Added commandline partitions for block devices

Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/305
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>
Reviewed-by: Linus WALLEIJ <linus.walleij@stericsson.com>
Tested-by: Linus WALLEIJ <linus.walleij@stericsson.com>
Signed-off-by: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
Change-Id: Ic462a434f735fd722bb9f6a68560d1d1120ff024
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/2370

5 files changed, 165 insertions, 0 deletions

diff --git a/fs/partitions/Kconfig b/fs/partitions/Kconfig
index cb5f0a3f1b0..097be1934ee 100644
--- a/fs/partitions/Kconfig
+++ b/fs/partitions/Kconfig
@@ -68,6 +68,25 @@ config ACORN_PARTITION_RISCIX
 	  of machines called RISCiX.  If you say 'Y' here, Linux will be able
 	  to read disks partitioned under RISCiX.
 
+config BLKDEV_PARTITION
+	bool "Blockdev commandline partition support" if PARTITION_ADVANCED
+	default n
+	help
+	  Say Y if you like to setup partitions for block devices by reading
+	  from the kernel command line (kernel boot arguments).
+
+	  The format of the partitions on the command line:
+	  blkdevparts=<blkdev-def>[;<blkdev-def>]
+	  <blkdev-def> := <blkdev-id>:<partdef>[,<partdef>]
+	  <partdef>    := <size>[@<offset>]
+
+	  <blkdev-id>  := unique id used to map driver to blockdev name
+	  <size>       := size in numbers of sectors
+	  <offset>     := offset in sectors for partition to start at
+
+	  Example:
+	  blkdevparts=mmc0:1024@0,524288@1024;mmc1:8192@0,8192@8192
+
 config OSF_PARTITION
 	bool "Alpha OSF partition support" if PARTITION_ADVANCED
 	default y if ALPHA
diff --git a/fs/partitions/Makefile b/fs/partitions/Makefile
index 03af8eac51d..48b216c53db 100644
--- a/fs/partitions/Makefile
+++ b/fs/partitions/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_BLOCK) := check.o
 obj-$(CONFIG_ACORN_PARTITION) += acorn.o
 obj-$(CONFIG_AMIGA_PARTITION) += amiga.o
 obj-$(CONFIG_ATARI_PARTITION) += atari.o
+obj-$(CONFIG_BLKDEV_PARTITION) += blkdev_parts.o
 obj-$(CONFIG_MAC_PARTITION) += mac.o
 obj-$(CONFIG_LDM_PARTITION) += ldm.o
 obj-$(CONFIG_MSDOS_PARTITION) += msdos.o
diff --git a/fs/partitions/blkdev_parts.c b/fs/partitions/blkdev_parts.c
new file mode 100755
index 00000000000..48f4136d720
--- /dev/null
+++ b/fs/partitions/blkdev_parts.c
@@ -0,0 +1,127 @@
+/*
+ *
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * Author: Ulf Hansson <ulf.hansson@stericsson.com> for ST-Ericsson
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Create partitions for block devices by reading from the kernel
+ * command line (kernel boot arguments).
+ *
+ */
+
+#include "check.h"
+#include "blkdev_parts.h"
+
+static char *cmdline;
+
+/*
+ * This is the handler for our kernel commandline parameter,
+ * called from main.c::checksetup().
+ * Note that we can not yet kmalloc() anything, so we only save
+ * the commandline for later processing.
+ */
+static int cmdline_setup(char *s)
+{
+	cmdline = s;
+	return 1;
+}
+__setup("blkdevparts=", cmdline_setup);
+
+/* Parse for a matching blkdev-id and return pointer to partdef */
+static char *parse_blkdev_id(char *blkdev_name)
+{
+	int blkdev_id_len;
+	char *p, *blkdev_id;
+
+	/* Start parsing for a matching blkdev-id */
+	p = blkdev_id = cmdline;
+	while (blkdev_id != NULL) {
+
