mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-07 13:44:29 +00:00
50 lines
2.1 KiB
Text
50 lines
2.1 KiB
Text
|
mx6memcal - a tool for calibrating DDR on i.MX6 boards.
|
||
|
|
|
||
|
|
The mx6memcal board isn't a real board, but a tool for use in bring-up of
|
||
|
|
new i.MX6 board designs.
|
||
|
|
|
||
|
|
It provides a similar function to the tool from NXP([1]) with a number
|
||
|
|
of advantages:
|
||
|
|
|
||
|
|
1. It's open-source, so it's easier to change if needed.
|
||
|
|
Typical reasons for needing to change include the use of alternate
|
||
|
|
UARTs and PMIC initialization.
|
||
|
|
2. It produces an image that's directly loadable with imx_usb [2] or
|
||
|
|
SB_LOADER.exe [3].
|
||
|
|
The NXP tool requires either a cumbersome JTAG connection that
|
||
|
|
makes running the DDR very slow or a working U-Boot image that
|
||
|
|
suffers from a chicken-and-egg problem (i.e. where do you get the
|
||
|
|
DDR parameters for U-Boot?).
|
||
|
|
3. It doesn't prompt for parameters, so it's much faster to gather
|
||
|
|
data from multiple boards.
|
||
|
|
4. Parameters to the calibration process can be chosen through
|
||
|
|
'make menuconfig'.
|
||
|
|
|
||
|
|
When booted, the mx6memcal board will run the DDR calibration
|
||
|
|
routines and display the result in a form suitable for cut and
|
||
|
|
paste into struct mx6_mmdc_calibration. It can also optionally
|
||
|
|
produce output in a form usable in a DCD-style .cfg file.
|
||
|
|
|
||
|
|
Selections in Kconfig allow most system design settings to be chosen:
|
||
|
|
|
||
|
|
1. The UART number and pad configuration for the UART. Options
|
||
|
|
include support for the most frequent reference designs on
|
||
|
|
i.MX6DQ/SDL (SABRE Lite and SABRESD designs).
|
||
|
|
2. The memory bus width (64 and 32-bit)
|
||
|
|
3. The number of chip-selects in use
|
||
|
|
4. The type of DDR (DDR3 or LPDDR2). Note that LPDDR2 support
|
||
|
|
is incomplete as of this writing.
|
||
|
|
5. The type of DDR chips in use. This selection allows re-use of common
|
||
|
|
parts and four DDR3 and two LPDDR2 parts are currently defined
|
||
|
|
6. The On-die termination value for the DRAM lines
|
||
|
|
7. The DRAM drive strength
|
||
|
|
8. The RTT_NOM and RTT_WR termination settings
|
||
|
|
9. RALAT/WALAT latency values
|
||
|
|
|
||
|
|
References:
|
||
|
|
[1] - NXP DDR Stress Test Tool - https://community.nxp.com/docs/DOC-105652
|
||
|
|
[2] - Boundary Devices imx_usb_loader
|
||
|
|
https://github.com/boundarydevices/imx_usb_loader
|
||
|
|
[3] - Use of SB_Loader.exe
|
||
|
|
https://boundarydevices.com/windows-users-and-unbricking
|