 page, flags, ret;
	43	u64 content;
	44
	45	stampit();
	46
	47	if (count % sizeof(u64))
	48	return -EMSGSIZE;
	49
	50	if (mutex_lock_interruptible(&bfin_otp_lock))
	51	return -ERESTARTSYS;
	52
	53	bytes_done = 0;
	54	page = pos / (sizeof(u64) 2);
	55	while (bytes_done < count) {
	56	flags = (pos % (sizeof(u64) 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF);
156dd635 MF	57	stamp("processing page %i (0x%x:%s)", page, flags,
	58	(flags & OTP_UPPER_HALF ? "upper" : "lower"));
	59	ret = bfrom_OtpRead(page, flags, &content);
2dc63a84	60	if (ret & OTP_MASTER_ERROR) {
156dd635	61	stamp("error from otp: 0x%x", ret);
2dc63a84 MF	62	bytes_done = -EIO;
	63	break;
	64	}
	65	if (copy_to_user(buff + bytes_done, &content, sizeof(content))) {
	66	bytes_done = -EFAULT;
	67	break;
	68	}
156dd635	69	if (flags & OTP_UPPER_HALF)
2dc63a84 MF	70	++page;
	71	bytes_done += sizeof(content);
	72	*pos += sizeof(content);
	73	}
	74
	75	mutex_unlock(&bfin_otp_lock);
	76
	77	return bytes_done;
	78	}
	79
	80	#ifdef CONFIG_BFIN_OTP_WRITE_ENABLE
156dd635 MF	81	static bool allow_writes;
156dd635 MF	82
2dc63a84	83	/**
156dd635 MF	84	* bfin_otp_init_timing - setup OTP timing parameters
	85	*
	86	* Required before doing any write operation. Algorithms from HRM.
	87	*/
	88	static u32 bfin_otp_init_timing(void)
	89	{
	90	u32 tp1, tp2, tp3, timing;
	91
	92	tp1 = get_sclk() / 1000000;
	93	tp2 = (2 * get_sclk() / 10000000) << 8;
	94	tp3 = (0x1401) << 15;
	95	timing = tp1 \| tp2 \| tp3;
	96	if (bfrom_OtpCommand(OTP_INIT, timing))
	97	return 0;
	98
	99	return timing;
	100	}
	101
	102	/**
	103	* bfin_otp_deinit_timing - set timings to only allow reads
	104	*
	105	* Should be called after all writes are done.
	106	*/
	107	static void bfin_otp_deinit_timing(u32 timing)
	108	{
	109	/* mask bits [31:15] so that any attempts to write fail */
	110	bfrom_OtpCommand(OTP_CLOSE, 0);
	111	bfrom_OtpCommand(OTP_INIT, timing & ~(-1 << 15));
	112	bfrom_OtpCommand(OTP_CLOSE, 0);
	113	}
	114
	115	/**
	116	* bfin_otp_write - write OTP pages
2dc63a84 MF	117	*
	118	* All writes must be in half page chunks (half page == 64 bits).
