mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-11 05:42:58 +00:00
e03aa34bdf
On iMX8MM with Fast Boot fuse blown, the SIT and A-copy image are placed at different offset than on iMX8MM with Fast Boot fuse NOT blown. List both options and both offsets to avoid confusion. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Marcel Ziswiler <marcel.ziswiler@toradex.com> Cc: Peng Fan <peng.fan@nxp.com> Cc: Stefano Babic <sbabic@denx.de> Cc: Ye Li <ye.li@nxp.com> Cc: uboot-imx <uboot-imx@nxp.com> Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
176 lines
6.5 KiB
ReStructuredText
176 lines
6.5 KiB
ReStructuredText
i.MX7D/i.MX8MM SRC_GPR10 PERSIST_SECONDARY_BOOT for bootloader A/B switching
|
|
============================================================================
|
|
|
|
Introduction
|
|
------------
|
|
Since at least iMX53 until iMX8MM, it is possible to have two copies of
|
|
bootloader in SD/eMMC and switch between them. The switch is triggered
|
|
either by the BootROM in case the bootloader image is faulty OR can be
|
|
enforced by the user.
|
|
|
|
Operation
|
|
---------
|
|
#. Upon Power-On Reset (POR)
|
|
|
|
- SRC_GPR10 bit PERSIST_SECONDARY_BOOT is set to 0
|
|
- BootROM attempts to start bootloader A-copy
|
|
|
|
- if A-copy valid
|
|
|
|
- BootROM starts A-copy
|
|
- END
|
|
|
|
- if A-copy NOT valid
|
|
|
|
- BootROM sets SRC_GPR10 bit PERSIST_SECONDARY_BOOT to 1
|
|
- BootROM triggers WARM reset, GOTO 1)
|
|
- END
|
|
|
|
#. Upon COLD Reset
|
|
|
|
- GOTO 1)
|
|
- END
|
|
|
|
#. Upon WARM Reset
|
|
|
|
- SRC_GPR10 bit PERSIST_SECONDARY_BOOT is retained
|
|
|
|
- if SRC_GPR10 bit PERSIST_SECONDARY_BOOT is 0
|
|
|
|
- BootROM attempts to start bootloader A-copy
|
|
|
|
- if A-copy valid
|
|
|
|
- BootROM starts A-copy
|
|
- END
|
|
|
|
- if A-copy NOT valid
|
|
|
|
- BootROM sets SRC_GPR10 bit PERSIST_SECONDARY_BOOT to 1
|
|
- BootROM triggers WARM reset. GOTO 1.3)
|
|
- END
|
|
|
|
- if SRC_GPR10 bit PERSIST_SECONDARY_BOOT is 1
|
|
|
|
- BootROM attempts to start bootloader B-copy
|
|
|
|
- if B-copy valid
|
|
|
|
- BootROM starts B-copy
|
|
- END
|
|
|
|
- if B-copy NOT valid
|
|
- System hangs
|
|
- END
|
|
|
|
Setup
|
|
-----
|
|
The bootloader A-copy must be placed at predetermined offset in SD/eMMC. The
|
|
bootloader B-copy area offset is determined by an offset stored in Secondary
|
|
Image Table (SIT). The SIT must be placed at predetermined offset in SD/eMMC.
|
|
|
|
The following table contains offset of SIT, bootloader A-copy and recommended
|
|
bootloader B-copy offset. The offsets are in 512 Byte sector units (that is
|
|
offset 0x1 means 512 Bytes from the start of SD/eMMC card data partition).
|
|
For details on the addition of two numbers in recommended B-copy offset, see
|
|
SIT format below.
|
|
|
|
+----------+-----------------------------+--------------------+-----------------------+-----------------------------+
|
|
| SoC | Boot Device Type | SIT offset (fixed) | A-copy offset (fixed) | B-copy offset (recommended) |
|
|
+----------+-----------------------------+--------------------+-----------------------+-----------------------------+
|
|
| iMX7D | | 0x1 | 0x2 | 0x800+0x2 |
|
|
+----------+-----------------------------+--------------------+-----------------------+-----------------------------+
|
|
| iMX8MM | SD/eSD/MMC/eMMC normal boot | 0x41 | 0x42 | 0x1000+0x42 |
|
|
+----------+-----------------------------+--------------------+-----------------------+-----------------------------+
|
|
| iMX8MM | eMMC Fast boot fuse blown | 0x1 | 0x2 | 0x1000+0x2 |
|
|
+----------+-----------------------------+--------------------+-----------------------+-----------------------------+
|
|
|
|
SIT format
|
|
~~~~~~~~~~
|
|
SIT is a 20 byte long structure containing of 5 32-bit words. Those encode
|
|
bootloader B-copy area offset (called "firstSectorNumber"), magic value
|
|
(called "tag") that is always 0x00112233, and three unused words set to 0.
