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>
diff --git a/arch/xtensa/boot/dts/xtfpga.dtsi b/arch/xtensa/boot/dts/xtfpga.dtsi
index ded5698..91616a9 100644
--- a/arch/xtensa/boot/dts/xtfpga.dtsi
+++ b/arch/xtensa/boot/dts/xtfpga.dtsi
@@ -19,9 +19,7 @@
cpu@0 {
compatible = "cdns,xtensa-cpu";
reg = <0>;
- /* Filled in by platform_setup from FPGA register
- * clock-frequency = <100000000>;
- */
+ clocks = <&osc>;
};
};
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 7ed6368..d61c846 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 @@
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 b9ad9fe..9a5bcd0 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 @@
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);
diff --git a/arch/xtensa/platforms/xtfpga/setup.c b/arch/xtensa/platforms/xtfpga/setup.c
index 99a38a6..e236df4 100644
--- a/arch/xtensa/platforms/xtfpga/setup.c
+++ b/arch/xtensa/platforms/xtfpga/setup.c
@@ -66,29 +66,6 @@
#ifdef CONFIG_OF
-static void __init update_clock_frequency(struct device_node *node)
-{
- struct property *newfreq;
- u32 freq;
-
- if (!of_property_read_u32(node, "clock-frequency", &freq) && freq != 0)
- return;
-
- newfreq = kzalloc(sizeof(*newfreq) + sizeof(u32), GFP_KERNEL);
- if (!newfreq)
- return;
- newfreq->value = newfreq + 1;
- newfreq->length = sizeof(freq);
- newfreq->name = kstrdup("clock-frequency", GFP_KERNEL);
- if (!newfreq->name) {
- kfree(newfreq);
- return;
- }
-
- *(u32 *)newfreq->value = cpu_to_be32(*(u32 *)XTFPGA_CLKFRQ_VADDR);
- of_update_property(node, newfreq);
-}
-
static void __init xtfpga_clk_setup(struct device_node *np)
{
void __iomem *base = of_iomap(np, 0);
@@ -172,21 +149,7 @@
void __init platform_calibrate_ccount(void)
{
- long clk_freq = 0;
-#ifdef CONFIG_OF
- struct device_node *cpu =
- of_find_compatible_node(NULL, NULL, "cdns,xtensa-cpu");
- if (cpu) {
- u32 freq;
- update_clock_frequency(cpu);
- if (!of_property_read_u32(cpu, "clock-frequency", &freq))
- clk_freq = freq;
- }
-#endif
- if (!clk_freq)
- clk_freq = *(long *)XTFPGA_CLKFRQ_VADDR;
-
- ccount_freq = clk_freq;
+ ccount_freq = *(long *)XTFPGA_CLKFRQ_VADDR;
}
#endif
