gpu: nvgpu: Debugfs for Volt

Changes:
1. Reading operating voltage and minimum voltage of chip.
2. Added nvgpu_volt_init_debugfs for creating the debugfs interface.
3. Command for reading current voltage:
   cat /sys/kernel/debug/gpu_pci/volt/current_voltage
4. Command for reading minimum voltage:
   cat /sys/kernel/debug/gpu_pci/volt/minimum_voltage

Jira NVGPU-1731

Change-Id: I76d42fc376235f37c44d259398bd6f125a90413b
Signed-off-by: rmylavarapu <rmylavarapu@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1986403
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vijayakumar Subbu <vsubbu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/Makefile

@@ -205,7 +205,8 @@ nvgpu-$(CONFIG_DEBUG_FS) += \
 	os/linux/debug_bios.o \
 	os/linux/debug_ltc.o \
 	os/linux/debug_xve.o \
-	os/linux/debug_clk_gv100.o
+	os/linux/debug_clk_gv100.o \
+	os/linux/debug_volt.o
 
 ifeq ($(CONFIG_NVGPU_TRACK_MEM_USAGE),y)
 nvgpu-$(CONFIG_DEBUG_FS) += \

drivers/gpu/nvgpu/os/linux/debug_volt.c

@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 2019, NVIDIA Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/debugfs.h>
+#include "os_linux.h"
+
+#include <nvgpu/pmu/volt.h>
+#include <common/pmu/volt/volt_rail.h>
+
+static int get_curr_voltage(void *data, u64 *val)
+{
+	struct gk20a *g = (struct gk20a *)data;
+	u32 readval;
+	int err;
+
+	if (!g->ops.pmu_ver.volt.volt_get_voltage)
+		return -EINVAL;
+
+	err = g->ops.pmu_ver.volt.volt_get_voltage(g,
+			CTRL_VOLT_DOMAIN_LOGIC, &readval);
+	if (!err)
+		*val = readval;
+
+	return err;
+}
+DEFINE_SIMPLE_ATTRIBUTE(curr_volt_ctrl_fops, get_curr_voltage, NULL, "%llu\n");
+
+static int get_min_voltage(void *data, u64 *val)
+{
+	struct gk20a *g = (struct gk20a *)data;
+	u32 readval;
+	int err;
+
+	if (!g->ops.pmu_ver.volt.volt_get_vmin)
+		return -EINVAL;
+
+	err = g->ops.pmu_ver.volt.volt_get_vmin(g, &readval);
+	if (!err)
+		*val = readval;
+
+	return err;
+}
+DEFINE_SIMPLE_ATTRIBUTE(min_volt_ctrl_fops, get_min_voltage, NULL, "%llu\n");
+
+int nvgpu_volt_init_debugfs(struct gk20a *g)
+{
+	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+	struct dentry *dbgentry, *volt_root;
+
+	volt_root = debugfs_create_dir("volt", l->debugfs);
+
+	dbgentry = debugfs_create_file(
+		"current_voltage", S_IRUGO, volt_root, g, &curr_volt_ctrl_fops);
+	if (!dbgentry) {
+		pr_err("%s: Failed to make debugfs node\n", __func__);
+		return -ENOMEM;
+	}
+
+	dbgentry = debugfs_create_file("minimum_voltage",
+			S_IRUGO, volt_root, g, &min_volt_ctrl_fops);
+	if (!dbgentry) {
+		pr_err("%s: Failed to make debugfs node\n", __func__);
+		return -ENOMEM;
+	}
+
+	return 0;
+}

drivers/gpu/nvgpu/os/linux/debug_volt.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2019, NVIDIA Corporation.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __DEBUG_VOLT_H
+#define __DEBUG_VOLT_H
+
+#ifdef CONFIG_DEBUG_FS
+int nvgpu_volt_init_debugfs(struct gk20a *g);
+#else
+static inline int nvgpu_volt_init_debugfs(struct gk20a *g)
+{
+	return 0;
+}
+#endif
+
+#endif

drivers/gpu/nvgpu/os/linux/module.c

@@ -233,6 +233,14 @@ int nvgpu_finalize_poweron_linux(struct nvgpu_os_linux *l)
 		}
 	}
 
+	if (l->ops.volt.init_debugfs) {
+		err = l->ops.volt.init_debugfs(g);
+		if (err) {
+			nvgpu_err(g, "failed to init linux volt debugfs");
+			return err;
+		}
+	}
+
 	err = nvgpu_pmgr_init_debugfs_linux(l);
 	if (err) {
 		nvgpu_err(g, "failed to init linux pmgr debugfs");

drivers/gpu/nvgpu/os/linux/os_linux.h

@@ -52,6 +52,10 @@ struct nvgpu_os_linux_ops {
 	struct {
 		int (*init_debugfs)(struct gk20a *g);
 	} fecs_trace;
+
+	struct {
+		int (*init_debugfs)(struct gk20a *g);
+	} volt;
 };
 
 struct nvgpu_os_linux {

drivers/gpu/nvgpu/os/linux/os_ops_tu104.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, NVIDIA Corporation.  All rights reserved.
+ * Copyright (c) 2018-2019, NVIDIA Corporation.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -18,6 +18,7 @@
 
 #include "os/linux/debug_therm_gp106.h"
 #include "os/linux/debug_clk_gv100.h"
+#include "os/linux/debug_volt.h"
 
 static struct nvgpu_os_linux_ops tu104_os_linux_ops = {
 	.therm = {
@@ -26,10 +27,14 @@ static struct nvgpu_os_linux_ops tu104_os_linux_ops = {
 	.clk = {
 		.init_debugfs = gv100_clk_init_debugfs,
 	},
+	.volt = {
+		.init_debugfs = nvgpu_volt_init_debugfs,
+	},
 };
 
 void nvgpu_tu104_init_os_ops(struct nvgpu_os_linux *l)
 {
 	l->ops.therm = tu104_os_linux_ops.therm;
 	l->ops.clk = tu104_os_linux_ops.clk;
+	l->ops.volt = tu104_os_linux_ops.volt;
 }