dmaengine: Add Broadcom SBA RAID driver

The Broadcom stream buffer accelerator (SBA) provides offloading
capabilities for RAID operations. This SBA offload engine is
accessible via Broadcom SoC specific ring manager.

This patch adds Broadcom SBA RAID driver which provides one
DMA device with RAID capabilities using one or more Broadcom
SoC specific ring manager channels. The SBA RAID driver in its
current shape implements memcpy, xor, and pq operations.
Signed-off-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/Kconfig

@@ -99,6 +99,20 @@ config AXI_DMAC
 	  controller is often used in Analog Device's reference designs for FPGA
 	  platforms.
 
+config BCM_SBA_RAID
+	tristate "Broadcom SBA RAID engine support"
+	depends on (ARM64 && MAILBOX && RAID6_PQ) || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_ENGINE_RAID
+	select ASYNC_TX_DISABLE_XOR_VAL_DMA
+	select ASYNC_TX_DISABLE_PQ_VAL_DMA
+	default ARCH_BCM_IPROC
+	help
+	  Enable support for Broadcom SBA RAID Engine. The SBA RAID
+	  engine is available on most of the Broadcom iProc SoCs. It
+	  has the capability to offload memcpy, xor and pq computation
+	  for raid5/6.
+
 config COH901318
 	bool "ST-Ericsson COH901318 DMA support"
 	select DMA_ENGINE

drivers/dma/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
 obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
 obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
 obj-$(CONFIG_AXI_DMAC) += dma-axi-dmac.o
+obj-$(CONFIG_BCM_SBA_RAID) += bcm-sba-raid.o
 obj-$(CONFIG_COH901318) += coh901318.o coh901318_lli.o
 obj-$(CONFIG_DMA_BCM2835) += bcm2835-dma.o
 obj-$(CONFIG_DMA_JZ4740) += dma-jz4740.o

drivers/dma/bcm-sba-raid.c

+/*
+ * Copyright (C) 2017 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * Broadcom SBA RAID Driver
+ *
+ * The Broadcom stream buffer accelerator (SBA) provides offloading
+ * capabilities for RAID operations. The SBA offload engine is accessible
+ * via Broadcom SoC specific ring manager. Two or more offload engines
+ * can share same Broadcom SoC specific ring manager due to this Broadcom
+ * SoC specific ring manager driver is implemented as a mailbox controller
+ * driver and offload engine drivers are implemented as mallbox clients.
+ *
+ * Typically, Broadcom SoC specific ring manager will implement larger
+ * number of hardware rings over one or more SBA hardware devices. By
+ * design, the internal buffer size of SBA hardware device is limited
+ * but all offload operations supported by SBA can be broken down into
+ * multiple small size requests and executed parallely on multiple SBA
+ * hardware devices for achieving high through-put.
+ *
+ * The Broadcom SBA RAID driver does not require any register programming
+ * except submitting request to SBA hardware device via mailbox channels.
+ * This driver implements a DMA device with one DMA channel using a set
+ * of mailbox channels provided by Broadcom SoC specific ring manager
+ * driver. To exploit parallelism (as described above), all DMA request
+ * coming to SBA RAID DMA channel are broken down to smaller requests
+ * and submitted to multiple mailbox channels in round-robin fashion.
+ * For having more SBA DMA channels, we can create more SBA device nodes
+ * in Broadcom SoC specific DTS based on number of hardware rings supported
+ * by Broadcom SoC ring manager.
+ */
+
+#include <linux/bitops.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/list.h>
+#include <linux/mailbox_client.h>
+#include <linux/mailbox/brcm-message.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/raid/pq.h>
+
+#include "dmaengine.h"
+
+/* SBA command related defines */
+#define SBA_TYPE_SHIFT					48
+#define SBA_TYPE_MASK					GENMASK(1, 0)
+#define SBA_TYPE_A					0x0
+#define SBA_TYPE_B					0x2
+#define SBA_TYPE_C					0x3
+#define SBA_USER_DEF_SHIFT				32
+#define SBA_USER_DEF_MASK				GENMASK(15, 0)
+#define SBA_R_MDATA_SHIFT				24
+#define SBA_R_MDATA_MASK				GENMASK(7, 0)
+#define SBA_C_MDATA_MS_SHIFT				18
+#define SBA_C_MDATA_MS_MASK				GENMASK(1, 0)
+#define SBA_INT_SHIFT					17
+#define SBA_INT_MASK					BIT(0)
+#define SBA_RESP_SHIFT					16
+#define SBA_RESP_MASK					BIT(0)
+#define SBA_C_MDATA_SHIFT				8
+#define SBA_C_MDATA_MASK				GENMASK(7, 0)
+#define SBA_C_MDATA_BNUMx_SHIFT(__bnum)			(2 * (__bnum))
+#define SBA_C_MDATA_BNUMx_MASK				GENMASK(1, 0)
+#define SBA_C_MDATA_DNUM_SHIFT				5
+#define SBA_C_MDATA_DNUM_MASK				GENMASK(4, 0)
+#define SBA_C_MDATA_LS(__v)				((__v) & 0xff)
+#define SBA_C_MDATA_MS(__v)				(((__v) >> 8) & 0x3)
+#define SBA_CMD_SHIFT					0
+#define SBA_CMD_MASK					GENMASK(3, 0)
+#define SBA_CMD_ZERO_BUFFER				0x4
+#define SBA_CMD_ZERO_ALL_BUFFERS			0x8
+#define SBA_CMD_LOAD_BUFFER				0x9
+#define SBA_CMD_XOR					0xa
+#define SBA_CMD_GALOIS_XOR				0xb
+#define SBA_CMD_WRITE_BUFFER				0xc
+#define SBA_CMD_GALOIS					0xe
+
+/* Driver helper macros */
+#define to_sba_request(tx)		\
+	container_of(tx, struct sba_request, tx)
+#define to_sba_device(dchan)		\
+	container_of(dchan, struct sba_device, dma_chan)
+
+enum sba_request_state {
+	SBA_REQUEST_STATE_FREE = 1,
+	SBA_REQUEST_STATE_ALLOCED = 2,
+	SBA_REQUEST_STATE_PENDING = 3,
+	SBA_REQUEST_STATE_ACTIVE = 4,
+	SBA_REQUEST_STATE_RECEIVED = 5,
+	SBA_REQUEST_STATE_COMPLETED = 6,
+	SBA_REQUEST_STATE_ABORTED = 7,
+};
+
+struct sba_request {
+	/* Global state */
+	struct list_head node;
+	struct sba_device *sba;
+	enum sba_request_state state;
+	bool fence;
+	/* Chained requests management */
+	struct sba_request *first;
+	struct list_head next;
+	unsigned int next_count;
+	atomic_t next_pending_count;
+	/* BRCM message data */
+	void *resp;
+	dma_addr_t resp_dma;
+	struct brcm_sba_command *cmds;
+	struct brcm_message msg;
+	struct dma_async_tx_descriptor tx;
+};
+
+enum sba_version {
+	SBA_VER_1 = 0,
+	SBA_VER_2
+};
+
+struct sba_device {
+	/* Underlying device */
+	struct device *dev;
+	/* DT configuration parameters */
+	enum sba_version ver;
+	/* Derived configuration parameters */
+	u32 max_req;
+	u32 hw_buf_size;
+	u32 hw_resp_size;
+	u32 max_pq_coefs;
+	u32 max_pq_srcs;
+	u32 max_cmd_per_req;
+	u32 max_xor_srcs;
+	u32 max_resp_pool_size;
+	u32 max_cmds_pool_size;
+	/* Maibox client and Mailbox channels */
+	struct mbox_client client;
+	int mchans_count;
+	atomic_t mchans_current;
+	struct mbox_chan **mchans;
+	struct device *mbox_dev;
+	/* DMA device and DMA channel */
+	struct dma_device dma_dev;
+	struct dma_chan dma_chan;
+	/* DMA channel resources */
+	void *resp_base;
+	dma_addr_t resp_dma_base;
+	void *cmds_base;
+	dma_addr_t cmds_dma_base;
+	spinlock_t reqs_lock;
+	struct sba_request *reqs;
+	bool reqs_fence;
+	struct list_head reqs_alloc_list;
