[PATCH] clocksource: arch_timer: Allow the device tree to specify the physical timer

On Thu, Sep 11, 2014 at 05:04:11PM +0100, Doug Anderson wrote:

On Thu, Sep 11, 2014 at 8:58 AM, Christopher Covington
[off-list ref] wrote:

quoted

On 09/11/2014 11:52 AM, Doug Anderson wrote:

quoted

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 5163ec1..8ca07a9 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c

@@ -649,6 +649,9 @@ static void __init arch_timer_init(struct device_node *np)
              arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
      arch_timer_detect_rate(NULL, np);

+     if (of_property_read_bool(np, "arm,use-physical-timer"))
+             arch_timer_use_virtual = false;

Can you #ifdef CONFIG_ARM here please?

quoted

quoted

      /*
       * If HYP mode is available, we know that the physical timer
       * has been configured to be accessible from PL1. Use it, so

How's the VDSO supposed to deal with this? It currently does:

cycle_now = arch_counter_get_cntvct()

I don't see that line of code anywhere when I do a "git grep" on linux
or linuxnext.  Can you give me a clearer pointer?

It's in the actual vdso code (arch/arm64/kernel/vdso/gettimeofday.S):

	/* Read the virtual counter. */
	isb
	mrs	x15, cntvct_el0

Will