[PATCH V2] oprofile: VR5500 performance counter driver

[Mark Asselstine <mark.asselstine@windriver.com>]

This is inspired by op_model_mipsxx.c with some modification
in regards to register layout and overflow handling. This has
been tested on a NEC VR5500 board and shown to produce sane
results.

Signed-off-by: Mark Asselstine <mark.asselstine@windriver.com>
---

I have left this as a new file as there is enough differences
to make combining it combersome. If pushed I would possibly
change my mind but I am not convinced yet. The userspace
events are seen as mips/vr5500 so if there is a desire to
have everything be r5500 some userspace changes would need
to be made.

 arch/mips/oprofile/Makefile         |    1 +
 arch/mips/oprofile/common.c         |    5 +
 arch/mips/oprofile/op_model_r5500.c |  161 +++++++++++++++++++++++++++++++++++
 3 files changed, 167 insertions(+), 0 deletions(-)
 create mode 100644 arch/mips/oprofile/op_model_r5500.c

diff --git a/arch/mips/oprofile/Makefile b/arch/mips/oprofile/Makefile
index bf3be6f..586e64e 100644
--- a/arch/mips/oprofile/Makefile
+++ b/arch/mips/oprofile/Makefile
@@ -14,4 +14,5 @@ oprofile-$(CONFIG_CPU_MIPS32)		+= op_model_mipsxx.o
 oprofile-$(CONFIG_CPU_MIPS64)		+= op_model_mipsxx.o
 oprofile-$(CONFIG_CPU_R10000)		+= op_model_mipsxx.o
 oprofile-$(CONFIG_CPU_SB1)		+= op_model_mipsxx.o
+oprofile-$(CONFIG_CPU_R5500)		+= op_model_r5500.o
 oprofile-$(CONFIG_CPU_RM9000)		+= op_model_rm9000.o
diff --git a/arch/mips/oprofile/common.c b/arch/mips/oprofile/common.c
index 3bf3354..26780c7 100644
--- a/arch/mips/oprofile/common.c
+++ b/arch/mips/oprofile/common.c
@@ -16,6 +16,7 @@
 
 extern struct op_mips_model op_model_mipsxx_ops __attribute__((weak));
 extern struct op_mips_model op_model_rm9000_ops __attribute__((weak));
+extern struct op_mips_model op_model_r5500_ops __attribute__((weak));
 
 static struct op_mips_model *model;
 
@@ -93,6 +94,10 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
 	case CPU_RM9000:
 		lmodel = &op_model_rm9000_ops;
 		break;
+
+	case CPU_R5500:
+		lmodel = &op_model_r5500_ops;
+		break;
 	};
 
