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Diffstat (limited to 'roms/u-boot/doc/imx/misc')
| -rw-r--r-- | roms/u-boot/doc/imx/misc/index.rst | 9 | ||||
| -rw-r--r-- | roms/u-boot/doc/imx/misc/psb.rst | 174 | ||||
| -rw-r--r-- | roms/u-boot/doc/imx/misc/sdp.txt | 118 |
3 files changed, 301 insertions, 0 deletions
diff --git a/roms/u-boot/doc/imx/misc/index.rst b/roms/u-boot/doc/imx/misc/index.rst new file mode 100644 index 000000000..85fbdb658 --- /dev/null +++ b/roms/u-boot/doc/imx/misc/index.rst @@ -0,0 +1,9 @@ +.. SPDX-License-Identifier: GPL-2.0+ + +Miscellaneous +============= + +.. toctree:: + :maxdepth: 2 + + psb diff --git a/roms/u-boot/doc/imx/misc/psb.rst b/roms/u-boot/doc/imx/misc/psb.rst new file mode 100644 index 000000000..71ac09fac --- /dev/null +++ b/roms/u-boot/doc/imx/misc/psb.rst @@ -0,0 +1,174 @@ +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 diff --git a/roms/u-boot/doc/imx/misc/sdp.txt b/roms/u-boot/doc/imx/misc/sdp.txt new file mode 100644 index 000000000..49b281234 --- /dev/null +++ b/roms/u-boot/doc/imx/misc/sdp.txt @@ -0,0 +1,118 @@ +------------- +SDP in U-Boot +------------- + +SDP stands for serial download protocol. It is the protocol used in NXP's +i.MX SoCs ROM Serial Downloader and provides means to download a program +image to the chip over USB and UART serial connection. + +The implementation in U-Boot uses the USB Downloader Gadget (g_dnl) to +provide a SDP implementation over USB. This allows to download program +images to the target in SPL/U-Boot using the same protocol/tooling the +SoC's recovery mechanism is using. + +The SDP protocol over USB is a USB HID class protocol. USB HID class +protocols allow to access a USB device without OS specific drivers. The +U-Boot implementation has primarly been tested using the open source +imx_loader utility (https://github.com/boundarydevices/imx_usb_loader). + +imx_usb_loader is a very nice tool by Boundary Devices that allow to +install U-Boot without a JTAG debugger, using the USB boot mode as +described in the manual. It is a replacement for Freescale's +MFGTOOLS. + +The host side utilities are typically capable to interpret the i.MX +specific image header (see doc/imx/mkimage/imximage.txt). There are extensions +for imx_loader's imx_usb utility which allow to interpret the U-Boot +specific legacy image format (see mkimage(1)). Also the U-Boot side +support beside the i.MX specific header the U-Boot legacy header. + +1. Using imx_usb_loader for first install with SPL +-------------------------------------------------- + +This implementation can be started in U-Boot using the sdp command +(CONFIG_CMD_USB_SDP) or in SPL if Serial Downloader boot mode has been +detected (CONFIG_SPL_USB_SDP_SUPPORT). + +A typical use case is downloading full U-Boot after SPL has been +downloaded through the boot ROM's Serial Downloader. Using boot mode +detection the SPL will run the SDP implementation automatically in +this case: + + # imx_usb SPL + +Targets Serial Console: + + Trying to boot from USB SDP + SDP: initialize... + SDP: handle requests... + +At this point the SPL reenumerated as a new HID device and emulating +the boot ROM's SDP protocol. The USB VID/PID will depend on standard +U-Boot configurations CONFIG_G_DNL_(VENDOR|PRODUCT)_NUM. Make sure +imx_usb is aware of the USB VID/PID for your device by adding a +configuration entry in imx_usb.conf: + + 0x1b67:0x4fff, mx6_usb_sdp_spl.conf + +And the device specific configuration file mx6_usb_sdp_spl.conf: + + mx6_spl_sdp + hid,uboot_header,1024,0x910000,0x10000000,1G,0x00900000,0x40000 + +This allows to download the regular U-Boot with legacy image headers +(u-boot.img) using a second invocation of imx_usb: + + # imx_usb u-boot.img + +Furthermore, when U-Boot is running the sdp command can be used to +download and run scripts: + + # imx_usb script.scr + +imx_usb configuration files can be also used to download multiple +files and of arbitrary types, e.g. + + mx6_usb_sdp_uboot + hid,1024,0x10000000,1G,0x00907000,0x31000 + full.itb:load 0x12100000 + boot.scr:load 0x12000000,jump 0x12000000 + +There is also a batch mode which allows imx_usb to handle multiple +consecutive reenumerations by adding multiple VID/PID specifications +in imx_usb.conf: + + 0x15a2:0x0061, mx6_usb_rom.conf, 0x1b67:0x4fff, mx6_usb_sdp_spl.conf + +In this mode the file to download (imx_usb job) needs to be specified +in the configuration files. + +mx6_usb_rom.conf: + + mx6_qsb + hid,1024,0x910000,0x10000000,1G,0x00900000,0x40000 + SPL:jump header2 + +mx6_usb_sdp_spl.conf: + + mx6_spl_sdp + hid,uboot_header,1024,0x10000000,1G,0x00907000,0x31000 + u-boot.img:jump header2 + +With that SPL and U-Boot can be downloaded with a single invocation +of imx_usb without arguments: + + # imx_usb + +2. Using imx_usb_loader non-SPL images +--------------------------------------- + +Booting in USB mode, the i.MX6 announces itself to the Linux Host as: + +Bus 001 Device 111: ID 15a2:0061 Freescale Semiconductor, Inc. + +imx_usb_loader is able to download a single file (u-boot.imx) +to the board. For boards without SPL support, it is enough to +issue the command: + + sudo ../imx_usb_loader/imx_usb -v u-boot.imx |