vm: add vm_iomap_memory() helper function

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 494526ae024a3173fc200d47e36087f6252852c2..ba94dec5b25900e47093544e11f8c765bf243f9d 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -216,6 +216,7 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
        tlb->mm = mm;
 
        tlb->fullmm     = fullmm;
+       tlb->need_flush_all = 0;
        tlb->start      = -1UL;
        tlb->end        = 0;
        tlb->need_flush = 0;
@@ -2392,6 +2393,53 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
 }
 EXPORT_SYMBOL(remap_pfn_range);
 
+/**
+ * vm_iomap_memory - remap memory to userspace
+ * @vma: user vma to map to
+ * @start: start of area
+ * @len: size of area
+ *
+ * This is a simplified io_remap_pfn_range() for common driver use. The
+ * driver just needs to give us the physical memory range to be mapped,
+ * we'll figure out the rest from the vma information.
+ *
+ * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
+ * whatever write-combining details or similar.
+ */
+int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
+{
+       unsigned long vm_len, pfn, pages;
+
+       /* Check that the physical memory area passed in looks valid */
+       if (start + len < start)
+               return -EINVAL;
+       /*
+        * You *really* shouldn't map things that aren't page-aligned,
+        * but we've historically allowed it because IO memory might
+        * just have smaller alignment.
+        */
+       len += start & ~PAGE_MASK;
+       pfn = start >> PAGE_SHIFT;
+       pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
+       if (pfn + pages < pfn)
+               return -EINVAL;
+
+       /* We start the mapping 'vm_pgoff' pages into the area */
+       if (vma->vm_pgoff > pages)
+               return -EINVAL;
+       pfn += vma->vm_pgoff;
+       pages -= vma->vm_pgoff;
+
+       /* Can we fit all of the mapping? */
+       vm_len = vma->vm_end - vma->vm_start;
+       if (vm_len >> PAGE_SHIFT > pages)
+               return -EINVAL;
+
+       /* Ok, let it rip */
+       return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_iomap_memory);
+
 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
                                     unsigned long addr, unsigned long end,
                                     pte_fn_t fn, void *data)