gpu: nvgpu: hal for timestamps correlation

In order to perform timestamps correlation for FECS
traces, we need to collect GPU / GPU timestamps
samples. In virtualization case, it is possible for
a guest to get GPU timestamps by using read_ptimer.
However, if the CPU timestamp is read on guest side,
and the GPU timestamp is read on vm-server side,
then it introduces some latency that will create an
artificial offset for GPU timestamps (~2 us in
average). For better CPU / GPU timestamps correlation,
Added a command to collect all timestamps on vm-server
side.

Bug 1900475

Change-Id: Idfdc6ae4c16c501dc5e00053a5b75932c55148d6
Signed-off-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-on: http://git-master/r/1472447
(cherry picked from commit 56f56b5cd9d2e75cf7d2613b5e115bfebdbee0ce)
Reviewed-on: http://git-master/r/1489183
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 18 insertions, 60 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/ioctl_ctrl.c b/drivers/gpu/nvgpu/common/linux/ioctl_ctrl.c
index 90a3fbd4..025a30fe 100644
--- a/drivers/gpu/nvgpu/common/linux/ioctl_ctrl.c
+++ b/drivers/gpu/nvgpu/common/linux/ioctl_ctrl.c
@@ -533,76 +533,34 @@ static int gk20a_ctrl_get_buffer_info(
                                         &args->out.id, &args->out.length);
 }
 
-static inline u64 get_cpu_timestamp_tsc(void)
-{
-        return ((u64) get_cycles());
-}
-
-static inline u64 get_cpu_timestamp_jiffies(void)
-{
-        return (get_jiffies_64() - INITIAL_JIFFIES);
-}
-
-static inline u64 get_cpu_timestamp_timeofday(void)
-{
-        struct timeval tv;
-
-        do_gettimeofday(&tv);
-        return timeval_to_jiffies(&tv);
-}
-
-static inline int get_timestamps_zipper(struct gk20a *g,
-                u64 (*get_cpu_timestamp)(void),
-                struct nvgpu_gpu_get_cpu_time_correlation_info_args *args)
-{
-        int err = 0;
-        unsigned int i = 0;
-
-        if (gk20a_busy(g)) {
-                nvgpu_err(g, "GPU not powered on");
-                err = -EINVAL;
-                goto end;
-        }
-
-        for (i = 0; i < args->count; i++) {
-                err = g->ops.bus.read_ptimer(g, &args->samples[i].gpu_timestamp);
-                if (err)
-                        return err;
-
-                args->samples[i].cpu_timestamp = get_cpu_timestamp();
-        }
-
-end:
-        gk20a_idle(g);
-        return err;
-}
-
 static int nvgpu_gpu_get_cpu_time_correlation_info(
         struct gk20a *g,
         struct nvgpu_gpu_get_cpu_time_correlation_info_args *args)
 {
-        int err = 0;
-        u64 (*get_cpu_timestamp)(void) = NULL;
+        struct nvgpu_cpu_time_correlation_sample *samples;
+        int err;
+        u32 i;
 
         if (args->count > NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_MAX_COUNT)
                 return -EINVAL;
 
-        switch (args->source_id) {
-        case NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_TSC:
-                get_cpu_timestamp = get_cpu_timestamp_tsc;
-                break;
-        case NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_JIFFIES:
-                get_cpu_timestamp = get_cpu_timestamp_jiffies;
-                break;
-        case NVGPU_GPU_GET_CPU_TIME_CORRELATION_INFO_SRC_ID_TIMEOFDAY:
-                get_cpu_timestamp = get_cpu_timestamp_timeofday;
-                break;
-        default:
-                nvgpu_err(g, "invalid cpu clock source id");
-                return -EINVAL;
+        samples = nvgpu_kzalloc(g, args->count *
+                sizeof(struct nvgpu_cpu_time_correlation_sample));
+        if (!samples) {
+                return -ENOMEM;
         }
 
-        err = get_timestamps_zipper(g, get_cpu_timestamp, args);
+        err = g->ops.bus.get_timestamps_zipper(g,
+                        args->source_id, args->count, samples);
+        if (!err) {
+                for (i = 0; i < args->count; i++) {
+                        args->samples[i].cpu_timestamp = samples[i].cpu_timestamp;
+                        args->samples[i].gpu_timestamp = samples[i].gpu_timestamp;
+                }
+        }
+
+        nvgpu_kfree(g, samples);
+
         return err;
 }