	119	*/
	120	static ssize_t bfin_otp_write(struct file filp, const char __user buff, size_t count, loff_t *pos)
	121	{
156dd635 MF	122	ssize_t bytes_done;
	123	u32 timing, page, base_flags, flags, ret;
	124	u64 content;
	125
	126	if (!allow_writes)
	127	return -EACCES;
2dc63a84 MF	128
	129	if (count % sizeof(u64))
	130	return -EMSGSIZE;
	131
	132	if (mutex_lock_interruptible(&bfin_otp_lock))
	133	return -ERESTARTSYS;
	134
156dd635 MF	135	stampit();
	136
	137	timing = bfin_otp_init_timing();
	138	if (timing == 0) {
	139	mutex_unlock(&bfin_otp_lock);
	140	return -EIO;
	141	}
	142
	143	base_flags = OTP_CHECK_FOR_PREV_WRITE;
	144
	145	bytes_done = 0;
	146	page = pos / (sizeof(u64) 2);
	147	while (bytes_done < count) {
	148	flags = base_flags \| (pos % (sizeof(u64) 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF);
	149	stamp("processing page %i (0x%x:%s) from %p", page, flags,
	150	(flags & OTP_UPPER_HALF ? "upper" : "lower"), buff + bytes_done);
	151	if (copy_from_user(&content, buff + bytes_done, sizeof(content))) {
	152	bytes_done = -EFAULT;
	153	break;
	154	}
	155	ret = bfrom_OtpWrite(page, flags, &content);
	156	if (ret & OTP_MASTER_ERROR) {
	157	stamp("error from otp: 0x%x", ret);
	158	bytes_done = -EIO;
	159	break;
	160	}
	161	if (flags & OTP_UPPER_HALF)
	162	++page;
	163	bytes_done += sizeof(content);
	164	*pos += sizeof(content);
	165	}
	166
	167	bfin_otp_deinit_timing(timing);
2dc63a84 MF	168
	169	mutex_unlock(&bfin_otp_lock);
	170
156dd635 MF	171	return bytes_done;
	172	}
	173
	174	static long bfin_otp_ioctl(struct file *filp, unsigned cmd, unsigned long arg)
	175	{
	176	stampit();
	177
	178	switch (cmd) {
	179	case OTPLOCK: {
	180	u32 timing;
	181	int ret = -EIO;
	182
	183	if (!allow_writes)
	184	return -EACCES;
	185
	186	if (mutex_lock_interruptible(&bfin_otp_lock))
	187	return -ERESTARTSYS;
	188
	189	timing = bfin_otp_init_timing();
	190	if (timing) {
	191	u32 otp_result = bfrom_OtpWrite(arg, OTP_LOCK, NULL);
	192	stamp("locking page %lu resulted in 0x%x", arg, otp_result);
	193	if (!(otp_result & OTP_MASTER_ERROR))
	194	ret = 0;
	195
	196	bfin_otp_deinit_timing(timing);
	197	}
	198
	199	mutex_unlock(&bfin_otp_lock);
	200
	201	return ret;
	202	}
	203
	204	case MEMLOCK:
	205	allow_writes = false;
	206	return 0;
	207
	208	case MEMUNLOCK:
	209	allow_writes = true;
	210	return 0;
	211	}
	212
2dc63a84 MF	213	return -EINVAL;
	214	}
	215	#else
	216	# define bfin_otp_write NULL
156dd635	217	# define bfin_otp_ioctl NULL
2dc63a84 MF	218	#endif
2dc63a84 MF	219
828c0950	220	static const struct file_operations bfin_otp_fops = {
156dd635 MF	221	.owner = THIS_MODULE,
	222	.unlocked_ioctl = bfin_otp_ioctl,
	223	.read = bfin_otp_read,
	224	.write = bfin_otp_write,
6038f373	225	.llseek = default_llseek,
2dc63a84 MF	226	};
	227
	228	static struct miscdevice bfin_otp_misc_device = {
	229	.minor = MISC_DYNAMIC_MINOR,
	230	.name = DRIVER_NAME,
	231	.fops = &bfin_otp_fops,
	232	};
	233
	234	/**
	235	* bfin_otp_init - Initialize module
	236	*
	237	* Registers the device and notifier handler. Actual device
	238	* initialization is handled by bfin_otp_open().
	239	*/
	240	static int __init bfin_otp_init(void)
	241	{
	242	int ret;
	243
	244	stampit();
	245
	246	ret = misc_register(&bfin_otp_misc_device);
	247	if (ret) {
	248	pr_init(KERN_ERR PFX "unable to register a misc device\n");
	249	return ret;
	250	}
	251
	252	pr_init(KERN_INFO PFX "initialized\n");
	253
	254	return 0;
	255	}
	256
	257	/**
	258	* bfin_otp_exit - Deinitialize module
	259	*
	260	* Unregisters the device and notifier handler. Actual device
	261	* deinitialization is handled by bfin_otp_close().
	262	*/
	263	static void __exit bfin_otp_exit(void)
	264	{
	265	stampit();
	266
	267	misc_deregister(&bfin_otp_misc_device);
	268	}
	269
	270	module_init(bfin_otp_init);
	271	module_exit(bfin_otp_exit);
	272
	273	MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
	274	MODULE_DESCRIPTION("Blackfin OTP Memory Interface");
	275	MODULE_LICENSE("GPL");