patch-2.4.0-test12 linux/drivers/mtd/mtdpart.c

• Lines: 229
• Date: Mon Dec 11 14:57:58 2000
• Orig file: v2.4.0-test11/linux/drivers/mtd/mtdpart.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.0-test11/linux/drivers/mtd/mtdpart.c linux/drivers/mtd/mtdpart.c
@@ -0,0 +1,228 @@
+/*
+ * Simple MTD partitioning layer
+ *
+ * (C) 2000 Nicolas Pitre <nico@cam.org>
+ *
+ * This code is GPL
+ *
+ * $Id: mtdpart.c,v 1.7 2000/12/09 23:29:47 dwmw2 Exp $
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/malloc.h>
+#include <linux/list.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+
+/* Our partition linked list */
+static LIST_HEAD(mtd_partitions);
+
+/* Our partition node structure */
+struct mtd_part {
+	struct mtd_info mtd;
+	struct mtd_info *master;
+	loff_t offset;
+	int index;
+	struct list_head list;
+};
+
+/*
+ * Given a pointer to the MTD object in the mtd_part structure, we can retrieve
+ * the pointer to that structure with this macro.
+ */
+#define PART(x)  ((struct mtd_part *)(x))
+
+	
+/* 
+ * MTD methods which simply translate the effective address and pass through
+ * to the _real_ device.
+ */
+
+static int part_read (struct mtd_info *mtd, loff_t from, size_t len, 
+			size_t *retlen, u_char *buf)
+{
+	struct mtd_part *part = PART(mtd);
+	if (from >= mtd->size)
+		len = 0;
+	else if (from + len > mtd->size)
+		len = mtd->size - from;
+	return part->master->read (part->master, from + part->offset, 
+					len, retlen, buf);
+}
+
+static int part_write (struct mtd_info *mtd, loff_t to, size_t len,
+			size_t *retlen, const u_char *buf)
+{
+	struct mtd_part *part = PART(mtd);
+	if (!(mtd->flags & MTD_WRITEABLE))
+		return -EROFS;
+	if (to >= mtd->size)
+		len = 0;
+	else if (to + len > mtd->size)
+		len = mtd->size - to;
+	return part->master->write (part->master, to + part->offset, 
+					len, retlen, buf);
+}
+
+static int part_writev (struct mtd_info *mtd,  const struct iovec *vecs,
+			 unsigned long count, loff_t to, size_t *retlen)
+{
+	struct mtd_part *part = PART(mtd);
+	if (!(mtd->flags & MTD_WRITEABLE))
+		return -EROFS;
+	return part->master->writev (part->master, vecs, count,
+					to + part->offset, retlen);
+}
+
+static int part_readv (struct mtd_info *mtd,  struct iovec *vecs,
+			 unsigned long count, loff_t from, size_t *retlen)
+{
+	struct mtd_part *part = PART(mtd);
+	return part->master->readv (part->master, vecs, count,
+					from + part->offset, retlen);
+}
+
+static int part_erase (struct mtd_info *mtd, struct erase_info *instr)
+{
+	struct mtd_part *part = PART(mtd);
+	if (!(mtd->flags & MTD_WRITEABLE))
+		return -EROFS;
+	if (instr->addr >= mtd->size)
+		return -EINVAL;
+	instr->addr += part->offset;
+	return part->master->erase(part->master, instr);
+}
+
+static int part_lock (struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+	struct mtd_part *part = PART(mtd);
+	return part->master->lock(part->master, ofs + part->offset, len);
+}
+
+static int part_unlock (struct mtd_info *mtd, loff_t ofs, size_t len)
+{
+	struct mtd_part *part = PART(mtd);
+	return part->master->unlock(part->master, ofs + part->offset, len);
+}
+
+
+/* 
+ * This function unregisters and destroy all slave MTD objects which are 
+ * attached to the given master MTD object.