+	struct list_head reqs_pending_list;
+	struct list_head reqs_active_list;
+	struct list_head reqs_received_list;
+	struct list_head reqs_completed_list;
+	struct list_head reqs_aborted_list;
+	struct list_head reqs_free_list;
+	int reqs_free_count;
+};
+
+/* ====== SBA command helper routines ===== */
+
+static inline u64 __pure sba_cmd_enc(u64 cmd, u32 val, u32 shift, u32 mask)
+{
+	cmd &= ~((u64)mask << shift);
+	cmd |= ((u64)(val & mask) << shift);
+	return cmd;
+}
+
+static inline u32 __pure sba_cmd_load_c_mdata(u32 b0)
+{
+	return b0 & SBA_C_MDATA_BNUMx_MASK;
+}
+
+static inline u32 __pure sba_cmd_write_c_mdata(u32 b0)
+{
+	return b0 & SBA_C_MDATA_BNUMx_MASK;
+}
+
+static inline u32 __pure sba_cmd_xor_c_mdata(u32 b1, u32 b0)
+{
+	return (b0 & SBA_C_MDATA_BNUMx_MASK) |
+	       ((b1 & SBA_C_MDATA_BNUMx_MASK) << SBA_C_MDATA_BNUMx_SHIFT(1));
+}
+
+static inline u32 __pure sba_cmd_pq_c_mdata(u32 d, u32 b1, u32 b0)
+{
+	return (b0 & SBA_C_MDATA_BNUMx_MASK) |
+	       ((b1 & SBA_C_MDATA_BNUMx_MASK) << SBA_C_MDATA_BNUMx_SHIFT(1)) |
+	       ((d & SBA_C_MDATA_DNUM_MASK) << SBA_C_MDATA_DNUM_SHIFT);
+}
+
+/* ====== Channel resource management routines ===== */
+
+static struct sba_request *sba_alloc_request(struct sba_device *sba)
+{
+	unsigned long flags;
+	struct sba_request *req = NULL;
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	req = list_first_entry_or_null(&sba->reqs_free_list,
+				       struct sba_request, node);
+	if (req) {
+		list_move_tail(&req->node, &sba->reqs_alloc_list);
+		req->state = SBA_REQUEST_STATE_ALLOCED;
+		req->fence = false;
+		req->first = req;
+		INIT_LIST_HEAD(&req->next);
+		req->next_count = 1;
+		atomic_set(&req->next_pending_count, 1);
+
+		sba->reqs_free_count--;
+
+		dma_async_tx_descriptor_init(&req->tx, &sba->dma_chan);
+	}
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+
+	return req;
+}
+
+/* Note: Must be called with sba->reqs_lock held */
+static void _sba_pending_request(struct sba_device *sba,
+				 struct sba_request *req)
+{
+	lockdep_assert_held(&sba->reqs_lock);
+	req->state = SBA_REQUEST_STATE_PENDING;
+	list_move_tail(&req->node, &sba->reqs_pending_list);
+	if (list_empty(&sba->reqs_active_list))
+		sba->reqs_fence = false;
+}
+
+/* Note: Must be called with sba->reqs_lock held */
+static bool _sba_active_request(struct sba_device *sba,
+				struct sba_request *req)
+{
+	lockdep_assert_held(&sba->reqs_lock);
+	if (list_empty(&sba->reqs_active_list))
+		sba->reqs_fence = false;
+	if (sba->reqs_fence)
+		return false;
+	req->state = SBA_REQUEST_STATE_ACTIVE;
+	list_move_tail(&req->node, &sba->reqs_active_list);
+	if (req->fence)
+		sba->reqs_fence = true;
+	return true;
+}
+
+/* Note: Must be called with sba->reqs_lock held */
+static void _sba_abort_request(struct sba_device *sba,
+			       struct sba_request *req)
+{
+	lockdep_assert_held(&sba->reqs_lock);
+	req->state = SBA_REQUEST_STATE_ABORTED;
+	list_move_tail(&req->node, &sba->reqs_aborted_list);
+	if (list_empty(&sba->reqs_active_list))
+		sba->reqs_fence = false;
+}
+
+/* Note: Must be called with sba->reqs_lock held */
+static void _sba_free_request(struct sba_device *sba,
+			      struct sba_request *req)
+{
+	lockdep_assert_held(&sba->reqs_lock);
+	req->state = SBA_REQUEST_STATE_FREE;
+	list_move_tail(&req->node, &sba->reqs_free_list);
+	if (list_empty(&sba->reqs_active_list))
+		sba->reqs_fence = false;
+	sba->reqs_free_count++;
+}
+
+static void sba_received_request(struct sba_request *req)
+{
+	unsigned long flags;
+	struct sba_device *sba = req->sba;
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+	req->state = SBA_REQUEST_STATE_RECEIVED;
+	list_move_tail(&req->node, &sba->reqs_received_list);
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+}
+
+static void sba_complete_chained_requests(struct sba_request *req)
+{
+	unsigned long flags;
+	struct sba_request *nreq;
+	struct sba_device *sba = req->sba;
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	req->state = SBA_REQUEST_STATE_COMPLETED;
+	list_move_tail(&req->node, &sba->reqs_completed_list);
+	list_for_each_entry(nreq, &req->next, next) {
+		nreq->state = SBA_REQUEST_STATE_COMPLETED;
+		list_move_tail(&nreq->node, &sba->reqs_completed_list);
+	}
+	if (list_empty(&sba->reqs_active_list))
+		sba->reqs_fence = false;
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+}
+
+static void sba_free_chained_requests(struct sba_request *req)
+{
+	unsigned long flags;
+	struct sba_request *nreq;
+	struct sba_device *sba = req->sba;
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	_sba_free_request(sba, req);
+	list_for_each_entry(nreq, &req->next, next)
+		_sba_free_request(sba, nreq);
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+}
+
+static void sba_chain_request(struct sba_request *first,
+			      struct sba_request *req)
+{
+	unsigned long flags;
+	struct sba_device *sba = req->sba;
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	list_add_tail(&req->next, &first->next);
+	req->first = first;
+	first->next_count++;
+	atomic_set(&first->next_pending_count, first->next_count);
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+}
+
+static void sba_cleanup_nonpending_requests(struct sba_device *sba)
+{
+	unsigned long flags;
+	struct sba_request *req, *req1;
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	/* Freeup all alloced request */
+	list_for_each_entry_safe(req, req1, &sba->reqs_alloc_list, node)
+		_sba_free_request(sba, req);
+
+	/* Freeup all received request */
+	list_for_each_entry_safe(req, req1, &sba->reqs_received_list, node)
+		_sba_free_request(sba, req);
+
+	/* Freeup all completed request */
+	list_for_each_entry_safe(req, req1, &sba->reqs_completed_list, node)
+		_sba_free_request(sba, req);
+
+	/* Set all active requests as aborted */
+	list_for_each_entry_safe(req, req1, &sba->reqs_active_list, node)
+		_sba_abort_request(sba, req);
+
+	/*
+	 * Note: We expect that aborted request will be eventually
+	 * freed by sba_receive_message()
+	 */
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+}
+
+static void sba_cleanup_pending_requests(struct sba_device *sba)
+{
+	unsigned long flags;
+	struct sba_request *req, *req1;
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	/* Freeup all pending request */
+	list_for_each_entry_safe(req, req1, &sba->reqs_pending_list, node)
+		_sba_free_request(sba, req);
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+}
+
+/* ====== DMAENGINE callbacks ===== */
+
+static void sba_free_chan_resources(struct dma_chan *dchan)
+{
+	/*
+	 * Channel resources are pre-alloced so we just free-up
+	 * whatever we can so that we can re-use pre-alloced
+	 * channel resources next time.
