v4.19.13 snapshot.
diff --git a/include/uapi/mtd/mtd-abi.h b/include/uapi/mtd/mtd-abi.h
new file mode 100644
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+++ b/include/uapi/mtd/mtd-abi.h
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+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org> et al.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#ifndef __MTD_ABI_H__
+#define __MTD_ABI_H__
+
+#include <linux/types.h>
+
+struct erase_info_user {
+	__u32 start;
+	__u32 length;
+};
+
+struct erase_info_user64 {
+	__u64 start;
+	__u64 length;
+};
+
+struct mtd_oob_buf {
+	__u32 start;
+	__u32 length;
+	unsigned char __user *ptr;
+};
+
+struct mtd_oob_buf64 {
+	__u64 start;
+	__u32 pad;
+	__u32 length;
+	__u64 usr_ptr;
+};
+
+/**
+ * MTD operation modes
+ *
+ * @MTD_OPS_PLACE_OOB:	OOB data are placed at the given offset (default)
+ * @MTD_OPS_AUTO_OOB:	OOB data are automatically placed at the free areas
+ *			which are defined by the internal ecclayout
+ * @MTD_OPS_RAW:	data are transferred as-is, with no error correction;
+ *			this mode implies %MTD_OPS_PLACE_OOB
+ *
+ * These modes can be passed to ioctl(MEMWRITE) and are also used internally.
+ * See notes on "MTD file modes" for discussion on %MTD_OPS_RAW vs.
+ * %MTD_FILE_MODE_RAW.
+ */
+enum {
+	MTD_OPS_PLACE_OOB = 0,
+	MTD_OPS_AUTO_OOB = 1,
+	MTD_OPS_RAW = 2,
+};
+
+/**
+ * struct mtd_write_req - data structure for requesting a write operation
+ *
+ * @start:	start address
+ * @len:	length of data buffer
+ * @ooblen:	length of OOB buffer
+ * @usr_data:	user-provided data buffer
+ * @usr_oob:	user-provided OOB buffer
+ * @mode:	MTD mode (see "MTD operation modes")
+ * @padding:	reserved, must be set to 0
+ *
+ * This structure supports ioctl(MEMWRITE) operations, allowing data and/or OOB
+ * writes in various modes. To write to OOB-only, set @usr_data == NULL, and to
+ * write data-only, set @usr_oob == NULL. However, setting both @usr_data and
+ * @usr_oob to NULL is not allowed.
+ */
+struct mtd_write_req {
+	__u64 start;
+	__u64 len;
+	__u64 ooblen;
+	__u64 usr_data;
+	__u64 usr_oob;
+	__u8 mode;
+	__u8 padding[7];
+};
+
+#define MTD_ABSENT		0
+#define MTD_RAM			1
+#define MTD_ROM			2
+#define MTD_NORFLASH		3
+#define MTD_NANDFLASH		4	/* SLC NAND */
+#define MTD_DATAFLASH		6
+#define MTD_UBIVOLUME		7
+#define MTD_MLCNANDFLASH	8	/* MLC NAND (including TLC) */
+
+#define MTD_WRITEABLE		0x400	/* Device is writeable */
+#define MTD_BIT_WRITEABLE	0x800	/* Single bits can be flipped */
+#define MTD_NO_ERASE		0x1000	/* No erase necessary */
+#define MTD_POWERUP_LOCK	0x2000	/* Always locked after reset */
+
+/* Some common devices / combinations of capabilities */
+#define MTD_CAP_ROM		0
+#define MTD_CAP_RAM		(MTD_WRITEABLE | MTD_BIT_WRITEABLE | MTD_NO_ERASE)
+#define MTD_CAP_NORFLASH	(MTD_WRITEABLE | MTD_BIT_WRITEABLE)
+#define MTD_CAP_NANDFLASH	(MTD_WRITEABLE)
+#define MTD_CAP_NVRAM		(MTD_WRITEABLE | MTD_BIT_WRITEABLE | MTD_NO_ERASE)
+
+/* Obsolete ECC byte placement modes (used with obsolete MEMGETOOBSEL) */
+#define MTD_NANDECC_OFF		0	// Switch off ECC (Not recommended)
+#define MTD_NANDECC_PLACE	1	// Use the given placement in the structure (YAFFS1 legacy mode)
+#define MTD_NANDECC_AUTOPLACE	2	// Use the default placement scheme
+#define MTD_NANDECC_PLACEONLY	3	// Use the given placement in the structure (Do not store ecc result on read)
+#define MTD_NANDECC_AUTOPL_USR 	4	// Use the given autoplacement scheme rather than using the default
