fs: partitions: Add command line partitioning

Signed-off-by: Colin Cross <ccross@android.com>

5 files changed, 228 insertions, 0 deletions

diff --git a/fs/partitions/Kconfig b/fs/partitions/Kconfig
index cb5f0a3f1b03..6115cde646fa 100644
--- a/fs/partitions/Kconfig
+++ b/fs/partitions/Kconfig
@@ -249,3 +249,9 @@ config SYSV68_PARTITION
 	  partition table format used by Motorola Delta machines (using
 	  sysv68).
 	  Otherwise, say N.
+
+config CMDLINE_PARTITION
+       bool "Kernel command line partition table support" if PARTITION_ADVANCED
+       help
+	 Say Y here if you would like to pass the partition table for a device
+	 on the kernel command line.
diff --git a/fs/partitions/Makefile b/fs/partitions/Makefile
index 03af8eac51da..11e3a899559b 100644
--- a/fs/partitions/Makefile
+++ b/fs/partitions/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_IBM_PARTITION) += ibm.o
 obj-$(CONFIG_EFI_PARTITION) += efi.o
 obj-$(CONFIG_KARMA_PARTITION) += karma.o
 obj-$(CONFIG_SYSV68_PARTITION) += sysv68.o
+obj-$(CONFIG_CMDLINE_PARTITION) += cmdline.o
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index dba7af33ea3a..46170c82406a 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -38,6 +38,7 @@
 #include "efi.h"
 #include "karma.h"
 #include "sysv68.h"
+#include "cmdline.h"
 
 #ifdef CONFIG_BLK_DEV_MD
 extern void md_autodetect_dev(dev_t dev);
@@ -46,6 +47,9 @@ extern void md_autodetect_dev(dev_t dev);
 int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
 