+		/* Find the end of the blkdev-id string */
+		p = strchr(blkdev_id, ':');
+		if (p == NULL)
+			return NULL;
+
+		/* Check if we found a matching blkdev-id */
+		blkdev_id_len = p - blkdev_id;
+		if (strlen(blkdev_name)	== blkdev_id_len) {
+			if (strncmp(blkdev_name, blkdev_id, blkdev_id_len) == 0)
+				return p;
+		}
+
+		/* Move to next blkdev-id string if there is one */
+		blkdev_id = strchr(p, ';');
+		if (blkdev_id != NULL)
+			blkdev_id++;
+	}
+	return NULL;
+}
+
+static int parse_partdef(char **part, struct parsed_partitions *state, int part_nbr)
+{
+	sector_t size, offset;
+	char *p = *part;
+
+	/* Skip the beginning "," or ":" */
+	p++;
+
+	/* Fetch and verify size from partdef */
+	size = simple_strtoull(p, &p, 10);
+	if ((size == 0) || (*p != '@'))
+		return 0;
+
+	/* Skip the "@" */
+	p++;
+
+	/* Fetch offset from partdef and check if there are more parts */
+	offset = simple_strtoull(p, &p, 10);
+	if (*p == ',')
+		*part = p;
+	else
+		*part = NULL;
+
+	/* Add partition to state */
+	put_partition(state, part_nbr, offset, size);
+	printk(KERN_INFO "\nPartition: size=%llu, offset=%llu\n",
+		(unsigned long long) size,
+		(unsigned long long) offset);
+	return 1;
+}
+
+static int parse_blkdev_parts(char *blkdev_name, struct parsed_partitions *state)
+{
+	char *partdef;
+	int part_nbr = 0;
+
+	/* Find partdef */
+	partdef = parse_blkdev_id(blkdev_name);
+
+	/* Add parts */
+	while (partdef != NULL) {
+		/* Find next part and add it to state */
+		part_nbr++;
+		if (!parse_partdef(&partdef, state, part_nbr))
+			return 0;
+	}
+	return part_nbr;
+}
+
+int blkdev_partition(struct parsed_partitions *state, struct block_device *bdev)
+{
+	char blkdev_name[BDEVNAME_SIZE];
+
+	/* Check if there are any partitions to handle */
+	if (cmdline == NULL)
+		return 0;
+
+	/* Get the name of the blockdevice we are operating upon */
+	if (bdevname(bdev, blkdev_name) == NULL) {
+		printk(KERN_WARNING "Could not get a blkdev name\n");
+		return 0;
+	}
+
+	/* Parse for partitions and add them to the state */
+	return parse_blkdev_parts(blkdev_name, state);
+}
+
diff --git a/fs/partitions/blkdev_parts.h b/fs/partitions/blkdev_parts.h
new file mode 100755
index 00000000000..e6c5d40ed76
--- /dev/null
+++ b/fs/partitions/blkdev_parts.h
@@ -0,0 +1,14 @@
+/*
+ *
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * Author: Ulf Hansson <ulf.hansson@stericsson.com> for ST-Ericsson
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Create partitions for block devices by reading from the kernel
+ * command line (kernel boot arguments).
+ *
+ */
+
+int blkdev_partition(struct parsed_partitions *state, struct block_device *bdev);
+
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index e238ab23a9e..e6690592e70 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -27,6 +27,7 @@
 #include "acorn.h"
 #include "amiga.h"
 #include "atari.h"
+#include "blkdev_parts.h"
 #include "ldm.h"
 #include "mac.h"
 #include "msdos.h"
@@ -50,6 +51,9 @@ static int (*check_part[])(struct parsed_partitions *, struct block_device *) =
 	 * Probe partition formats with tables at disk address 0
 	 * that also have an ADFS boot block at 0xdc0.
 	 */
+#ifdef CONFIG_BLKDEV_PARTITION
+	blkdev_partition,
+#endif
 #ifdef CONFIG_ACORN_PARTITION_ICS
 	adfspart_check_ICS,
 #endif