1 files changed, 94 insertions, 0 deletions
diff --git a/arch/kvx/lib/dma-default.c b/arch/kvx/lib/dma-default.c
new file mode 100644
index 0000000000..2a4144696c
--- /dev/null
+++ b/arch/kvx/lib/dma-default.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: 2021 Yann Sionneau <ysionneau@kalray.eu>, Kalray Inc.
+
+#include <dma.h>
+#include <asm/barrier.h>
+#include <asm/io.h>
+#include <asm/cache.h>
+#include <asm/sfr.h>
+#include <asm/sys_arch.h>
+
+/*
+ * The implementation of arch should follow the following rules:
+ *		map		for_cpu		for_device	unmap
+ * TO_DEV	writeback	none		writeback	none
+ * FROM_DEV	invalidate	invalidate(*)	invalidate	invalidate(*)
+ * BIDIR	writeback	invalidate	writeback	invalidate
+ *
+ * (*) - only necessary if the CPU speculatively prefetches.
+ *
+ * (see https://lkml.org/lkml/2018/5/18/979)
+ */
+
+void dma_sync_single_for_device(dma_addr_t addr, size_t size,
+				enum dma_data_direction dir)
+{
+	/* dcache is Write-Through: no need to flush to force writeback */
+	switch (dir) {
+	case DMA_FROM_DEVICE:
+		invalidate_dcache_range(addr, addr + size);
+		break;
+	case DMA_TO_DEVICE:
+	case DMA_BIDIRECTIONAL:
+		/* allow device to read buffer written by CPU */
+		wmb();
+		break;
+	default:
+		BUG();
+	}
+}
+
+void dma_sync_single_for_cpu(dma_addr_t addr, size_t size,
+				enum dma_data_direction dir)
+{
+	/* CPU does not speculatively prefetches */
+	switch (dir) {
+	case DMA_FROM_DEVICE:
+		/* invalidate has been done during map/for_device */
+	case DMA_TO_DEVICE:
+		break;
+	case DMA_BIDIRECTIONAL:
+		invalidate_dcache_range(addr, addr + size);
+		break;
+	default:
+		BUG();
+	}
+}
+
+#define KVX_DDR_ALIAS_OFFSET \
+	(KVX_DDR_64BIT_RAM_WINDOW_BA - KVX_DDR_32BIT_RAM_WINDOW_BA)
+#define KVX_DDR_ALIAS_WINDOW \
+	(KVX_DDR_64BIT_RAM_WINDOW_BA + KVX_DDR_ALIAS_OFFSET)
+
+/* Local smem is aliased between 0 and 16MB */
+#define KVX_SMEM_LOCAL_ALIAS 0x1000000ULL
+
+dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
+			  enum dma_data_direction dir)
+{
+	uintptr_t addr = (uintptr_t) ptr;
+
+	dma_sync_single_for_device(addr, size, dir);
+
+	/* Local smem alias should never be used for dma */
+	if (addr < KVX_SMEM_LOCAL_ALIAS)
+		return addr + (1 + kvx_cluster_id()) * KVX_SMEM_LOCAL_ALIAS;
+
+	if (dev->dma_mask && addr <= dev->dma_mask)
+		return addr;
+
+	if (addr >= KVX_DDR_ALIAS_WINDOW)
+		return DMA_ERROR_CODE;
+
+	addr -= KVX_DDR_ALIAS_OFFSET;
+	if (dev->dma_mask && addr > dev->dma_mask)
+		return DMA_ERROR_CODE;
+
+	return addr;
+}
+
+void dma_unmap_single(struct device_d *dev, dma_addr_t addr, size_t size,
+		      enum dma_data_direction dir)
+{
+	dma_sync_single_for_cpu(addr, size, dir);
+}