+
+/* OTP mode selection */
+#define MTD_OTP_OFF		0
+#define MTD_OTP_FACTORY		1
+#define MTD_OTP_USER		2
+
+struct mtd_info_user {
+	__u8 type;
+	__u32 flags;
+	__u32 size;	/* Total size of the MTD */
+	__u32 erasesize;
+	__u32 writesize;
+	__u32 oobsize;	/* Amount of OOB data per block (e.g. 16) */
+	__u64 padding;	/* Old obsolete field; do not use */
+};
+
+struct region_info_user {
+	__u32 offset;		/* At which this region starts,
+				 * from the beginning of the MTD */
+	__u32 erasesize;	/* For this region */
+	__u32 numblocks;	/* Number of blocks in this region */
+	__u32 regionindex;
+};
+
+struct otp_info {
+	__u32 start;
+	__u32 length;
+	__u32 locked;
+};
+
+/*
+ * Note, the following ioctl existed in the past and was removed:
+ * #define MEMSETOOBSEL           _IOW('M', 9, struct nand_oobinfo)
+ * Try to avoid adding a new ioctl with the same ioctl number.
+ */
+
+/* Get basic MTD characteristics info (better to use sysfs) */
+#define MEMGETINFO		_IOR('M', 1, struct mtd_info_user)
+/* Erase segment of MTD */
+#define MEMERASE		_IOW('M', 2, struct erase_info_user)
+/* Write out-of-band data from MTD */
+#define MEMWRITEOOB		_IOWR('M', 3, struct mtd_oob_buf)
+/* Read out-of-band data from MTD */
+#define MEMREADOOB		_IOWR('M', 4, struct mtd_oob_buf)
+/* Lock a chip (for MTD that supports it) */
+#define MEMLOCK			_IOW('M', 5, struct erase_info_user)
+/* Unlock a chip (for MTD that supports it) */
+#define MEMUNLOCK		_IOW('M', 6, struct erase_info_user)
+/* Get the number of different erase regions */
+#define MEMGETREGIONCOUNT	_IOR('M', 7, int)
+/* Get information about the erase region for a specific index */
+#define MEMGETREGIONINFO	_IOWR('M', 8, struct region_info_user)
+/* Get info about OOB modes (e.g., RAW, PLACE, AUTO) - legacy interface */
+#define MEMGETOOBSEL		_IOR('M', 10, struct nand_oobinfo)
+/* Check if an eraseblock is bad */
+#define MEMGETBADBLOCK		_IOW('M', 11, __kernel_loff_t)
+/* Mark an eraseblock as bad */
+#define MEMSETBADBLOCK		_IOW('M', 12, __kernel_loff_t)
+/* Set OTP (One-Time Programmable) mode (factory vs. user) */
+#define OTPSELECT		_IOR('M', 13, int)
+/* Get number of OTP (One-Time Programmable) regions */
+#define OTPGETREGIONCOUNT	_IOW('M', 14, int)
+/* Get all OTP (One-Time Programmable) info about MTD */
+#define OTPGETREGIONINFO	_IOW('M', 15, struct otp_info)
+/* Lock a given range of user data (must be in mode %MTD_FILE_MODE_OTP_USER) */
+#define OTPLOCK			_IOR('M', 16, struct otp_info)
+/* Get ECC layout (deprecated) */
+#define ECCGETLAYOUT		_IOR('M', 17, struct nand_ecclayout_user)
+/* Get statistics about corrected/uncorrected errors */
+#define ECCGETSTATS		_IOR('M', 18, struct mtd_ecc_stats)
+/* Set MTD mode on a per-file-descriptor basis (see "MTD file modes") */
+#define MTDFILEMODE		_IO('M', 19)
+/* Erase segment of MTD (supports 64-bit address) */
+#define MEMERASE64		_IOW('M', 20, struct erase_info_user64)
+/* Write data to OOB (64-bit version) */
+#define MEMWRITEOOB64		_IOWR('M', 21, struct mtd_oob_buf64)
+/* Read data from OOB (64-bit version) */
+#define MEMREADOOB64		_IOWR('M', 22, struct mtd_oob_buf64)
+/* Check if chip is locked (for MTD that supports it) */
+#define MEMISLOCKED		_IOR('M', 23, struct erase_info_user)
+/*
+ * Most generic write interface; can write in-band and/or out-of-band in various
+ * modes (see "struct mtd_write_req"). This ioctl is not supported for flashes
+ * without OOB, e.g., NOR flash.
