On Mon, Apr 28, 2014 at 11:12:08PM +0200, Sebastian Hesselbarth wrote: > Non-DT irq handlers were working through irq causes from most-significant > to least-significant bit, while DT irqchip driver does it the other way > round. This revealed some more HW issues on Kirkwood peripheral IP, where > spurious sdio irqs can happen although irqs are masked. > > Also, the generated binaries show that original non-DT order compared > to DT order save two instructions for each bit count check: > > irqchip DT order with ffs(): > 60: e3a06001 mov r6, #1 > 64: e2643000 rsb r3, r4, #0 > 68: e0033004 and r3, r3, r4 > 6c: e16f3f13 clz r3, r3 > 70: e263301f rsb r3, r3, #31 > 74: e1c44316 bic r4, r4, r6, lsl r3 > 78: e5971004 ldr r1, [r7, #4] > > Original non-DT order with fls(): > 60: e3a07001 mov r7, #1 > 64: e16f3f14 clz r3, r4 > 68: e263301f rsb r3, r3, #31 > 6c: e1c44317 bic r4, r4, r7, lsl r3 > 70: e5951004 ldr r1, [r5, #4] > > Therefore, reverse irq bit handling back to original order by replacing > ffs() with fls(). > > Signed-off-by: Sebastian Hesselbarth <sebastian.hesselba...@gmail.com> > Acked-by: Jason Cooper <ja...@lakedaemon.net> > --- > Changelog: > v1->v2: > - reword commit msg to state less number of instructions > > Cc: Jason Cooper <ja...@lakedaemon.net> > Cc: Andrew Lunn <and...@lunn.ch> > Cc: Gregory Clement <gregory.clem...@free-electrons.com> > Cc: Thomas Gleixner <t...@linutronix.de> > Cc: linux-arm-ker...@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > --- > drivers/irqchip/irq-orion.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-)
Applied to mvebu/irqchip for routing through the tip tree. Tweaked capitalization of subject line to match the other commits in that directory. thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
