On Tue, Feb 18, 2014 at 11:49:51AM +0800, Li Guang wrote: > Beniamino Galvani wrote: > >According to this mail thread [1], writing to pending register seems > >to have no effect on actual pending status of interrupts. This means > >that the only way to clear a pending interrupt is to clear the > >interrupt source. This patch implements such behaviour. > > > >[1] http://lkml.org/lkml/2013/7/6/59 > > > >Signed-off-by: Beniamino Galvani<b.galv...@gmail.com> > >--- > > hw/intc/allwinner-a10-pic.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > >diff --git a/hw/intc/allwinner-a10-pic.c b/hw/intc/allwinner-a10-pic.c > >index bb2351f..afd57ef 100644 > >--- a/hw/intc/allwinner-a10-pic.c > >+++ b/hw/intc/allwinner-a10-pic.c > >@@ -49,6 +49,8 @@ static void aw_a10_pic_set_irq(void *opaque, int irq, int > >level) > > > > if (level) { > > set_bit(irq % 32, (void *)&s->irq_pending[irq / 32]); > >+ } else { > >+ clear_bit(irq % 32, (void *)&s->irq_pending[irq / 32]); > > } > > aw_a10_pic_update(s); > > } > >@@ -105,10 +107,10 @@ static void aw_a10_pic_write(void *opaque, hwaddr > >offset, uint64_t value, > > s->nmi = value; > > break; > > case AW_A10_PIC_IRQ_PENDING ... AW_A10_PIC_IRQ_PENDING + 8: > >- s->irq_pending[index]&= ~value; > >+ /* Nothing to do */ > > break; > > case AW_A10_PIC_FIQ_PENDING ... AW_A10_PIC_FIQ_PENDING + 8: > >- s->fiq_pending[index]&= ~value; > >+ /* Ditto */ > > break; > > case AW_A10_PIC_SELECT ... AW_A10_PIC_SELECT + 8: > > s->select[index] = value; > > pending registers are also clear registers by a10 datasheet, > also you found bits are marked as 'R', so, ..., contradict itself.
Yes, the datasheet is inconsistent about this because the register can't be read-only and 'clear' at the same time. Unfortunately at the moment I cannot test if the clearing functionality of the pending register works on real hardware but the idea I got from the linked discussion is that it's either not implemented or broken and therefore interrupts remain pending until they are disabled at the source. Do you have a chance to try it on a real board? Beniamino
