From: DebBarma, Tarun Kanti <tarun.kanti@xxxxxx>
[ARM Cortex-A8 Errata 628216]
If a Perf Counter OVFL occurs simultaneously with an update to a CP14 or
CP15 register, the OVFL status can be lost.
In order to workaround problem in Cortex-A8 Performance Counter, OMAP
GPTIMER is used by OProfile.
Signed-off-by: Tarun Kanti DebBarma <tarun.kanti@xxxxxx>
Cc: Siarhei Siamashka <siarhei.siamashka@xxxxxxxxx>
Cc: Manjunatha GK <manjugk@xxxxxx>
---
arch/arm/Kconfig | 59 +++++++++++++++---
arch/arm/oprofile/Makefile | 1 +
arch/arm/oprofile/common.c | 4 +
arch/arm/oprofile/op_arm_model.h | 1 +
arch/arm/oprofile/op_model_omap_gptimer.c | 96 +++++++++++++++++++++++++++++
5 files changed, 153 insertions(+), 8 deletions(-)
create mode 100644 arch/arm/oprofile/op_model_omap_gptimer.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 410d3e3..a753c8c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -175,27 +175,70 @@ config ARM_L1_CACHE_SHIFT_6
help
Setting ARM L1 cache line size to 64 Bytes.
-if OPROFILE
+menuconfig INSTRUMENTATION
+ bool "Instrumentation Support"
+ default y
+ ---help---
+ Say Y here to get to see options related to performance measurement,
+ system-wide debugging and testing. This option alone does not add any
+ kernel code.
+
+ If you say N, all options in this submenu will be skipped and
+ disabled. If you're trying to debug the kernel itself, check the
+ Kernel Hacking menu.
+
+if INSTRUMENTATION
+
+config PROFILING
+ bool "Profiling support"
+ help
+ Say Y here to enable the extended profiling support mechanisms
+ used by profilers such as OProfile.
+
+config OPROFILE
+ tristate "OProfile system profiling"
+ depends on PROFILING
+ help
+ OProfile is a profiling system capable of profiling the
+ whole system, including the kernel, kernel modules, libraries,
+ and applications.
+
+ If unsure, say N.
+choice
+ prompt "Oprofile Mode"
+ depends on OPROFILE
+ default OPROFILE_OMAP_GPTIMER
config OPROFILE_ARMV6
- def_bool y
+ bool "Oprofile ARMv6"
depends on CPU_V6 && !SMP
select OPROFILE_ARM11_CORE
config OPROFILE_MPCORE
- def_bool y
+ bool "Oprofile MPcore"
depends on CPU_V6 && SMP
select OPROFILE_ARM11_CORE
-config OPROFILE_ARM11_CORE
- bool
-
config OPROFILE_ARMV7
- def_bool y
+ bool "Oprofile ARMv7"
depends on CPU_V7 && !SMP
+ help
+ Uses Performance counters for profiling
+
+config OPROFILE_OMAP_GPTIMER
+ bool "Oprofile GPTimer"
+ depends on ARCH_OMAP
+ select OMAP_32K_TIMER
+ select OMAP_DM_TIMER
+ help
+ Uses GPTIMER for profiling. Currently this is the preferred
+ way since Performance counters have known bugs in Cortex-A8
+endchoice
+
+config OPROFILE_ARM11_CORE
bool
-endif
+endif # INSTRUMENTATION
config VECTORS_BASE
hex
diff --git a/arch/arm/oprofile/Makefile b/arch/arm/oprofile/Makefile
index 88e31f5..fc2bc02 100644
--- a/arch/arm/oprofile/Makefile
+++ b/arch/arm/oprofile/Makefile
@@ -8,6 +8,7 @@ DRIVER_OBJS = $(addprefix ../../../drivers/oprofile/, \
oprofile-y := $(DRIVER_OBJS) common.o backtrace.o
oprofile-$(CONFIG_CPU_XSCALE) += op_model_xscale.o
+oprofile-$(CONFIG_OPROFILE_OMAP_GPTIMER) += op_model_omap_gptimer.o
oprofile-$(CONFIG_OPROFILE_ARM11_CORE) += op_model_arm11_core.o
oprofile-$(CONFIG_OPROFILE_ARMV6) += op_model_v6.o
oprofile-$(CONFIG_OPROFILE_MPCORE) += op_model_mpcore.o
diff --git a/arch/arm/oprofile/common.c b/arch/arm/oprofile/common.c
