RP2_CHAN_STAT
status = readl(up->base + RP2_CHAN_STAT);
status = readl(up->base + RP2_CHAN_STAT);
writel(status, up->base + RP2_CHAN_STAT);
rp2_rmw(up, RP2_CHAN_STAT, 0, 0);
rp2_rmw(up, RP2_CHAN_STAT, 0, 0);