+ */
+#define MEMWRITE		_IOWR('M', 24, struct mtd_write_req)
+
+/*
+ * Obsolete legacy interface. Keep it in order not to break userspace
+ * interfaces
+ */
+struct nand_oobinfo {
+	__u32 useecc;
+	__u32 eccbytes;
+	__u32 oobfree[8][2];
+	__u32 eccpos[32];
+};
+
+struct nand_oobfree {
+	__u32 offset;
+	__u32 length;
+};
+
+#define MTD_MAX_OOBFREE_ENTRIES	8
+#define MTD_MAX_ECCPOS_ENTRIES	64
+/*
+ * OBSOLETE: ECC layout control structure. Exported to user-space via ioctl
+ * ECCGETLAYOUT for backwards compatbility and should not be mistaken as a
+ * complete set of ECC information. The ioctl truncates the larger internal
+ * structure to retain binary compatibility with the static declaration of the
+ * ioctl. Note that the "MTD_MAX_..._ENTRIES" macros represent the max size of
+ * the user struct, not the MAX size of the internal OOB layout representation.
+ */
+struct nand_ecclayout_user {
+	__u32 eccbytes;
+	__u32 eccpos[MTD_MAX_ECCPOS_ENTRIES];
+	__u32 oobavail;
+	struct nand_oobfree oobfree[MTD_MAX_OOBFREE_ENTRIES];
+};
+
+/**
+ * struct mtd_ecc_stats - error correction stats
+ *
+ * @corrected:	number of corrected bits
+ * @failed:	number of uncorrectable errors
+ * @badblocks:	number of bad blocks in this partition
+ * @bbtblocks:	number of blocks reserved for bad block tables
+ */
+struct mtd_ecc_stats {
+	__u32 corrected;
+	__u32 failed;
+	__u32 badblocks;
+	__u32 bbtblocks;
+};
+
+/*
+ * MTD file modes - for read/write access to MTD
+ *
+ * @MTD_FILE_MODE_NORMAL:	OTP disabled, ECC enabled
+ * @MTD_FILE_MODE_OTP_FACTORY:	OTP enabled in factory mode
+ * @MTD_FILE_MODE_OTP_USER:	OTP enabled in user mode
+ * @MTD_FILE_MODE_RAW:		OTP disabled, ECC disabled
+ *
+ * These modes can be set via ioctl(MTDFILEMODE). The mode mode will be retained
+ * separately for each open file descriptor.
+ *
+ * Note: %MTD_FILE_MODE_RAW provides the same functionality as %MTD_OPS_RAW -
+ * raw access to the flash, without error correction or autoplacement schemes.
+ * Wherever possible, the MTD_OPS_* mode will override the MTD_FILE_MODE_* mode
+ * (e.g., when using ioctl(MEMWRITE)), but in some cases, the MTD_FILE_MODE is
+ * used out of necessity (e.g., `write()', ioctl(MEMWRITEOOB64)).
+ */
+enum mtd_file_modes {
+	MTD_FILE_MODE_NORMAL = MTD_OTP_OFF,
+	MTD_FILE_MODE_OTP_FACTORY = MTD_OTP_FACTORY,
+	MTD_FILE_MODE_OTP_USER = MTD_OTP_USER,
+	MTD_FILE_MODE_RAW,
+};
+
+static inline int mtd_type_is_nand_user(const struct mtd_info_user *mtd)
+{
+	return mtd->type == MTD_NANDFLASH || mtd->type == MTD_MLCNANDFLASH;
+}
+
+#endif /* __MTD_ABI_H__ */