Blackfin char driver for Blackfin on-chip OTP memory (v3) (2dc63a84) · Commits · e / devices / android_kernel_teracube_emerald

drivers/char/Kconfig

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		@@ -481,6 +481,34 @@ config BRIQ_PANEL

		It's safe to say N here.

		config BFIN_OTP
		tristate "Blackfin On-Chip OTP Memory Support"
		depends on BLACKFIN && (BF52x \|\| BF54x)
		default y
		help
		If you say Y here, you will get support for a character device
		interface into the One Time Programmable memory pages that are
		stored on the Blackfin processor. This will not get you access
		to the secure memory pages however. You will need to write your
		own secure code and reader for that.

		To compile this driver as a module, choose M here: the module
		will be called bfin-otp.

		If unsure, it is safe to say Y.

		config BFIN_OTP_WRITE_ENABLE
		bool "Enable writing support of OTP pages"
		depends on BFIN_OTP
		default n
		help
		If you say Y here, you will enable support for writing of the
		OTP pages. This is dangerous by nature as you can only program
		the pages once, so only enable this option when you actually
		need it so as to not inadvertently clobber data.

		If unsure, say N.

		config PRINTER
		tristate "Parallel printer support"
		depends on PARPORT

drivers/char/Makefile

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		@@ -59,6 +59,7 @@ obj-$(CONFIG_VIOTAPE) += viotape.o
		obj-$(CONFIG_HVCS) += hvcs.o
		obj-$(CONFIG_SGI_MBCS) += mbcs.o
		obj-$(CONFIG_BRIQ_PANEL) += briq_panel.o
		obj-$(CONFIG_BFIN_OTP) += bfin-otp.o

		obj-$(CONFIG_PRINTER) += lp.o
		obj-$(CONFIG_TIPAR) += tipar.o

drivers/char/bfin-otp.c

0 → 100644

+189 −0

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		/*
		* 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");