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    Subject[PATCH 12/15] ARM: etm: Add sysfs entry to enable timestamps if supported
    Date
    From: Arve Hjønnevåg <arve@android.com>

    Add sysfs entry to enable timestamps if supported

    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 | 7 +++++
    arch/arm/kernel/etm.c | 44 +++++++++++++++++++++++++++++
    2 files changed, 51 insertions(+)

    diff --git a/arch/arm/include/asm/hardware/coresight.h b/arch/arm/include/asm/hardware/coresight.h
    index 0fad8f8..42059d3 100644
    --- a/arch/arm/include/asm/hardware/coresight.h
    +++ b/arch/arm/include/asm/hardware/coresight.h
    @@ -18,10 +18,12 @@
    #define TRACER_RUNNING_BIT 1
    #define TRACER_CYCLE_ACC_BIT 2
    #define TRACER_TRACE_DATA_BIT 3
    +#define TRACER_TIMESTAMP_BIT 4
    #define TRACER_ACCESSED BIT(TRACER_ACCESSED_BIT)
    #define TRACER_RUNNING BIT(TRACER_RUNNING_BIT)
    #define TRACER_CYCLE_ACC BIT(TRACER_CYCLE_ACC_BIT)
    #define TRACER_TRACE_DATA BIT(TRACER_TRACE_DATA_BIT)
    +#define TRACER_TIMESTAMP BIT(TRACER_TIMESTAMP_BIT)

    #define TRACER_TIMEOUT 10000

    @@ -57,6 +59,7 @@
    #define ETMCTRL_DATA_DO_BOTH (ETMCTRL_DATA_DO_DATA | ETMCTRL_DATA_DO_ADDR)
    #define ETMCTRL_BRANCH_OUTPUT (1 << 8)
    #define ETMCTRL_CYCLEACCURATE (1 << 12)
    +#define ETMCTRL_TIMESTAMP_EN (1 << 28)

    /* ETM configuration code register */
    #define ETMR_CONFCODE (0x04)
    @@ -129,8 +132,12 @@

    #define ETMR_ID 0x1e4
    #define ETMIDR_VERSION(x) (((x) >> 4) & 0xff)
    +#define ETMIDR_VERSION_3_1 0x21
    #define ETMIDR_VERSION_PFT_1_0 0x30

    +#define ETMR_CCE 0x1e8
    +#define ETMCCER_TIMESTAMPING_IMPLEMENTED BIT(22)
    +
    #define ETMR_TRACEIDR 0x200

    /* ETM management registers, "ETM Architecture", 3.5.24 */
    diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
    index e42b706..460a7d8 100644
    --- a/arch/arm/kernel/etm.c
    +++ b/arch/arm/kernel/etm.c
    @@ -116,6 +116,9 @@ static int trace_start_etm(struct tracectx *t, int id)
    if (t->flags & TRACER_TRACE_DATA)
    v |= ETMCTRL_DATA_DO_ADDR;

    + if (t->flags & TRACER_TIMESTAMP)
    + v |= ETMCTRL_TIMESTAMP_EN;
    +
    etm_unlock(t, id);

    etm_writel(t, id, v, ETMR_CTRL);
    @@ -647,6 +650,36 @@ 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_timestamp_show(struct kobject *kobj,
    + struct kobj_attribute *attr,
    + char *buf)
    +{
    + return sprintf(buf, "%d\n", !!(tracer.flags & TRACER_TIMESTAMP));
    +}
    +
    +static ssize_t trace_timestamp_store(struct kobject *kobj,
    + struct kobj_attribute *attr,
    + const char *buf, size_t n)
    +{
    + unsigned int timestamp;
    +
    + if (sscanf(buf, "%u", &timestamp) != 1)
    + return -EINVAL;
    +
    + mutex_lock(&tracer.mutex);
    + if (timestamp)
    + tracer.flags |= TRACER_TIMESTAMP;
    + else
    + tracer.flags &= ~TRACER_TIMESTAMP;
    + mutex_unlock(&tracer.mutex);
    +
    + return n;
    +}
    +
    +static struct kobj_attribute trace_timestamp_attr =
    + __ATTR(trace_timestamp, 0644,
    + trace_timestamp_show, trace_timestamp_store);
    +
    static ssize_t trace_range_show(struct kobject *kobj,
    struct kobj_attribute *attr,
    char *buf)
    @@ -726,6 +759,7 @@ static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id
    int new_count;
    u32 etmccr;
    u32 etmidr;
    + u32 etmccer = 0;
    u8 etm_version = 0;

    mutex_lock(&t->mutex);
    @@ -766,6 +800,8 @@ static int __devinit etm_probe(struct amba_device *dev, const struct amba_id *id
    if (etmccr & ETMCCR_ETMIDR_PRESENT) {
    etmidr = etm_readl(t, t->etm_regs_count, ETMR_ID);
    etm_version = ETMIDR_VERSION(etmidr);
    + if (etm_version >= ETMIDR_VERSION_3_1)
    + etmccer = etm_readl(t, t->etm_regs_count, ETMR_CCE);
    }
    etm_writel(t, t->etm_regs_count, 0x441, ETMR_CTRL);
    etm_writel(t, t->etm_regs_count, new_count, ETMR_TRACEIDR);
    @@ -785,6 +821,14 @@ 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");

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