+	 */
+	sba_cleanup_nonpending_requests(to_sba_device(dchan));
+}
+
+static int sba_device_terminate_all(struct dma_chan *dchan)
+{
+	/* Cleanup all pending requests */
+	sba_cleanup_pending_requests(to_sba_device(dchan));
+
+	return 0;
+}
+
+static int sba_send_mbox_request(struct sba_device *sba,
+				 struct sba_request *req)
+{
+	int mchans_idx, ret = 0;
+
+	/* Select mailbox channel in round-robin fashion */
+	mchans_idx = atomic_inc_return(&sba->mchans_current);
+	mchans_idx = mchans_idx % sba->mchans_count;
+
+	/* Send message for the request */
+	req->msg.error = 0;
+	ret = mbox_send_message(sba->mchans[mchans_idx], &req->msg);
+	if (ret < 0) {
+		dev_err(sba->dev, "send message failed with error %d", ret);
+		return ret;
+	}
+	ret = req->msg.error;
+	if (ret < 0) {
+		dev_err(sba->dev, "message error %d", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void sba_issue_pending(struct dma_chan *dchan)
+{
+	int ret;
+	unsigned long flags;
+	struct sba_request *req, *req1;
+	struct sba_device *sba = to_sba_device(dchan);
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	/* Process all pending request */
+	list_for_each_entry_safe(req, req1, &sba->reqs_pending_list, node) {
+		/* Try to make request active */
+		if (!_sba_active_request(sba, req))
+			break;
+
+		/* Send request to mailbox channel */
+		spin_unlock_irqrestore(&sba->reqs_lock, flags);
+		ret = sba_send_mbox_request(sba, req);
+		spin_lock_irqsave(&sba->reqs_lock, flags);
+
+		/* If something went wrong then keep request pending */
+		if (ret < 0) {
+			_sba_pending_request(sba, req);
+			break;
+		}
+	}
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+}
+
+static dma_cookie_t sba_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	unsigned long flags;
+	dma_cookie_t cookie;
+	struct sba_device *sba;
+	struct sba_request *req, *nreq;
+
+	if (unlikely(!tx))
+		return -EINVAL;
+
+	sba = to_sba_device(tx->chan);
+	req = to_sba_request(tx);
+
+	/* Assign cookie and mark all chained requests pending */
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+	cookie = dma_cookie_assign(tx);
+	_sba_pending_request(sba, req);
+	list_for_each_entry(nreq, &req->next, next)
+		_sba_pending_request(sba, nreq);
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+
+	return cookie;
+}
+
+static enum dma_status sba_tx_status(struct dma_chan *dchan,
+				     dma_cookie_t cookie,
+				     struct dma_tx_state *txstate)
+{
+	int mchan_idx;
+	enum dma_status ret;
+	struct sba_device *sba = to_sba_device(dchan);
+
+	for (mchan_idx = 0; mchan_idx < sba->mchans_count; mchan_idx++)
+		mbox_client_peek_data(sba->mchans[mchan_idx]);
+
+	ret = dma_cookie_status(dchan, cookie, txstate);
+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	return dma_cookie_status(dchan, cookie, txstate);
+}
+
+static void sba_fillup_interrupt_msg(struct sba_request *req,
+				     struct brcm_sba_command *cmds,
+				     struct brcm_message *msg)
+{
+	u64 cmd;
+	u32 c_mdata;
+	struct brcm_sba_command *cmdsp = cmds;
+
+	/* Type-B command to load dummy data into buf0 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, req->sba->hw_resp_size,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	c_mdata = sba_cmd_load_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_LOAD_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+	cmdsp->data = req->resp_dma;
+	cmdsp->data_len = req->sba->hw_resp_size;
+	cmdsp++;
+
+	/* Type-A command to write buf0 to dummy location */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, req->sba->hw_resp_size,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	cmd = sba_cmd_enc(cmd, 0x1,
+			  SBA_RESP_SHIFT, SBA_RESP_MASK);
+	c_mdata = sba_cmd_write_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_WRITE_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+	if (req->sba->hw_resp_size) {
+		cmdsp->flags |= BRCM_SBA_CMD_HAS_RESP;
+		cmdsp->resp = req->resp_dma;
+		cmdsp->resp_len = req->sba->hw_resp_size;
+	}
+	cmdsp->flags |= BRCM_SBA_CMD_HAS_OUTPUT;
+	cmdsp->data = req->resp_dma;
+	cmdsp->data_len = req->sba->hw_resp_size;
+	cmdsp++;
+
+	/* Fillup brcm_message */
+	msg->type = BRCM_MESSAGE_SBA;
+	msg->sba.cmds = cmds;
+	msg->sba.cmds_count = cmdsp - cmds;
+	msg->ctx = req;
+	msg->error = 0;
+}
+
+static struct dma_async_tx_descriptor *
+sba_prep_dma_interrupt(struct dma_chan *dchan, unsigned long flags)
+{
+	struct sba_request *req = NULL;
+	struct sba_device *sba = to_sba_device(dchan);
+
+	/* Alloc new request */
+	req = sba_alloc_request(sba);
+	if (!req)
+		return NULL;
+
+	/*
+	 * Force fence so that no requests are submitted
+	 * until DMA callback for this request is invoked.
