IB/ipath: Implement new verbs DMA mapping functions

This patch implements the interposing DMA mapping functions to allow
support for IOMMUs and remove the dependence on phys_to_virt() and
bus_to_virt().

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

6 files changed, 201 insertions, 7 deletions

diff --git a/drivers/infiniband/hw/ipath/Makefile b/drivers/infiniband/hw/ipath/Makefile
index 7dc1055..ec2e603 100644
--- a/drivers/infiniband/hw/ipath/Makefile
+++ b/drivers/infiniband/hw/ipath/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_INFINIBAND_IPATH) += ib_ipath.o
 ib_ipath-y := \
 	ipath_cq.o \
 	ipath_diag.o \
+	ipath_dma.o \
 	ipath_driver.o \
 	ipath_eeprom.o \
 	ipath_file_ops.o \
diff --git a/drivers/infiniband/hw/ipath/ipath_dma.c b/drivers/infiniband/hw/ipath/ipath_dma.c
new file mode 100644
index 0000000..6e0f2b8
--- /dev/null
+++ b/drivers/infiniband/hw/ipath/ipath_dma.c
@@ -0,0 +1,189 @@
+/*
+ * Copyright (c) 2006 QLogic, Corporation. 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 <rdma/ib_verbs.h>
+
+#include "ipath_verbs.h"
+
+#define BAD_DMA_ADDRESS ((u64) 0)
+
+/*
+ * The following functions implement driver specific replacements
+ * for the ib_dma_*() functions.
+ *
+ * These functions return kernel virtual addresses instead of
+ * device bus addresses since the driver uses the CPU to copy
+ * data instead of using hardware DMA.
+ */
+
+static int ipath_mapping_error(struct ib_device *dev, u64 dma_addr)
+{
+	return dma_addr == BAD_DMA_ADDRESS;
+}
+
+static u64 ipath_dma_map_single(struct ib_device *dev,
+			        void *cpu_addr, size_t size,
+			        enum dma_data_direction direction)
+{
+	BUG_ON(!valid_dma_direction(direction));
+	return (u64) cpu_addr;
+}
+
+static void ipath_dma_unmap_single(struct ib_device *dev,
+				   u64 addr, size_t size,
+				   enum dma_data_direction direction)
+{
+	BUG_ON(!valid_dma_direction(direction));
+}
+
+static u64 ipath_dma_map_page(struct ib_device *dev,
+			      struct page *page,
+			      unsigned long offset,
+			      size_t size,
+			      enum dma_data_direction direction)
+{
+	u64 addr;
+
+	BUG_ON(!valid_dma_direction(direction));
+
+	if (offset + size > PAGE_SIZE) {
+		addr = BAD_DMA_ADDRESS;
+		goto done;
+	}
+
+	addr = (u64) page_address(page);
+	if (addr)
+		addr += offset;
+	/* TODO: handle highmem pages */
+
+done:
+	return addr;
+}
+
+static void ipath_dma_unmap_page(struct ib_device *dev,
+				 u64 addr, size_t size,
+				 enum dma_data_direction direction)
+{
+	BUG_ON(!valid_dma_direction(direction));
+}
+
+int ipath_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents,
+		 enum dma_data_direction direction)
+{
+	u64 addr;
+	int i;
+	int ret = nents;
+
+	BUG_ON(!valid_dma_direction(direction));
+
+	for (i = 0; i < nents; i++) {
+		addr = (u64) page_address(sg[i].page);
+		/* TODO: handle highmem pages */
+		if (!addr) {
+			ret = 0;
+			break;
+		}
+	}
+	return ret;
+}
+
+static void ipath_unmap_sg(struct ib_device *dev,
+			   struct scatterlist *sg, int nents,
+			   enum dma_data_direction direction)
+{
+	BUG_ON(!valid_dma_direction(direction));
+}
+
+static u64 ipath_sg_dma_address(struct ib_device *dev, struct scatterlist *sg)
+{
+	u64 addr = (u64) page_address(sg->page);
+
+	if (addr)
+		addr += sg->offset;
+	return addr;
+}
+
+static unsigned int ipath_sg_dma_len(struct ib_device *dev,
+				     struct scatterlist *sg)
+{
+	return sg->length;
+}
+
+static void ipath_sync_single_for_cpu(struct ib_device *dev,
+				      u64 addr,
+				      size_t size,
+				      enum dma_data_direction dir)
+{
+}
+
+static void ipath_sync_single_for_device(struct ib_device *dev,
+					 u64 addr,
+					 size_t size,
+					 enum dma_data_direction dir)
+{
+}
+
+static void *ipath_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 ipath_dma_free_coherent(struct ib_device *dev, size_t size,
+				    void *cpu_addr, dma_addr_t dma_handle)
+{
+	free_pages((unsigned long) cpu_addr, get_order(size));
+}
+
+struct ib_dma_mapping_ops ipath_dma_mapping_ops = {
+	ipath_mapping_error,
+	ipath_dma_map_single,
+	ipath_dma_unmap_single,
+	ipath_dma_map_page,
+	ipath_dma_unmap_page,
+	ipath_map_sg,
+	ipath_unmap_sg,
+	ipath_sg_dma_address,
+	ipath_sg_dma_len,
+	ipath_sync_single_for_cpu,
+	ipath_sync_single_for_device,
+	ipath_dma_alloc_coherent,
+	ipath_dma_free_coherent
+};
diff --git a/drivers/infiniband/hw/ipath/ipath_keys.c b/drivers/infiniband/hw/ipath/ipath_keys.c
index 9a6cbd0..851763d 100644
--- a/drivers/infiniband/hw/ipath/ipath_keys.c
+++ b/drivers/infiniband/hw/ipath/ipath_keys.c
@@ -134,7 +134,7 @@ int ipath_lkey_ok(struct ipath_qp *qp, struct ipath_sge *isge,
 	 */
 	if (sge->lkey == 0) {
 		isge->mr = NULL;
-		isge->vaddr = bus_to_virt(sge->addr);
+		isge->vaddr = (void *) sge->addr;
 		isge->length = sge->length;
 		isge->sge_length = sge->length;
 		ret = 1;
@@ -202,12 +202,12 @@ int ipath_rkey_ok(struct ipath_qp *qp, struct ipath_sge_state *ss,
 	int ret;
 
