Commit e3c1f1c9 authored by Michael Walle's avatar Michael Walle Committed by Miquel Raynal
Browse files

mtd: add OTP (one-time-programmable) erase ioctl 



This may sound like a contradiction but some SPI-NOR flashes really
support erasing their OTP region until it is finally locked. Having the
possibility to erase an OTP region might come in handy during
development.

The ioctl argument follows the OTPLOCK style.

Signed-off-by: default avatarMichael Walle <michael@walle.cc>
Acked-by: default avatarVignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210303201819.2752-1-michael@walle.cc
parent 1e97743f

drivers/mtd/mtdchar.c

+6 −1
Original line number Diff line number Diff line
@@ -666,6 +666,7 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg) 
	case MEMWRITEOOB64:

	case MEMWRITE:

	case OTPLOCK:

	case OTPERASE:

		if (!(file->f_mode & FMODE_WRITE))

			return -EPERM;

		break;
@@ -930,6 +931,7 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg) 
	}



	case OTPLOCK:

	case OTPERASE:

	{

		struct otp_info oinfo;
@@ -937,7 +939,10 @@ static int mtdchar_ioctl(struct file *file, u_int cmd, u_long arg) 
			return -EINVAL;

		if (copy_from_user(&oinfo, argp, sizeof(oinfo)))

			return -EFAULT;

		if (cmd == OTPLOCK)

			ret = mtd_lock_user_prot_reg(mtd, oinfo.start, oinfo.length);

		else

			ret = mtd_erase_user_prot_reg(mtd, oinfo.start, oinfo.length);

		break;

	}

drivers/mtd/mtdcore.c

+12 −0
Original line number Diff line number Diff line
@@ -1919,6 +1919,18 @@ int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len) 
}

EXPORT_SYMBOL_GPL(mtd_lock_user_prot_reg);



int mtd_erase_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)

{

	struct mtd_info *master = mtd_get_master(mtd);



	if (!master->_erase_user_prot_reg)

		return -EOPNOTSUPP;

	if (!len)

		return 0;

	return master->_erase_user_prot_reg(master, from, len);

}

EXPORT_SYMBOL_GPL(mtd_erase_user_prot_reg);



/* Chip-supported device locking */

int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)

{

include/linux/mtd/mtd.h

+3 −0
Original line number Diff line number Diff line
@@ -337,6 +337,8 @@ struct mtd_info { 
				     size_t len, size_t *retlen, u_char *buf);

	int (*_lock_user_prot_reg) (struct mtd_info *mtd, loff_t from,

				    size_t len);

	int (*_erase_user_prot_reg) (struct mtd_info *mtd, loff_t from,

				     size_t len);

	int (*_writev) (struct mtd_info *mtd, const struct kvec *vecs,

			unsigned long count, loff_t to, size_t *retlen);

	void (*_sync) (struct mtd_info *mtd);
@@ -518,6 +520,7 @@ int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len, 
int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,

			    size_t *retlen, u_char *buf);

int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len);

int mtd_erase_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len);



int mtd_writev(struct mtd_info *mtd, const struct kvec *vecs,

	       unsigned long count, loff_t to, size_t *retlen);

include/uapi/mtd/mtd-abi.h

+2 −0
Original line number Diff line number Diff line
@@ -205,6 +205,8 @@ struct otp_info { 
 * without OOB, e.g., NOR flash.

 */

#define MEMWRITE		_IOWR('M', 24, struct mtd_write_req)

/* Erase a given range of user data (must be in mode %MTD_FILE_MODE_OTP_USER) */

#define OTPERASE		_IOW('M', 25, struct otp_info)



/*

 * Obsolete legacy interface. Keep it in order not to break userspace