+ */
+
+int del_mtd_partitions(struct mtd_info *master)
+{
+	struct list_head *node;
+	struct mtd_part *slave;
+
+	for (node = mtd_partitions.next;
+	     node != &mtd_partitions;
+	     node = node->next) {
+		slave = list_entry(node, struct mtd_part, list);
+		if (slave->master == master) {
+			struct list_head *prev = node->prev;
+			__list_del(prev, node->next);
+			del_mtd_device(&slave->mtd);
+			kfree(slave);
+			node = prev;
+			MOD_DEC_USE_COUNT;
+		}
+	}
+
+	return 0;
+}
+
+
+/*
+ * This function, given a master MTD object and a partition table, creates
+ * and registers slave MTD objects which are bound to the master according to
+ * the partition definitions.
+ * (Q: should we register the master MTD object as well?)
+ */
+
+int add_mtd_partitions(struct mtd_info *master, 
+		       struct mtd_partition *parts,
+		       int nbparts)
+{
+	struct mtd_part *slave;
+	u_long cur_offset = 0;
+	int i;
+
+	for (i = 0; i < nbparts; i++) {
+		/* allocate the partition structure */
+		slave = kmalloc (sizeof(*slave), GFP_KERNEL);
+		if (!slave) {
+			printk ("memory allocation error while creating partitions for \"%s\"\n",
+				master->name);
+			del_mtd_partitions(master);
+			return -ENOMEM;
+		}
+		list_add(&slave->list, &mtd_partitions);
+
+		/* set up the MTD object for this partition */
+		slave->mtd = *master;
+		slave->mtd.name = parts[i].name;
+		slave->mtd.size = parts[i].size;
+		slave->mtd.flags &= ~parts[i].mask_flags;
+		slave->mtd.read = part_read;
+		slave->mtd.write = part_write;
+		if (slave->mtd.writev)
+			slave->mtd.writev = part_writev;
+		if (slave->mtd.readv)
+			slave->mtd.readv = part_readv;
+		if (slave->mtd.lock)
+			slave->mtd.lock = part_lock;
+		if (slave->mtd.unlock)
+			slave->mtd.unlock = part_unlock;
+		slave->mtd.erase = part_erase;
+		slave->master = master;
+		slave->offset = parts[i].offset;
+		slave->index = i;
+
+		if (slave->offset == 0)
+			slave->offset = cur_offset;
+		if (slave->mtd.size == 0)
+			slave->mtd.size = master->size - slave->offset;
+		cur_offset = slave->offset + slave->mtd.size;
+
+		/* let's do some sanity checks */
+		if ((slave->mtd.flags & MTD_WRITEABLE) && 
+		    (parts[i].offset % master->erasesize)) {
+			slave->mtd.flags &= ~MTD_WRITEABLE;
+			printk ("mtd: partition \"%s\" doesn't start on an erase block boundary -- force read-only\n",
+					parts[i].name);
+		}
+		if ((slave->mtd.flags & MTD_WRITEABLE) && 
+		    (parts[i].size % master->erasesize)) {
+			slave->mtd.flags &= ~MTD_WRITEABLE;
+			printk ("mtd: partition \"%s\" doesn't end on an erase block -- force read-only\n",
+					parts[i].name);
+		}
+		if (parts[i].offset >= master->size) {
+			/* let's register it anyway to preserve ordering */
+			slave->offset = 0;
+			slave->mtd.size = 0;
+			printk ("mtd: partition \"%s\" is out of reach -- disabled\n",
+					parts[i].name);
+		}
+		if (parts[i].offset + parts[i].size > master->size) {
+			slave->mtd.size = master->size - parts[i].offset;
+			printk ("mtd: partition \"%s\" extends beyond the end of device \"%s\" -- size truncated to %#lx\n",
+					parts[i].name, master->name, slave->mtd.size);
+		}
+
+		/* register our partition */
+		add_mtd_device(&slave->mtd);
+		MOD_INC_USE_COUNT;
+	}
+
+	return 0;
+}
+
+EXPORT_SYMBOL(add_mtd_partitions);
+EXPORT_SYMBOL(del_mtd_partitions);