|
|
SIT is documented in [1]_ and [2]_. Example SIT are below::
|
|
|
|
$ hexdump -vC sit-mx7d.bin
|
|
00000000 00 00 00 00
|
|
00000004 00 00 00 00
|
|
00000008 33 22 11 00 <--- This is the "tag"
|
|
0000000c 00 08 00 00 <--- This is the "firstSectorNumber"
|
|
00000010 00 00 00 00
|
|
|
|
$ hexdump -vC sit-mx8mm.bin
|
|
00000000 00 00 00 00
|
|
00000004 00 00 00 00
|
|
00000008 33 22 11 00 <--- This is the "tag"
|
|
0000000c 00 10 00 00 <--- This is the "firstSectorNumber"
|
|
00000010 00 00 00 00
|
|
|
|
B-copy area offset ("firstSectorNumber") is offset, in units of 512 Byte
|
|
sectors, that is added to the start of boot media when switching between
|
|
A-copy and B-copy. For A-copy, this offset is 0x0. For B-copy, this offset
|
|
is determined by SIT (e.g. if firstSectorNumber is 0x1000 as it is above
|
|
in sit-mx8mm.bin, then the B-copy offset is 0x1000 sectors = 2 MiB).
|
|
|
|
Bootloader A-copy (e.g. u-boot.imx or flash.bin) is placed at fixed offset
|
|
from A-copy area offset (e.g. 0x2 sectors from sector 0x0 for iMX7D, which
|
|
means u-boot.imx A-copy must be written to sector 0x2).
|
|
|
|
The same applies to bootloader B-copy, which is placed at fixed offset from
|
|
B-copy area offset determined by SIT (e.g. 0x2 sectors from sector 0x800 [see
|
|
sit-mx7d.bin example above, this can be changed in SIT firstSectorNumber] for
|
|
iMX7D, which means u-boot.imx B-copy must be written to sector 0x802)
|
|
|
|
**WARNING:**
|
|
B-copy area offset ("firstSectorNumber") is NOT equal to bootloader
|
|
(image, which is u-boot.imx or flash.bin) B-copy offset.
|
|
|
|
To generate SIT, use for example the following bourne shell printf command::
|
|
|
|
$ printf '\x0\x0\x0\x0\x0\x0\x0\x0\x33\x22\x11\x00\x00\x08\x00\x00\x0\x0\x0\x0' > sit-mx7d.bin
|
|
$ printf '\x0\x0\x0\x0\x0\x0\x0\x0\x33\x22\x11\x00\x00\x10\x00\x00\x0\x0\x0\x0' > sit-mx8mm.bin
|
|
|
|
Write bootloader A/B copy and SIT to SD/eMMC
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Examples of writing SIT and two copies of bootloader to SD or eMMC:
|
|
|
|
- iMX8MM, SD card at /dev/sdX, Linux command line
|
|
::
|
|
|
|
$ dd if=sit-mx8mm.bin of=/dev/sdX bs=512 seek=65
|
|
$ dd if=flash.bin of=/dev/sdX bs=512 seek=66
|
|
$ dd if=flash.bin of=/dev/sdX bs=512 seek=4162
|
|
|
|
- iMX8MM, eMMC 1 data partition, U-Boot command line
|
|
::
|
|
|
|
=> mmc partconf 1 0 0 0
|
|
|
|
=> dhcp ${loadaddr} sit-mx8mm.bin
|
|
=> mmc dev 1
|
|
=> mmc write ${loadaddr} 0x41 0x1
|
|
|
|
=> dhcp ${loadaddr} flash.bin
|
|
=> setexpr blkcnt ${filesize} + 0x1ff && setexpr blkcnt ${blkcnt} / 0x200
|
|
=> mmc dev 1
|
|
=> mmc write ${loadaddr} 0x42 ${blkcnt}
|
|
=> mmc write ${loadaddr} 0x1042 ${blkcnt}
|
|
|
|
WARM reset into B-copy using WDT
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
To perform a reboot into B-copy, the PERSIST_SECONDARY_BOOT must be set
|
|
in SRC_GPR10 register. Example on iMX8MM::
|
|
|
|
=> mw 0x30390098 0x40000000
|
|
|
|
A WARM reset can be triggered using WDT as follows::
|
|
|
|
=> mw.w 0x30280000 0x25
|
|
|
|
References
|
|
----------
|
|
|
|
.. [1] i.MX 7Dual Applications Processor Reference Manual, Rev. 1, 01/2018 ; section 6.6.5.3.5 Redundant boot support for expansion device
|
|
.. [2] i.MX 8M Mini Applications Processor Reference Manual, Rev. 3, 11/2020 ; section 6.1.5.4.5 Redundant boot support for expansion device
|