Implementing perf related APIs to activate and terminate a trace session. More specifically dealing with the sink buffer's internal mechanic along with perf's API to start and stop interactions with the ring buffers.
Signed-off-by: Mathieu Poirier <[email protected]> --- drivers/hwtracing/coresight/coresight-etb10.c | 42 +++++++++++++++++++++++++++ include/linux/coresight.h | 8 +++++ 2 files changed, 50 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c index ca2fbf65a454..3239036f4609 100644 --- a/drivers/hwtracing/coresight/coresight-etb10.c +++ b/drivers/hwtracing/coresight/coresight-etb10.c @@ -28,6 +28,7 @@ #include <linux/amba/bus.h> #include <linux/clk.h> #include <linux/mm.h> +#include <linux/perf_event.h> #include <asm/local.h> @@ -306,10 +307,51 @@ static void *etb_setup_aux(struct coresight_device *csdev, int cpu, return buf; } +static int etb_set_buffer(struct coresight_device *csdev, + struct perf_event *event, + struct perf_output_handle *handle) +{ + unsigned long head; + struct cs_buffers *buf; + + buf = perf_aux_output_begin(handle, event); + if (!buf) + return -EINVAL; + + /* how much space do we have in this session */ + buf->size = handle->size; + + /* wrap head around to the amount of space we have */ + head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1); + + /* find the page to write to */ + buf->cur = head / PAGE_SIZE; + + /* and offset within that page */ + buf->offset = head % PAGE_SIZE; + + local_set(&buf->head, head); + local_set(&buf->data_size, 0); + + return 0; +} + +static void etb_unset_buffer(struct coresight_device *csdev, + struct perf_output_handle *handle) +{ + struct cs_buffers *buf = perf_get_aux(handle); + + if (buf) + perf_aux_output_end(handle, local_xchg(&buf->data_size, 0), + local_xchg(&buf->lost, 0)); +} + static const struct coresight_ops_sink etb_sink_ops = { .enable = etb_enable, .disable = etb_disable, .setup_aux = etb_setup_aux, + .set_buffer = etb_set_buffer, + .unset_buffer = etb_unset_buffer, }; static const struct coresight_ops etb_cs_ops = { diff --git a/include/linux/coresight.h b/include/linux/coresight.h index 71cc23709422..25bdce345ec3 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -15,6 +15,7 @@ #include <linux/device.h> #include <linux/sched.h> +#include <linux/perf_event.h> /* Peripheral id registers (0xFD0-0xFEC) */ #define CORESIGHT_PERIPHIDR4 0xfd0 @@ -186,12 +187,19 @@ struct coresight_device { * @enable: enables the sink. * @disable: disables the sink. * @setup_aux: initialises perf's ring buffer for trace collection. + * @set_buffer: initialises buffer mechanic before a trace session. + * @unset_buffer: finalises buffer mechanic after a trace session. */ struct coresight_ops_sink { int (*enable)(struct coresight_device *csdev); void (*disable)(struct coresight_device *csdev); void *(*setup_aux)(struct coresight_device *csdev, int cpu, void **pages, int nr_pages, bool overwrite); + int (*set_buffer)(struct coresight_device *csdev, + struct perf_event *event, + struct perf_output_handle *handle); + void (*unset_buffer)(struct coresight_device *csdev, + struct perf_output_handle *handle); }; /** -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
