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Subject[PATCH v4 11/16] [loongson] add oprofile support
Date
From: Wu Zhangjin <wuzj@lemote.com>

this kernel support is needed by the user-space tool:oprofile to profile
linux kernel or applications via loongson2 performance counters. you can
enable this driver via CONFIG_OPROFILE = y or m.

In loongson2, there are two performance counters, each one can count 16 events
respectively. when anyone of the performance counter overflows, an interrupt
will generate and goes to the interrupt line: MIPS_CPU_IRQ_BASE + 6

Signed-off-by: Yanhua <yanh@lemote.com>
Signed-off-by: Wu Zhangjin <wuzj@lemote.com>
---
arch/mips/include/asm/mach-lemote/loongson.h | 3 +
arch/mips/lemote/lm2e/irq.c | 2 +
arch/mips/oprofile/Makefile | 1 +
arch/mips/oprofile/common.c | 4 +
arch/mips/oprofile/op_model_loongson2.c | 177 ++++++++++++++++++++++++++
5 files changed, 187 insertions(+), 0 deletions(-)
create mode 100644 arch/mips/oprofile/op_model_loongson2.c
diff --git a/arch/mips/include/asm/mach-lemote/loongson.h b/arch/mips/include/asm/mach-lemote/loongson.h
index 916eace..95ee4c8 100644
--- a/arch/mips/include/asm/mach-lemote/loongson.h
+++ b/arch/mips/include/asm/mach-lemote/loongson.h
@@ -50,4 +50,7 @@ extern void __init prom_init_env(void);
#define LOONGSON_PXARB_CFG BONITO(BONITO_REGBASE + 0x68)
#define LOONGSON_PXARB_STATUS BONITO(BONITO_REGBASE + 0x6c)

+/* loongson2-specific perf counter IRQ */
+#define LOONGSON2_PERFCNT_IRQ (MIPS_CPU_IRQ_BASE + 6)
+
#endif /* __ASM_MACH_LOONGSON_LOONGSON_H */
diff --git a/arch/mips/lemote/lm2e/irq.c b/arch/mips/lemote/lm2e/irq.c
index fb7643a..9585f5a 100644
--- a/arch/mips/lemote/lm2e/irq.c
+++ b/arch/mips/lemote/lm2e/irq.c
@@ -58,6 +58,8 @@ asmlinkage void plat_irq_dispatch(void)

if (pending & CAUSEF_IP7)
do_IRQ(MIPS_CPU_IRQ_BASE + 7);
+ else if (pending & CAUSEF_IP6) /* perf counter loverflow */
+ do_IRQ(LOONGSON2_PERFCNT_IRQ);
else if (pending & CAUSEF_IP5)
i8259_irqdispatch();
else if (pending & CAUSEF_IP2)
diff --git a/arch/mips/oprofile/Makefile b/arch/mips/oprofile/Makefile
index bf3be6f..02cc65e 100644
--- a/arch/mips/oprofile/Makefile
+++ b/arch/mips/oprofile/Makefile
@@ -15,3 +15,4 @@ 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_RM9000) += op_model_rm9000.o
+oprofile-$(CONFIG_CPU_LOONGSON2) += op_model_loongson2.o
diff --git a/arch/mips/oprofile/common.c b/arch/mips/oprofile/common.c
index 3bf3354..7832ad2 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_loongson2_ops __attribute__((weak));

static struct op_mips_model *model;

@@ -93,6 +94,9 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
case CPU_RM9000:
lmodel = &op_model_rm9000_ops;
break;
+ case CPU_LOONGSON2:
+ lmodel = &op_model_loongson2_ops;
+ break;
};

