gpu: nvgpu: support cpu unix timestamps for cpu-gpu correlation

This patch extends the CPU-GPU query interface to also support
CPU UNIX-based timestamps.

Bug 4059666

Change-Id: Iecb937df38d3913559499fed1027a7157ad8d151
Signed-off-by: Martin Radev <mradev@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2973572
Reviewed-by: Sagar Kamble <skamble@nvidia.com>
Reviewed-by: Ankur Kishore <ankkishore@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

drivers/gpu/nvgpu/common/ptimer/ptimer.c

@@ -26,6 +26,7 @@
 #include <nvgpu/timers.h>
 #include <nvgpu/nvgpu_init.h>
 #include <nvgpu/power_features/cg.h>
+#include <nvgpu/ptimer.h>
 #endif
 
 static u32 ptimer_scalingfactor10x(u32 ptimer_src_freq)
@@ -77,14 +78,13 @@ int nvgpu_ptimer_init(struct gk20a *g)
 }
 
 int nvgpu_get_timestamps_zipper(struct gk20a *g,
-		u32 source_id, u32 count,
+		enum nvgpu_cpu_timestamp_source cpu_timestamp_source,
+		u32 count,
 		struct nvgpu_cpu_time_correlation_sample *samples)
 {
 	int err = 0;
 	unsigned int i = 0;
 
-	(void)source_id;
-
 	if (gk20a_busy(g) != 0) {
 		nvgpu_err(g, "GPU not powered on\n");
 		err = -EINVAL;
@@ -97,7 +97,12 @@ int nvgpu_get_timestamps_zipper(struct gk20a *g,
 			goto idle;
 		}
 
+		/* The cpu timestamp is already validated when handling ioctl/devctls */
+		if (cpu_timestamp_source == NVGPU_CPU_TIMESTAMP_SOURCE_TSC) {
 			samples[i].cpu_timestamp = nvgpu_hr_timestamp();
+		} else if (cpu_timestamp_source == NVGPU_CPU_TIMESTAMP_SOURCE_UNIX) {
+			samples[i].cpu_timestamp = nvgpu_current_unix_time_us();
+		}
 	}
 
 idle:

drivers/gpu/nvgpu/include/nvgpu/ptimer.h

@@ -144,8 +144,21 @@ struct nvgpu_cpu_time_correlation_sample {
 int nvgpu_ptimer_scale(struct gk20a *g, u32 timeout, u32 *scaled_timeout);
 
 #ifdef CONFIG_NVGPU_IOCTL_NON_FUSA
+
+/*
+
+ */
+enum nvgpu_cpu_timestamp_source {
+	/* The timestamp is selected to originate from the current core's TSC */
+	NVGPU_CPU_TIMESTAMP_SOURCE_TSC,
+
+	/* The timestamp is selected to be calculated as UNIX time in microseconds */
+	NVGPU_CPU_TIMESTAMP_SOURCE_UNIX,
+};
+
 int nvgpu_get_timestamps_zipper(struct gk20a *g,
-		u32 source_id, u32 count,
+		enum nvgpu_cpu_timestamp_source cpu_timestamp_source,
+		u32 count,
 		struct nvgpu_cpu_time_correlation_sample *samples);
 int nvgpu_ptimer_init(struct gk20a *g);
 #endif /* CONFIG_NVGPU_IOCTL_NON_FUSA */

drivers/gpu/nvgpu/include/nvgpu/timers.h

@@ -363,6 +363,13 @@ u64 nvgpu_hr_timestamp_us(void);
  * @return High resolution time stamp value.
  */
 u64 nvgpu_hr_timestamp(void);
+
+/**
+ * @brief UNIX timestamp.
+ *
+ * @return High resolution UNIX time stamp value.
+ */
+u64 nvgpu_current_unix_time_us(void);
 #endif
 
 /**

drivers/gpu/nvgpu/os/linux/ioctl_ctrl.c

@@ -1230,13 +1230,24 @@ static int nvgpu_gpu_get_cpu_time_correlation_info(
 	struct nvgpu_gpu_get_cpu_time_correlation_info_args *args)
 {
 	struct nvgpu_cpu_time_correlation_sample *samples;
+	enum nvgpu_cpu_timestamp_source timestamp_source;
 	int err;
 	u32 i;
 
-	if (args->count > NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_MAX_COUNT ||
+	if (args->count > NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_MAX_COUNT)
-	    args->source_id != NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_TSC)
 		return -EINVAL;
 
+	switch(args->source_id) {
+	case NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_TSC:
+		timestamp_source = NVGPU_CPU_TIMESTAMP_SOURCE_TSC;
+		break;
+	case NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_OSTIME:
+		timestamp_source = NVGPU_CPU_TIMESTAMP_SOURCE_UNIX;
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	samples = nvgpu_kzalloc(g, args->count *
 		sizeof(struct nvgpu_cpu_time_correlation_sample));
 	if (!samples) {
@@ -1244,7 +1255,7 @@ static int nvgpu_gpu_get_cpu_time_correlation_info(
 	}
 
 	err = g->ops.ptimer.get_timestamps_zipper(g,
-			args->source_id, args->count, samples);
+			timestamp_source, args->count, samples);
 	if (!err) {
 		for (i = 0; i < args->count; i++) {
 			args->samples[i].cpu_timestamp = samples[i].cpu_timestamp;

drivers/gpu/nvgpu/os/linux/timers.c

@@ -271,6 +271,17 @@ s64 nvgpu_current_time_ns(void)
 	return ktime_to_ns(ktime_get());
 }
 
+/**
+ * nvgpu_current_unix_time_us - UNIX time in microseconds from a monotonic clock.
+ *
+ * Returns the UNIX clock in microseconds units. The start time of the clock is
+ * 1970 00:00:00.
+ */
+u64 nvgpu_current_unix_time_us(void)
+{
+	return (u64)ktime_to_us(ktime_get_real());
+}
+
 /**
  * nvgpu_hr_timestamp_us - Time in microseconds from a monotonic clock.
  *

include/uapi/linux/nvgpu-ctrl.h

@@ -684,6 +684,7 @@ struct nvgpu_gpu_get_buffer_info_args {
 
 #define NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_MAX_COUNT		16
 #define NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_TSC		1
+#define NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_OSTIME	2
 
 struct nvgpu_gpu_get_cpu_time_correlation_sample {
 	/* gpu timestamp value */