Hi Wolfgang,
On Tuesday 17 May 2011 10:57 AM, Wolfgang Denk wrote:
Dear Simon Glass,
In messageBANLkTine7BFSYOusgxwg0rg3owNbPN_dOQ@mail.gmail.com you wrote:
There are a few very primitive macros in setbits and clrbits. I would very much like to see at least:
Maybe we can agree to use these existing macros then instead of inventing new ones with the same functionality.
- define a field once in a header in an easy format along with any
enums which define allowable values if applicable
- pack and unpack a value into a field: so set a bitfield to 13, for exampl=
e
- obtain a mask for a field (i.e. with all bits set)
- equivalent of writel and readl for a bitfield (writel in fact being
read/modify/write so perhaps a different name)
Some of these exist, some don't.
Do you know of examples of such more complex definitions in the Linux kernel code?
In fact I had searched for a macro for similar needs as my set_bit_field() is addressing in Linux Kernel too but didn't find any.
Please note that my requirement is not for doing IO but doing bit field operations on a C integer variable: 1. Prepare a variable field by field to be finally written to a register using writel() 2. Extract a field from a variable that typically holds the value of a register after a readl()
I couldn't find any utility macros/functions for doing something like this.
Please somebody correct me if I am wrong.
best regards, Aneesh