gpu: nvgpu: Add sysfs node to enable rail gating

Add sysfs node "railgate_enable" to enable
gpu railgating dynamically.

Bug 1552469

Reviewed-on: http://git-master/r/804746
(cherry picked from commit 53d76d1d1576a96c70f66b744411d2909ec8414f)

Change-Id: I69ac63958b00ae4ea5d9ccbaed03316d35ddc5eb
Signed-off-by: Seshendra Gadagottu <sgadagottu@nvidia.com>
Reviewed-on: http://git-master/r/822208
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
index 996fe221..945b332d 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
@@ -226,6 +226,64 @@ static DEVICE_ATTR(ptimer_scale_factor,
                         ptimer_scale_factor_show,
                         NULL);
 
+#if defined(CONFIG_PM_RUNTIME) && defined(CONFIG_PM_GENERIC_DOMAINS)
+static ssize_t railgate_enable_store(struct device *dev,
+        struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct gk20a_platform *platform = dev_get_drvdata(dev);
+        struct generic_pm_domain *genpd = dev_to_genpd(dev);
+        struct platform_device *ndev = to_platform_device(dev);
+        struct gk20a *g = get_gk20a(ndev);
+        unsigned long railgate_enable = 0;
+        int err;
+
+        if (kstrtoul(buf, 10, &railgate_enable) < 0)
+                return -EINVAL;
+        if (railgate_enable && !platform->can_railgate) {
+                mutex_lock(&platform->railgate_lock);
+                platform->can_railgate = true;
+                genpd->gov = NULL;
+                pm_genpd_set_poweroff_delay(genpd, platform->railgate_delay);
+                /* release extra ref count:if power domains not enabled */
+                if ((platform->railgate) && \
+                                !IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS))
+                        err = platform->railgate(ndev);
+                mutex_unlock(&platform->railgate_lock);
+        } else if (railgate_enable == 0 && platform->can_railgate) {
+                mutex_lock(&platform->railgate_lock);
+                platform->can_railgate = false;
+                genpd->gov = &pm_domain_always_on_gov;
+                pm_genpd_set_poweroff_delay(genpd, platform->railgate_delay);
+                /* take extra ref count - incase of power domains not enabled */
+                if ((platform->unrailgate) && \
+                                !IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS))
+                        err = platform->unrailgate(ndev);
+                mutex_unlock(&platform->railgate_lock);
+        }
+        dev_info(dev, "railgate is %s.\n", platform->can_railgate ?
+                "enabled" : "disabled");
+        /* wake-up system to make railgating_enable effective immediately */
+        err = gk20a_busy(g->dev);
+        if (err)
+                return err;
+        gk20a_idle(g->dev);
+
+        return count;
+}
+
+static ssize_t railgate_enable_read(struct device *device,
+        struct device_attribute *attr, char *buf)
+{
+        struct platform_device *ndev = to_platform_device(device);
+        struct gk20a_platform *platform = dev_get_drvdata(&ndev->dev);
+
+        return sprintf(buf, "%d\n", platform->can_railgate ? 1 : 0);
+}
+
+static DEVICE_ATTR(railgate_enable, ROOTRW, railgate_enable_read,
+                        railgate_enable_store);
+#endif
+
 static ssize_t railgate_delay_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
@@ -711,6 +769,9 @@ void gk20a_remove_sysfs(struct device *dev)
         device_remove_file(dev, &dev_attr_clockgate_delay);
 #ifdef CONFIG_PM_RUNTIME
         device_remove_file(dev, &dev_attr_force_idle);
+#if defined(CONFIG_PM_GENERIC_DOMAINS)
+        device_remove_file(dev, &dev_attr_railgate_enable);
+#endif
 #endif
         device_remove_file(dev, &dev_attr_aelpg_param);
         device_remove_file(dev, &dev_attr_aelpg_enable);
@@ -741,6 +802,9 @@ void gk20a_create_sysfs(struct platform_device *dev)
         error |= device_create_file(&dev->dev, &dev_attr_clockgate_delay);
 #ifdef CONFIG_PM_RUNTIME
         error |= device_create_file(&dev->dev, &dev_attr_force_idle);
+#if defined(CONFIG_PM_GENERIC_DOMAINS)
+        error |= device_create_file(&dev->dev, &dev_attr_railgate_enable);
+#endif
 #endif
         error |= device_create_file(&dev->dev, &dev_attr_aelpg_param);
         error |= device_create_file(&dev->dev, &dev_attr_aelpg_enable);