Dummy DMA processing for RXE device.

Signed-off-by: Kamal Heib <kam...@mellanox.com>
Signed-off-by: Amir Vadai <am...@mellanox.com>
Reviewed-by: Haggai Eran <hagg...@mellanox.com>
---
 drivers/staging/rdma/rxe/rxe_dma.c | 166 +++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 drivers/staging/rdma/rxe/rxe_dma.c

diff --git a/drivers/staging/rdma/rxe/rxe_dma.c 
b/drivers/staging/rdma/rxe/rxe_dma.c
new file mode 100644
index 0000000..265b03d
--- /dev/null
+++ b/drivers/staging/rdma/rxe/rxe_dma.c
@@ -0,0 +1,166 @@
+/*
+ * Copyright (c) 2015 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *     - Redistributions of source code must retain the above
+ *       copyright notice, this list of conditions and the following
+ *       disclaimer.
+ *
+ *     - Redistributions in binary form must reproduce the above
+ *       copyright notice, this list of conditions and the following
+ *       disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "rxe.h"
+#include "rxe_loc.h"
+
+#define DMA_BAD_ADDER ((u64)0)
+
+static int rxe_mapping_error(struct ib_device *dev, u64 dma_addr)
+{
+       return dma_addr == DMA_BAD_ADDER;
+}
+
+static u64 rxe_dma_map_single(struct ib_device *dev,
+                             void *cpu_addr, size_t size,
+                             enum dma_data_direction direction)
+{
+       WARN_ON(!valid_dma_direction(direction));
+       return (u64)cpu_addr;
+}
+
+static void rxe_dma_unmap_single(struct ib_device *dev,
+                                u64 addr, size_t size,
+                                enum dma_data_direction direction)
+{
+       WARN_ON(!valid_dma_direction(direction));
+}
+
+static u64 rxe_dma_map_page(struct ib_device *dev,
+                           struct page *page,
+                           unsigned long offset,
+                           size_t size, enum dma_data_direction direction)
+{
+       u64 addr;
+
+       WARN_ON(!valid_dma_direction(direction));
+
+       if (offset + size > PAGE_SIZE) {
+               addr = DMA_BAD_ADDER;
+               goto done;
+       }
+
+       addr = (u64)page_address(page);
+       if (addr)
+               addr += offset;
+
+done:
+       return addr;
+}
+
+static void rxe_dma_unmap_page(struct ib_device *dev,
+                              u64 addr, size_t size,
+                              enum dma_data_direction direction)
+{
+       WARN_ON(!valid_dma_direction(direction));
+}
+
+static int rxe_map_sg(struct ib_device *dev, struct scatterlist *sgl,
+                     int nents, enum dma_data_direction direction)
+{
+       struct scatterlist *sg;
+       u64 addr;
+       int i;
+       int ret = nents;
+
+       WARN_ON(!valid_dma_direction(direction));
+
+       for_each_sg(sgl, sg, nents, i) {
+               addr = (u64)page_address(sg_page(sg));
+               if (!addr) {
+                       ret = 0;
+                       break;
+               }
+               sg->dma_address = addr + sg->offset;
+#ifdef CONFIG_NEED_SG_DMA_LENGTH
+               sg->dma_length = sg->length;
+#endif
+       }
+
+       return ret;
+}
+
+static void rxe_unmap_sg(struct ib_device *dev,
+                        struct scatterlist *sg, int nents,
+                        enum dma_data_direction direction)
+{
+       WARN_ON(!valid_dma_direction(direction));
+}
+
+static void rxe_sync_single_for_cpu(struct ib_device *dev,
+                                   u64 addr,
+                                   size_t size, enum dma_data_direction dir)
+{
+}
+
+static void rxe_sync_single_for_device(struct ib_device *dev,
+                                      u64 addr,
+                                      size_t size, enum dma_data_direction dir)
+{
+}
+
+static void *rxe_dma_alloc_coherent(struct ib_device *dev, size_t size,
+                                   u64 *dma_handle, gfp_t flag)
+{
+       struct page *p;
+       void *addr = NULL;
+
+       p = alloc_pages(flag, get_order(size));
+       if (p)
+               addr = page_address(p);
+
+       if (dma_handle)
+               *dma_handle = (u64)addr;
+
+       return addr;
+}
+
+static void rxe_dma_free_coherent(struct ib_device *dev, size_t size,
+                                 void *cpu_addr, u64 dma_handle)
+{
+       free_pages((unsigned long)cpu_addr, get_order(size));
+}
+
+struct ib_dma_mapping_ops rxe_dma_mapping_ops = {
+       .mapping_error          = rxe_mapping_error,
+       .map_single             = rxe_dma_map_single,
+       .unmap_single           = rxe_dma_unmap_single,
+       .map_page               = rxe_dma_map_page,
+       .unmap_page             = rxe_dma_unmap_page,
+       .map_sg                 = rxe_map_sg,
+       .unmap_sg               = rxe_unmap_sg,
+       .sync_single_for_cpu    = rxe_sync_single_for_cpu,
+       .sync_single_for_device = rxe_sync_single_for_device,
+       .alloc_coherent         = rxe_dma_alloc_coherent,
+       .free_coherent          = rxe_dma_free_coherent
+};
-- 
1.8.3.1

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