Hi
On a PXA270 based system I modified the framebuffer driver to use SRAM on
the SoC to reduce bus load caused by DMA transfers. For this I just
assigned the entire SRAM to the fb driver. It works.
Then Eric Miao (CCed) rightfully noticed, that other devices might also
benefit from using SRAM. So, I started thinking about creating a special
(platform) device owning that SRAM block and making all its potential
users its children. The device-local memory API even has provisional
support for this with the DMA_MEMORY_INCLUDES_CHILDREN flag.
But there are problems with this approach too. For example, some PXA
machines already occupy framebuffer's parent. I think, they are fixing
power up/down sequence problems in this way, but I am not sure that's a
good idea from the point of view of the bus locality.
Otherwise, maybe the best way would be assigning that SRAM block to the
struct device platform_bus directly? But that way all platform devices
would get their DMA buffers from that (rather small) block on the "first
come first served" basis.
What would be the best way to solve this?
Thanks
Guennadi
---
Guennadi Liakhovetski
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