index 3fcd752..9eb2b9b 100644
--- a/arch/arm/oprofile/common.c
+++ b/arch/arm/oprofile/common.c
@@ -133,6 +133,10 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
ops->backtrace = arm_backtrace;
+#ifdef CONFIG_OPROFILE_OMAP_GPTIMER
+ spec = &op_omap_gptimer_spec;
+#endif
+
#ifdef CONFIG_CPU_XSCALE
spec = &op_xscale_spec;
#endif
diff --git a/arch/arm/oprofile/op_arm_model.h b/arch/arm/oprofile/op_arm_model.h
index 8c4e4f6..55f22e4 100644
--- a/arch/arm/oprofile/op_arm_model.h
+++ b/arch/arm/oprofile/op_arm_model.h
@@ -24,6 +24,7 @@ struct op_arm_model_spec {
extern struct op_arm_model_spec op_xscale_spec;
#endif
+extern struct op_arm_model_spec op_omap_gptimer_spec;
extern struct op_arm_model_spec op_armv6_spec;
extern struct op_arm_model_spec op_mpcore_spec;
extern struct op_arm_model_spec op_armv7_spec;
diff --git a/arch/arm/oprofile/op_model_omap_gptimer.c b/arch/arm/oprofile/op_model_omap_gptimer.c
new file mode 100644
index 0000000..49bab30
--- /dev/null
+++ b/arch/arm/oprofile/op_model_omap_gptimer.c
@@ -0,0 +1,96 @@
+/**
+ * OMAP gptimer based event monitor driver for oprofile
+ *
+ * Copyright (C) 2009 Nokia Corporation
+ * Author: Siarhei Siamashka <siarhei.siamashka@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/oprofile.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <plat/dmtimer.h>
+
+#include "op_counter.h"
+#include "op_arm_model.h"
+
+static struct omap_dm_timer *gptimer;
+
+static int gptimer_init(void)
+{
+ return 0;
+}
+
+static int gptimer_setup(void)
+{
+ return 0;
+}
+
+static irqreturn_t gptimer_interrupt(int irq, void *arg)
+{
+ omap_dm_timer_write_status(gptimer, OMAP_TIMER_INT_OVERFLOW);
+ oprofile_add_sample(get_irq_regs(), 0);
+ return IRQ_HANDLED;
+}
+
+static int gptimer_start(void)
+{
+ int err;
+ u32 count = counter_config[0].count;
+
+ BUG_ON(gptimer != NULL);
+ /* First try to request timers from CORE power domain for OMAP3 */
+ if (cpu_is_omap34xx()) {
+ gptimer = omap_dm_timer_request_specific(10);
+ if (gptimer == NULL)
+ gptimer = omap_dm_timer_request_specific(11);
+ }
+ /* Just any timer would be fine */
+ if (gptimer == NULL)
+ gptimer = omap_dm_timer_request();
+
+ if (gptimer == NULL)
+ return -ENODEV;
+
+ omap_dm_timer_set_source(gptimer, OMAP_TIMER_SRC_32_KHZ);
+ err = request_irq(omap_dm_timer_get_irq(gptimer), gptimer_interrupt,
+ IRQF_DISABLED, "oprofile gptimer", NULL);
+ if (err) {
+ omap_dm_timer_free(gptimer);
+ gptimer = NULL;
+ printk(KERN_ERR "oprofile: unable to request gptimer IRQ\n");
+ return err;
+ }
+
+ /* opcontrol sets default value as 100000 which makes the sample rate
+ * too low, hence resetting
+ */
+ if ((count < 0) || (count == 100000))
+ count = 1;
+
+ omap_dm_timer_set_load_start(gptimer, 1, 0xffffffff - count);
+ omap_dm_timer_set_int_enable(gptimer, OMAP_TIMER_INT_OVERFLOW);
+ return 0;
+}
+
+static void gptimer_stop(void)
+{
+ omap_dm_timer_set_int_enable(gptimer, 0);
+ free_irq(omap_dm_timer_get_irq(gptimer), NULL);
+ omap_dm_timer_free(gptimer);
+ gptimer = NULL;
+}
+
+struct op_arm_model_spec op_omap_gptimer_spec = {
+ .init = gptimer_init,
+ .num_counters = 1,
+ .setup_ctrs = gptimer_setup,
+ .start = gptimer_start,
+ .stop = gptimer_stop,
+ .name = "arm/armv6",
+};
--
1.6.0.4
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