Message-Id: <20070314151944.1112.44.sendpatchset@localhost.localdomain>
Date:	Wed, 14 Mar 2007 17:19:44 +0200
From:	Artem Bityutskiy <dedekind@...radead.org>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:	Frank Haverkamp <haver@...t.ibm.com>,
	Christoph Hellwig <hch@...radead.org>,
	David Woodhouse <dwmw2@...radead.org>,
	Josh Boyer <jwboyer@...ux.vnet.ibm.com>,
	Artem Bityutskiy <dedekind@...radead.org>
Subject: [PATCH 02/22 take 3] UBI: user-space API header

diff -auNrp tmp-from/include/mtd/ubi-user.h tmp-to/include/mtd/ubi-user.h
--- tmp-from/include/mtd/ubi-user.h	1970-01-01 02:00:00.000000000 +0200
+++ tmp-to/include/mtd/ubi-user.h	2007-03-14 17:15:49.000000000 +0200
@@ -0,0 +1,163 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Artem B. Bityutskiy
+ */
+
+#ifndef __UBI_USER_H__
+#define __UBI_USER_H__
+
+/*
+ * UBI volume creation
+ * ~~~~~~~~~~~~~~~~~~~
+ *
+ * UBI volumes are created via the %UBI_IOCMKVOL IOCTL command of UBI character
+ * device. A &struct ubi_mkvol_req object has to be properly filled and a
+ * pointer to it has to be passed to the IOCTL.
+ *
+ * UBI volume deletion
+ * ~~~~~~~~~~~~~~~~~~~
+ *
+ * To delete a volume, the %UBI_IOCRMVOL IOCTL command of the UBI character
+ * device should be used. A pointer to the 32-bit volume ID hast to be passed
+ * to the IOCTL.
+ *
+ * UBI volume re-size
+ * ~~~~~~~~~~~~~~~~~~
+ *
+ * To re-size a volume, the %UBI_IOCRSVOL IOCTL command of the UBI character
+ * device should be used. A &struct ubi_rsvol_req object has to be properly
+ * filled and a pointer to it has to be passed to the IOCTL.
+ *
+ * UBI volume update
+ * ~~~~~~~~~~~~~~~~~
+ *
+ * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
+ * corresponding UBI volume character device. A pointer to a 64-bit update
+ * size should be passed to the IOCTL. After then, UBI expects user to write
+ * this number of bytes to the volume character device. The update is finished
+ * when the claimed number of bytes is passed. So, the volume update sequence
+ * is something like:
+ *
+ * fd = open("/dev/my_volume");
+ * ioctl(fd, UBI_IOCVOLUP, &image_size);
+ * write(fd, buf, image_size);
+ * close(fd);
+ */
+
+/*
+ * When a new volume is created, users may either specify the volume number they
+ * want to create or to let UBI automatically assign a volume number using this
+ * constant.
+ */
+#define UBI_VOL_NUM_AUTO (-1)
+
+/* Maximum volume name length */
+#define UBI_MAX_VOLUME_NAME 127
+
+/* IOCTL commands of UBI character devices */
+
+#define UBI_IOC_MAGIC 'o'
+
+/* Create an UBI volume */
+#define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
+/* Remove an UBI volume */
+#define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
+/* Re-size an UBI volume */
+#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
+
+/* IOCTL commands of UBI volume character devices */
+
+#define UBI_VOL_IOC_MAGIC 'O'
+
+/* Start UBI volume update */
+#define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
+/* An eraseblock erasure command, used for debugging, disabled by default */
+#define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
+
+/*
+ * UBI volume type constants.
+ *
+ * @UBI_DYNAMIC_VOLUME: dynamic volume
+ * @UBI_STATIC_VOLUME:  static volume
+ */
+enum {
+	UBI_DYNAMIC_VOLUME = 3,
+	UBI_STATIC_VOLUME = 4
+};
+
+/**
+ * struct ubi_mkvol_req - volume description data structure used in
+ * volume creation requests.
+ *
+ * @vol_id: volume number
+ * @alignment: volume alignment
+ * @bytes: volume size in bytes
+ * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
+ * @padding1: reserved for future, not used
+ * @name_len: volume name length
+ * @padding2: reserved for future, not used
+ * @name: volume name
+ *
+ * This structure is used by userspace programs when creating new volumes. The
+ * @used_bytes field is only necessary when creating static volumes.
+ *
+ * The @alignment field specifies the required alignment of the volume logical
+ * eraseblock. This means, that the size of logical eraseblocks will be aligned
+ * to this number, i.e.,
+ *	(UBI device logical eraseblock size) mod (@alignment) = 0.
+ *
+ * To put it differently, the logical eraseblock of this volume may be slightly
+ * shortened in order to make it properly aligned. The alignment has to be
+ * multiple of the flash minimal input/output unit, or %1 to utilize the entire
+ * available space of logical eraseblocks.
+ *
+ * The @alignment field may be useful, for example, when one wants to maintain
+ * a block device on top of an UBI volume. In this case, it is desirable to fit
+ * an integer number of blocks in logical eraseblocks of this UBI volume. With
+ * alignment it is possible to update this volume using plane UBI volume image
+ * BLOBs, without caring about how to properly align them.
+ */
+struct ubi_mkvol_req {
+	int32_t vol_id;
+	int32_t alignment;
+	int64_t bytes;
+	int8_t vol_type;
+	int8_t padding1;
+	int16_t name_len;
+	int8_t padding2[4];
+	char name[UBI_MAX_VOLUME_NAME + 1];
+} __attribute__ ((packed));
+
+/**
+ * struct ubi_rsvol_req - a data structure used in volume re-size requests.
+ *
+ * @vol_id: ID of the volume to re-size
+ * @bytes: new size of the volume in bytes
+ *
+ * Re-sizing is possible for both dynamic and static volumes. But while dynamic
+ * volumes may be re-sized arbitrarily, static volumes cannot be made to be
+ * smaller then the number of bytes they bear. To arbitrarily shrink a static
+ * volume, it must be wiped out first (by means of volume update operation with
+ * zero number of bytes).
+ */
+struct ubi_rsvol_req {
+	int64_t bytes;
+	int32_t vol_id;
+} __attribute__ ((packed));
+
+#endif /* __UBI_USER_H__ */
-
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