Fixed MTP to work with TWRP

drivers/mtd/cmdlinepart.c

@@ -0,0 +1,415 @@
+/*
+ * Read flash partition table from command line
+ *
+ * Copyright © 2002      SYSGO Real-Time Solutions GmbH
+ * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
+ *
+ * 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
+ *
+ * The format for the command line is as follows:
+ *
+ * mtdparts=<mtddef>[;<mtddef]
+ * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
+ * <partdef> := <size>[@<offset>][<name>][ro][lk]
+ * <mtd-id>  := unique name used in mapping driver/device (mtd->name)
+ * <size>    := standard linux memsize OR "-" to denote all remaining space
+ *              size is automatically truncated at end of device
+ *              if specified or truncated size is 0 the part is skipped
+ * <offset>  := standard linux memsize
+ *              if omitted the part will immediately follow the previous part
+ *              or 0 if the first part
+ * <name>    := '(' NAME ')'
+ *              NAME will appear in /proc/mtd
+ *
+ * <size> and <offset> can be specified such that the parts are out of order
+ * in physical memory and may even overlap.
+ *
+ * The parts are assigned MTD numbers in the order they are specified in the
+ * command line regardless of their order in physical memory.
+ *
+ * Examples:
+ *
+ * 1 NOR Flash, with 1 single writable partition:
+ * edb7312-nor:-
+ *
+ * 1 NOR Flash with 2 partitions, 1 NAND with one
+ * edb7312-nor:256k(ARMboot)ro,-(root);edb7312-nand:-(home)
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/module.h>
+#include <linux/err.h>
+
+/* error message prefix */
+#define ERRP "mtd: "
+
+/* debug macro */
+#if 0
+#define dbg(x) do { printk("DEBUG-CMDLINE-PART: "); printk x; } while(0)
+#else
+#define dbg(x)
+#endif
+
+
+/* special size referring to all the remaining space in a partition */
+#define SIZE_REMAINING ULLONG_MAX
+#define OFFSET_CONTINUOUS ULLONG_MAX
+
+struct cmdline_mtd_partition {
+	struct cmdline_mtd_partition *next;
+	char *mtd_id;
+	int num_parts;
+	struct mtd_partition *parts;
+};
+
+/* mtdpart_setup() parses into here */
+static struct cmdline_mtd_partition *partitions;
+
+/* the command line passed to mtdpart_setup() */
+static char *mtdparts;
+static char *cmdline;
+static int cmdline_parsed;
+
+/*
+ * Parse one partition definition for an MTD. Since there can be many
+ * comma separated partition definitions, this function calls itself
+ * recursively until no more partition definitions are found. Nice side
+ * effect: the memory to keep the mtd_partition structs and the names
+ * is allocated upon the last definition being found. At that point the
+ * syntax has been verified ok.
+ */
+static struct mtd_partition * newpart(char *s,
+				      char **retptr,
+				      int *num_parts,
+				      int this_part,
+				      unsigned char **extra_mem_ptr,
+				      int extra_mem_size)
+{
+	struct mtd_partition *parts;
+	unsigned long long size, offset = OFFSET_CONTINUOUS;
+	char *name;
+	int name_len;
+	unsigned char *extra_mem;
+	char delim;
+	unsigned int mask_flags;
+
+	/* fetch the partition size */
+	if (*s == '-') {
+		/* assign all remaining space to this partition */
+		size = SIZE_REMAINING;
+		s++;
+	} else {
+		size = memparse(s, &s);
+		if (size < PAGE_SIZE) {
+			printk(KERN_ERR ERRP "partition size too small (%llx)\n",
+			       size);
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* fetch partition name and flags */
+	mask_flags = 0; /* this is going to be a regular partition */
+	delim = 0;
+
+	/* check for offset */
+	if (*s == '@') {
+		s++;
+		offset = memparse(s, &s);
+	}
+
+	/* now look for name */
+	if (*s == '(')
+		delim = ')';
+
+	if (delim) {
+		char *p;
+
+		name = ++s;
+		p = strchr(name, delim);
+		if (!p) {
+			printk(KERN_ERR ERRP "no closing %c found in partition name\n", delim);
+			return ERR_PTR(-EINVAL);
+		}
+		name_len = p - name;
+		s = p + 1;
+	} else {
+		name = NULL;
+		name_len = 13; /* Partition_000 */
+	}
+
+	/* record name length for memory allocation later */
+	extra_mem_size += name_len + 1;
