efDataDiscreteRateMining dataMonitoring.c 韩正义 commit at 2020-09-08

efDataDiscreteRateMining/externalListeningThread/dataMonitoring.c

@@ -183,3 +183,97 @@ static u64 get_coherent_dma_mask(struct device *dev)
 
 	return mask;
 }
+
+static void __dma_clear_buffer(struct page *page, size_t size)
+{
+	void *ptr;
+	/*
+	 * Ensure that the allocated pages are zeroed, and that any data
+	 * lurking in the kernel direct-mapped region is invalidated.
+	 */
+	ptr = page_address(page);
+	if (ptr) {
+		memset(ptr, 0, size);
+		dmac_flush_range(ptr, ptr + size);
+		outer_flush_range(__pa(ptr), __pa(ptr) + size);
+	}
+}
+
+/*
+ * Allocate a DMA buffer for 'dev' of size 'size' using the
+ * specified gfp mask.  Note that 'size' must be page aligned.
+ */
+static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gfp)
+{
+	unsigned long order = get_order(size);
+	struct page *page, *p, *e;
+
+	page = alloc_pages(gfp, order);
+	if (!page)
+		return NULL;
+
+	/*
+	 * Now split the huge page and free the excess pages
+	 */
+	split_page(page, order);
+	for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++)
+		__free_page(p);
+
+	__dma_clear_buffer(page, size);
+
+	return page;
+}
+
+/*
+ * Free a DMA buffer.  'size' must be page aligned.
+ */
+static void __dma_free_buffer(struct page *page, size_t size)
+{
+	struct page *e = page + (size >> PAGE_SHIFT);
+
+	while (page < e) {
+		__free_page(page);
+		page++;
+	}
+}
+
+#ifdef CONFIG_MMU
+#ifdef CONFIG_HUGETLB_PAGE
+#error ARM Coherent DMA allocator does not (yet) support huge TLB
+#endif
+
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+				     pgprot_t prot, struct page **ret_page);
+
+static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
+				 pgprot_t prot, struct page **ret_page,
+				 const void *caller);
+
+static void *
+__dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
+	const void *caller)
+{
+	struct vm_struct *area;
+	unsigned long addr;
+
+	/*
+	 * DMA allocation can be mapped to user space, so lets
+	 * set VM_USERMAP flags too.
+	 */
+	area = get_vm_area_caller(size, VM_ARM_DMA_CONSISTENT | VM_USERMAP,
+				  caller);
+	if (!area)
+		return NULL;
+	addr = (unsigned long)area->addr;
+	area->phys_addr = __pfn_to_phys(page_to_pfn(page));
+
+	if (ioremap_page_range(addr, addr + size, area->phys_addr, prot)) {
+		vunmap((void *)addr);
+		return NULL;
+	}
+	return (void *)addr;
+}
+
+static void __dma_free_remap(void *cpu_addr, size_t size)
+{
+	unsigned int flags = VM_ARM_DMA_CONSISTENT | VM_USERMAP;