* [U-Boot] U-Boot NOR Flash Copy Time Reduction
@ 2016-05-13 10:05 yyurtcan
2016-05-13 18:19 ` Wolfgang Denk
0 siblings, 1 reply; 2+ messages in thread
From: yyurtcan @ 2016-05-13 10:05 UTC (permalink / raw)
To: u-boot
We have P4080DS board and u-boot for bootloader. We want to reduce to time to
copy kernel image from NOR Flash to RAM. Can we optimize p4080ds u-boot NOR
Flash copy time? If so, How?
Best Regards.
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* [U-Boot] U-Boot NOR Flash Copy Time Reduction
2016-05-13 10:05 [U-Boot] U-Boot NOR Flash Copy Time Reduction yyurtcan
@ 2016-05-13 18:19 ` Wolfgang Denk
0 siblings, 0 replies; 2+ messages in thread
From: Wolfgang Denk @ 2016-05-13 18:19 UTC (permalink / raw)
To: u-boot
Dear yyurtcan,
In message <1463133956025-254877.post@n7.nabble.com> you wrote:
> We have P4080DS board and u-boot for bootloader. We want to reduce to time to
> copy kernel image from NOR Flash to RAM. Can we optimize p4080ds u-boot NOR
> Flash copy time? If so, How?
If you think about it, then you will realize that the copy time
depends on the bandwidth for the copy operation and the amount of data
being copied. So you want to do two things:
- maximize copy bandwidth:
o Make sure your CPU and your memory busses are configured for
maximum clock speed
o Make sure both your RAM and your NOR flash (I assume you are
talking about parallel NOR flash here) get initialized with
optimal (fasted still stable) parameters
o Make sure instruction and data caches are enabled
- minimize image size:
o Remove everything from your kernel configuration what is not
really essentially needed for your system
o Compile any drivers that are not needed for initial startup as
modules and only load these when convenient
o Chose optimal compression method for the kernel image [*]
That's it. Actually quite simple...
[*] You may notice that you will get different results what the
"optimal compression method" is when you consider only the "image
load time" (as was your question here) versus "total boot time",
which will also include the time needed to uncompress the image.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"Ahead warp factor 1" - Captain Kirk
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