doc: move i.MX7D/i.MX8MM A/B booting to board specific

Having "i.MX7D/i.MX8MM SRC_GPR10 PERSIST_SECONDARY_BOOT for bootloader A/B
switching" at the top level of the documentation tree does not make sense.
Move it to board specific information.

Fixes: 59e3d1bd4992 ("doc: imx: psb: Document usage of SRC_GPR10 PERSIST_SECONDARY_BOOT for A/B switching")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

3 files changed, 0 insertions, 192 deletions

diff --git a/doc/imx/index.rst b/doc/imx/index.rst
deleted file mode 100644
index b225b1d183..0000000000
--- a/doc/imx/index.rst
+++ /dev/null
@@ -1,9 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0+
-
-NXP i.MX Machine-specific doc
-=============================
-
-.. toctree::
-   :maxdepth: 2
-
-   misc/index
diff --git a/doc/imx/misc/index.rst b/doc/imx/misc/index.rst
deleted file mode 100644
index 85fbdb6588..0000000000
--- a/doc/imx/misc/index.rst
+++ /dev/null
@@ -1,9 +0,0 @@
-.. SPDX-License-Identifier: GPL-2.0+
-
-Miscellaneous
-=============
-
-.. toctree::
-   :maxdepth: 2
-
-   psb
diff --git a/doc/imx/misc/psb.rst b/doc/imx/misc/psb.rst
deleted file mode 100644
index 71ac09fac8..0000000000
--- a/doc/imx/misc/psb.rst
+++ /dev/null
@@ -1,174 +0,0 @@
-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    | SIT offset (fixed) | A-copy offset (fixed) | B-copy offset (recommended) |
-+----------+--------------------+-----------------------+-----------------------------+
-| iMX7D    |         0x1        |          0x2          |          0x800+0x2          |
-+----------+--------------------+-----------------------+-----------------------------+
-| iMX8MM   |        0x41        |         0x42          |         0x1000+0x42         |
-+----------+--------------------+-----------------------+-----------------------------+
-
-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_GPR0 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