drm/msm: Implement msm drm fb_mmap callback function

This change implements msm drm specific fb_mmap function for fb device
to properly map the fb address to userspace.

Signed-off-by: Hai Li <hali@codeaurora.org>
Signed-off-by: Stephane Viau <sviau@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com> (+ minor comment tweak)

1 files changed, 42 insertions, 3 deletions

diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index c437065933e3..9c5221ce391a 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -19,6 +19,11 @@
 
 #include "drm_crtc.h"
 #include "drm_fb_helper.h"
+#include "msm_gem.h"
+
+extern int msm_gem_mmap_obj(struct drm_gem_object *obj,
+                                        struct vm_area_struct *vma);
+static int msm_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma);
 
 /*
  * fbdev funcs, to implement legacy fbdev interface on top of drm driver
@@ -43,6 +48,7 @@ static struct fb_ops msm_fb_ops = {
         .fb_fillrect = sys_fillrect,
         .fb_copyarea = sys_copyarea,
         .fb_imageblit = sys_imageblit,
+        .fb_mmap = msm_fbdev_mmap,
 
         .fb_check_var = drm_fb_helper_check_var,
         .fb_set_par = drm_fb_helper_set_par,
@@ -51,6 +57,31 @@ static struct fb_ops msm_fb_ops = {
         .fb_setcmap = drm_fb_helper_setcmap,
 };
 
+static int msm_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma)
+{
+        struct drm_fb_helper *helper = (struct drm_fb_helper *)info->par;
+        struct msm_fbdev *fbdev = to_msm_fbdev(helper);
+        struct drm_gem_object *drm_obj = fbdev->bo;
+        struct drm_device *dev = helper->dev;
+        int ret = 0;
+
+        if (drm_device_is_unplugged(dev))
+                return -ENODEV;
+
+        mutex_lock(&dev->struct_mutex);
+
+        ret = drm_gem_mmap_obj(drm_obj, drm_obj->size, vma);
+
+        mutex_unlock(&dev->struct_mutex);
+
+        if (ret) {
+                pr_err("%s:drm_gem_mmap_obj fail\n", __func__);
+                return ret;
+        }
+
+        return msm_gem_mmap_obj(drm_obj, vma);
+}
+
 static int msm_fbdev_create(struct drm_fb_helper *helper,
                 struct drm_fb_helper_surface_size *sizes)
 {
@@ -104,8 +135,16 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
 
         mutex_lock(&dev->struct_mutex);
 
-        /* TODO implement our own fb_mmap so we don't need this: */
-        msm_gem_get_iova_locked(fbdev->bo, 0, &paddr);
+        /*
+         * NOTE: if we can be guaranteed to be able to map buffer
+         * in panic (ie. lock-safe, etc) we could avoid pinning the
+         * buffer now:
+         */
+        ret = msm_gem_get_iova_locked(fbdev->bo, 0, &paddr);
+        if (ret) {
+                dev_err(dev->dev, "failed to get buffer obj iova: %d\n", ret);
+                goto fail;
+        }
 
         fbi = framebuffer_alloc(0, dev->dev);
         if (!fbi) {
@@ -189,7 +228,7 @@ struct drm_fb_helper *msm_fbdev_init(struct drm_device *dev)
         struct msm_drm_private *priv = dev->dev_private;
         struct msm_fbdev *fbdev = NULL;
         struct drm_fb_helper *helper;
-        int ret = 0;
+        int ret;
 
         fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
         if (!fbdev)