[PATCH v1] realtek: use fixed-clock as CPU clock

[Sander Vanheule]

CPU clock definition in devicetree should be specified per CPU, not in
the cpus node.

The implementation of plat_init_time() needs to be modified to look for
the clock frequency in the changed location. To achieve this, the
relevant code is copied from the generic MIPS implementation in
arch/mips/generic/init.c.

Signed-off-by: Sander Vanheule <sander at svanheule.net>
---
 target/linux/realtek/dts-5.10/rtl838x.dtsi    |  9 +++++-
 target/linux/realtek/dts-5.10/rtl930x.dtsi    |  9 +++++-
 target/linux/realtek/dts-5.10/rtl931x.dtsi    |  5 ++-
 .../files-5.10/arch/mips/rtl838x/setup.c      | 32 +++++++++++--------
 4 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/target/linux/realtek/dts-5.10/rtl838x.dtsi b/target/linux/realtek/dts-5.10/rtl838x.dtsi
index 11cabc3f63cb..aa6c131753db 100644
--- a/target/linux/realtek/dts-5.10/rtl838x.dtsi
+++ b/target/linux/realtek/dts-5.10/rtl838x.dtsi
@@ -56,11 +56,12 @@
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		frequency = <500000000>;
 
 		cpu at 0 {
 			compatible = "mips,mips4KEc";
 			reg = <0>;
+			clocks = <&cpu_clk>;
+			clock-names = "cpu";
 		};
 	};
 
@@ -68,6 +69,12 @@
 		bootargs = "console=ttyS0,115200";
 	};
 
+	cpu_clk: cpu_clk {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <500000000>;
+	};
+
 	lx_clk: lx_clk {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;
diff --git a/target/linux/realtek/dts-5.10/rtl930x.dtsi b/target/linux/realtek/dts-5.10/rtl930x.dtsi
index bfde5e6ff6ae..74c7181c96e2 100644
--- a/target/linux/realtek/dts-5.10/rtl930x.dtsi
+++ b/target/linux/realtek/dts-5.10/rtl930x.dtsi
@@ -11,11 +11,12 @@
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		frequency = <800000000>;
 
 		cpu at 0 {
 			compatible = "mips,mips34Kc";
 			reg = <0>;
+			clocks = <&cpu_clk>;
+			clock-names = "cpu";
 		};
 	};
 
@@ -35,6 +36,12 @@
 		interrupt-controller;
 	};
 
+	cpu_clk: cpu_clk {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency  = <800000000>;
+	};
+
 	lx_clk: lx_clk {
 		compatible = "fixed-clock";
 		#clock-cells = <0>;
diff --git a/target/linux/realtek/dts-5.10/rtl931x.dtsi b/target/linux/realtek/dts-5.10/rtl931x.dtsi
index 29aee1f7b268..f6f39222fde8 100644
--- a/target/linux/realtek/dts-5.10/rtl931x.dtsi
+++ b/target/linux/realtek/dts-5.10/rtl931x.dtsi
@@ -11,16 +11,19 @@
 	cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		frequency = <1000000000>;
 
 		cpu at 0 {
 			compatible = "mti,interaptive";
 			reg = <0>;
+			clocks = <&cpuclock>;
+			clock-names = "cpu";
 		};
 
 		cpu at 1 {
 			compatible = "mti,interaptive";
 			reg = <1>;
+			clocks = <&cpuclock>;
+			clock-names = "cpu";
 		};
 	};
 
diff --git a/target/linux/realtek/files-5.10/arch/mips/rtl838x/setup.c b/target/linux/realtek/files-5.10/arch/mips/rtl838x/setup.c
index 55419c7b0b7a..86eb3c5eeaf5 100644
--- a/target/linux/realtek/files-5.10/arch/mips/rtl838x/setup.c
+++ b/target/linux/realtek/files-5.10/arch/mips/rtl838x/setup.c
@@ -11,9 +11,9 @@
 
 #include <linux/console.h>
 #include <linux/init.h>
-#include <linux/clkdev.h>
-#include <linux/clk-provider.h>
+#include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/of_clk.h>
 #include <linux/of_fdt.h>
 #include <linux/irqchip.h>
 
@@ -91,23 +91,29 @@ void __init plat_mem_setup(void)
 void __init plat_time_init(void)
 {
 	struct device_node *np;
-	u32 freq = 500000000;
+	struct clk *clk;
 
 	of_clk_init(NULL);
-	timer_probe();
 
-	np = of_find_node_by_name(NULL, "cpus");
+	np = of_get_cpu_node(0, NULL);
 	if (!np) {
-		pr_err("Missing 'cpus' DT node, using default frequency.");
-	} else {
-		if (of_property_read_u32(np, "frequency", &freq) < 0)
-			pr_err("No 'frequency' property in DT, using default.");
-		else
-			pr_info("CPU frequency from device tree: %dMHz", freq / 1000000);
-		of_node_put(np);
+		pr_err("Failed to get CPU node\n");
+		return;
+	}
+
+	clk = of_clk_get(np, 0);
+	if (IS_ERR(clk)) {
+		pr_err("Failed to get CPU clock: %ld\n", PTR_ERR(clk));
+		return;
 	}
 
-	mips_hpt_frequency = freq / 2;
+	mips_hpt_frequency = clk_get_rate(clk);
+	clk_put(clk);
+
+	/* The counter runs at half the CPU clock rate */
+	mips_hpt_frequency /= 2;
+
+	timer_probe();
 }
 
 void __init arch_init_irq(void)
-- 
2.36.1