gpu: ion: Refactor common mapping functions out of system heap

The system heap contained several general purpose functions to map
buffers to the kernel and userspace.  This patch refactors those
into ion_heap.c so they can be used by other heaps.

Change-Id: If64591798bdc2c248bf9064ace2c927909d7adb8
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/drivers/gpu/ion/ion_heap.c b/drivers/gpu/ion/ion_heap.c
index 8ce3c1907ba..b000eb39294 100644
--- a/drivers/gpu/ion/ion_heap.c
+++ b/drivers/gpu/ion/ion_heap.c
@@ -16,8 +16,83 @@
 
 #include <linux/err.h>
 #include <linux/ion.h>
+#include <linux/mm.h>
+#include <linux/scatterlist.h>
+#include <linux/vmalloc.h>
 #include "ion_priv.h"
 
+void *ion_heap_map_kernel(struct ion_heap *heap,
+			  struct ion_buffer *buffer)
+{
+	struct scatterlist *sg;
+	int i, j;
+	void *vaddr;
+	pgprot_t pgprot;
+	struct sg_table *table = buffer->sg_table;
+	int npages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
+	struct page **pages = vmalloc(sizeof(struct page *) * npages);
+	struct page **tmp = pages;
+
+	if (!pages)
+		return 0;
+
+	if (buffer->flags & ION_FLAG_CACHED)
+		pgprot = PAGE_KERNEL;
+	else
+		pgprot = pgprot_writecombine(PAGE_KERNEL);
+
+	for_each_sg(table->sgl, sg, table->nents, i) {
+		int npages_this_entry = PAGE_ALIGN(sg_dma_len(sg)) / PAGE_SIZE;
+		struct page *page = sg_page(sg);
+		BUG_ON(i >= npages);
+		for (j = 0; j < npages_this_entry; j++) {
+			*(tmp++) = page++;
+		}
+	}
+	vaddr = vmap(pages, npages, VM_MAP, pgprot);
+	vfree(pages);
+
+	return vaddr;
+}
+
+void ion_heap_unmap_kernel(struct ion_heap *heap,
+			   struct ion_buffer *buffer)
+{
+	vunmap(buffer->vaddr);
+}
+
+int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer,
+		      struct vm_area_struct *vma)
+{
+	struct sg_table *table = buffer->sg_table;
+	unsigned long addr = vma->vm_start;
+	unsigned long offset = vma->vm_pgoff * PAGE_SIZE;
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(table->sgl, sg, table->nents, i) {
+		struct page *page = sg_page(sg);
+		unsigned long remainder = vma->vm_end - addr;
+		unsigned long len = sg_dma_len(sg);
+
+		if (offset >= sg_dma_len(sg)) {
+			offset -= sg_dma_len(sg);
+			continue;
+		} else if (offset) {
+			page += offset / PAGE_SIZE;
+			len = sg_dma_len(sg) - offset;
+			offset = 0;
+		}
+		len = min(len, remainder);
+		remap_pfn_range(vma, addr, page_to_pfn(page), len,
+				vma->vm_page_prot);
+		addr += len;
+		if (addr >= vma->vm_end)
+			return 0;
+	}
+	return 0;
+}
+
 struct ion_heap *ion_heap_create(struct ion_platform_heap *heap_data)
 {
 	struct ion_heap *heap = NULL;