[PATCH 1/2] drm/mediatek: Implement gem prime vmap/vunmap function

[CK Hu]

For some application which need kernel virtual address, such as fbcon,
implement these function to map/unmap kernel virtual address of prime
buffer.

Signed-off-by: CK Hu <ck...@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c |  2 ++
 drivers/gpu/drm/mediatek/mtk_drm_gem.c | 46 ++++++++++++++++++++++++++
 drivers/gpu/drm/mediatek/mtk_drm_gem.h |  3 ++
 3 files changed, 51 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c 
b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 6422e99952fe..6ec4ca070382 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -341,6 +341,8 @@ static struct drm_driver mtk_drm_driver = {
        .gem_prime_get_sg_table = mtk_gem_prime_get_sg_table,
        .gem_prime_import_sg_table = mtk_gem_prime_import_sg_table,
        .gem_prime_mmap = mtk_drm_gem_mmap_buf,
+       .gem_prime_vmap = mtk_drm_gem_prime_vmap,
+       .gem_prime_vunmap = mtk_drm_gem_prime_vunmap,
        .fops = &mtk_drm_fops,
 
        .name = DRIVER_NAME,
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c 
b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
index 259b7b0de1d2..38483e9ee071 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
@@ -241,3 +241,49 @@ struct drm_gem_object 
*mtk_gem_prime_import_sg_table(struct drm_device *dev,
        kfree(mtk_gem);
        return ERR_PTR(ret);
 }
+
+void *mtk_drm_gem_prime_vmap(struct drm_gem_object *obj)
+{
+       struct mtk_drm_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
+       struct sg_table *sgt;
+       struct sg_page_iter iter;
+       unsigned int npages;
+       unsigned int i = 0;
+
+       if (mtk_gem->kvaddr)
+               return mtk_gem->kvaddr;
+
+       sgt = mtk_gem_prime_get_sg_table(obj);
+       if (IS_ERR(sgt))
+               return NULL;
+
+       npages = obj->size >> PAGE_SHIFT;
+       mtk_gem->pages = kcalloc(npages, sizeof(*mtk_gem->pages), GFP_KERNEL);
+       if (!mtk_gem->pages)
+               goto out;
+
+       for_each_sg_page(sgt->sgl, &iter, sgt->orig_nents, 0) {
+               mtk_gem->pages[i++] = sg_page_iter_page(&iter);
+               if (i > npages)
+                       break;
+       }
+       mtk_gem->kvaddr = vmap(mtk_gem->pages, npages, VM_MAP,
+                              pgprot_writecombine(PAGE_KERNEL));
+
+out:
+       kfree((void *)sgt);
+
+       return mtk_gem->kvaddr;
+}
+
+void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
+{
+       struct mtk_drm_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
+
+       if (!mtk_gem->pages)
+               return;
+
+       vunmap(vaddr);
+       mtk_gem->kvaddr = 0;
+       kfree((void *)mtk_gem->pages);
+}
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.h 
b/drivers/gpu/drm/mediatek/mtk_drm_gem.h
index 534639b43a1c..c047a7ef294f 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_gem.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.h
@@ -37,6 +37,7 @@ struct mtk_drm_gem_obj {
        dma_addr_t              dma_addr;
        unsigned long           dma_attrs;
        struct sg_table         *sg;
+       struct page             **pages;
 };
 
 #define to_mtk_gem_obj(x)      container_of(x, struct mtk_drm_gem_obj, base)
@@ -52,5 +53,7 @@ int mtk_drm_gem_mmap_buf(struct drm_gem_object *obj,
 struct sg_table *mtk_gem_prime_get_sg_table(struct drm_gem_object *obj);
 struct drm_gem_object *mtk_gem_prime_import_sg_table(struct drm_device *dev,
                        struct dma_buf_attachment *attach, struct sg_table *sg);
+void *mtk_drm_gem_prime_vmap(struct drm_gem_object *obj);
+void mtk_drm_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
 
 #endif
-- 
2.18.1

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