 	/*
-	 * We use RKEY == zero for physical addresses
-	 * (see ipath_get_dma_mr).
+	 * We use RKEY == zero for kernel virtual addresses
+	 * (see ipath_get_dma_mr and ipath_dma.c).
 	 */
 	if (rkey == 0) {
 		sge->mr = NULL;
-		sge->vaddr = phys_to_virt(vaddr);
+		sge->vaddr = (void *) vaddr;
 		sge->length = len;
 		sge->sge_length = len;
 		ss->sg_list = NULL;
diff --git a/drivers/infiniband/hw/ipath/ipath_mr.c b/drivers/infiniband/hw/ipath/ipath_mr.c
index a0673c1e..8cc8598 100644
--- a/drivers/infiniband/hw/ipath/ipath_mr.c
+++ b/drivers/infiniband/hw/ipath/ipath_mr.c
@@ -54,6 +54,8 @@ static inline struct ipath_fmr *to_ifmr(struct ib_fmr *ibfmr)
  * @acc: access flags
  *
  * Returns the memory region on success, otherwise returns an errno.
+ * Note that all DMA addresses should be created via the
+ * struct ib_dma_mapping_ops functions (see ipath_dma.c).
  */
 struct ib_mr *ipath_get_dma_mr(struct ib_pd *pd, int acc)
 {
@@ -149,8 +151,7 @@ struct ib_mr *ipath_reg_phys_mr(struct ib_pd *pd,
 	m = 0;
 	n = 0;
 	for (i = 0; i < num_phys_buf; i++) {
-		mr->mr.map[m]->segs[n].vaddr =
-			phys_to_virt(buffer_list[i].addr);
+		mr->mr.map[m]->segs[n].vaddr = (void *) buffer_list[i].addr;
 		mr->mr.map[m]->segs[n].length = buffer_list[i].size;
 		mr->mr.length += buffer_list[i].size;
 		n++;
@@ -347,7 +348,7 @@ int ipath_map_phys_fmr(struct ib_fmr *ibfmr, u64 * page_list,
 	n = 0;
 	ps = 1 << fmr->page_shift;
 	for (i = 0; i < list_len; i++) {
-		fmr->mr.map[m]->segs[n].vaddr = phys_to_virt(page_list[i]);
+		fmr->mr.map[m]->segs[n].vaddr = (void *) page_list[i];
 		fmr->mr.map[m]->segs[n].length = ps;
 		if (++n == IPATH_SEGSZ) {
 			m++;
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.c b/drivers/infiniband/hw/ipath/ipath_verbs.c
index acdee33..2aaacdb 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.c
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.c
@@ -1599,6 +1599,7 @@ int ipath_register_ib_device(struct ipath_devdata *dd)
 	dev->detach_mcast = ipath_multicast_detach;
 	dev->process_mad = ipath_process_mad;
 	dev->mmap = ipath_mmap;
+	dev->dma_ops = &ipath_dma_mapping_ops;
 
 	snprintf(dev->node_desc, sizeof(dev->node_desc),
 		 IPATH_IDSTR " %s", init_utsname()->nodename);
diff --git a/drivers/infiniband/hw/ipath/ipath_verbs.h b/drivers/infiniband/hw/ipath/ipath_verbs.h
index 8039f6e..c0c8d5b 100644
--- a/drivers/infiniband/hw/ipath/ipath_verbs.h
+++ b/drivers/infiniband/hw/ipath/ipath_verbs.h
@@ -812,4 +812,6 @@ extern unsigned int ib_ipath_max_srq_wrs;
 
 extern const u32 ib_ipath_rnr_table[];
 
+extern struct ib_dma_mapping_ops ipath_dma_mapping_ops;
+
 #endif				/* IPATH_VERBS_H */