 	if (!lmodel)
diff --git a/arch/mips/oprofile/op_model_r5500.c b/arch/mips/oprofile/op_model_r5500.c
new file mode 100644
index 0000000..9b0d20f
--- /dev/null
+++ b/arch/mips/oprofile/op_model_r5500.c
@@ -0,0 +1,161 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (c) 2009 Wind River Systems, Inc.
+ *
+ * Derived from op_model_mipsxx.c Copyright Ralf Baechle, MIPS Technologies Inc
+ */
+#include <linux/oprofile.h>
+#include <linux/interrupt.h>
+#include <asm/irq_regs.h>
+
+#include "op_impl.h"
+
+#define M_PERFCTL_EXL			(1UL      <<  0)
+#define M_PERFCTL_KERNEL		(1UL      <<  1)
+#define M_PERFCTL_SUPERVISOR		(1UL      <<  2)
+#define M_PERFCTL_USER			(1UL      <<  3)
+#define M_PERFCTL_INTERRUPT_ENABLE	(1UL      <<  4)
+#define M_PERFCTL_INTERRUPT		(1UL      <<  5)
+#define M_PERFCTL_EVENT(event)		(((event) & 0xf)  << 6)
+#define M_PERFCTL_COUNT_ENABLE		(1UL      <<  10)
+
+#define NUM_COUNTERS                    2
+
+static int (*save_perf_irq) (void);
+
+struct op_mips_model op_model_r5500_ops;
+
+static struct r5500_register_config {
+	unsigned int control[NUM_COUNTERS];
+	unsigned int counter[NUM_COUNTERS];
+} reg;
+
+/* Compute all of the registers in preparation for enabling profiling.  */
+static void r5500_reg_setup(struct op_counter_config *ctr)
+{
+	int i;
+	unsigned int counters = NUM_COUNTERS;
+
+	/* Compute the performance counter control word.  */
+	for (i = 0; i < counters; i++) {
+		reg.control[i] = 0;
+		reg.counter[i] = 0;
+
+		if (!ctr[i].enabled)
+			continue;
+
+		reg.control[i] = M_PERFCTL_EVENT(ctr[i].event) |
+		    M_PERFCTL_INTERRUPT_ENABLE | M_PERFCTL_COUNT_ENABLE;
+		if (ctr[i].kernel)
+			reg.control[i] |= M_PERFCTL_KERNEL;
+		if (ctr[i].user)
+			reg.control[i] |= M_PERFCTL_USER;
+		if (ctr[i].exl)
+			reg.control[i] |= M_PERFCTL_EXL;
+
+		reg.counter[i] = 0xffffffff - ctr[i].count + 1;
+	}
+}
+
+/* Program all of the registers in preparation for enabling profiling.  */
+static void r5500_cpu_setup(void *args)
+{
+	write_c0_perfctrl1(0);
+	write_c0_perfcntr1(reg.counter[1]);
+
+	write_c0_perfctrl0(0);
+	write_c0_perfcntr0(reg.counter[0]);
+}
+
+/* Start all counters on current CPU */
+static void r5500_cpu_start(void *args)
+{
+	write_c0_perfctrl1(reg.control[1]);
+	write_c0_perfctrl0(reg.control[0]);
+}
+
+/* Stop all counters on current CPU */
+static void r5500_cpu_stop(void *args)
+{
+	write_c0_perfctrl1(0);
+	write_c0_perfctrl0(0);
+}
+
+static int r5500_perfcount_handler(void)
+{
+	unsigned int control;
+	unsigned int counter;
+	int handled = IRQ_NONE;
+
+	control = read_c0_perfctrl0();
+	counter = read_c0_perfcntr0();
+	if ((control & M_PERFCTL_INTERRUPT_ENABLE) &&
+			(control & M_PERFCTL_INTERRUPT)) {
+		oprofile_add_sample(get_irq_regs(), 0);
+		write_c0_perfcntr0(reg.counter[0]);
+		write_c0_perfctrl0(control & ~M_PERFCTL_INTERRUPT);
+		handled = IRQ_HANDLED;
+	}
+
+	control = read_c0_perfctrl1();
+	counter = read_c0_perfcntr1();
+	if ((control & M_PERFCTL_INTERRUPT_ENABLE) &&
+			(control & M_PERFCTL_INTERRUPT)) {
+		oprofile_add_sample(get_irq_regs(), 1);
+		write_c0_perfcntr1(reg.counter[1]);
+		write_c0_perfctrl1(control & ~M_PERFCTL_INTERRUPT);
+		handled = IRQ_HANDLED;
+	}
+
+	return handled;
+}
+
+static void reset_counters(void *arg)
+{
+	write_c0_perfctrl1(0);
+	write_c0_perfcntr1(0);
+
+	write_c0_perfctrl0(0);
+	write_c0_perfcntr0(0);
+}
+
+static int __init r5500_init(void)
+{
+	on_each_cpu(reset_counters, NULL, 1);
+
+	switch (current_cpu_type()) {
+	case CPU_R5500:
+		op_model_r5500_ops.cpu_type = "mips/vr5500";
+		break;
+
+	default:
+		printk(KERN_ERR "Profiling unsupported for this CPU\n");
+
+		return -ENODEV;
+	}
+
+	save_perf_irq = perf_irq;
+	perf_irq = r5500_perfcount_handler;
+
+	return 0;
+}
+
+static void r5500_exit(void)
+{
+	on_each_cpu(reset_counters, NULL, 1);
+
+	perf_irq = save_perf_irq;
+}
+
+struct op_mips_model op_model_r5500_ops = {
+	.reg_setup     = r5500_reg_setup,
+	.cpu_setup     = r5500_cpu_setup,
+	.init          = r5500_init,
+	.exit          = r5500_exit,
+	.cpu_start     = r5500_cpu_start,
+	.cpu_stop      = r5500_cpu_stop,
+	.num_counters  = NUM_COUNTERS,
+};
-- 
1.6.0.3