Re: [PATCH 1/9] ARC: timer: gfrc, rtc: Read BCR to detect whether hardware exists ...

Daniel Lezcano
2016-11-03T17:01:07Z

On Mon, Oct 31, 2016 at 03:48:08PM -0700, Vineet Gupta wrote:
> ... don't rely on cpuinfo populated in arc boot code. This paves wat for
> moving this code in drivers/clocksource/
>
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> ---
> arch/arc/kernel/time.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
> index f927b8dc6edd..a2db010cde18 100644
> --- a/arch/arc/kernel/time.c
> +++ b/arch/arc/kernel/time.c
> @@ -118,10 +118,11 @@ static struct clocksource arc_counter_gfrc = {
>
> static int __init arc_cs_setup_gfrc(struct device_node *node)
> {
> - int exists = cpuinfo_arc700[0].extn.gfrc;
> + struct mcip_bcr mp;
> int ret;
>
> - if (WARN(!exists, "Global-64-bit-Ctr clocksource not detected"))
> + READ_BCR(ARC_REG_MCIP_BCR, mp);
> + if (WARN(!mp.gfrc, "Global-64-bit-Ctr clocksource not detected"))

Take the opportunity to replace this WARN by a pr_err.

> return -ENXIO;
>
> ret = arc_get_timer_clk(node);
> @@ -174,10 +175,11 @@ static struct clocksource arc_counter_rtc = {
>
> static int __init arc_cs_setup_rtc(struct device_node *node)
> {
> - int exists = cpuinfo_arc700[smp_processor_id()].extn.rtc;
> + struct bcr_timer timer;
> int ret;
>
> - if (WARN(!exists, "Local-64-bit-Ctr clocksource not detected"))
> + READ_BCR(ARC_REG_TIMERS_BCR, timer);
> + if (WARN(!timer.rtc, "Local-64-bit-Ctr clocksource not detected"))
> return -ENXIO;o

Ditto and ^^

So the READ_BCR() is only there to check the timer is physically present ?

> /* Local to CPU hence not usable in SMP */
> --
> 2.7.4
>