146 lines
6.4 KiB
Plaintext
146 lines
6.4 KiB
Plaintext
|
================================================================================
|
||
|
|
Useful notes on bulding and using of U-Boot on
|
||
|
|
ARC IoT Development Kit (AKA IoTDK)
|
||
|
|
================================================================================
|
||
|
|
|
||
|
|
BOARD OVERVIEW
|
||
|
|
|
||
|
|
The DesignWare ARC IoT Development Kit is a versatile platform that includes
|
||
|
|
the necessary hardware and software to accelerate software development and
|
||
|
|
debugging of sensor fusion, voice recognition and face detection designs.
|
||
|
|
|
||
|
|
The ARC IoT Development Kit includes a silicon implementation of the
|
||
|
|
ARC Data Fusion IP Subsystem running at 144 MHz on SMIC's
|
||
|
|
55-nm ultra-low power process, and a rich set of peripherals commonly used
|
||
|
|
in IoT designs such as USB, UART, SPI, I2C, PWM, SDIO and ADCs.
|
||
|
|
|
||
|
|
The board is shipped with pre-installed U-Boot in non-volatile memory
|
||
|
|
(eFlash) so on power-on user sees U-Boot start header and command line
|
||
|
|
prompt which might be used for U-Boot environment fine-tuning, manual
|
||
|
|
loading and execution of user application binaries etc.
|
||
|
|
|
||
|
|
The board has the following features useful for U-Boot:
|
||
|
|
* On-board 2-channel FTDI TTL-to-USB converter
|
||
|
|
- The first channel is used for serial debug port (which makes it possible
|
||
|
|
to use a serial connection on pretty much any host machine be it
|
||
|
|
Windows, Linux or Mac).
|
||
|
|
On Linux machine typucally FTDI serial port would be /dev/ttyUSB0.
|
||
|
|
There's no HW flow-control and baud-rate is 115200.
|
||
|
|
|
||
|
|
- The second channel is used for built-in Digilent USB JTAG probe.
|
||
|
|
That means no extra hardware is required to access ARC core from a
|
||
|
|
debugger on development host. Both proprietary MetaWare debugger and
|
||
|
|
open source OpenOCD + GDB client are supported.
|
||
|
|
|
||
|
|
- Also with help of this FTDI chip it is possible to reset entire
|
||
|
|
board with help of a special `rff-ftdi-reset` utility, see:
|
||
|
|
https://github.com/foss-for-synopsys-dwc-arc-processors/rff-ftdi-reset
|
||
|
|
|
||
|
|
* Micro SD-card slot
|
||
|
|
- U-Boot expects to see the very first partition on the card formatted as
|
||
|
|
FAT file-system and uses it for keeping its environment in `uboot.env`
|
||
|
|
file. Note uboot.env is not just a text file but it is auto-generated
|
||
|
|
file created by U-Boot on invocation of `saveenv` command.
|
||
|
|
It contains a checksum which makes this saved environment invalid in
|
||
|
|
case of maual modification.
|
||
|
|
|
||
|
|
- There might be more useful files on that first FAT partition like
|
||
|
|
user applications, data files etc.
|
||
|
|
|
||
|
|
* USB OTG connector
|
||
|
|
- U-Boot may access USB mass-storage devices attached to this connector.
|
||
|
|
Note only FAT file-system is supported. It might be used for storing
|
||
|
|
user application binaries as well as micro SD-card mentioned above.
|
||
|
|
|
||
|
|
* The following memories are avaialble on the board:
|
||
|
|
- eFlash: 256 KiB @ 0x0000_0000
|
||
|
|
A non-volatile memory from which ARC core may execute code directly.
|
||
|
|
Still is is not direcly writable, thus this is not an ordinary RAM.
|
||
|
|
|
||
|
|
- ICCM: 256 KiB @ 0x2000_0000
|
||
|
|
Instruction Closely Coupled Memory - fast on-chip memory primary used
|
||
|
|
for code being executed, still data could be placed in this memory too.
|
||
|
|
In that sense it's just a general purpose RAM.
