gpu: nvgpu: sysfs queries

Export the gpu's safe fmax_at_vmin frequency so it can be
queried from userspace (e.g. PHS).

Bug 1566108

Change-Id: I47326588ebd443f189a6051edbf95b35b35636d1
Signed-off-by: Anders Kugler <akugler@nvidia.com>
Reviewed-on: http://git-master/r/743501
(cherry picked from commit a977495878a486ca45c7de969582fd9ea949b0f0)
Reviewed-on: http://git-master/r/753279
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
index 5fe10273..d8da34d9 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
@@ -554,6 +554,21 @@ static ssize_t emc3d_ratio_read(struct device *device,
 
 static DEVICE_ATTR(emc3d_ratio, ROOTRW, emc3d_ratio_read, emc3d_ratio_store);
 
+static ssize_t fmax_at_vmin_safe_read(struct device *device,
+        struct device_attribute *attr, char *buf)
+{
+        struct platform_device *ndev = to_platform_device(device);
+        struct gk20a *g = get_gk20a(ndev);
+        unsigned long gpu_fmax_at_vmin_hz = 0;
+
+        gpu_fmax_at_vmin_hz = tegra_dvfs_get_fmax_at_vmin_safe_t(
+                clk_get_parent(g->clk.tegra_clk));
+
+        return sprintf(buf, "%d\n", (int)(gpu_fmax_at_vmin_hz));
+}
+
+static DEVICE_ATTR(fmax_at_vmin_safe, S_IRUGO, fmax_at_vmin_safe_read, NULL);
+
 #ifdef CONFIG_PM_RUNTIME
 static ssize_t force_idle_store(struct device *device,
         struct device_attribute *attr, const char *buf, size_t count)
@@ -671,6 +686,7 @@ void gk20a_remove_sysfs(struct device *dev)
         device_remove_file(dev, &dev_attr_ptimer_scale_factor);
         device_remove_file(dev, &dev_attr_elpg_enable);
         device_remove_file(dev, &dev_attr_emc3d_ratio);
+        device_remove_file(dev, &dev_attr_fmax_at_vmin_safe);
         device_remove_file(dev, &dev_attr_counters);
         device_remove_file(dev, &dev_attr_counters_reset);
         device_remove_file(dev, &dev_attr_load);
@@ -699,6 +715,7 @@ void gk20a_create_sysfs(struct platform_device *dev)
         error |= device_create_file(&dev->dev, &dev_attr_ptimer_scale_factor);
         error |= device_create_file(&dev->dev, &dev_attr_elpg_enable);
         error |= device_create_file(&dev->dev, &dev_attr_emc3d_ratio);
+        error |= device_create_file(&dev->dev, &dev_attr_fmax_at_vmin_safe);
         error |= device_create_file(&dev->dev, &dev_attr_counters);
         error |= device_create_file(&dev->dev, &dev_attr_counters_reset);
         error |= device_create_file(&dev->dev, &dev_attr_load);