Hi Michael,
The ColdFire is 523x and using UART serial interface.
Thanks & regards,
Raju B
On Tue, Nov 5, 2013 at 10:47 PM, Michael Durrant <mdurr...@uclinux.org>wrote:
>
> Raj,
>
> Which ColdFire are you using?
> Which serial interface are you seeing this with (UART/SPI/I2C/..)?
>
> Michael
>
>
> On 11/05/2013 07:40 AM, Raju B wrote:
>
> whenever i am trying to receive data from serial communication
> continuously in uClinux, I am getting every 10th byte is overwrite by 11
> byte and so on....
>
> Iam using freescale coldfire processor. Could you any body please help
> me to resolve this issue.
>
> Thanks & Regards,
> Raj
>
>
> On Fri, Sep 13, 2013 at 10:16 PM, Lennart Sorensen <
> lsore...@csclub.uwaterloo.ca> wrote:
>
>> On Fri, Sep 13, 2013 at 11:28:52AM -0400, Bair, Richard wrote:
>> > I have a 4.7MB application that runs on the 2.6.26 kernel (Freescale
>> BSP) and am working to make it run on the 2.6.38 kernel released in the
>> ColdFire BSP in Feb 2012. I'm concerned about memory allocation as my
>> first attempt to run on the 38 kernel appears to be using 2^n memory
>> allocation vs. allocation that sizes just 1-page over the application.
>> >
>> > 1) Can anyone tell me the exact kernel config name that needs to be
>> adjusted for the 38 kernel to set the default memory allocation?
>> > - Older posts indicate modules like page_alloc2 or Kmalloc2
>> control this so I'm going to investigate these in more detail
>> > - RTFMing indicate that this might be the area but I don't see it
>> in the 38 version (LTIB or make menucionfig):
>> > menuconfig -> kernel settings -> general settings, try
>> enabling either the "Permit large allocations" setting, or the
>> "non-power-of-2"
>> >
>> > 2) Historically, we use LTIB to create the kernel. Does LTIB expose
>> most/all settings of the 2.6.38 kernel? Can it be out of sync with the
>> make menuconfig uClinus kernel?
>>
>> Maybe this changed the behaviour you see:
>>
>> commit fc4d5c292b68ef02514d2072dcbf82d090c34875
>> Author: David Howells <dhowe...@redhat.com>
>> Date: Wed May 6 16:03:05 2009 -0700
>>
>> nommu: make the initial mmap allocation excess behaviour Kconfig
>> configurable
>>
>> NOMMU mmap() has an option controlled by a sysctl variable that
>> determines
>> whether the allocations made by do_mmap_private() should have the
>> excess
>> space trimmed off and returned to the allocator. Make the initial
>> setting
>> of this variable a Kconfig configuration option.
>>
>> The reason there can be excess space is that the allocator only
>> allocates
>> in power-of-2 size chunks, but mmap()'s can be made in sizes that
>> aren't a
>> power of 2.
>>
>> There are two alternatives:
>>
>> (1) Keep the excess as dead space. The dead space then remains
>> unused for the
>> lifetime of the mapping. Mappings of shared objects such as
>> libc, ld.so
>> or busybox's text segment may retain their dead space forever.
>>
>> (2) Return the excess to the allocator. This means that the dead
>> space is
>> limited to less than a page per mapping, but it means that for a
>> transient
>> process, there's more chance of fragmentation as the excess
>> space may be
>> reused fairly quickly.
>>
>> During the boot process, a lot of transient processes are created, and
>> this can cause a lot of fragmentation as the pagecache and various
>> slabs
>> grow greatly during this time.
>>
>> By turning off the trimming of excess space during boot and disabling
>> batching of frees, Coldfire can manage to boot.
>>
>> A better way of doing things might be to have /sbin/init turn this
>> option
>> off. By that point libc, ld.so and init - which are all long-duration
>> processes - have all been loaded and trimmed.
>>
>> Reported-by: Lanttor Guo <lanttor....@freescale.com>
>> Signed-off-by: David Howells <dhowe...@redhat.com>
>> Tested-by: Lanttor Guo <lanttor....@freescale.com>
>> Cc: Greg Ungerer <g...@snapgear.com>
>> Signed-off-by: Andrew Morton <a...@linux-foundation.org>
>> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
>>
>> After all before this commit, trimming after allocating was always done.
>> Now it is only done if you enable this CONFIG, or set the sysctl flag
>> at runtime, which of course affects behaviour for all allocations after
>> you change the setting.
>>
>> --
>> Len Sorensen
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>
>
>
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