gpu: nvgpu: Provide cpu gpu time correlation via ioctl

bug 1648908

Provides pairs of CPU and GPU timestamps that
can be used for correlatiing the two timebases

- IOCTL made available /dev/nvhost-ctrl-gpu

Change-Id: I1458b9d33d794b1b02ec9fd29ed9426756b94bcd
Signed-off-by: Arul Sekar <aruls@nvidia.com>
Reviewed-on: http://git-master/r/1029732
Reviewed-by: Arun Gona <agona@nvidia.com>
Tested-by: Arun Gona <agona@nvidia.com>
Reviewed-on: http://git-master/r/1111715
GVS: Gerrit_Virtual_Submit
Reviewed-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 94 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
index 11790f4a..b2ae224f 100644
--- a/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/ctrl_gk20a.c
@@ -29,6 +29,7 @@
 #include "hw_gr_gk20a.h"
 #include "hw_fb_gk20a.h"
 #include "hw_proj_gk20a.h"
+#include "hw_timer_gk20a.h"
 
 int gk20a_ctrl_dev_open(struct inode *inode, struct file *filp)
 {
@@ -530,6 +531,94 @@ 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;
+        int i = 0;
+        u32 gpu_timestamp_hi_new = 0;
+        u32 gpu_timestamp_hi_old = 0;
+
+        if (gk20a_busy(g->dev)) {
+                gk20a_err(dev_from_gk20a(g), "GPU not powered on\n");
+                err = -EINVAL;
+                goto end;
+        }
+
+        /* get zipper reads of gpu and cpu counter values */
+        gpu_timestamp_hi_old = gk20a_readl(g, timer_time_1_r());
+        for (i = 0; i < args->count; i++) {
+                u32 gpu_timestamp_lo = 0;
+                u32 gpu_timestamp_hi = 0;
+
+                gpu_timestamp_lo = gk20a_readl(g, timer_time_0_r());
+                args->samples[i].cpu_timestamp = get_cpu_timestamp();
+                rmb(); /* maintain zipper read order */
+                gpu_timestamp_hi_new = gk20a_readl(g, timer_time_1_r());
+
+                /* pick the appropriate gpu counter hi bits */
+                gpu_timestamp_hi = (gpu_timestamp_lo & (1L << 31)) ?
+                        gpu_timestamp_hi_old : gpu_timestamp_hi_new;
+
+                args->samples[i].gpu_timestamp =
+                        ((u64)gpu_timestamp_hi << 32) | (u64)gpu_timestamp_lo;
+
+                gpu_timestamp_hi_old = gpu_timestamp_hi_new;
+        }
+
+end:
+        gk20a_idle(g->dev);
+        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;
+
+        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:
+                gk20a_err(dev_from_gk20a(g), "invalid cpu clock source id\n");
+                return -EINVAL;
+        }
+
+        err = get_timestamps_zipper(g, get_cpu_timestamp, args);
+        return err;
+}
+
 long gk20a_ctrl_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
         struct platform_device *dev = filp->private_data;
@@ -762,6 +851,11 @@ long gk20a_ctrl_dev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg
                         (struct nvgpu_gpu_get_buffer_info_args *)buf);
                 break;
 
+        case NVGPU_GPU_IOCTL_GET_CPU_TIME_CORRELATION_INFO:
+                err = nvgpu_gpu_get_cpu_time_correlation_info(g,
+                        (struct nvgpu_gpu_get_cpu_time_correlation_info_args *)buf);
+                break;
+
         default:
                 dev_dbg(dev_from_gk20a(g), "unrecognized gpu ioctl cmd: 0x%x", cmd);
                 err = -ENOTTY;