+
+	/* test for options */
+	if (strncmp(s, "ro", 2) == 0) {
+		mask_flags |= MTD_WRITEABLE;
+		s += 2;
+	}
+
+	/* if lk is found do NOT unlock the MTD partition*/
+	if (strncmp(s, "lk", 2) == 0) {
+		mask_flags |= MTD_POWERUP_LOCK;
+		s += 2;
+	}
+
+	/* test if more partitions are following */
+	if (*s == ',') {
+		if (size == SIZE_REMAINING) {
+			printk(KERN_ERR ERRP "no partitions allowed after a fill-up partition\n");
+			return ERR_PTR(-EINVAL);
+		}
+		/* more partitions follow, parse them */
+		parts = newpart(s + 1, &s, num_parts, this_part + 1,
+				&extra_mem, extra_mem_size);
+		if (IS_ERR(parts))
+			return parts;
+	} else {
+		/* this is the last partition: allocate space for all */
+		int alloc_size;
+
+		*num_parts = this_part + 1;
+		alloc_size = *num_parts * sizeof(struct mtd_partition) +
+			     extra_mem_size;
+
+		parts = kzalloc(alloc_size, GFP_KERNEL);
+		if (!parts)
+			return ERR_PTR(-ENOMEM);
+		extra_mem = (unsigned char *)(parts + *num_parts);
+	}
+
+	/* enter this partition (offset will be calculated later if it is zero at this point) */
+	parts[this_part].size = size;
+	parts[this_part].offset = offset;
+	parts[this_part].mask_flags = mask_flags;
+	if (name)
+		strlcpy(extra_mem, name, name_len + 1);
+	else
+		sprintf(extra_mem, "Partition_%03d", this_part);
+	parts[this_part].name = extra_mem;
+	extra_mem += name_len + 1;
+
+	dbg(("partition %d: name <%s>, offset %llx, size %llx, mask flags %x\n",
+	     this_part, parts[this_part].name, parts[this_part].offset,
+	     parts[this_part].size, parts[this_part].mask_flags));
+
+	/* return (updated) pointer to extra_mem memory */
+	if (extra_mem_ptr)
+		*extra_mem_ptr = extra_mem;
+
+	/* return (updated) pointer command line string */
+	*retptr = s;
+
+	/* return partition table */
+	return parts;
+}
+
+/*
+ * Parse the command line.
+ */
+static int mtdpart_setup_real(char *s)
+{
+	cmdline_parsed = 1;
+
+	for( ; s != NULL; )
+	{
+		struct cmdline_mtd_partition *this_mtd;
+		struct mtd_partition *parts;
+		int mtd_id_len, num_parts;
+		char *p, *mtd_id;
+
+		mtd_id = s;
+
+		/* fetch <mtd-id> */
+		p = strchr(s, ':');
+		if (!p) {
+			printk(KERN_ERR ERRP "no mtd-id\n");
+			return -EINVAL;
+		}
+		mtd_id_len = p - mtd_id;
+
+		dbg(("parsing <%s>\n", p+1));
+
+		/*
+		 * parse one mtd. have it reserve memory for the
+		 * struct cmdline_mtd_partition and the mtd-id string.
+		 */
+		parts = newpart(p + 1,		/* cmdline */
+				&s,		/* out: updated cmdline ptr */
+				&num_parts,	/* out: number of parts */
+				0,		/* first partition */
+				(unsigned char**)&this_mtd, /* out: extra mem */
+				mtd_id_len + 1 + sizeof(*this_mtd) +
+				sizeof(void*)-1 /*alignment*/);
+		if (IS_ERR(parts)) {
+			/*
+			 * An error occurred. We're either:
+			 * a) out of memory, or
+			 * b) in the middle of the partition spec
+			 * Either way, this mtd is hosed and we're
+			 * unlikely to succeed in parsing any more
+			 */
+			 return PTR_ERR(parts);
+		 }
+
+		/* align this_mtd */
+		this_mtd = (struct cmdline_mtd_partition *)
+				ALIGN((unsigned long)this_mtd, sizeof(void *));
+		/* enter results */
+		this_mtd->parts = parts;
+		this_mtd->num_parts = num_parts;
+		this_mtd->mtd_id = (char*)(this_mtd + 1);
+		strlcpy(this_mtd->mtd_id, mtd_id, mtd_id_len + 1);
+
+		/* link into chain */
+		this_mtd->next = partitions;
+		partitions = this_mtd;
+
+		dbg(("mtdid=<%s> num_parts=<%d>\n",
+		     this_mtd->mtd_id, this_mtd->num_parts));
+
+
+		/* EOS - we're done */
+		if (*s == 0)
+			break;
+
+		/* does another spec follow? */
+		if (*s != ';') {
+			printk(KERN_ERR ERRP "bad character after partition (%c)\n", *s);
+			return -EINVAL;
+		}
+		s++;
+	}
+
+	return 0;
+}
+
+/*
+ * Main function to be called from the MTD mapping driver/device to
+ * obtain the partitioning information. At this point the command line
+ * arguments will actually be parsed and turned to struct mtd_partition
+ * information. It returns partitions for the requested mtd device, or
+ * the first one in the chain if a NULL mtd_id is passed in.
