Difference between revisions of "APF6 EMMC"
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==Links== | ==Links== | ||
* [http://fr.slideshare.net/linaroorg/intro-to-emmc http://fr.slideshare.net/linaroorg/intro-to-emmc] | * [http://fr.slideshare.net/linaroorg/intro-to-emmc http://fr.slideshare.net/linaroorg/intro-to-emmc] | ||
+ | * https://fr.wikipedia.org/wiki/Master_boot_record |
Revision as of 18:55, 17 July 2015
APF6 eMMC layout
By default, the 4GB eMMC on APF6 board has 4 physical/hardware partitions:
Boot0 | Boot1 | RPMB | User Data |
Name | U-Boot name | Size | Comment |
---|---|---|---|
boot0 | mmc dev 0 1 | 2MBytes | U-Boot is installed on this partition |
boot1 | mmc dev 0 2 | 2MBytes | Not used |
rpmb | mmc dev 0 3 | 512KBytes | Not used |
User Data | mmc dev 0 0 | remaining space | Kernel, device tree and rootfs |
Boot0 partition layout
. | SPL | IMG | ... | ENV1 | ... | ENV2 | ... |
- Linux device: /dev/mmcblk2boot0
Offset (blocks) | Offset (bytes) | Size (bytes) | Comment |
---|---|---|---|
0 | 0 | 1 KB (0x400) | Free |
0x02 | 1 KB (0x400) | 68 KB | U-Boot SPL (apf6-u-boot.spl) |
0x8a | 69 KB (0x11400) | 512 KB | U-Boot IMG (apf6-u-boot.img) |
Free | |||
0x800 (2048) | 1024 KB (0x100000) | 10 KB (0x2800) | U-Boot environment |
Free | |||
0xc00 (3072) | 1536 KB (0x180000) | 10 KB (0x2800) | Redundant U-Boot environment |
Free |
User Data partition layout
There are two primary partitions on the "User Data" physical partition:
... | Boot | Rootfs |
Name | U-Boot device | Linux device | Offset (blocks) | Size | Comment |
---|---|---|---|---|---|
MBR | NA | NA | 0 | 512 bytes (1 block) | Master Boot Record. (Don't touch it :-) ) |
... | NA | NA | 512 (1) | 1 MBytes (2047 blocks) | Free |
Boot | mmc 0:1 | /dev/mmcblk2p1 | 2048 (0x800) | 24 MBytes (49152 blocks) | The kernel and the device tree (inside a dtbs/ directory) are on this partition (ext4 formatted) |
Rootfs | mmc 0:2 | /dev/mmcblk2p2 | 51200 (0xc800) | Rest of space (< 7682048 blocks) | the rootfs is on this partition (ext4 formatted) |
- By default rootfs is only occupying the size of the .ext4 image flashed with U-Boot. If you want to increase the rootfs to all available free space then, after Linux has booted, use the following command:
# resize2fs /dev/mmcblk2p2
Rootfs will then be extended to all the "Rootfs" eMMC partition space.