aw3som3: hax the partition table!

Developers have long tried to sqeeze in ROMs into legacy
devices with low internal memory, and one of the ways to
do this was by using custom tailored mtd_parts, which
gave the kernel a partition table to use, with resized
partitions. This was widely used on many devices like
the HTC G1, MT3G, Hero, Evo4G, Desire, etc.

While that was a viable option for the HTC Pico, a small
"problem" that popped up was that different phones have
different NAND Devices, with different partition tables
and pagesizes. Incase the modified custom mtd_parts even
*accidentally* touched the boot partition, or has been
offset'ed out of the available space, a partition would
be *lost*.

As a solution, dynamically obtain 32 mB from userdata
partition, and 48 mB from the cache partition, and hax
the partition table as soon as the information is got
from ATAG. This should make this method work on *almost*
all Pico's out there, which have partition layouts as
misc:recovery:boot:system:cache:userdata:devlog and
partitions in the order misc:rec..cache:devlog:userdata.

Enable PICO_NAND_RESIZE_PART in defconfigs.

PS1: initial, add logging
PS2: add the hax
PS3: remove logging from mtdpart.c
PS4: remove notes for self
PS5: whitespace fix
PS6: unbloat code
PS7: unbloat code (again)
PS8: Add KConfig option

Change-Id: I2d1eefa72ded09cf48b8f649da812c4d4a5ffb15
Signed-off-by: Vineeth Raj <contact.twn@opmbx.org>

arch/arm/mach-msm/Kconfig

@@ -315,6 +315,16 @@ config MACH_PICO
 		help
 			Support for Pico (PDA phone).
 
+config PICO_NAND_RESIZE_PART
+		depends on MACH_PICO
+		bool "Repartition NAND Devices on Pico"
+		default n
+		help
+			dynamically resize the system partiton by obtaining
+			32 mB from userdata partition, and 48 mB from the
+			cache partition, and hax the partition table as soon
+			as the information is got from ATAG.
+
 config MACH_GOLFU
 		depends on ARCH_MSM7X27A
 		depends on !MSM_STACKED_MEMORY

arch/arm/mach-msm/nand_partitions.c

@@ -5,6 +5,7 @@
  *
  * Copyright (C) 2007 Google, Inc.
  * Copyright (c) 2008-2009, Code Aurora Forum. All rights reserved.
+ * Copyright (c) 2014, Vineeth Raj <contact.twn@opmbx.org>.
  * Author: Brian Swetland <swetland@google.com>
  *
  * This software is licensed under the terms of the GNU General Public
@@ -86,6 +87,18 @@ static int __init parse_tag_msm_partition(const struct tag *tag)
 	msm_nand_data.nr_parts = count;
 	msm_nand_data.parts = msm_nand_partitions;
 
+#ifdef CONFIG_PICO_NAND_RESIZE_PART
+#define PICO_PART_BOOT 2
+	unsigned one_mb = 0;
+	for (one_mb = 0, n = 0; n < msm_nand_partitions[PICO_PART_BOOT].size; one_mb++, n+=4) ;
+	msm_nand_partitions[PICO_PART_BOOT + 2].size -= (48 * one_mb);
+	msm_nand_partitions[PICO_PART_BOOT + 3].size -= (32 * one_mb);
+	msm_nand_partitions[PICO_PART_BOOT + 1].size += (80 * one_mb);
+	msm_nand_partitions[PICO_PART_BOOT + 2].offset = msm_nand_partitions[PICO_PART_BOOT + 1].offset + msm_nand_partitions[PICO_PART_BOOT + 1].size;
+	msm_nand_partitions[PICO_PART_BOOT + 4].offset = msm_nand_partitions[PICO_PART_BOOT + 2].offset + msm_nand_partitions[PICO_PART_BOOT + 2].size;
+	msm_nand_partitions[PICO_PART_BOOT + 3].offset = msm_nand_partitions[PICO_PART_BOOT + 4].offset + msm_nand_partitions[PICO_PART_BOOT + 4].size;
+#endif
+
 	return 0;
 }