irqchip: mips-gic: Clean up mti, reserved-cpu-vectors handling
When parsing mti,reserved-cpu-vectors we generate a mask of all bits
that have been declared reserved, the loop through starting from bit 2
to find one that isn't reserved (ie. is zero).
This patch accomplishes the same task more simply by:
- Inititialising the reserved mask to 0x3 (ie. the 2 software
interrupts). This means we don't need to skip them later as the loop
previously has.
- Replacing the loop checking for zero bits with find_first_zero_bit,
which fits our needs now that the 2 software interrupts are marked
reserved. This requires that the type of reserved is changed to
unsigned long so that it's suitable for use with bitmap functions.
- Replacing the magic number 8 with the hamming weight of the ST0_IM
field - ie. the number of bits that a MIPS CPU has for interrupt
inputs. This is still a compile-time constant 8, but makes it
clearer why it's 8.
Signed-off-by: Paul Burton <paul.burton@imgtec.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17054/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>