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authorMax Filippov <jcmvbkbc@gmail.com>2016-09-20 11:11:08 -0700
committerMax Filippov <jcmvbkbc@gmail.com>2016-09-20 18:52:59 -0700
commit205ad548a7426fb6813760cd9917d3fc24122576 (patch)
treeafee669f50dad5b75f622cecc03074d12c9b8e5f /arch/xtensa/kernel
parent58c3e3ac7a1daf56523567507a096a3e4026596d (diff)
downloadlinux-205ad548a7426fb6813760cd9917d3fc24122576.tar.bz2
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>
Diffstat (limited to 'arch/xtensa/kernel')
-rw-r--r--arch/xtensa/kernel/setup.c2
-rw-r--r--arch/xtensa/kernel/time.c40
2 files changed, 39 insertions, 3 deletions
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 7ed63688f93c..d61c8468abea 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -23,7 +23,6 @@
#include <linux/bootmem.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
-#include <linux/clk-provider.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
@@ -249,7 +248,6 @@ void __init early_init_devtree(void *params)
static int __init xtensa_device_probe(void)
{
- of_clk_init(NULL);
of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
return 0;
}
diff --git a/arch/xtensa/kernel/time.c b/arch/xtensa/kernel/time.c
index b9ad9feadc2d..9a5bcd0381a7 100644
--- a/arch/xtensa/kernel/time.c
+++ b/arch/xtensa/kernel/time.c
@@ -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);