Hello everyone, I'm using an ARMv7 platform (Cortex A9).
The hardware designer said something that confused me: he said that when a driver writes to a device memory-mapped register, there is no way to "know" when the write has actually reached the device, other than to read the value back. I had been using this kind of code: static void __iomem *device_base; device_base = ioremap(DEVICE_ADDR, RANGE); writel_relaxed(val, device_base + N); The situation where he said this would bite me is: write to a device register to clear an interrupt notification unmask interrupts The interrupt might fire because the interrupt bit has not been cleared yet. Does that make any sense? Should I use writel instead of writel_relaxed in that situation? Do I really have to read-after-write? Regards. -- 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/