On Tue, 29 Mar 2011 10:47:04 +0800 Lei Wen adrian.wenl@gmail.com wrote:
Hi Scott,
On Tue, Mar 29, 2011 at 12:05 AM, Scott Wood scottwood@freescale.com wrote:
What does this do that setbits*/clrbits* don't?
Those and*/or* include the dmb() operation included in the read*/write*, which is not included in the __raw_read*/__raw_write* that setbits*/clrbits* refer to. I think it's better to keep another instance to set the bit, since there is read* and __raw_read* exist and have difference.
But why are setbits/clrbits using raw accesses? That's not how they're defined on powerpc, which is where these accessors originated. I suspect they were defined that way out of laziness from before ARM made a distinction between raw and non-raw accessors, and it is now a bug in setbits/clrbits (and out_be*, in_le*, etc) which should be fixed rather than introducing an alternative.
And then if you want a raw version of these functions, introduce raw_setbits_le32, raw_in_le16, etc.
-Scott