 static int (*check_part[])(struct parsed_partitions *) = {
+#ifdef CONFIG_CMDLINE_PARTITION
+	cmdline_partition,
+#endif
 	/*
 	 * Probe partition formats with tables at disk address 0
 	 * that also have an ADFS boot block at 0xdc0.
diff --git a/fs/partitions/cmdline.c b/fs/partitions/cmdline.c
new file mode 100644
index 000000000000..8531acd5d9a3
--- /dev/null
+++ b/fs/partitions/cmdline.c
@@ -0,0 +1,194 @@
+/*
+ * fs/partitions/cmdline.c
+ *
+ * Copyright (C) 2010 Google, Inc.
+ * Author: Colin Cross <ccross@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+/*#define DEBUG 1*/
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+
+#include "check.h"
+#include "cmdline.h"
+
+static char *cmdline;
+static int cmdline_parsed;
+static struct part_device *cmdline_device;
+
+struct part {
+	char *name;
+	unsigned long from;
+	unsigned long size;
+	unsigned long sector_size;
+	struct part *next_part;
+};
+
+struct part_device {
+	char *name;
+	struct part *first_part;
+	struct part_device *next_device;
+};
+
+
+/* Passed a string like:
+ * system:3600:10000:800
+ */
+static struct part *parse_partition(char *s, int alloc_size, void **alloc)
+{
+	char *p;
+	struct part *this_part;
+	pr_debug("%s: '%s', %d, %p\n", __func__, s, alloc_size, alloc);
+
+	if (*alloc == NULL)
+		*alloc = kzalloc(alloc_size, GFP_KERNEL);
+
+	this_part = *alloc;
+	*alloc += sizeof(*this_part);
+
+	/* Name */
+	p = strchr(s, ':');
+	if (!p)
+		return this_part;
+	*p = 0;
+	this_part->name = s;
+
+	/* From */
+	s = p+1;
+	p = strchr(s, ':');
+	if (!p)
+		return this_part;
+	*p = 0;
+	this_part->from = simple_strtoul(s, NULL, 16);
+
+	/* Size */
+	s = p+1;
+	p = strchr(s, ':');
+	if (!p)
+		return this_part;
+	*p = 0;
+	this_part->size = simple_strtoul(s, NULL, 16);
+
+	/* Sector size */
+	s = p+1;
+	this_part->sector_size = simple_strtoul(s, NULL, 16);
+	pr_debug("%s: Found %s %lu %lu %lu\n", __func__, this_part->name,
+		this_part->from, this_part->size, this_part->sector_size);
+	return this_part;
+}
+
+/* Passed a string like:
+ * system:3600:10000:800,cache:13600:4000:800,userdata:17600:80000:800
+ * Could be an empty string
+ */
+static struct part *parse_partition_list(char *s, int alloc_size, void **alloc)
+{
+	char *p;
+	struct part *this_part;
+	struct part *next_part = NULL;
+	pr_debug("%s: '%s', %d, %p\n", __func__, s, alloc_size, alloc);
+
+	alloc_size += sizeof(struct part);
+	p = strchr(s, ',');
+	if (p) {
+		*p = 0;
+		next_part = parse_partition_list(p+1, alloc_size, alloc);
+		if (!next_part)
+			BUG();
+	}
+	this_part = parse_partition(s, alloc_size, alloc);
+	this_part->next_part = next_part;
+	return this_part;
+}
+/* Passed a string like:
+ * sdhci.0=system:3600:10000:800,cache:13600:4000:800,userdata:17600:80000:800
+ */
+static struct part_device *parse_device(char *s, int alloc_size, void **alloc) {
+	char *p;
+	struct part *part;
+	struct part_device *device;
+
+	pr_debug("%s: '%s', %d, %p\n", __func__, s, alloc_size, alloc);
+	p = strchr(s, '=');
+	if (!p)
+		return NULL;
+	*p = 0;
+	alloc_size += sizeof(struct part_device);
+	part = parse_partition_list(p+1, alloc_size, alloc);
+	if (part) {
+		device = *alloc;
+		*alloc += sizeof(struct part_device);
+		device->name = s;
+		device->first_part = part;
+	}
+	return device;
+}
+
+
+static void parse_cmdline(void) {
+	char *s = cmdline;
+	void *alloc = 0;
+	if (cmdline_parsed)
+		return;
+	cmdline_device = parse_device(s, 0, &alloc);
+	cmdline_parsed = 1;
+}
+
+
+int copy_partitions_to_state(struct part_device *device,
+	struct parsed_partitions *state, unsigned int ssz)
+{
+	int i = 0;
+	struct part *part = device->first_part;
+	while (part) {
+		sector_t from = part->from * part->sector_size / ssz;
+		sector_t size = part->size * part->sector_size / ssz;
+		put_named_partition(state, i+1, from, size, part->name,
+			strlen(part->name));
+		i++;
+		part = part->next_part;
+	}
+	return i;
+}
+
+int cmdline_partition(struct parsed_partitions *state)
+{
+	struct block_device *bdev = state->bdev;
+	unsigned int ssz = bdev_logical_block_size(bdev);
+	parse_cmdline();
+	pr_debug("%s: %s\n", __func__, dev_name(disk_to_dev(bdev->bd_disk)));
+
+	if (!cmdline_device)
+		return 0;
+
+	if (strcmp(cmdline_device->name, dev_name(disk_to_dev(bdev->bd_disk))))
+		return 0;
+
+	/* We have a command line partition that matches this device */
+	copy_partitions_to_state(cmdline_device, state, ssz);
+	return 1;
+}
+
+
+__init static int cmdline_partition_setup(char *s)
+{
+	cmdline = s;
+	return 1;
+}
+
+__setup("tegrapart=", cmdline_partition_setup);
+
+
diff --git a/fs/partitions/cmdline.h b/fs/partitions/cmdline.h
new file mode 100644
index 000000000000..68dfd2c51b28
--- /dev/null
+++ b/fs/partitions/cmdline.h
@@ -0,0 +1,23 @@
+/*
+ * fs/partitions/cmdline.h
+ *
+ * Copyright (C) 2010 Google, Inc.
+ * Author: Colin Cross <ccross@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#ifndef FS_PART_CMDLINE_H
+#define FS_PART_CMDLINE_H
+
+extern int cmdline_partition(struct parsed_partitions *state);
+
+#endif