gpu: sysfs mode for allowing access to registers

Through this sysfs entry, the register space becomes accessible.
This is be accessible root-only.

Bug 1523403

Change-Id: Ia46f130a0cfd8324c5b675d19e7cbfba9dcb17ca
Signed-off-by: sujeet baranwal <sbaranwal@nvidia.com>
Reviewed-on: http://git-master/r/454198
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
index 97a0452c..7e0183ca 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_sysfs.c
@@ -439,6 +439,36 @@ static ssize_t aelpg_enable_read(struct device *device,
 static DEVICE_ATTR(aelpg_enable, ROOTRW,
                 aelpg_enable_read, aelpg_enable_store);
 
+
+static ssize_t allow_all_enable_read(struct device *device,
+                struct device_attribute *attr, char *buf)
+{
+        struct platform_device *ndev = to_platform_device(device);
+        struct gk20a *g = get_gk20a(ndev);
+        return sprintf(buf, "%d\n", g->allow_all ? 1 : 0);
+}
+
+static ssize_t allow_all_enable_store(struct device *device,
+                struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct platform_device *ndev = to_platform_device(device);
+        struct gk20a *g = get_gk20a(ndev);
+        unsigned long val = 0;
+        int err;
+
+        if (kstrtoul(buf, 10, &val) < 0)
+                return -EINVAL;
+
+        err = gk20a_busy(g->dev);
+        g->allow_all = (val ? true : false);
+        gk20a_idle(g->dev);
+
+        return count;
+}
+
+static DEVICE_ATTR(allow_all, ROOTRW,
+                allow_all_enable_read, allow_all_enable_store);
+
 #ifdef CONFIG_PM_RUNTIME
 static ssize_t force_idle_store(struct device *device,
         struct device_attribute *attr, const char *buf, size_t count)
@@ -509,6 +539,7 @@ void gk20a_remove_sysfs(struct device *dev)
 #endif
         device_remove_file(dev, &dev_attr_aelpg_param);
         device_remove_file(dev, &dev_attr_aelpg_enable);
+        device_remove_file(dev, &dev_attr_allow_all);
 
         if (g->host1x_dev && (dev->parent != &g->host1x_dev->dev))
                 sysfs_remove_link(&dev->kobj, dev_name(dev));
@@ -534,6 +565,7 @@ void gk20a_create_sysfs(struct platform_device *dev)
 #endif
         error |= device_create_file(&dev->dev, &dev_attr_aelpg_param);
         error |= device_create_file(&dev->dev, &dev_attr_aelpg_enable);
+        error |= device_create_file(&dev->dev, &dev_attr_allow_all);
 
         if (g->host1x_dev && (dev->dev.parent != &g->host1x_dev->dev))
                 error |= sysfs_create_link(&g->host1x_dev->dev.kobj,