if (!lmodel)
diff --git a/arch/mips/oprofile/op_model_loongson2.c b/arch/mips/oprofile/op_model_loongson2.c
new file mode 100644
index 0000000..655cb8d
--- /dev/null
+++ b/arch/mips/oprofile/op_model_loongson2.c
@@ -0,0 +1,177 @@
+/*
+ * Loongson2 performance counter driver for oprofile
+ *
+ * Copyright (C) 2009 Lemote Inc. & Insititute of Computing Technology
+ * Author: Yanhua <yanh@lemote.com>
+ * Author: Wu Zhangjin <wuzj@lemote.com>
+ *
+ * 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.
+ *
+ */
+#include <linux/init.h>
+#include <linux/oprofile.h>
+#include <linux/interrupt.h>
+
+#include <loongson.h> /* LOONGSON2_PERFCNT_IRQ */
+#include "op_impl.h"
+
+/*
+ * a patch should be sent to oprofile with the loongson-specific support.
+ * otherwise, the oprofile tool will not recognize this and complain about
+ * "cpu_type 'unset' is not valid".
+ */
+#define LOONGSON2_CPU_TYPE "mips/godson2"
+
+#define LOONGSON2_COUNTER1_EVENT(event) ((event & 0x0f) << 5)
+#define LOONGSON2_COUNTER2_EVENT(event) ((event & 0x0f) << 9)
+
+#define LOONGSON2_PERFCNT_EXL (1UL << 0)
+#define LOONGSON2_PERFCNT_KERNEL (1UL << 1)
+#define LOONGSON2_PERFCNT_SUPERVISOR (1UL << 2)
+#define LOONGSON2_PERFCNT_USER (1UL << 3)
+#define LOONGSON2_PERFCNT_INT_EN (1UL << 4)
+#define LOONGSON2_PERFCNT_OVERFLOW (1ULL << 31)
+
+/* Loongson2 performance counter register */
+#define read_c0_perfctrl() __read_64bit_c0_register($24, 0)
+#define write_c0_perfctrl(val) __write_64bit_c0_register($24, 0, val)
+#define read_c0_perfcnt() __read_64bit_c0_register($25, 0)
+#define write_c0_perfcnt(val) __write_64bit_c0_register($25, 0, val)
+
+static struct loongson2_register_config {
+ unsigned int ctrl;
+ unsigned long long reset_counter1;
+ unsigned long long reset_counter2;
+ int cnt1_enalbed, cnt2_enalbed;
+} reg;
+
+DEFINE_SPINLOCK(sample_lock);
+
+static char *oprofid = "LoongsonPerf";
+static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id);
+/* Compute all of the registers in preparation for enabling profiling. */
+
+static void loongson2_reg_setup(struct op_counter_config *cfg)
+{
+ unsigned int ctrl = 0;
+
+ reg.reset_counter1 = 0;
+ reg.reset_counter2 = 0;
+ /* Compute the performance counter ctrl word. */
+ /* For now count kernel and user mode */
+ if (cfg[0].enabled) {
+ ctrl |= LOONGSON2_COUNTER1_EVENT(cfg[0].event);
+ reg.reset_counter1 = 0x80000000ULL - cfg[0].count;
+ }
+
+ if (cfg[1].enabled) {
+ ctrl |= LOONGSON2_COUNTER2_EVENT(cfg[1].event);
+ reg.reset_counter2 = (0x80000000ULL - cfg[1].count);
+ }
+
+ if (cfg[0].enabled || cfg[1].enabled) {
+ ctrl |= LOONGSON2_PERFCNT_EXL | LOONGSON2_PERFCNT_INT_EN;
+ if (cfg[0].kernel || cfg[1].kernel)
+ ctrl |= LOONGSON2_PERFCNT_KERNEL;
+ if (cfg[0].user || cfg[1].user)
+ ctrl |= LOONGSON2_PERFCNT_USER;
+ }
+
+ reg.ctrl = ctrl;
+
+ reg.cnt1_enalbed = cfg[0].enabled;
+ reg.cnt2_enalbed = cfg[1].enabled;
+
+}
+
+/* Program all of the registers in preparation for enabling profiling. */
+
+static void loongson2_cpu_setup(void *args)
+{
+ uint64_t perfcount;
+
+ perfcount = (reg.reset_counter2 << 32) | reg.reset_counter1;
+ write_c0_perfcnt(perfcount);
+}
+
+static void loongson2_cpu_start(void *args)
+{
+ /* Start all counters on current CPU */
+ if (reg.cnt1_enalbed || reg.cnt2_enalbed)
+ write_c0_perfctrl(reg.ctrl);
+}
+
+static void loongson2_cpu_stop(void *args)
+{
+ /* Stop all counters on current CPU */
+ write_c0_perfctrl(0);
+ memset(&reg, 0, sizeof(reg));
+}
+
+static irqreturn_t loongson2_perfcount_handler(int irq, void *dev_id)
+{
+ uint64_t counter, counter1, counter2;
+ struct pt_regs *regs = get_irq_regs();
+ int enabled;
+ unsigned long flags;
+
+ /*
+ * LOONGSON2 defines two 32-bit performance counters.
+ * To avoid a race updating the registers we need to stop the counters
+ * while we're messing with
+ * them ...
+ */
+
+ /* Check whether the irq belongs to me */
+ enabled = reg.cnt1_enalbed | reg.cnt2_enalbed;
+ if (!enabled)
+ return IRQ_NONE;
+
+ counter = read_c0_perfcnt();
+ counter1 = counter & 0xffffffff;
+ counter2 = counter >> 32;
+
+ spin_lock_irqsave(&sample_lock, flags);
+
+ if (counter1 & LOONGSON2_PERFCNT_OVERFLOW) {
+ if (reg.cnt1_enalbed)
+ oprofile_add_sample(regs, 0);
+ counter1 = reg.reset_counter1;
+ }
+ if (counter2 & LOONGSON2_PERFCNT_OVERFLOW) {
+ if (reg.cnt2_enalbed)
+ oprofile_add_sample(regs, 1);
+ counter2 = reg.reset_counter2;
+ }
+
+ spin_unlock_irqrestore(&sample_lock, flags);
+
+ write_c0_perfcnt((counter2 << 32) | counter1);
+
+ return IRQ_HANDLED;
+}
+
+static int __init loongson2_init(void)
+{
+ return request_irq(LOONGSON2_PERFCNT_IRQ, loongson2_perfcount_handler,
+ IRQF_SHARED, "Perfcounter", oprofid);
+}
+
+static void loongson2_exit(void)
+{
+ write_c0_perfctrl(0);
+ free_irq(LOONGSON2_PERFCNT_IRQ, oprofid);
+}
+
+struct op_mips_model op_model_loongson2_ops = {
+ .reg_setup = loongson2_reg_setup,
+ .cpu_setup = loongson2_cpu_setup,
+ .init = loongson2_init,
+ .exit = loongson2_exit,
+ .cpu_start = loongson2_cpu_start,
+ .cpu_stop = loongson2_cpu_stop,
+ .cpu_type = LOONGSON2_CPU_TYPE,
+ .num_counters = 2
+};
--
1.6.2.1


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