gpu: nvgpu: add read_ptimer to gops

Move all places that read ptimer to use the callback.
It's for add vgpu implementation of read ptimer.

Bug 1395833

Change-Id: Ia339f2f08d75ca4969a443fffc9a61cff1d3d2b7
Signed-off-by: Richard Zhao <rizhao@nvidia.com>
Reviewed-on: http://git-master/r/1159587
(cherry picked from commit a01f804684f875c9cffc31eb2c1038f2f29ec66f)
Reviewed-on: http://git-master/r/1158449
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 5 insertions, 38 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
index 39581eb2..3e34b6b8 100644
--- a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
@@ -626,50 +626,17 @@ static int nvgpu_gpu_get_gpu_time(
         struct gk20a *g,
         struct nvgpu_gpu_get_gpu_time_args *args)
 {
-        int err = 0;
-        const unsigned int max_iterations = 3;
-        unsigned int i = 0;
-        u32 gpu_timestamp_hi_prev = 0;
+        u64 time;
+        int err;
 
         err = gk20a_busy(g->dev);
         if (err)
                 return err;
 
-        /* Note. The GPU nanosecond timer consists of two 32-bit
-         * registers (high & low). To detect a possible low register
-         * wrap-around between the reads, we need to read the high
-         * register before and after low. The wraparound happens
-         * approximately once per 4 secs. */
+        err = g->ops.read_ptimer(g, &time);
+        if (!err)
+                args->gpu_timestamp = time;
 
-        /* get initial gpu_timestamp_hi value */
-        gpu_timestamp_hi_prev = gk20a_readl(g, timer_time_1_r());
-
-        for (i = 0; i < max_iterations; ++i) {
-                u32 gpu_timestamp_hi = 0;
-                u32 gpu_timestamp_lo = 0;
-
-                rmb(); /* maintain read order */
-                gpu_timestamp_lo = gk20a_readl(g, timer_time_0_r());
-                rmb(); /* maintain read order */
-                gpu_timestamp_hi = gk20a_readl(g, timer_time_1_r());
-
-                if (gpu_timestamp_hi == gpu_timestamp_hi_prev) {
-                        args->gpu_timestamp =
-                                (((u64)gpu_timestamp_hi) << 32) |
-                                gpu_timestamp_lo;
-                        goto clean_up;
-                }
-
-                /* wrap-around detected, retry */
-                gpu_timestamp_hi_prev = gpu_timestamp_hi;
-        }
-
-        /* too many iterations, bail out */
-        gk20a_err(dev_from_gk20a(g),
-                  "Failed to read GPU time. Clock or bus unstable?\n");
-        err = -EBUSY;
-
-clean_up:
         gk20a_idle(g->dev);
         return err;
 }