Endian issue

["Laurent Lagrange" <lagrange@fr.oleane.com>]

Hi
 
I'm writing a framebuffer driver and I have some endian problems. 
My board is big endian (powerpc inside) and I use a little endian 
graphic card. I try to get a 16 bpp RGBA (5/5/5/1) true color mode 
working. Nevertheless, I have troubles with the framebuffer layer.
 
For example, in the color_imageblit function of cfbimgblt.c, if I 
want to draw two 16bpp rgba pixels P0 (0xFFFE) and P1 (0x0001), 
they are packed together like this 0xFFFE_0001. 
In memory, 0xFF is LSB, 0x01 is MSB (big endian). Then this 32bit 
value is "__raw_writel" to the memory of the video card. 

As my videocard works in little endian, I get 0x0100_FEFF. So the 
pixels are at the correct place, but don't have the correct color. 
It would be OK if it was 0x0001_FFFE.
 
My question is :
- is it possible to use generic drawing function (blit, fillrect...) 
on a big endian board with a little endian graphics card ?
- if yes, how can I describe the colors bitfields, without 
patching the kernel code, to get the correct color ?
 
Thanks
Laurent
 

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