es1371.o sound module on a IBM 405 walnut platform
I am trying to get an es1371. sound module working on an IBM405 walunt developement kit. 8 bit sound works ok
but 16 bit sound sounds like noise. Will this driver have to be made endian aware?
Thanks in advance
--
Ralph "Chip" Blach
KF4WBK
Chapel Hill, North Carolina
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Quoted 2 lines · Ralph Blach
... Will this driver have to be made
endian aware?
Probably. I've had a couple of the ES boards running in Walnut, I don't remember the details now. The board was confiscated for other more urgent work, so someday I hope to get back to it.
-- Dan
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Dan,
Well it does. And I recomend a new kernel interface, and Dan, I KNOW YOU WILL not like THE VERY IDEA,
by here it is.
I beleive that a kmalloc_little_endian and a kmalloc_nocache should be added to the port.
The ability to allocate a little endian memory would by defaut handle conversion in a seamless and quick manner.copy_from_user and copy_to_use would then do the bit to little endian conversions.
By the same token, an interface to allocate noncached memory would be spiffy. I would also assist in the porting of device drivers that need lots of little non cached spaces like scsi and USB drivers.
Chip
The 405gp has the ability
Quoted 12 lines · Dan Malek
Quoted 2 lines · Ralph Blach
... Will this driver have to be made
endian aware?Probably. I've had a couple of the ES boards running in Walnut, I don't remember the details now. The board was confiscated for other more urgent work, so someday I hope to get back to it.
-- Dan
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Quoted 3 lines · Ralph Blach
Well it does. And I recomend a new kernel interface, and Dan, I KNOW YOU WILL not like THE VERY IDEA,
by here it is.
You are right, I won't :-). Here is why. First of all, all Linux ports understand how to manage the little-endian PCI interface. We don't want help from hardware swapping bytes in the lanes because it just complicates software with special case functions and actually introduces more overhead instead of removing it like the design you thought would work. Second, I have worked with hardware like this in the past, and have painfully learned you simply can't arbitrarily swap the bytes in the lanes. If you have data structures you are trying to share, the data has to be swapped based upon the size of the object. The hardware has no clue what you are trying to access and will screw it up. Just believe me, I've been there.
Quoted 2 lines
copy_from_userandcopy_to_usewould then do the bit to little endian conversions.
Nope, the sound drivers already know how to do this if necessary.
Quoted 2 lines
By the same token, an interface to allocate noncached memory would be spiffy.
That's already been done for the 8xx and 4xx ports in the kernel trees.
-- Dan
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Quoted 9 lines · Dan Malek
Quoted 3 lines · Ralph Blach
Well it does. And I recomend a new kernel interface, and Dan, I KNOW YOU WILL not like THE VERY IDEA,
by here it is.
Quoted 7 lines
Quoted 2 lines
By the same token, an interface to allocate noncached memory would be spiffy.
That's already been done for the 8xx and 4xx ports in the kernel trees.
-- Dan
Yes it has, only for non cached pages. But what propose is a new interface like kmalloc_noncache, and kfree_noncache.
This would allow one to allocate noncached buffers for usb and SCSI work.
--
Ralph "Chip" Blach
KF4WBK
Chapel Hill, North Carolina
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
Quoted 1 line · Ralph Blach
This would allow one to allocate noncached buffers for usb and SCSI work.
Ummmm....I added those at the request of the people doing the usb work. If they aren't correct or sufficient, the usb wouldn't be working on the 4xx or 8xx processors.
-- Dan
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