+	 */
+	req->fence = true;
+
+	/* Fillup request message */
+	sba_fillup_interrupt_msg(req, req->cmds, &req->msg);
+
+	/* Init async_tx descriptor */
+	req->tx.flags = flags;
+	req->tx.cookie = -EBUSY;
+
+	return (req) ? &req->tx : NULL;
+}
+
+static void sba_fillup_memcpy_msg(struct sba_request *req,
+				  struct brcm_sba_command *cmds,
+				  struct brcm_message *msg,
+				  dma_addr_t msg_offset, size_t msg_len,
+				  dma_addr_t dst, dma_addr_t src)
+{
+	u64 cmd;
+	u32 c_mdata;
+	struct brcm_sba_command *cmdsp = cmds;
+
+	/* Type-B command to load data into buf0 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	c_mdata = sba_cmd_load_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_LOAD_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+	cmdsp->data = src + msg_offset;
+	cmdsp->data_len = msg_len;
+	cmdsp++;
+
+	/* Type-A command to write buf0 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	cmd = sba_cmd_enc(cmd, 0x1,
+			  SBA_RESP_SHIFT, SBA_RESP_MASK);
+	c_mdata = sba_cmd_write_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_WRITE_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+	if (req->sba->hw_resp_size) {
+		cmdsp->flags |= BRCM_SBA_CMD_HAS_RESP;
+		cmdsp->resp = req->resp_dma;
+		cmdsp->resp_len = req->sba->hw_resp_size;
+	}
+	cmdsp->flags |= BRCM_SBA_CMD_HAS_OUTPUT;
+	cmdsp->data = dst + msg_offset;
+	cmdsp->data_len = msg_len;
+	cmdsp++;
+
+	/* Fillup brcm_message */
+	msg->type = BRCM_MESSAGE_SBA;
+	msg->sba.cmds = cmds;
+	msg->sba.cmds_count = cmdsp - cmds;
+	msg->ctx = req;
+	msg->error = 0;
+}
+
+static struct sba_request *
+sba_prep_dma_memcpy_req(struct sba_device *sba,
+			dma_addr_t off, dma_addr_t dst, dma_addr_t src,
+			size_t len, unsigned long flags)
+{
+	struct sba_request *req = NULL;
+
+	/* Alloc new request */
+	req = sba_alloc_request(sba);
+	if (!req)
+		return NULL;
+	req->fence = (flags & DMA_PREP_FENCE) ? true : false;
+
+	/* Fillup request message */
+	sba_fillup_memcpy_msg(req, req->cmds, &req->msg,
+			      off, len, dst, src);
+
+	/* Init async_tx descriptor */
+	req->tx.flags = flags;
+	req->tx.cookie = -EBUSY;
+
+	return req;
+}
+
+static struct dma_async_tx_descriptor *
+sba_prep_dma_memcpy(struct dma_chan *dchan, dma_addr_t dst, dma_addr_t src,
+		    size_t len, unsigned long flags)
+{
+	size_t req_len;
+	dma_addr_t off = 0;
+	struct sba_device *sba = to_sba_device(dchan);
+	struct sba_request *first = NULL, *req;
+
+	/* Create chained requests where each request is upto hw_buf_size */
+	while (len) {
+		req_len = (len < sba->hw_buf_size) ? len : sba->hw_buf_size;
+
+		req = sba_prep_dma_memcpy_req(sba, off, dst, src,
+					      req_len, flags);
+		if (!req) {
+			if (first)
+				sba_free_chained_requests(first);
+			return NULL;
+		}
+
+		if (first)
+			sba_chain_request(first, req);
+		else
+			first = req;
+
+		off += req_len;
+		len -= req_len;
+	}
+
+	return (first) ? &first->tx : NULL;
+}
+
+static void sba_fillup_xor_msg(struct sba_request *req,
+				struct brcm_sba_command *cmds,
+				struct brcm_message *msg,
+				dma_addr_t msg_offset, size_t msg_len,
+				dma_addr_t dst, dma_addr_t *src, u32 src_cnt)
+{
+	u64 cmd;
+	u32 c_mdata;
+	unsigned int i;
+	struct brcm_sba_command *cmdsp = cmds;
+
+	/* Type-B command to load data into buf0 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	c_mdata = sba_cmd_load_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_LOAD_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+	cmdsp->data = src[0] + msg_offset;
+	cmdsp->data_len = msg_len;
+	cmdsp++;
+
+	/* Type-B commands to xor data with buf0 and put it back in buf0 */
+	for (i = 1; i < src_cnt; i++) {
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		c_mdata = sba_cmd_xor_c_mdata(0, 0);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_XOR,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+		cmdsp->data = src[i] + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+	}
+
+	/* Type-A command to write buf0 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	cmd = sba_cmd_enc(cmd, 0x1,
+			  SBA_RESP_SHIFT, SBA_RESP_MASK);
+	c_mdata = sba_cmd_write_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_WRITE_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+	if (req->sba->hw_resp_size) {
+		cmdsp->flags |= BRCM_SBA_CMD_HAS_RESP;
+		cmdsp->resp = req->resp_dma;
+		cmdsp->resp_len = req->sba->hw_resp_size;
+	}
+	cmdsp->flags |= BRCM_SBA_CMD_HAS_OUTPUT;
+	cmdsp->data = dst + msg_offset;
+	cmdsp->data_len = msg_len;
+	cmdsp++;
+
+	/* Fillup brcm_message */
+	msg->type = BRCM_MESSAGE_SBA;
+	msg->sba.cmds = cmds;
+	msg->sba.cmds_count = cmdsp - cmds;
+	msg->ctx = req;
+	msg->error = 0;
+}
+
+struct sba_request *
+sba_prep_dma_xor_req(struct sba_device *sba,
+		     dma_addr_t off, dma_addr_t dst, dma_addr_t *src,
+		     u32 src_cnt, size_t len, unsigned long flags)
+{
+	struct sba_request *req = NULL;
+
+	/* Alloc new request */
+	req = sba_alloc_request(sba);
+	if (!req)
+		return NULL;
+	req->fence = (flags & DMA_PREP_FENCE) ? true : false;
+
+	/* Fillup request message */
+	sba_fillup_xor_msg(req, req->cmds, &req->msg,
+			   off, len, dst, src, src_cnt);
+
+	/* Init async_tx descriptor */
+	req->tx.flags = flags;
+	req->tx.cookie = -EBUSY;
+
+	return req;
+}
+
+static struct dma_async_tx_descriptor *
+sba_prep_dma_xor(struct dma_chan *dchan, dma_addr_t dst, dma_addr_t *src,
+		 u32 src_cnt, size_t len, unsigned long flags)
+{
+	size_t req_len;
+	dma_addr_t off = 0;
+	struct sba_device *sba = to_sba_device(dchan);
+	struct sba_request *first = NULL, *req;
+
+	/* Sanity checks */
+	if (unlikely(src_cnt > sba->max_xor_srcs))
+		return NULL;
+
+	/* Create chained requests where each request is upto hw_buf_size */
+	while (len) {
+		req_len = (len < sba->hw_buf_size) ? len : sba->hw_buf_size;
+
+		req = sba_prep_dma_xor_req(sba, off, dst, src, src_cnt,
+					   req_len, flags);
+		if (!req) {
+			if (first)
+				sba_free_chained_requests(first);
+			return NULL;
+		}
+
+		if (first)
+			sba_chain_request(first, req);
+		else
+			first = req;
+
+		off += req_len;
+		len -= req_len;
+	}
+
+	return (first) ? &first->tx : NULL;
+}
+
+static void sba_fillup_pq_msg(struct sba_request *req,
+				bool pq_continue,
+				struct brcm_sba_command *cmds,
+				struct brcm_message *msg,
+				dma_addr_t msg_offset, size_t msg_len,
+				dma_addr_t *dst_p, dma_addr_t *dst_q,
+				const u8 *scf, dma_addr_t *src, u32 src_cnt)
+{
+	u64 cmd;
+	u32 c_mdata;
+	unsigned int i;
+	struct brcm_sba_command *cmdsp = cmds;
+
+	if (pq_continue) {
+		/* Type-B command to load old P into buf0 */
+		if (dst_p) {
+			cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+			cmd = sba_cmd_enc(cmd, msg_len,
+				SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+			c_mdata = sba_cmd_load_c_mdata(0);
