PHYTEC
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Enable background operations handshake [BKOPS_EN]: 0x01
#OR
Enable background operations handshake [BKOPS_EN]: 0x00
Where value 0x00 means
is disabled and device write performance suffers. Where value 0x01 means
is enabled and the host
BKOPS_EN
BKOPS_EN
will issue background operations from time to time.
To set the
bit execute:
BKOPS_EN
target$ mmc bkops enable /dev/mmcblk2
To ensure that the new setting is taken over and the kernel triggers BKOPS by itself, shut down the system with:
eMMC Boot Partitions
An eMMC device contains four different hardware partitions:
,
,
and
.
user boot1 boot2,
rpmb
The
partition is called the
in the JEDEC standard and is the main storage partition. The partitions
and
can be used to
user
User Data Area
boot1
boot2
host the bootloader and are more reliable. Which partition the i.MX 8M Plus uses to load the bootloader is controlled by the boot configuration of the
eMMC device. The partition
is a small partition and can only be accessed via
.
rpmb
trusted mechanism
Furthermore, the
partition can be divided into four user-defined
. An explanation of this feature exceeds the scope of
user
General Purpose Area Partitions
this document. For further information, see the JEDEC Standard chapter "7.2 Partition Management".
The current PHYTEC BSP does not use the extra partitioning feature of eMMC devices. The
is flashed at the beginning of the
partition. The
u-boot
user
u-
environment is placed at a fixed location after the
. An MBR partition table is used to create two partitions, a FAT32 boot, and
boot
u-boot
ext4 rootfs
partition. They are located right after the
and the
environment. The FAT32 boot partition contains the kernel and device tree.
u-boot
u-boot
There are two ways to flash the bootloader to one of the two boot partitions and to switch the boot device: via bootloader or via userspace commands as
shown in the following examples.
1. Via bootloader
Detect the eMMC if not already done:
bootloader$ mmc rescan
List all detected MMC devices:
bootloader$ mmc list
FSL_SDHC: 1 (SD)
FSL_SDHC: 2
Select eMMC device:
bootloader$ mmc dev 2
switch to partitions #0, OK
mmc2(part 0) is current device
Query some information about the eMMC device:
bootloader$ mmc info
Tip
The
bit is a one-time-programmable only. It cannot be reversed.
BKOPS_EN
Tip
Do not confuse eMMC partitions with partitions of a DOS, MBR, or GPT partition table.
