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From: Liem Pham Tan <tanliemph@gmail.com>
To: linux-omap-open-source@linux.omap.com
Subject: Process 32-bit data without endianess-conversion between ARM – DSP?
Date: Tue, 10 Oct 2006 12:14:43 +0700	[thread overview]
Message-ID: <452B2C43.9010508@gmail.com> (raw)

Hi All,
I’m using DSP/BIOS LINK 1.10.1 to communicate between ARM and DSP on 
OMAP5912.
I need to process 32-bit data on both ARM and DSP. The problem is DSP 
uses big-endian and ARM uses little-endian.
The application note “Using Endianess Conversion in the OMAP5912 device” 
(SWPA027) stated that :  if both MPU and DSP access the data using the 
same access size, then no endianess conversion is needed.
But when I pass data between them, the DSP always perform an 
word-endianess conversion (16-bit). For example : If I write 0x00000001 
on GPP and send via DSP/BIOS LINK to DSP, the data on DSP will be read 
0x00010000 (and vice versa). I used Int32 on GPP and long on DSP 
(32-bit) to access the buffer.
The DSP endianess can be controlled by the DSP MMU endianess control 
register, but I can’t find any good way to set this register in DSP/BIOS 
LINK ( I did try to set the channel attribute to ChannelDataSize_32bits* 
*but it didn’t work).
Do you have any ideas on this problem?
Best regards,
Liem Pham

                 reply	other threads:[~2006-10-10  5:14 UTC|newest]

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