+			cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+			cmd = sba_cmd_enc(cmd, SBA_CMD_LOAD_BUFFER,
+				SBA_CMD_SHIFT, SBA_CMD_MASK);
+			cmdsp->cmd = cmd;
+			*cmdsp->cmd_dma = cpu_to_le64(cmd);
+			cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+			cmdsp->data = *dst_p + msg_offset;
+			cmdsp->data_len = msg_len;
+			cmdsp++;
+		}
+
+		/* Type-B command to load old Q into buf1 */
+		if (dst_q) {
+			cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+			cmd = sba_cmd_enc(cmd, msg_len,
+				SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+			c_mdata = sba_cmd_load_c_mdata(1);
+			cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+			cmd = sba_cmd_enc(cmd, SBA_CMD_LOAD_BUFFER,
+				SBA_CMD_SHIFT, SBA_CMD_MASK);
+			cmdsp->cmd = cmd;
+			*cmdsp->cmd_dma = cpu_to_le64(cmd);
+			cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+			cmdsp->data = *dst_q + msg_offset;
+			cmdsp->data_len = msg_len;
+			cmdsp++;
+		}
+	} else {
+		/* Type-A command to zero all buffers */
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_ZERO_ALL_BUFFERS,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+		cmdsp++;
+	}
+
+	/* Type-B commands for generate P onto buf0 and Q onto buf1 */
+	for (i = 0; i < src_cnt; i++) {
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		c_mdata = sba_cmd_pq_c_mdata(raid6_gflog[scf[i]], 1, 0);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_MS(c_mdata),
+				  SBA_C_MDATA_MS_SHIFT, SBA_C_MDATA_MS_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_GALOIS_XOR,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+		cmdsp->data = src[i] + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+	}
+
+	/* Type-A command to write buf0 */
+	if (dst_p) {
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		cmd = sba_cmd_enc(cmd, 0x1,
+				  SBA_RESP_SHIFT, SBA_RESP_MASK);
+		c_mdata = sba_cmd_write_c_mdata(0);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_WRITE_BUFFER,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+		if (req->sba->hw_resp_size) {
+			cmdsp->flags |= BRCM_SBA_CMD_HAS_RESP;
+			cmdsp->resp = req->resp_dma;
+			cmdsp->resp_len = req->sba->hw_resp_size;
+		}
+		cmdsp->flags |= BRCM_SBA_CMD_HAS_OUTPUT;
+		cmdsp->data = *dst_p + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+	}
+
+	/* Type-A command to write buf1 */
+	if (dst_q) {
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		cmd = sba_cmd_enc(cmd, 0x1,
+				  SBA_RESP_SHIFT, SBA_RESP_MASK);
+		c_mdata = sba_cmd_write_c_mdata(1);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_WRITE_BUFFER,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+		if (req->sba->hw_resp_size) {
+			cmdsp->flags |= BRCM_SBA_CMD_HAS_RESP;
+			cmdsp->resp = req->resp_dma;
+			cmdsp->resp_len = req->sba->hw_resp_size;
+		}
+		cmdsp->flags |= BRCM_SBA_CMD_HAS_OUTPUT;
+		cmdsp->data = *dst_q + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+	}
+
+	/* Fillup brcm_message */
+	msg->type = BRCM_MESSAGE_SBA;
+	msg->sba.cmds = cmds;
+	msg->sba.cmds_count = cmdsp - cmds;
+	msg->ctx = req;
+	msg->error = 0;
+}
+
+struct sba_request *
+sba_prep_dma_pq_req(struct sba_device *sba, dma_addr_t off,
+		    dma_addr_t *dst_p, dma_addr_t *dst_q, dma_addr_t *src,
+		    u32 src_cnt, const u8 *scf, size_t len, unsigned long flags)
+{
+	struct sba_request *req = NULL;
+
+	/* Alloc new request */
+	req = sba_alloc_request(sba);
+	if (!req)
+		return NULL;
+	req->fence = (flags & DMA_PREP_FENCE) ? true : false;
+
+	/* Fillup request messages */
+	sba_fillup_pq_msg(req, dmaf_continue(flags),
+			  req->cmds, &req->msg,
+			  off, len, dst_p, dst_q, scf, src, src_cnt);
+
+	/* Init async_tx descriptor */
+	req->tx.flags = flags;
+	req->tx.cookie = -EBUSY;
+
+	return req;
+}
+
+static void sba_fillup_pq_single_msg(struct sba_request *req,
+				bool pq_continue,
+				struct brcm_sba_command *cmds,
+				struct brcm_message *msg,
+				dma_addr_t msg_offset, size_t msg_len,
+				dma_addr_t *dst_p, dma_addr_t *dst_q,
+				dma_addr_t src, u8 scf)
+{
+	u64 cmd;
+	u32 c_mdata;
+	u8 pos, dpos = raid6_gflog[scf];
+	struct brcm_sba_command *cmdsp = cmds;
+
+	if (!dst_p)
+		goto skip_p;
+
+	if (pq_continue) {
+		/* Type-B command to load old P into buf0 */
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		c_mdata = sba_cmd_load_c_mdata(0);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_LOAD_BUFFER,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+		cmdsp->data = *dst_p + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+
+		/*
+		 * Type-B commands to xor data with buf0 and put it
+		 * back in buf0
+		 */
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		c_mdata = sba_cmd_xor_c_mdata(0, 0);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_XOR,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+		cmdsp->data = src + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+	} else {
+		/* Type-B command to load old P into buf0 */
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		c_mdata = sba_cmd_load_c_mdata(0);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_LOAD_BUFFER,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+		cmdsp->data = src + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+	}
+
+	/* Type-A command to write buf0 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	cmd = sba_cmd_enc(cmd, 0x1,
+			  SBA_RESP_SHIFT, SBA_RESP_MASK);
+	c_mdata = sba_cmd_write_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_WRITE_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+	if (req->sba->hw_resp_size) {
+		cmdsp->flags |= BRCM_SBA_CMD_HAS_RESP;
+		cmdsp->resp = req->resp_dma;
+		cmdsp->resp_len = req->sba->hw_resp_size;
+	}
+	cmdsp->flags |= BRCM_SBA_CMD_HAS_OUTPUT;
+	cmdsp->data = *dst_p + msg_offset;
+	cmdsp->data_len = msg_len;
+	cmdsp++;
+
+skip_p:
+	if (!dst_q)
+		goto skip_q;
+
+	/* Type-A command to zero all buffers */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_ZERO_ALL_BUFFERS,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+	cmdsp++;
+
+	if (dpos == 255)
+		goto skip_q_computation;
+	pos = (dpos < req->sba->max_pq_coefs) ?
+		dpos : (req->sba->max_pq_coefs - 1);
+
+	/*
+	 * Type-B command to generate initial Q from data
+	 * and store output into buf0
+	 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	c_mdata = sba_cmd_pq_c_mdata(pos, 0, 0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_MS(c_mdata),
+			  SBA_C_MDATA_MS_SHIFT, SBA_C_MDATA_MS_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_GALOIS,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+	cmdsp->data = src + msg_offset;
+	cmdsp->data_len = msg_len;
+	cmdsp++;
+
+	dpos -= pos;
+
+	/* Multiple Type-A command to generate final Q */
+	while (dpos) {
+		pos = (dpos < req->sba->max_pq_coefs) ?
