[mirror_ubuntu-artful-kernel.git] / drivers / char / bfin-otp.c

/*
 * Blackfin On-Chip OTP Memory Interface
 *  Supports BF52x/BF54x
 *
 * Copyright 2007-2008 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 <asm/blackfin.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);

/* OTP Boot ROM functions */
#define _BOOTROM_OTP_COMMAND           0xEF000018
#define _BOOTROM_OTP_READ              0xEF00001A
#define _BOOTROM_OTP_WRITE             0xEF00001C

static u32 (* const otp_command)(u32 command, u32 value) = (void *)_BOOTROM_OTP_COMMAND;
static u32 (* const otp_read)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_READ;
static u32 (* const otp_write)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_WRITE;

/* otp_command(): defines for "command" */
#define OTP_INIT             0x00000001
#define OTP_CLOSE            0x00000002

/* otp_{read,write}(): defines for "flags" */
#define OTP_LOWER_HALF       0x00000000 /* select upper/lower 64-bit half (bit 0) */
#define OTP_UPPER_HALF       0x00000001
#define OTP_NO_ECC           0x00000010 /* do not use ECC */
#define OTP_LOCK             0x00000020 /* sets page protection bit for page */
#define OTP_ACCESS_READ      0x00001000
#define OTP_ACCESS_READWRITE 0x00002000

/* Return values for all functions */
#define OTP_SUCCESS          0x00000000
#define OTP_MASTER_ERROR     0x001
#define OTP_WRITE_ERROR      0x003
#define OTP_READ_ERROR       0x005
#define OTP_ACC_VIO_ERROR    0x009
#define OTP_DATA_MULT_ERROR  0x011
#define OTP_ECC_MULT_ERROR   0x021
#define OTP_PREV_WR_ERROR    0x041
#define OTP_DATA_SB_WARN     0x100
#define OTP_ECC_SB_WARN      0x200

/**
 *	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 (%s)", page, (flags == OTP_UPPER_HALF ? "upper" : "lower"));
		ret = otp_read(page, flags, &content);
		if (ret & OTP_MASTER_ERROR) {
			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
/**
 *	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)
{
	stampit();

	if (count % sizeof(u64))
		return -EMSGSIZE;

	if (mutex_lock_interruptible(&bfin_otp_lock))
		return -ERESTARTSYS;

	/* need otp_init() documentation before this can be implemented */

	mutex_unlock(&bfin_otp_lock);

	return -EINVAL;
}
#else
# define bfin_otp_write NULL
#endif

static struct file_operations bfin_otp_fops = {
	.owner    = THIS_MODULE,
	.read     = bfin_otp_read,
	.write    = bfin_otp_write,
};

