[meta-freescale] Boot on eMMC

[Thomas]

Gary Thomas <gary at ...> writes:

> 
> On 2015-04-14 08:28, Otavio Salvador wrote:
> > On Tue, Apr 14, 2015 at 11:12 AM, Shanx <shanx at ...> wrote:
> >> Hello,
> >> I've tried a lot of things, but I can't boot on eMMC. I've flashed it 
from
> >> u-boot, or from the system (booted from the sdcard). For exemple, I've 
tried
> >> : dd if=rootfs.sdcard of=/dev/mmcblk3
> >> I've also tried to flash only u-boot.imx (with dd and seek=2)
> >>
> >> When booting on eMMC (with the boot switch setup given on the Linux 
User
> >> Guide), nothing append. Any idea why ?
> >
> > eMMC has some details which differ from the uSD normal usage. Mainly
> > regarding the use of Boot Partitions. So you must to write it to the
> > boot partition otherwise it won't work.
> >
> 
> I'm not sure this is correct.  I have an i.MX6Q board which has
> eMMC on SD4 and SD on SD3 and I can boot from either, using the
> same command to install U-Boot
>    dd if=/tmp/disk/${UBOOT_NAME} of=${DISK} seek=2 bs=512 conv=notrunc
> 
> Maybe it's a difference in the eMMC device (mine is Sandisk SDIN5 (or7)C2-
32G-L)
> 
Then you're actually booting in SD fallback mode (if your board is 
configured for emmc boot). To boot in emmc mode place u-boot on one of the 
boot partitions and enable the correct boot partition for boot via sysfs.

First enable write to boot partition:
echo 0 > /sys/block/mmcblk0boot0/force_ro

Write uboot:
dd if=u-boot.imx of=/dev/mmcblk0boot0 bs=512 seek=2

Re-enable read-only access to the boot partition:
echo 1 > /sys/block/mmcblk0boot0/force_ro

Then boot partition (here 0) must be activated e.g. like this:
echo 8 > /sys/devices/platform/sdhci-esdhc-
imx.1/mmc_host/mmc0/mmc0:0001/boot_config

Then set the fuses/gpio for emmc boot.