+			dpos : (req->sba->max_pq_coefs - 1);
+
+		/*
+		 * Type-A command to generate Q with buf0 and
+		 * buf1 store result in buf0
+		 */
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		c_mdata = sba_cmd_pq_c_mdata(pos, 0, 1);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_MS(c_mdata),
+				  SBA_C_MDATA_MS_SHIFT, SBA_C_MDATA_MS_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_GALOIS,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+		cmdsp++;
+
+		dpos -= pos;
+	}
+
+skip_q_computation:
+	if (pq_continue) {
+		/*
+		 * Type-B command to XOR previous output with
+		 * buf0 and write it into buf0
+		 */
+		cmd = sba_cmd_enc(0x0, SBA_TYPE_B,
+				  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+		cmd = sba_cmd_enc(cmd, msg_len,
+				  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+		c_mdata = sba_cmd_xor_c_mdata(0, 0);
+		cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+				  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+		cmd = sba_cmd_enc(cmd, SBA_CMD_XOR,
+				  SBA_CMD_SHIFT, SBA_CMD_MASK);
+		cmdsp->cmd = cmd;
+		*cmdsp->cmd_dma = cpu_to_le64(cmd);
+		cmdsp->flags = BRCM_SBA_CMD_TYPE_B;
+		cmdsp->data = *dst_q + msg_offset;
+		cmdsp->data_len = msg_len;
+		cmdsp++;
+	}
+
+	/* Type-A command to write buf0 */
+	cmd = sba_cmd_enc(0x0, SBA_TYPE_A,
+			  SBA_TYPE_SHIFT, SBA_TYPE_MASK);
+	cmd = sba_cmd_enc(cmd, msg_len,
+			  SBA_USER_DEF_SHIFT, SBA_USER_DEF_MASK);
+	cmd = sba_cmd_enc(cmd, 0x1,
+			  SBA_RESP_SHIFT, SBA_RESP_MASK);
+	c_mdata = sba_cmd_write_c_mdata(0);
+	cmd = sba_cmd_enc(cmd, SBA_C_MDATA_LS(c_mdata),
+			  SBA_C_MDATA_SHIFT, SBA_C_MDATA_MASK);
+	cmd = sba_cmd_enc(cmd, SBA_CMD_WRITE_BUFFER,
+			  SBA_CMD_SHIFT, SBA_CMD_MASK);
+	cmdsp->cmd = cmd;
+	*cmdsp->cmd_dma = cpu_to_le64(cmd);
+	cmdsp->flags = BRCM_SBA_CMD_TYPE_A;
+	if (req->sba->hw_resp_size) {
+		cmdsp->flags |= BRCM_SBA_CMD_HAS_RESP;
+		cmdsp->resp = req->resp_dma;
+		cmdsp->resp_len = req->sba->hw_resp_size;
+	}
+	cmdsp->flags |= BRCM_SBA_CMD_HAS_OUTPUT;
+	cmdsp->data = *dst_q + msg_offset;
+	cmdsp->data_len = msg_len;
+	cmdsp++;
+
+skip_q:
+	/* Fillup brcm_message */
+	msg->type = BRCM_MESSAGE_SBA;
+	msg->sba.cmds = cmds;
+	msg->sba.cmds_count = cmdsp - cmds;
+	msg->ctx = req;
+	msg->error = 0;
+}
+
+struct sba_request *
+sba_prep_dma_pq_single_req(struct sba_device *sba, dma_addr_t off,
+			   dma_addr_t *dst_p, dma_addr_t *dst_q,
+			   dma_addr_t src, u8 scf, size_t len,
+			   unsigned long flags)
+{
+	struct sba_request *req = NULL;
+
+	/* Alloc new request */
+	req = sba_alloc_request(sba);
+	if (!req)
+		return NULL;
+	req->fence = (flags & DMA_PREP_FENCE) ? true : false;
+
+	/* Fillup request messages */
+	sba_fillup_pq_single_msg(req,  dmaf_continue(flags),
+				 req->cmds, &req->msg, off, len,
+				 dst_p, dst_q, src, scf);
+
+	/* Init async_tx descriptor */
+	req->tx.flags = flags;
+	req->tx.cookie = -EBUSY;
+
+	return req;
+}
+
+static struct dma_async_tx_descriptor *
+sba_prep_dma_pq(struct dma_chan *dchan, dma_addr_t *dst, dma_addr_t *src,
+		u32 src_cnt, const u8 *scf, size_t len, unsigned long flags)
+{
+	u32 i, dst_q_index;
+	size_t req_len;
+	bool slow = false;
+	dma_addr_t off = 0;
+	dma_addr_t *dst_p = NULL, *dst_q = NULL;
+	struct sba_device *sba = to_sba_device(dchan);
+	struct sba_request *first = NULL, *req;
+
+	/* Sanity checks */
+	if (unlikely(src_cnt > sba->max_pq_srcs))
+		return NULL;
+	for (i = 0; i < src_cnt; i++)
+		if (sba->max_pq_coefs <= raid6_gflog[scf[i]])
+			slow = true;
+
+	/* Figure-out P and Q destination addresses */
+	if (!(flags & DMA_PREP_PQ_DISABLE_P))
+		dst_p = &dst[0];
+	if (!(flags & DMA_PREP_PQ_DISABLE_Q))
+		dst_q = &dst[1];
+
+	/* Create chained requests where each request is upto hw_buf_size */
+	while (len) {
+		req_len = (len < sba->hw_buf_size) ? len : sba->hw_buf_size;
+
+		if (slow) {
+			dst_q_index = src_cnt;
+
+			if (dst_q) {
+				for (i = 0; i < src_cnt; i++) {
+					if (*dst_q == src[i]) {
+						dst_q_index = i;
+						break;
+					}
+				}
+			}
+
+			if (dst_q_index < src_cnt) {
+				i = dst_q_index;
+				req = sba_prep_dma_pq_single_req(sba,
+					off, dst_p, dst_q, src[i], scf[i],
+					req_len, flags | DMA_PREP_FENCE);
+				if (!req)
+					goto fail;
+
+				if (first)
+					sba_chain_request(first, req);
+				else
+					first = req;
+
+				flags |= DMA_PREP_CONTINUE;
+			}
+
+			for (i = 0; i < src_cnt; i++) {
+				if (dst_q_index == i)
+					continue;
+
+				req = sba_prep_dma_pq_single_req(sba,
+					off, dst_p, dst_q, src[i], scf[i],
+					req_len, flags | DMA_PREP_FENCE);
+				if (!req)
+					goto fail;
+
+				if (first)
+					sba_chain_request(first, req);
+				else
+					first = req;
+
+				flags |= DMA_PREP_CONTINUE;
+			}
+		} else {
+			req = sba_prep_dma_pq_req(sba, off,
+						  dst_p, dst_q, src, src_cnt,
+						  scf, req_len, flags);
+			if (!req)
+				goto fail;
+
+			if (first)
+				sba_chain_request(first, req);
+			else
+				first = req;
+		}
+
+		off += req_len;
+		len -= req_len;
+	}
+
+	return (first) ? &first->tx : NULL;
+
+fail:
+	if (first)
+		sba_free_chained_requests(first);
+	return NULL;
+}
+
+/* ====== Mailbox callbacks ===== */
+
+static void sba_dma_tx_actions(struct sba_request *req)
+{
+	struct dma_async_tx_descriptor *tx = &req->tx;
+
+	WARN_ON(tx->cookie < 0);
+
+	if (tx->cookie > 0) {
+		dma_cookie_complete(tx);
+
+		/*
+		 * Call the callback (must not sleep or submit new
+		 * operations to this channel)
+		 */
+		if (tx->callback)
+			tx->callback(tx->callback_param);
+
+		dma_descriptor_unmap(tx);
+	}
+
+	/* Run dependent operations */
+	dma_run_dependencies(tx);
+
+	/* If waiting for 'ack' then move to completed list */
