1 files changed, 124 insertions, 0 deletions
diff --git a/arch/powerpc/mm/dma-noncoherent.c b/arch/powerpc/mm/dma-noncoherent.c
new file mode 100644
index 000000000..30260b5d1
--- /dev/null
+++ b/arch/powerpc/mm/dma-noncoherent.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  PowerPC version derived from arch/arm/mm/consistent.c
+ *    Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
+ *
+ *  Copyright (C) 2000 Russell King
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/highmem.h>
+#include <linux/dma-direct.h>
+#include <linux/dma-map-ops.h>
+
+#include <asm/tlbflush.h>
+#include <asm/dma.h>
+
+/*
+ * make an area consistent.
+ */
+static void __dma_sync(void *vaddr, size_t size, int direction)
+{
+	unsigned long start = (unsigned long)vaddr;
+	unsigned long end   = start + size;
+
+	switch (direction) {
+	case DMA_NONE:
+		BUG();
+	case DMA_FROM_DEVICE:
+		/*
+		 * invalidate only when cache-line aligned otherwise there is
+		 * the potential for discarding uncommitted data from the cache
+		 */
+		if ((start | end) & (L1_CACHE_BYTES - 1))
+			flush_dcache_range(start, end);
+		else
+			invalidate_dcache_range(start, end);
+		break;
+	case DMA_TO_DEVICE:		/* writeback only */
+		clean_dcache_range(start, end);
+		break;
+	case DMA_BIDIRECTIONAL:	/* writeback and invalidate */
+		flush_dcache_range(start, end);
+		break;
+	}
+}
+
+#ifdef CONFIG_HIGHMEM
+/*
+ * __dma_sync_page() implementation for systems using highmem.
+ * In this case, each page of a buffer must be kmapped/kunmapped
+ * in order to have a virtual address for __dma_sync(). This must
+ * not sleep so kmap_atomic()/kunmap_atomic() are used.
+ *
+ * Note: yes, it is possible and correct to have a buffer extend
+ * beyond the first page.
+ */
+static inline void __dma_sync_page_highmem(struct page *page,
+		unsigned long offset, size_t size, int direction)
+{
+	size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
+	size_t cur_size = seg_size;
+	unsigned long flags, start, seg_offset = offset;
+	int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
+	int seg_nr = 0;
+
+	local_irq_save(flags);
+
+	do {
+		start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset;
+
+		/* Sync this buffer segment */
+		__dma_sync((void *)start, seg_size, direction);
+		kunmap_atomic((void *)start);
+		seg_nr++;
+
+		/* Calculate next buffer segment size */
+		seg_size = min((size_t)PAGE_SIZE, size - cur_size);
+
+		/* Add the segment size to our running total */
+		cur_size += seg_size;
+		seg_offset = 0;
+	} while (seg_nr < nr_segs);
+
+	local_irq_restore(flags);
+}
+#endif /* CONFIG_HIGHMEM */
+
+/*
+ * __dma_sync_page makes memory consistent. identical to __dma_sync, but
+ * takes a struct page instead of a virtual address
+ */
+static void __dma_sync_page(phys_addr_t paddr, size_t size, int dir)
+{
+	struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
+	unsigned offset = paddr & ~PAGE_MASK;
+
+#ifdef CONFIG_HIGHMEM
+	__dma_sync_page_highmem(page, offset, size, dir);
+#else
+	unsigned long start = (unsigned long)page_address(page) + offset;
+	__dma_sync((void *)start, size, dir);
+#endif
+}
+
+void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	__dma_sync_page(paddr, size, dir);
+}
+
+void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	__dma_sync_page(paddr, size, dir);
+}
+
+void arch_dma_prep_coherent(struct page *page, size_t size)
+{
+	unsigned long kaddr = (unsigned long)page_address(page);
+
+	flush_dcache_range(kaddr, kaddr + size);
+}