On 2017/1/19 17:44, Fu Wei wrote:

Hi Hanjun,

On 19 January 2017 at 16:02, Hanjun Guo [off-list ref] wrote:

quoted

Hi Fuwei,

One comments below.


On 2017/1/18 21:25, fu.wei at linaro.org wrote:

quoted

From: Fu Wei <redacted>

The counter frequency detection call(arch_timer_detect_rate) combines two
ways to get counter frequency: system coprocessor register and MMIO timer.
But in a specific timer init code, we only need one way to try:
getting frequency from MMIO timer register will be needed only when we
init MMIO timer; getting frequency from system coprocessor register will
be needed only when we init arch timer.

This patch separates paths to determine frequency:
Separate out the MMIO frequency and the sysreg frequency detection call,
and use the appropriate one for the counter.

Signed-off-by: Fu Wei <redacted>
---
 drivers/clocksource/arm_arch_timer.c | 40
++++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/drivers/clocksource/arm_arch_timer.c

b/drivers/clocksource/arm_arch_timer.c
index 6484f84..9482481 100644

--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c

@@ -488,23 +488,33 @@ static int arch_timer_starting_cpu(unsigned int cpu)
        return 0;
 }

-static void arch_timer_detect_rate(void __iomem *cntbase)
+static void __arch_timer_determine_rate(u32 rate)
 {
-       /* Who has more than one independent system counter? */
-       if (arch_timer_rate)
-               return;
+       /* Check the timer frequency. */
+       if (!arch_timer_rate) {
+               if (rate)
+                       arch_timer_rate = rate;
+               else
+                       pr_warn("frequency not available\n");
+       } else if (rate && arch_timer_rate != rate) {

                        ^
Typo? I think it's "&" here.

Not a typo, It's definitely a ?&&?  :-)

Here arch_timer_rate is not zero.

If rate is not zero(that means we got a valid rate), and
arch_timer_rate != rate ,
we will print warning message.

Ah, misreading the code, thanks for clarify :)

Hanjun