[PATCH 13/15] ARM: etm: Add sysfs entry to set context-id-size

John Stultz
2012-06-20T22:49:58Z

From: Arve Hjønnevåg <arve@android.com>

Add sysfs entry to set context-id-size

CC: Russell King <linux@arm.linux.org.uk>
CC: Paul Gortmaker <paul.gortmaker@windriver.com>
CC: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
arch/arm/include/asm/hardware/coresight.h | 5 ++--
arch/arm/kernel/etm.c | 40 +++++++++++++++++++++++++++++
2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/arch/arm/include/asm/hardware/coresight.h b/arch/arm/include/asm/hardware/coresight.h
index 42059d3..47b7696 100644
--- a/arch/arm/include/asm/hardware/coresight.h
+++ b/arch/arm/include/asm/hardware/coresight.h
@@ -47,7 +47,7 @@
#define ETMCTRL_POWERDOWN 1
#define ETMCTRL_PROGRAM (1 << 10)
#define ETMCTRL_PORTSEL (1 << 11)
-#define ETMCTRL_DO_CONTEXTID (3 << 14)
+#define ETMCTRL_CONTEXTIDSIZE(x) (((x) & 3) << 14)
#define ETMCTRL_PORTMASK1 (7 << 4)
#define ETMCTRL_PORTMASK2 (1 << 21)
#define ETMCTRL_PORTMASK (ETMCTRL_PORTMASK1 | ETMCTRL_PORTMASK2)
@@ -127,8 +127,7 @@
#define ETMVDC3_EXCLONLY BIT(16)

#define ETMCTRL_OPTS (ETMCTRL_DO_CPRT | \
- ETMCTRL_BRANCH_OUTPUT | \
- ETMCTRL_DO_CONTEXTID)
+ ETMCTRL_BRANCH_OUTPUT)

#define ETMR_ID 0x1e4
#define ETMIDR_VERSION(x) (((x) >> 4) & 0xff)
diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index 460a7d8..f00a3f39 100644
--- a/arch/arm/kernel/etm.c
+++ b/arch/arm/kernel/etm.c
@@ -43,6 +43,7 @@ struct tracectx {
unsigned long flags;
int ncmppairs;
int etm_portsz;
+ int etm_contextid_size;
u32 etb_fc;
unsigned long range_start;
unsigned long range_end;
@@ -109,6 +110,7 @@ static int trace_start_etm(struct tracectx *t, int id)
unsigned long timeout = TRACER_TIMEOUT;

v = ETMCTRL_OPTS | ETMCTRL_PROGRAM | ETMCTRL_PORTSIZE(t->etm_portsz);
+ v |= ETMCTRL_CONTEXTIDSIZE(t->etm_contextid_size);

if (t->flags & TRACER_CYCLE_ACC)
v |= ETMCTRL_CYCLEACCURATE;
@@ -650,6 +652,37 @@ static ssize_t trace_mode_store(struct kobject *kobj,
static struct kobj_attribute trace_mode_attr =
__ATTR(trace_mode, 0644, trace_mode_show, trace_mode_store);

+static ssize_t trace_contextid_size_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ /* 0: No context id tracing, 1: One byte, 2: Two bytes, 3: Four bytes */
+ return sprintf(buf, "%d\n", (1 << tracer.etm_contextid_size) >> 1);
+}
+
+static ssize_t trace_contextid_size_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ unsigned int contextid_size;
+
+ if (sscanf(buf, "%u", &contextid_size) != 1)
+ return -EINVAL;
+
+ if (contextid_size == 3 || contextid_size > 4)
+ return -EINVAL;
+
+ mutex_lock(&tracer.mutex);
+ tracer.etm_contextid_size = fls(contextid_size);
+ mutex_unlock(&tracer.mutex);
+
+ return n;
+}
+
+static struct kobj_attribute trace_contextid_size_attr =
+ __ATTR(trace_contextid_size, 0644,
+ trace_contextid_size_show, trace_contextid_size_store);
+
static ssize_t trace_timestamp_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
@@ -789,6 +822,7 @@ static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id

t->flags = TRACER_CYCLE_ACC | TRACER_TRACE_DATA;
t->etm_portsz = 1;
+ t->etm_contextid_size = 3;

etm_unlock(t, t->etm_regs_count);
(void)etm_readl(t, t->etm_regs_count, ETMMR_PDSR);
@@ -821,6 +855,12 @@ static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id
if (ret)
dev_dbg(&dev->dev, "Failed to create trace_mode in sysfs\n");

+ ret = sysfs_create_file(&dev->dev.kobj,
+ &trace_contextid_size_attr.attr);
+ if (ret)
+ dev_dbg(&dev->dev,
+ "Failed to create trace_contextid_size in sysfs\n");
+
if (etmccer & ETMCCER_TIMESTAMPING_IMPLEMENTED) {
ret = sysfs_create_file(&dev->dev.kobj,
&trace_timestamp_attr.attr);
--
1.7.9.5