Hi Roy,
On 08-06-15 10:38, Roy Spliet wrote:
Hello Michal,
Op 07-06-15 om 18:48 schreef Michal Suchanek:
Hello,
On 5 June 2015 at 13:52, Roy Spliet <r.spl...@ultimaker.com> wrote:
Based on the default layout of the android image used at least on Olimex Lime
Signed-off-by: Roy Spliet <r.spl...@ultimaker.com>
---
include/configs/sunxi-common.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/include/configs/sunxi-common.h b/include/configs/sunxi-common.h
index ec28c40..b38f2f5 100644
--- a/include/configs/sunxi-common.h
+++ b/include/configs/sunxi-common.h
@@ -404,8 +404,15 @@ extern int soft_i2c_gpio_scl;
#define BOOT_TARGET_DEVICES_USB(func)
#endif
+#ifdef CONFIG_NAND
+#define BOOT_TARGET_DEVICES_NAND(func) func(NAND, nand , 0)
+#else
+#define BOOT_TARGET_DEVICES_NAND(func)
+#endif
+
#define BOOT_TARGET_DEVICES(func) \
BOOT_TARGET_DEVICES_MMC(func) \
+ BOOT_TARGET_DEVICES_NAND(func) \
BOOT_TARGET_DEVICES_SCSI(func) \
BOOT_TARGET_DEVICES_USB(func) \
func(PXE, pxe, na) \
@@ -441,6 +448,8 @@ extern int soft_i2c_gpio_scl;
MEM_LAYOUT_ENV_SETTINGS \
"fdtfile=" CONFIG_DEFAULT_DEVICE_TREE ".dtb\0" \
"console=ttyS0,115200\0" \
+ "mtdids=nand0=mtd2\0" \
+ "mtdparts=mtdparts=mtd2:0xffc00000@0x400000(nand0_main)\0" \
BOOTENV
From what I heard the nand boot partition size should be specified in
nand pages rather than bytes because the boot rom loads a fixed number
of pages and just uses the start of each page regardless of page size.
Although I believe you have the facts mostly right, they do not apply in this
situation.
What you are looking for is the partition definition for U-boot. At this point
the boot
rom (BROM) is no longer active and thus it's inner workings are mostly
irrelevant.
The NAND partition lay-out for the boards I have seen (various Olimex +
Cubietruck..)
are as follows:
0-2MB U-Boot-SPL + U-Boot
2-4MB U-Boot SPL + U-Boot (for recovery)
4MB+ Main file system
The mtdparts env variable defines only the main file system because that's the
only
place with relevant files for U-Boot.
This said: I have replaced the default file system with a "custom" UBI FS
containing
just a boot and a rootfs partition. I am unsure whether these defaults apply
for the
Android image that ships with the Olimex boards. But then again: that image also
ships with a boot-loader, so do we care?
I did not find any document regarding the nand boot partition layout
so I would like to see some input from somebody familiar with the
driver.
While it is fine for testing to hand-edit the environment the final
nand support should have
1) way to express the boot partition size in nand pages
2) way to make the main partition start at the end of boot partition
and extend to the end of the flash
This should probably also go to Linux.
Linux can define partitions in the device tree. I'd prefer to carry this
approach to U-boot,
but current U-Boot has the partitioning part of the MTD code hacked away and
replaced by
custom mtdparts code without OF support. Doing this proper requires getting rid
of the
latter, which will likely break a lot of legacy. So as far as I agree, I have
to warn that is
a longer-term project, extended further by the ongoing (justified) discussion
we are having
regarding the MTD partitioning code in upstream Linux that may or may not lead
to parts
of the framework being re-architected.
Last time I discussed this with some kernel people, they pointed me to the fact
that
the kernel actually parses partition info provided by u-boot through the u-boot
mtdparts
command, and that that is the preferred way to pass partition info to the
kernel, so rather
then adding dts partition info to u-boot we would need to teach the existing
kernel mtdpart
code to deal with separate ecc / random setting and maybe use a list of
hardcoded
partitition names for which to use the brom compatible settings. These are all
things
which we need to figure out on the kernel side, it would be good to get a
discussion
started on this with the kernel mtd people.
Note that we will also need to have a u-boot env partition somewhare either at
the
nandpart level, or as a ubi volume, assuming the u-boot env code can deal with
ubi volumes (we are in the full u-boot environment when reading the env.)
Regards,
Hans
Roy
Thanks
Michal
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