+ */
+static int parse_cmdline_partitions(struct mtd_info *master,
+				    struct mtd_partition **pparts,
+				    struct mtd_part_parser_data *data)
+{
+	unsigned long long offset;
+	int i, err;
+	struct cmdline_mtd_partition *part;
+	const char *mtd_id = master->name;
+
+	/* parse command line */
+	if (!cmdline_parsed) {
+		err = mtdpart_setup_real(cmdline);
+		if (err)
+			return err;
+	}
+
+	/*
+	 * Search for the partition definition matching master->name.
+	 * If master->name is not set, stop at first partition definition.
+	 */
+	for (part = partitions; part; part = part->next) {
+		if ((!mtd_id) || (!strcmp(part->mtd_id, mtd_id)))
+			break;
+	}
+
+	if (!part)
+		return 0;
+
+	for (i = 0, offset = 0; i < part->num_parts; i++) {
+		if (part->parts[i].offset == OFFSET_CONTINUOUS)
+			part->parts[i].offset = offset;
+		else
+			offset = part->parts[i].offset;
+
+		if (part->parts[i].size == SIZE_REMAINING)
+			part->parts[i].size = master->size - offset;
+
+		if (offset + part->parts[i].size > master->size) {
+			printk(KERN_WARNING ERRP
+			       "%s: partitioning exceeds flash size, truncating\n",
+			       part->mtd_id);
+			part->parts[i].size = master->size - offset;
+		}
+		offset += part->parts[i].size;
+
+		if (part->parts[i].size == 0) {
+			printk(KERN_WARNING ERRP
+			       "%s: skipping zero sized partition\n",
+			       part->mtd_id);
+			part->num_parts--;
+			memmove(&part->parts[i], &part->parts[i + 1],
+				sizeof(*part->parts) * (part->num_parts - i));
+			i--;
+		}
+	}
+
+	*pparts = kmemdup(part->parts, sizeof(*part->parts) * part->num_parts,
+			  GFP_KERNEL);
+	if (!*pparts)
+		return -ENOMEM;
+
+	return part->num_parts;
+}
+
+
+/*
+ * This is the handler for our kernel parameter, called from
+ * main.c::checksetup(). Note that we can not yet kmalloc() anything,
+ * so we only save the commandline for later processing.
+ *
+ * This function needs to be visible for bootloaders.
+ */
+static int __init mtdpart_setup(char *s)
+{
+	cmdline = s;
+	return 1;
+}
+
+__setup("mtdparts=", mtdpart_setup);
+
+static struct mtd_part_parser cmdline_parser = {
+	.owner = THIS_MODULE,
+	.parse_fn = parse_cmdline_partitions,
+	.name = "cmdlinepart",
+};
+
+static int __init cmdline_parser_init(void)
+{
+	if (mtdparts)
+		mtdpart_setup(mtdparts);
+	register_mtd_parser(&cmdline_parser);
+	return 0;
+}
+
+static void __exit cmdline_parser_exit(void)
+{
+	deregister_mtd_parser(&cmdline_parser);
+}
+
+module_init(cmdline_parser_init);
+module_exit(cmdline_parser_exit);
+
+MODULE_PARM_DESC(mtdparts, "Partitioning specification");
+module_param(mtdparts, charp, 0);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Marius Groeger <mag@sysgo.de>");
+MODULE_DESCRIPTION("Command line configuration of MTD partitions");