microblaze: Add support for CCF

Add support for CCF for Microblaze.

Old binding:
system_timer: system-timer@41c00000 {
	clock-frequency = <75000000>;
	...
}

New binding:
system_timer: system-timer@41c00000 {
	clocks = <&clk_bus>;
	...
}

Both should be supported for a while

Microblaze clock binding:
clocks {
	#address-cells = <1>;
	#size-cells = <0>;
	clk_bus: bus {
		#clock-cells = <0>;
		clock-frequency = <75000000>;
		clock-output-names = "bus";
		compatible = "fixed-clock";
		reg = <1>;
	} ;
	clk_cpu: cpu {
		#clock-cells = <0>;
		clock-frequency = <75000000>;
		clock-output-names = "cpu";
		compatible = "fixed-clock";
		reg = <0>;
	} ;
} ;
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/microblaze/Kconfig

@@ -26,6 +26,7 @@ config MICROBLAZE
 	select GENERIC_CPU_DEVICES
 	select GENERIC_ATOMIC64
 	select GENERIC_CLOCKEVENTS
+	select COMMON_CLK
 	select GENERIC_IDLE_POLL_SETUP
 	select MODULES_USE_ELF_RELA
 	select CLONE_BACKWARDS3

arch/microblaze/include/asm/cpuinfo.h

@@ -91,6 +91,7 @@ extern struct cpuinfo cpuinfo;
 
 /* fwd declarations of the various CPUinfo populators */
 void setup_cpuinfo(void);
+void setup_cpuinfo_clk(void);
 
 void set_cpuinfo_static(struct cpuinfo *ci, struct device_node *cpu);
 void set_cpuinfo_pvr_full(struct cpuinfo *ci, struct device_node *cpu);

arch/microblaze/kernel/cpu/cpuinfo-pvr-full.c

@@ -112,7 +112,4 @@ void set_cpuinfo_pvr_full(struct cpuinfo *ci, struct device_node *cpu)
 	CI(num_wr_brk, NUMBER_OF_WR_ADDR_BRK);
 
 	CI(fpga_family_code, TARGET_FAMILY);
-
-	/* take timebase-frequency from DTS */
-	ci->cpu_clock_freq = fcpu(cpu, "timebase-frequency");
 }

arch/microblaze/kernel/cpu/cpuinfo-static.c

@@ -113,8 +113,6 @@ void __init set_cpuinfo_static(struct cpuinfo *ci, struct device_node *cpu)
 	ci->num_rd_brk = fcpu(cpu, "xlnx,number-of-rd-addr-brk");
 	ci->num_wr_brk = fcpu(cpu, "xlnx,number-of-wr-addr-brk");
 
-	ci->cpu_clock_freq = fcpu(cpu, "timebase-frequency");
-
 	ci->pvr_user1 = fcpu(cpu, "xlnx,pvr-user1");
 	ci->pvr_user2 = fcpu(cpu, "xlnx,pvr-user2");
 

arch/microblaze/kernel/cpu/cpuinfo.c

@@ -8,6 +8,7 @@
  * for more details.
  */
 
+#include <linux/clk.h>
 #include <linux/init.h>
 #include <asm/cpuinfo.h>
 #include <asm/pvr.h>
@@ -68,11 +69,10 @@ const struct family_string_key family_string_lookup[] = {
 };
 
 struct cpuinfo cpuinfo;
+static struct device_node *cpu;
 
 void __init setup_cpuinfo(void)
 {
-	struct device_node *cpu = NULL;
-
 	cpu = (struct device_node *) of_find_node_by_type(NULL, "cpu");
 	if (!cpu)
 		pr_err("You don't have cpu!!!\n");
@@ -102,3 +102,22 @@ void __init setup_cpuinfo(void)
 		pr_warn("%s: Stream instructions enabled"
 			" - USERSPACE CAN LOCK THIS KERNEL!\n", __func__);
 }
+
+void __init setup_cpuinfo_clk(void)
+{
+	struct clk *clk;
+
+	clk = of_clk_get(cpu, 0);
+	if (IS_ERR(clk)) {
+		pr_err("ERROR: CPU CCF input clock not found\n");
+		/* take timebase-frequency from DTS */
+		cpuinfo.cpu_clock_freq = fcpu(cpu, "timebase-frequency");
+	} else {
+		cpuinfo.cpu_clock_freq = clk_get_rate(clk);
+	}
+
+	if (!cpuinfo.cpu_clock_freq) {
+		pr_err("ERROR: CPU clock frequency not setup\n");
+		BUG();
+	}
+}

arch/microblaze/kernel/setup.c

@@ -9,6 +9,7 @@
  */
 
 #include <linux/init.h>
+#include <linux/clk-provider.h>
 #include <linux/clocksource.h>
 #include <linux/string.h>
 #include <linux/seq_file.h>
@@ -195,6 +196,8 @@ void __init machine_early_init(const char *cmdline, unsigned int ram,
 
 void __init time_init(void)
 {
+	of_clk_init(NULL);
+	setup_cpuinfo_clk();
 	clocksource_of_init();
 }
 

arch/microblaze/kernel/timer.c

@@ -230,9 +230,9 @@ static int timer_initialized;
 
 static void __init xilinx_timer_init(struct device_node *timer)
 {
+	struct clk *clk;
 	u32 irq;
 	u32 timer_num = 1;
-	int ret;
 
 	timer_baseaddr = of_iomap(timer, 0);
 	if (!timer_baseaddr) {
@@ -250,10 +250,20 @@ static void __init xilinx_timer_init(struct device_node *timer)
 
 	pr_info("%s: irq=%d\n", timer->full_name, irq);
 
-	/* If there is clock-frequency property than use it */
-	ret = of_property_read_u32(timer, "clock-frequency", &timer_clock_freq);
-	if (ret < 0)
+	clk = of_clk_get(timer, 0);
+	if (IS_ERR(clk)) {
+		pr_err("ERROR: timer CCF input clock not found\n");
+		/* If there is clock-frequency property than use it */
+		of_property_read_u32(timer, "clock-frequency",
+				    &timer_clock_freq);
+	} else {
+		timer_clock_freq = clk_get_rate(clk);
+	}
+
+	if (!timer_clock_freq) {
+		pr_err("ERROR: Using CPU clock frequency\n");
 		timer_clock_freq = cpuinfo.cpu_clock_freq;
+	}
 
 	freq_div_hz = timer_clock_freq / HZ;