David Brownell <[email protected]> writes:
> Appended is an updated version of a patch I sent around earlier.
>
> ====== CUT HERE
> From: David Brownell <[email protected]>
>
> Update NAND partitioning for the dm6446 evm, unmasking the hidden
> data at the beginning and letting the kernel be updated from Linux.
>
> - This is boot-compatible with TI's software (U-Boot 1.20 and both
> the 2.6.10 and 2.6.18 kernels), in terms of startup and loading
> kernels from flash.
>
> - In the same way, it's also boot-compatible with mainline U-Boot,
> which stores U-Boot params in block 0 not block 16.
>
> - It's not quite compatible with systems that previously used NAND
> partitions to hold (filesystem) data. The compatibilities are a
> bit different based on which kernel was used previously
> + Users of TI/MV kernels no longer see mtd2 "params"
> (mainline u-boot env is in a different place)
> * Filesystem is now mtd2 ... vs mtd3
> + Users of GIT kernels now see mtd0 and mtd1 partitions
> * Filesystem partition starts 640 KBytes earlier
> * Filesystem is now mtd2 ... vs mtd0
> * Linux now *uses* the flash-resident BBT
> * Removes annoying slowdown/hiccup during boot
> * Potentially ~64KB less space available with TI/MV kernels
>
> If you *used* NAND partitions from Linux, there is no solution that's
> fully compatible with all previous kernels in those respects ... ergo
> this "best compromise". It'd be good to back back up the filesystem
> data; or, carry your own backwards-compatibility patch for awhile.
>
> Signed-off-by: David Brownell <[email protected]>
> ---
> NOTE: if this gets merged, I've got a patch I'll submit to make
> mainline U-Boot default to this partition layout. (It now knows
> about "partitions".)
OK, I'll push this to DaVinci git today and will include it in
the series I'm pushing upstream.
Kevin
> arch/arm/mach-davinci/board-dm644x-evm.c | 35 ++++++++++++++++++++++++++---
> 1 file changed, 32 insertions(+), 3 deletions(-)
>
> --- a/arch/arm/mach-davinci/board-dm644x-evm.c
> +++ b/arch/arm/mach-davinci/board-dm644x-evm.c
> @@ -120,20 +120,49 @@ static struct platform_device davinci_ev
> .resource = &davinci_evm_norflash_resource,
> };
>
> +/* DM644x EVM includes a 64 MByte small-page NAND flash (16K blocks).
> + * It may used instead of the (default) NOR chip to boot, using TI's
> + * tools to install the secondary boot loader (UBL) and U-Boot.
> + */
> struct mtd_partition davinci_evm_nandflash_partition[] = {
> - /* 5 MB space at the beginning for bootloader and kernel */
> + /* Bootloader layout depends on whose u-boot is installed, but we
> + * can hide all the details.
> + * - block 0 for u-boot environment ... in mainline u-boot
> + * - block 1 for UBL (plus up to four backup copies in blocks 2..5)
> + * - blocks 6...? for u-boot
> + * - blocks 16..23 for u-boot environment ... in TI's u-boot
> + */
> {
> - .name = "NAND filesystem",
> - .offset = 5 * SZ_1M,
> + .name = "bootloader",
> + .offset = 0,
> + .size = SZ_256K + SZ_128K,
> + .mask_flags = MTD_WRITEABLE, /* force read-only */
> + },
> + /* Kernel */
> + {
> + .name = "kernel",
> + .offset = MTDPART_OFS_APPEND,
> + .size = SZ_4M,
> + .mask_flags = 0,
> + },
> + /* File system (older GIT kernels started this on the 5MB mark) */
> + {
> + .name = "filesystem",
> + .offset = MTDPART_OFS_APPEND,
> .size = MTDPART_SIZ_FULL,
> .mask_flags = 0,
> }
> + /* A few blocks at end hold a flash BBT ... created by TI's CCS
> + * using flashwriter_nand.out, but ignored by TI's versions of
> + * Linux and u-boot. We boot faster by using them.
> + */
> };
>
> static struct davinci_nand_pdata davinci_evm_nandflash_data = {
> .parts = davinci_evm_nandflash_partition,
> .nr_parts = ARRAY_SIZE(davinci_evm_nandflash_partition),
> .ecc_mode = NAND_ECC_HW,
> + .options = NAND_USE_FLASH_BBT,
> };
>
> static struct resource davinci_evm_nandflash_resource[] = {
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