|
||
|
|
|
||
|
|
- SRAM: 128 KiB @ 0x3000_0000
|
||
|
|
On-chip SRAM. From user perspective is the same as ICCM above.
|
||
|
|
|
||
|
|
- DCCM: 128 KiB @ 0x8000_0000
|
||
|
|
Data Closely Coupled Memory is similar to ICCM with a major difference -
|
||
|
|
ARC core cannot execute code from DCCM. So this is very special RAM
|
||
|
|
only suitable for data.
|
||
|
|
|
||
|
|
BUILDING U-BOOT
|
||
|
|
|
||
|
|
1. Configure U-Boot:
|
||
|
|
------------------------->8----------------------
|
||
|
|
make iot_devkit_defconfig
|
||
|
|
------------------------->8----------------------
|
||
|
|
|
||
|
|
2. To build Elf file (for example to be used with host debugger via JTAG
|
||
|
|
connection to the target board):
|
||
|
|
------------------------->8----------------------
|
||
|
|
make mdbtrick
|
||
|
|
------------------------->8----------------------
|
||
|
|
|
||
|
|
This will produce `u-boot` Elf file.
|
||
|
|
|
||
|
|
3. To build binary image to be put in "ROM":
|
||
|
|
------------------------->8----------------------
|
||
|
|
make u-boot.bin
|
||
|
|
------------------------->8----------------------
|
||
|
|
|
||
|
|
|
||
|
|
EXECUTING U-BOOT
|
||
|
|
|
||
|
|
1. The IoTDK board is supposed to auto-start U-Boot image stored in eFlash on
|
||
|
|
power-on. Note it's possible to update that image - follow instructions in
|
||
|
|
user's manual.
|
||
|
|
|
||
|
|
2. Though it is possible to load and start U-Boot as a simple Elf file
|
||
|
|
via JTAG right in ICCM. For that it's required to re-configure U-Boot
|
||
|
|
so it gets linked to ICCM address 0x2000_0000 (remember eFlash is not
|
||
|
|
direcly writable).
|
||
|
|
Run U-Boot's configuration utility with "make menuconfig", go to
|
||
|
|
"Boot images" and change "Text Base" from default 0x00000000 to
|
||
|
|
0x20000000. Exit & save new configuration. Now run "make mdbtrick" to
|
||
|
|
build new Elf.
|
||
|
|
|
||
|
|
2.1. In case of proprietary MetaWare debugger run:
|
||
|
|
------------------------->8----------------------
|
||
|
|
mdb -digilent u-boot
|
||
|
|
------------------------->8----------------------
|
||
|
|
|
||
|
|
USING U-BOOT
|
||
|
|
|
||
|
|
Note due to limited memory size it's supposed that user will run binary
|
||
|
|
images of their applications instead of loading Elf files.
|
||
|
|
|
||
|
|
1. To load and start application binary from micro SD-card execute
|
||
|
|
the following commands in U-Boot's shell:
|
||
|
|
------------------------->8----------------------
|
||
|
|
fatload mmc 0 0x20000000 yourapp.bin
|
||
|
|
go 0x20000000
|
||
|
|
------------------------->8----------------------
|
||
|
|
|
||
|
|
2. To load and start application binary from USB mass-storage device execute
|
||
|
|
the following commands in U-Boot's shell:
|
||
|
|
------------------------->8----------------------
|
||
|
|
usb start
|
||
|
|
fatload usb 0x20000000 yourapp.bin
|
||
|
|
go 0x20000000
|
||
|
|
------------------------->8----------------------
|
||
|
|
|
||
|
|
3. To have a sequence of commands executed on U-Boot start put those
|
||
|
|
commands in "bootcmd" with semicolon between them.
|
||
|
|
For example to get (1) done automatically:
|
||
|
|
------------------------->8----------------------
|
||
|
|
setenv bootcmd fatload mmc 0 0x20000000 yourapp.bin\; go 0x20000000
|
||
|
|
saveenv
|
||
|
|
------------------------->8----------------------
|
||
|
|
|
||
|
|
4. To reboot the board just run:
|
||
|
|
------------------------->8----------------------
|
||
|
|
reset
|
||
|
|
------------------------->8----------------------
|