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-rw-r--r--arch/powerpc/mm/dma-noncoherent.c124
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);
+}