xtensa: rearrange CCOUNT calibration

DT-enabled kernel should have a CPU node connected to a clock. This clock
is the CCOUNT clock. Use old platform_calibrate_ccount call as a fallback
when CPU node cannot be found or has no clock and in non-DT-enabled
configurations.

Drop no longer needed code that updates CPU clock-frequency property in
the DT; drop DT-related code from the platform_calibrate_ccount too.

Move of_clk_init to the top of time_init, so that clocks are initialized
before CCOUNT calibration is attempted.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov
2016-09-20 11:11:08 -07:00
vanhempi 58c3e3ac7a
commit 205ad548a7
4 muutettua tiedostoa jossa 41 lisäystä ja 44 poistoa

Näytä tiedosto

@@ -12,6 +12,8 @@
* Chris Zankel <chris@zankel.net>
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/time.h>
@@ -134,16 +136,52 @@ void local_timer_setup(unsigned cpu)
0xf, 0xffffffff);
}
#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
#ifdef CONFIG_OF
static void __init calibrate_ccount(void)
{
struct device_node *cpu;
struct clk *clk;
cpu = of_find_compatible_node(NULL, NULL, "cdns,xtensa-cpu");
if (cpu) {
clk = of_clk_get(cpu, 0);
if (!IS_ERR(clk)) {
ccount_freq = clk_get_rate(clk);
return;
} else {
pr_warn("%s: CPU input clock not found\n",
__func__);
}
} else {
pr_warn("%s: CPU node not found in the device tree\n",
__func__);
}
platform_calibrate_ccount();
}
#else
static inline void calibrate_ccount(void)
{
platform_calibrate_ccount();
}
#endif
#endif
void __init time_init(void)
{
of_clk_init(NULL);
#ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
printk("Calibrating CPU frequency ");
platform_calibrate_ccount();
calibrate_ccount();
printk("%d.%02d MHz\n", (int)ccount_freq/1000000,
(int)(ccount_freq/10000)%100);
#else
ccount_freq = CONFIG_XTENSA_CPU_CLOCK*1000000UL;
#endif
WARN(!ccount_freq,
"%s: CPU clock frequency is not set up correctly\n",
__func__);
clocksource_register_hz(&ccount_clocksource, ccount_freq);
local_timer_setup(0);
setup_irq(this_cpu_ptr(&ccount_timer)->evt.irq, &timer_irqaction);