/*
* 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");