+	if (!async_tx_test_ack(&req->tx))
+		sba_complete_chained_requests(req);
+	else
+		sba_free_chained_requests(req);
+}
+
+static void sba_receive_message(struct mbox_client *cl, void *msg)
+{
+	unsigned long flags;
+	struct brcm_message *m = msg;
+	struct sba_request *req = m->ctx, *req1;
+	struct sba_device *sba = req->sba;
+
+	/* Error count if message has error */
+	if (m->error < 0)
+		dev_err(sba->dev, "%s got message with error %d",
+			dma_chan_name(&sba->dma_chan), m->error);
+
+	/* Mark request as received */
+	sba_received_request(req);
+
+	/* Wait for all chained requests to be completed */
+	if (atomic_dec_return(&req->first->next_pending_count))
+		goto done;
+
+	/* Point to first request */
+	req = req->first;
+
+	/* Update request */
+	if (req->state == SBA_REQUEST_STATE_RECEIVED)
+		sba_dma_tx_actions(req);
+	else
+		sba_free_chained_requests(req);
+
+	spin_lock_irqsave(&sba->reqs_lock, flags);
+
+	/* Re-check all completed request waiting for 'ack' */
+	list_for_each_entry_safe(req, req1, &sba->reqs_completed_list, node) {
+		spin_unlock_irqrestore(&sba->reqs_lock, flags);
+		sba_dma_tx_actions(req);
+		spin_lock_irqsave(&sba->reqs_lock, flags);
+	}
+
+	spin_unlock_irqrestore(&sba->reqs_lock, flags);
+
+done:
+	/* Try to submit pending request */
+	sba_issue_pending(&sba->dma_chan);
+}
+
+/* ====== Platform driver routines ===== */
+
+static int sba_prealloc_channel_resources(struct sba_device *sba)
+{
+	int i, j, p, ret = 0;
+	struct sba_request *req = NULL;
+
+	sba->resp_base = dma_alloc_coherent(sba->dma_dev.dev,
+					    sba->max_resp_pool_size,
+					    &sba->resp_dma_base, GFP_KERNEL);
+	if (!sba->resp_base)
+		return -ENOMEM;
+
+	sba->cmds_base = dma_alloc_coherent(sba->dma_dev.dev,
+					    sba->max_cmds_pool_size,
+					    &sba->cmds_dma_base, GFP_KERNEL);
+	if (!sba->cmds_base) {
+		ret = -ENOMEM;
+		goto fail_free_resp_pool;
+	}
+
+	spin_lock_init(&sba->reqs_lock);
+	sba->reqs_fence = false;
+	INIT_LIST_HEAD(&sba->reqs_alloc_list);
+	INIT_LIST_HEAD(&sba->reqs_pending_list);
+	INIT_LIST_HEAD(&sba->reqs_active_list);
+	INIT_LIST_HEAD(&sba->reqs_received_list);
+	INIT_LIST_HEAD(&sba->reqs_completed_list);
+	INIT_LIST_HEAD(&sba->reqs_aborted_list);
+	INIT_LIST_HEAD(&sba->reqs_free_list);
+
+	sba->reqs = devm_kcalloc(sba->dev, sba->max_req,
+				 sizeof(*req), GFP_KERNEL);
+	if (!sba->reqs) {
+		ret = -ENOMEM;
+		goto fail_free_cmds_pool;
+	}
+
+	for (i = 0, p = 0; i < sba->max_req; i++) {
+		req = &sba->reqs[i];
+		INIT_LIST_HEAD(&req->node);
+		req->sba = sba;
+		req->state = SBA_REQUEST_STATE_FREE;
+		INIT_LIST_HEAD(&req->next);
+		req->next_count = 1;
+		atomic_set(&req->next_pending_count, 0);
+		req->fence = false;
+		req->resp = sba->resp_base + p;
+		req->resp_dma = sba->resp_dma_base + p;
+		p += sba->hw_resp_size;
+		req->cmds = devm_kcalloc(sba->dev, sba->max_cmd_per_req,
+					 sizeof(*req->cmds), GFP_KERNEL);
+		if (!req->cmds) {
+			ret = -ENOMEM;
+			goto fail_free_cmds_pool;
+		}
+		for (j = 0; j < sba->max_cmd_per_req; j++) {
+			req->cmds[j].cmd = 0;
+			req->cmds[j].cmd_dma = sba->cmds_base +
+				(i * sba->max_cmd_per_req + j) * sizeof(u64);
+			req->cmds[j].cmd_dma_addr = sba->cmds_dma_base +
+				(i * sba->max_cmd_per_req + j) * sizeof(u64);
+			req->cmds[j].flags = 0;
+		}
+		memset(&req->msg, 0, sizeof(req->msg));
+		dma_async_tx_descriptor_init(&req->tx, &sba->dma_chan);
+		req->tx.tx_submit = sba_tx_submit;
+		req->tx.phys = req->resp_dma;
+		list_add_tail(&req->node, &sba->reqs_free_list);
+	}
+
+	sba->reqs_free_count = sba->max_req;
+
+	return 0;
+
+fail_free_cmds_pool:
+	dma_free_coherent(sba->dma_dev.dev,
+			  sba->max_cmds_pool_size,
+			  sba->cmds_base, sba->cmds_dma_base);
+fail_free_resp_pool:
+	dma_free_coherent(sba->dma_dev.dev,
+			  sba->max_resp_pool_size,
+			  sba->resp_base, sba->resp_dma_base);
+	return ret;
+}
+
+static void sba_freeup_channel_resources(struct sba_device *sba)
+{
+	dmaengine_terminate_all(&sba->dma_chan);
+	dma_free_coherent(sba->dma_dev.dev, sba->max_cmds_pool_size,
+			  sba->cmds_base, sba->cmds_dma_base);
+	dma_free_coherent(sba->dma_dev.dev, sba->max_resp_pool_size,
+			  sba->resp_base, sba->resp_dma_base);
+	sba->resp_base = NULL;
+	sba->resp_dma_base = 0;
+}
+
+static int sba_async_register(struct sba_device *sba)
+{
+	int ret;
+	struct dma_device *dma_dev = &sba->dma_dev;
+
+	/* Initialize DMA channel cookie */
+	sba->dma_chan.device = dma_dev;
+	dma_cookie_init(&sba->dma_chan);
+
+	/* Initialize DMA device capability mask */
+	dma_cap_zero(dma_dev->cap_mask);
+	dma_cap_set(DMA_INTERRUPT, dma_dev->cap_mask);
+	dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
+	dma_cap_set(DMA_XOR, dma_dev->cap_mask);
+	dma_cap_set(DMA_PQ, dma_dev->cap_mask);
+
+	/*
+	 * Set mailbox channel device as the base device of
+	 * our dma_device because the actual memory accesses
+	 * will be done by mailbox controller
+	 */
+	dma_dev->dev = sba->mbox_dev;
+
+	/* Set base prep routines */
+	dma_dev->device_free_chan_resources = sba_free_chan_resources;
+	dma_dev->device_terminate_all = sba_device_terminate_all;
+	dma_dev->device_issue_pending = sba_issue_pending;
+	dma_dev->device_tx_status = sba_tx_status;
+
+	/* Set interrupt routine */
+	if (dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask))
+		dma_dev->device_prep_dma_interrupt = sba_prep_dma_interrupt;
+
+	/* Set memcpy routine */
+	if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask))
+		dma_dev->device_prep_dma_memcpy = sba_prep_dma_memcpy;
+
+	/* Set xor routine and capability */
+	if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
+		dma_dev->device_prep_dma_xor = sba_prep_dma_xor;
