26 Mar
2014
26 Mar
'14
9:30 a.m.
On Mon, 2014-03-24 at 21:54 +0100, Marek Vasut wrote:
cfg = readl(&pio->cfg[0] + index);cfg &= ~(0xf << offset);cfg |= val << offset;writel(cfg, &pio->cfg[0] + index);clrsetbits_le32() here.
I looked at this transform in a few different contexts and one concern I had was that readl and writel have barriers in them (after the read and before the write respectively) while clrsetbits and friends do not. I don't think this will matter for the read/modify/write bit twiddling itself (since there are register dependencies) but I was slightly concerned that the barriers were hiding the lack of explicit barriers which would be required between the various reads/writes.
But I think I am probably being overly cautious here and the obvious transformation can be made. Anyone got any thoughts?
Ian.