Re: [PATCH v23 06/11] clocksource: arm_arch_timer: refactor MMIO timer probing.

From: Mark Rutland
Date: Wed Apr 05 2017 - 14:43:12 EST


On Sat, Apr 01, 2017 at 01:51:00AM +0800, fu.wei@xxxxxxxxxx wrote:
> + arch_timer_mem_freq = arch_timer_mem_get_cntfrq(base);
> + if (!arch_timer_rate && arch_timer_mem_freq) {
> + arch_timer_rate = arch_timer_mem_freq;
> + } else if (!arch_timer_rate || arch_timer_rate != arch_timer_mem_freq) {
> + pr_err(FW_BUG "invalid MMIO frequency.\n");
> + iounmap(base);
> + return -EINVAL;
> + }

I thought I had previously mentioned that this last check has the
potential to break DT systems, which may be inadvertently relying on the
probe order.

I agree we must do this check for ACPI, but I think that for DT it needs
to be relaxed.

I'm happy to rework that locally, if you can address my comments on
patch 9.

Thanks,
Mark.