diff options
Diffstat (limited to 'drivers/char/bfin-otp.c')
| -rw-r--r-- | drivers/char/bfin-otp.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/char/bfin-otp.c b/drivers/char/bfin-otp.c new file mode 100644 index 00000000000..0a01329451e --- /dev/null +++ b/drivers/char/bfin-otp.c @@ -0,0 +1,189 @@ +/* + * 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"); |