mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-17 10:18:38 +00:00
101 lines
3.2 KiB
Text
101 lines
3.2 KiB
Text
|
-------------
|
||
|
|
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/toradex/imx_loader).
|
||
|
|
|
||
|
|
The host side utilities are typically capable to interpret the i.MX
|
||
|
|
specific image header (see doc/README.imximage). 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.
|
||
|
|
|
||
|
|
Usage
|
||
|
|
-----
|
||
|
|
|
||
|
|
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
|