gpu: nvgpu: Fix Gpu sysfs access to Fmax@Vmin

Currently gpu sysfs retrieves Fmax@Vmin by direct call into Tegra DVFS
driver that introduces compile time dependencies on CONFIG_TEGRA_DVFS.
In addition incorrect clock is used for DVFS information access.

Re-factored sysfs node to use generic GPU clock operation for Fmax@Vmin
read. This would fix a bug in target clock selection, and allows to
remove dependency of sysfs on CONFIG_TEGRA_DVFS.

Updated nvgpu_linux_get_fmax_at_vmin_safe operation itself so it can be
called on platforms that does not support Tegra DVFS, although 0 will
still be returned as Fmax@Vmin on such platforms.

Bug 2045903

Change-Id: I32cce25320df026288c82458c913b0cde9ad4f72
Signed-off-by: Alex Frid <afrid@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1710924
Reviewed-by: Alex Waterman <alexw@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

2 files changed, 15 insertions, 17 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/clk.c b/drivers/gpu/nvgpu/common/linux/clk.c
index 8bffc07b..a0e56455 100644
--- a/drivers/gpu/nvgpu/common/linux/clk.c
+++ b/drivers/gpu/nvgpu/common/linux/clk.c
@@ -84,15 +84,18 @@ static int nvgpu_linux_clk_set_rate(struct gk20a *g,
         return ret;
 }
 
-static unsigned long nvgpu_linux_get_fmax_at_vmin_safe(struct clk_gk20a *clk)
+static unsigned long nvgpu_linux_get_fmax_at_vmin_safe(struct gk20a *g)
 {
         /*
-         * On Tegra GPU clock exposed to frequency governor is a shared user on
-         * GPCPLL bus (gbus). The latter can be accessed as GPU clock parent.
-         * Respectively the grandparent is PLL reference clock.
+         * On Tegra platforms with GPCPLL bus (gbus) GPU tegra_clk clock exposed
+         * to frequency governor is a shared user on the gbus. The latter can be
+         * accessed as GPU clock parent, and incorporate DVFS related data.
          */
-        return tegra_dvfs_get_fmax_at_vmin_safe_t(
-                        clk_get_parent(clk->tegra_clk));
+        if (g->clk.tegra_clk)
+                return tegra_dvfs_get_fmax_at_vmin_safe_t(
+                        clk_get_parent(g->clk.tegra_clk));
+
+        return 0;
 }
 
 static u32 nvgpu_linux_get_ref_clock_rate(struct gk20a *g)
diff --git a/drivers/gpu/nvgpu/common/linux/sysfs.c b/drivers/gpu/nvgpu/common/linux/sysfs.c
index 1f6da803..e425e153 100644
--- a/drivers/gpu/nvgpu/common/linux/sysfs.c
+++ b/drivers/gpu/nvgpu/common/linux/sysfs.c
@@ -17,9 +17,6 @@
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
 #include <linux/fb.h>
-#ifdef CONFIG_TEGRA_DVFS
-#include <soc/tegra/tegra-dvfs.h>
-#endif
 
 #include <nvgpu/kmem.h>
 #include <nvgpu/nvhost.h>
@@ -781,21 +778,19 @@ static ssize_t emc3d_ratio_read(struct device *dev,
 
 static DEVICE_ATTR(emc3d_ratio, ROOTRW, emc3d_ratio_read, emc3d_ratio_store);
 
-#ifdef CONFIG_TEGRA_DVFS
 static ssize_t fmax_at_vmin_safe_read(struct device *dev,
         struct device_attribute *attr, char *buf)
 {
         struct gk20a *g = get_gk20a(dev);
         unsigned long gpu_fmax_at_vmin_hz = 0;
-        struct clk *clk = g->clk.tegra_clk;
 
-        gpu_fmax_at_vmin_hz = tegra_dvfs_get_fmax_at_vmin_safe_t(clk);
+        if (g->ops.clk.get_fmax_at_vmin_safe)
+                gpu_fmax_at_vmin_hz = g->ops.clk.get_fmax_at_vmin_safe(g);
 
         return snprintf(buf, PAGE_SIZE, "%d\n", (int)(gpu_fmax_at_vmin_hz));
 }
 
 static DEVICE_ATTR(fmax_at_vmin_safe, S_IRUGO, fmax_at_vmin_safe_read, NULL);
-#endif
 
 #ifdef CONFIG_PM
 static ssize_t force_idle_store(struct device *dev,
@@ -1116,9 +1111,9 @@ void nvgpu_remove_sysfs(struct device *dev)
         device_remove_file(dev, &dev_attr_elpg_enable);
         device_remove_file(dev, &dev_attr_mscg_enable);
         device_remove_file(dev, &dev_attr_emc3d_ratio);
-#ifdef CONFIG_TEGRA_DVFS
+
         device_remove_file(dev, &dev_attr_fmax_at_vmin_safe);
-#endif
+
         device_remove_file(dev, &dev_attr_counters);
         device_remove_file(dev, &dev_attr_counters_reset);
         device_remove_file(dev, &dev_attr_load);
@@ -1167,9 +1162,9 @@ int nvgpu_create_sysfs(struct device *dev)
         error |= device_create_file(dev, &dev_attr_mscg_enable);
         error |= device_create_file(dev, &dev_attr_emc3d_ratio);
         error |= device_create_file(dev, &dev_attr_ldiv_slowdown_factor);
-#ifdef CONFIG_TEGRA_DVFS
+
         error |= device_create_file(dev, &dev_attr_fmax_at_vmin_safe);
-#endif
+
         error |= device_create_file(dev, &dev_attr_counters);
         error |= device_create_file(dev, &dev_attr_counters_reset);
         error |= device_create_file(dev, &dev_attr_load);