mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-18 09:13:06 +00:00
35b65dd8ef
Historically, the reset_cpu() function had an `addr` parameter which was
meant to pass in an address of the reset vector location, where the CPU
should reset to. This feature is no longer used anywhere in U-Boot as
all reset_cpu() implementations now ignore the passed value. Generic
code has been added which always calls reset_cpu() with `0` which means
this feature can no longer be used easily anyway.
Over time, many implementations seem to have "misunderstood" the
existence of this parameter as a way to customize/parameterize the reset
(e.g. COLD vs WARM resets). As this is not properly supported, the
code will almost always not do what it is intended to (because all
call-sites just call reset_cpu() with 0).
To avoid confusion and to clean up the codebase from unused left-overs
of the past, remove the `addr` parameter entirely. Code which intends
to support different kinds of resets should be rewritten as a sysreset
driver instead.
This transformation was done with the following coccinelle patch:
@@
expression argvalue;
@@
- reset_cpu(argvalue)
+ reset_cpu()
@@
identifier argname;
type argtype;
@@
- reset_cpu(argtype argname)
+ reset_cpu(void)
{ ... }
Signed-off-by: Harald Seiler <hws@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
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|---|---|---|
| .. | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| mx6memcal.c | ||
| README | ||
| spl.c | ||
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