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	/*
	2	* Blackfin On-Chip OTP Memory Interface
	3	* Supports BF52x/BF54x
	4	*
	5	* Copyright 2007-2008 Analog Devices Inc.
	6	*
	7	* Enter bugs at http://blackfin.uclinux.org/
	8	*
	9	* Licensed under the GPL-2 or later.
	10	*/
	11
	12	#include <linux/device.h>
	13	#include <linux/errno.h>
	14	#include <linux/fs.h>
	15	#include <linux/init.h>
	16	#include <linux/miscdevice.h>
	17	#include <linux/module.h>
	18	#include <linux/mutex.h>
	19	#include <linux/types.h>
	20
	21	#include <asm/blackfin.h>
	22	#include <asm/uaccess.h>
	23
	24	#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
	25	#define stampit() stamp("here i am")
	26	#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
	27
	28	#define DRIVER_NAME "bfin-otp"
	29	#define PFX DRIVER_NAME ": "
	30
	31	static DEFINE_MUTEX(bfin_otp_lock);
	32
	33	/* OTP Boot ROM functions */
	34	#define _BOOTROM_OTP_COMMAND 0xEF000018
	35	#define _BOOTROM_OTP_READ 0xEF00001A
	36	#define _BOOTROM_OTP_WRITE 0xEF00001C
	37
	38	static u32 (* const otp_command)(u32 command, u32 value) = (void *)_BOOTROM_OTP_COMMAND;
	39	static u32 (* const otp_read)(u32 page, u32 flags, u64 page_content) = (void )_BOOTROM_OTP_READ;
	40	static u32 (* const otp_write)(u32 page, u32 flags, u64 page_content) = (void )_BOOTROM_OTP_WRITE;
	41
	42	/* otp_command(): defines for "command" */
	43	#define OTP_INIT 0x00000001
	44	#define OTP_CLOSE 0x00000002
	45
	46	/* otp_{read,write}(): defines for "flags" */
	47	#define OTP_LOWER_HALF 0x00000000 /* select upper/lower 64-bit half (bit 0) */
	48	#define OTP_UPPER_HALF 0x00000001
	49	#define OTP_NO_ECC 0x00000010 /* do not use ECC */
	50	#define OTP_LOCK 0x00000020 /* sets page protection bit for page */
	51	#define OTP_ACCESS_READ 0x00001000
	52	#define OTP_ACCESS_READWRITE 0x00002000
	53
	54	/* Return values for all functions */
	55	#define OTP_SUCCESS 0x00000000
	56	#define OTP_MASTER_ERROR 0x001
	57	#define OTP_WRITE_ERROR 0x003
	58	#define OTP_READ_ERROR 0x005
	59	#define OTP_ACC_VIO_ERROR 0x009
	60	#define OTP_DATA_MULT_ERROR 0x011
	61	#define OTP_ECC_MULT_ERROR 0x021
	62	#define OTP_PREV_WR_ERROR 0x041
	63	#define OTP_DATA_SB_WARN 0x100
	64	#define OTP_ECC_SB_WARN 0x200
65
66	/**
67	* bfin_otp_read - Read OTP pages
68	*
69	* All reads must be in half page chunks (half page == 64 bits).
70	*/
71	static ssize_t bfin_otp_read(struct file file, char __user buff, size_t count, loff_t *pos)
72	{
73	ssize_t bytes_done;
74	u32 page, flags, ret;
75	u64 content;
76
77	stampit();
78
79	if (count % sizeof(u64))
80	return -EMSGSIZE;
81
82	if (mutex_lock_interruptible(&bfin_otp_lock))
83	return -ERESTARTSYS;
84
85	bytes_done = 0;
86	page = pos / (sizeof(u64) 2);
87	while (bytes_done < count) {
88	flags = (pos % (sizeof(u64) 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF);
89	stamp("processing page %i (%s)", page, (flags == OTP_UPPER_HALF ? "upper" : "lower"));
90	ret = otp_read(page, flags, &content);
91	if (ret & OTP_MASTER_ERROR) {
92	bytes_done = -EIO;
93	break;
94	}
95	if (copy_to_user(buff + bytes_done, &content, sizeof(content))) {
96	bytes_done = -EFAULT;
97	break;
98	}
99	if (flags == OTP_UPPER_HALF)
100	++page;
101	bytes_done += sizeof(content);
102	*pos += sizeof(content);
103	}
104
105	mutex_unlock(&bfin_otp_lock);
106
107	return bytes_done;
108	}
109
110	#ifdef CONFIG_BFIN_OTP_WRITE_ENABLE
111	/**
112	* bfin_otp_write - Write OTP pages
113	*
114	* All writes must be in half page chunks (half page == 64 bits).
115	*/
116	static ssize_t bfin_otp_write(struct file filp, const char __user buff, size_t count, loff_t *pos)
117	{
118	stampit();
119
120	if (count % sizeof(u64))
121	return -EMSGSIZE;
122
123	if (mutex_lock_interruptible(&bfin_otp_lock))
124	return -ERESTARTSYS;
125
126	/* need otp_init() documentation before this can be implemented */
127
128	mutex_unlock(&bfin_otp_lock);
129
130	return -EINVAL;
131	}
132	#else
133	# define bfin_otp_write NULL
134	#endif
135
136	static struct file_operations bfin_otp_fops = {
137	.owner = THIS_MODULE,
138	.read = bfin_otp_read,
139	.write = bfin_otp_write,
140	};
141
142	static struct miscdevice bfin_otp_misc_device = {
143	.minor = MISC_DYNAMIC_MINOR,
144	.name = DRIVER_NAME,
145	.fops = &bfin_otp_fops,
146	};
147
148	/**
149	* bfin_otp_init - Initialize module
150	*
151	* Registers the device and notifier handler. Actual device
152	* initialization is handled by bfin_otp_open().
153	*/
154	static int __init bfin_otp_init(void)
155	{
156	int ret;
157
158	stampit();
159
160	ret = misc_register(&bfin_otp_misc_device);
161	if (ret) {
162	pr_init(KERN_ERR PFX "unable to register a misc device\n");
163	return ret;
164	}
165
166	pr_init(KERN_INFO PFX "initialized\n");
167
168	return 0;
169	}
170
171	/**
172	* bfin_otp_exit - Deinitialize module
173	*
174	* Unregisters the device and notifier handler. Actual device
175	* deinitialization is handled by bfin_otp_close().
176	*/
177	static void __exit bfin_otp_exit(void)
178	{
179	stampit();
180
181	misc_deregister(&bfin_otp_misc_device);
182	}
183
184	module_init(bfin_otp_init);
185	module_exit(bfin_otp_exit);
186
187	MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
188	MODULE_DESCRIPTION("Blackfin OTP Memory Interface");
189	MODULE_LICENSE("GPL");