+		dma_dev->max_xor = sba->max_xor_srcs;
+	}
+
+	/* Set pq routine and capability */
+	if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
+		dma_dev->device_prep_dma_pq = sba_prep_dma_pq;
+		dma_set_maxpq(dma_dev, sba->max_pq_srcs, 0);
+	}
+
+	/* Initialize DMA device channel list */
+	INIT_LIST_HEAD(&dma_dev->channels);
+	list_add_tail(&sba->dma_chan.device_node, &dma_dev->channels);
+
+	/* Register with Linux async DMA framework*/
+	ret = dma_async_device_register(dma_dev);
+	if (ret) {
+		dev_err(sba->dev, "async device register error %d", ret);
+		return ret;
+	}
+
+	dev_info(sba->dev, "%s capabilities: %s%s%s%s\n",
+	dma_chan_name(&sba->dma_chan),
+	dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask) ? "interrupt " : "",
+	dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask) ? "memcpy " : "",
+	dma_has_cap(DMA_XOR, dma_dev->cap_mask) ? "xor " : "",
+	dma_has_cap(DMA_PQ, dma_dev->cap_mask) ? "pq " : "");
+
+	return 0;
+}
+
+static int sba_probe(struct platform_device *pdev)
+{
+	int i, ret = 0, mchans_count;
+	struct sba_device *sba;
+	struct platform_device *mbox_pdev;
+	struct of_phandle_args args;
+
+	/* Allocate main SBA struct */
+	sba = devm_kzalloc(&pdev->dev, sizeof(*sba), GFP_KERNEL);
+	if (!sba)
+		return -ENOMEM;
+
+	sba->dev = &pdev->dev;
+	platform_set_drvdata(pdev, sba);
+
+	/* Determine SBA version from DT compatible string */
+	if (of_device_is_compatible(sba->dev->of_node, "brcm,iproc-sba"))
+		sba->ver = SBA_VER_1;
+	else if (of_device_is_compatible(sba->dev->of_node,
+					 "brcm,iproc-sba-v2"))
+		sba->ver = SBA_VER_2;
+	else
+		return -ENODEV;
+
+	/* Derived Configuration parameters */
+	switch (sba->ver) {
+	case SBA_VER_1:
+		sba->max_req = 1024;
+		sba->hw_buf_size = 4096;
+		sba->hw_resp_size = 8;
+		sba->max_pq_coefs = 6;
+		sba->max_pq_srcs = 6;
+		break;
+	case SBA_VER_2:
+		sba->max_req = 1024;
+		sba->hw_buf_size = 4096;
+		sba->hw_resp_size = 8;
+		sba->max_pq_coefs = 30;
+		/*
+		 * We can support max_pq_srcs == max_pq_coefs because
+		 * we are limited by number of SBA commands that we can
+		 * fit in one message for underlying ring manager HW.
+		 */
+		sba->max_pq_srcs = 12;
+		break;
+	default:
+		return -EINVAL;
+	}
+	sba->max_cmd_per_req = sba->max_pq_srcs + 3;
+	sba->max_xor_srcs = sba->max_cmd_per_req - 1;
+	sba->max_resp_pool_size = sba->max_req * sba->hw_resp_size;
+	sba->max_cmds_pool_size = sba->max_req *
+				  sba->max_cmd_per_req * sizeof(u64);
+
+	/* Setup mailbox client */
+	sba->client.dev			= &pdev->dev;
+	sba->client.rx_callback		= sba_receive_message;
+	sba->client.tx_block		= false;
+	sba->client.knows_txdone	= false;
+	sba->client.tx_tout		= 0;
+
+	/* Number of channels equals number of mailbox channels */
+	ret = of_count_phandle_with_args(pdev->dev.of_node,
+					 "mboxes", "#mbox-cells");
+	if (ret <= 0)
+		return -ENODEV;
+	mchans_count = ret;
+	sba->mchans_count = 0;
+	atomic_set(&sba->mchans_current, 0);
+
+	/* Allocate mailbox channel array */
+	sba->mchans = devm_kcalloc(&pdev->dev, sba->mchans_count,
+				   sizeof(*sba->mchans), GFP_KERNEL);
+	if (!sba->mchans)
+		return -ENOMEM;
+
+	/* Request mailbox channels */
+	for (i = 0; i < mchans_count; i++) {
+		sba->mchans[i] = mbox_request_channel(&sba->client, i);
+		if (IS_ERR(sba->mchans[i])) {
+			ret = PTR_ERR(sba->mchans[i]);
+			goto fail_free_mchans;
+		}
+		sba->mchans_count++;
+	}
+
+	/* Find-out underlying mailbox device */
+	ret = of_parse_phandle_with_args(pdev->dev.of_node,
+					 "mboxes", "#mbox-cells", 0, &args);
+	if (ret)
+		goto fail_free_mchans;
+	mbox_pdev = of_find_device_by_node(args.np);
+	of_node_put(args.np);
+	if (!mbox_pdev) {
+		ret = -ENODEV;
+		goto fail_free_mchans;
+	}
+	sba->mbox_dev = &mbox_pdev->dev;
+
+	/* All mailbox channels should be of same ring manager device */
+	for (i = 1; i < mchans_count; i++) {
+		ret = of_parse_phandle_with_args(pdev->dev.of_node,
+					 "mboxes", "#mbox-cells", i, &args);
+		if (ret)
+			goto fail_free_mchans;
+		mbox_pdev = of_find_device_by_node(args.np);
+		of_node_put(args.np);
+		if (sba->mbox_dev != &mbox_pdev->dev) {
+			ret = -EINVAL;
+			goto fail_free_mchans;
+		}
+	}
+
+	/* Register DMA device with linux async framework */
+	ret = sba_async_register(sba);
+	if (ret)
+		goto fail_free_mchans;
+
+	/* Prealloc channel resource */
+	ret = sba_prealloc_channel_resources(sba);
+	if (ret)
+		goto fail_async_dev_unreg;
+
+	/* Print device info */
+	dev_info(sba->dev, "%s using SBAv%d and %d mailbox channels",
+		 dma_chan_name(&sba->dma_chan), sba->ver+1,
+		 sba->mchans_count);
+
+	return 0;
+
+fail_async_dev_unreg:
+	dma_async_device_unregister(&sba->dma_dev);
+fail_free_mchans:
+	for (i = 0; i < sba->mchans_count; i++)
+		mbox_free_channel(sba->mchans[i]);
+	return ret;
+}
+
+static int sba_remove(struct platform_device *pdev)
+{
+	int i;
+	struct sba_device *sba = platform_get_drvdata(pdev);
+
+	sba_freeup_channel_resources(sba);
+
+	dma_async_device_unregister(&sba->dma_dev);
+
+	for (i = 0; i < sba->mchans_count; i++)
+		mbox_free_channel(sba->mchans[i]);
+
+	return 0;
+}
+
+static const struct of_device_id sba_of_match[] = {
+	{ .compatible = "brcm,iproc-sba", },
+	{ .compatible = "brcm,iproc-sba-v2", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sba_of_match);
+
+static struct platform_driver sba_driver = {
+	.probe = sba_probe,
+	.remove = sba_remove,
+	.driver = {
+		.name = "bcm-sba-raid",
+		.of_match_table = sba_of_match,
+	},
+};
+module_platform_driver(sba_driver);
+
+MODULE_DESCRIPTION("Broadcom SBA RAID driver");
+MODULE_AUTHOR("Anup Patel <anup.patel@broadcom.com>");
+MODULE_LICENSE("GPL v2");