dmaengine: mv_xor_v2: new driver

The new mv_xor_v2 driver supports the XOR engines found in the 64-bits
ARM from Marvell of the Armada 7K and Armada 8K family. This XOR
engine is a completely new hardware block, entirely different from the
one used on previous Marvell Armada platforms, which use the existing
mv_xor driver.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 879 insertions, 0 deletions

diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c
new file mode 100644
index 000000000000..83201556165d
--- /dev/null
+++ b/drivers/dma/mv_xor_v2.c
@@ -0,0 +1,879 @@
+/*
+ * Copyright (C) 2015-2016 Marvell International Ltd.
+
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#include "dmaengine.h"
+
+/* DMA Engine Registers */
+#define MV_XOR_V2_DMA_DESQ_BALR_OFF			0x000
+#define MV_XOR_V2_DMA_DESQ_BAHR_OFF			0x004
+#define MV_XOR_V2_DMA_DESQ_SIZE_OFF			0x008
+#define MV_XOR_V2_DMA_DESQ_DONE_OFF			0x00C
+#define   MV_XOR_V2_DMA_DESQ_DONE_PENDING_MASK		0x7FFF
+#define   MV_XOR_V2_DMA_DESQ_DONE_PENDING_SHIFT		0
+#define   MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_MASK		0x1FFF
+#define   MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_SHIFT	16
+#define MV_XOR_V2_DMA_DESQ_ARATTR_OFF			0x010
+#define   MV_XOR_V2_DMA_DESQ_ATTR_CACHE_MASK		0x3F3F
+#define   MV_XOR_V2_DMA_DESQ_ATTR_OUTER_SHAREABLE	0x202
+#define   MV_XOR_V2_DMA_DESQ_ATTR_CACHEABLE		0x3C3C
+#define MV_XOR_V2_DMA_IMSG_CDAT_OFF			0x014
+#define MV_XOR_V2_DMA_IMSG_THRD_OFF			0x018
+#define   MV_XOR_V2_DMA_IMSG_THRD_MASK			0x7FFF
+#define   MV_XOR_V2_DMA_IMSG_THRD_SHIFT			0x0
+#define MV_XOR_V2_DMA_DESQ_AWATTR_OFF			0x01C
+  /* Same flags as MV_XOR_V2_DMA_DESQ_ARATTR_OFF */
+#define MV_XOR_V2_DMA_DESQ_ALLOC_OFF			0x04C
+#define   MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_MASK		0xFFFF
+#define   MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_SHIFT		16
+#define MV_XOR_V2_DMA_IMSG_BALR_OFF			0x050
+#define MV_XOR_V2_DMA_IMSG_BAHR_OFF			0x054
+#define MV_XOR_V2_DMA_DESQ_CTRL_OFF			0x100
+#define	  MV_XOR_V2_DMA_DESQ_CTRL_32B			1
+#define   MV_XOR_V2_DMA_DESQ_CTRL_128B			7
+#define MV_XOR_V2_DMA_DESQ_STOP_OFF			0x800
+#define MV_XOR_V2_DMA_DESQ_DEALLOC_OFF			0x804
+#define MV_XOR_V2_DMA_DESQ_ADD_OFF			0x808
+
+/* XOR Global registers */
+#define MV_XOR_V2_GLOB_BW_CTRL				0x4
+#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_SHIFT	0
+#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_VAL	64
+#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_SHIFT	8
+#define   MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_VAL	8
+#define   MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_SHIFT	12
+#define   MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_VAL	4
+#define   MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_SHIFT	16
+#define	  MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_VAL	4
+#define MV_XOR_V2_GLOB_PAUSE				0x014
+#define   MV_XOR_V2_GLOB_PAUSE_AXI_TIME_DIS_VAL		0x8
+#define MV_XOR_V2_GLOB_SYS_INT_CAUSE			0x200
+#define MV_XOR_V2_GLOB_SYS_INT_MASK			0x204
+#define MV_XOR_V2_GLOB_MEM_INT_CAUSE			0x220
+#define MV_XOR_V2_GLOB_MEM_INT_MASK			0x224
+
+#define MV_XOR_V2_MIN_DESC_SIZE				32
+#define MV_XOR_V2_EXT_DESC_SIZE				128
+
+#define MV_XOR_V2_DESC_RESERVED_SIZE			12
+#define MV_XOR_V2_DESC_BUFF_D_ADDR_SIZE			12
+
+#define MV_XOR_V2_CMD_LINE_NUM_MAX_D_BUF		8
+
+/*
+ * Descriptors queue size. With 32 bytes descriptors, up to 2^14
+ * descriptors are allowed, with 128 bytes descriptors, up to 2^12
+ * descriptors are allowed. This driver uses 128 bytes descriptors,
+ * but experimentation has shown that a set of 1024 descriptors is
+ * sufficient to reach a good level of performance.
+ */
+#define MV_XOR_V2_DESC_NUM				1024
+
+/**
+ * struct mv_xor_v2_descriptor - DMA HW descriptor
+ * @desc_id: used by S/W and is not affected by H/W.
+ * @flags: error and status flags
+ * @crc32_result: CRC32 calculation result
+ * @desc_ctrl: operation mode and control flags
+ * @buff_size: amount of bytes to be processed
+ * @fill_pattern_src_addr: Fill-Pattern or Source-Address and
+ * AW-Attributes
+ * @data_buff_addr: Source (and might be RAID6 destination)
+ * addresses of data buffers in RAID5 and RAID6
+ * @reserved: reserved
+ */
+struct mv_xor_v2_descriptor {
+	u16 desc_id;
+	u16 flags;
+	u32 crc32_result;
+	u32 desc_ctrl;
+
+	/* Definitions for desc_ctrl */
+#define DESC_NUM_ACTIVE_D_BUF_SHIFT	22
+#define DESC_OP_MODE_SHIFT		28
+#define DESC_OP_MODE_NOP		0	/* Idle operation */
+#define DESC_OP_MODE_MEMCPY		1	/* Pure-DMA operation */
+#define DESC_OP_MODE_MEMSET		2	/* Mem-Fill operation */
+#define DESC_OP_MODE_MEMINIT		3	/* Mem-Init operation */
+#define DESC_OP_MODE_MEM_COMPARE	4	/* Mem-Compare operation */
+#define DESC_OP_MODE_CRC32		5	/* CRC32 calculation */
+#define DESC_OP_MODE_XOR		6	/* RAID5 (XOR) operation */
+#define DESC_OP_MODE_RAID6		7	/* RAID6 P&Q-generation */
+#define DESC_OP_MODE_RAID6_REC		8	/* RAID6 Recovery */
+#define DESC_Q_BUFFER_ENABLE		BIT(16)
+#define DESC_P_BUFFER_ENABLE		BIT(17)
+#define DESC_IOD			BIT(27)
+
+	u32 buff_size;
+	u32 fill_pattern_src_addr[4];
+	u32 data_buff_addr[MV_XOR_V2_DESC_BUFF_D_ADDR_SIZE];
+	u32 reserved[MV_XOR_V2_DESC_RESERVED_SIZE];
+};
+
+/**
+ * struct mv_xor_v2_device - implements a xor device
+ * @lock: lock for the engine
+ * @dma_base: memory mapped DMA register base
+ * @glob_base: memory mapped global register base
+ * @irq_tasklet:
+ * @free_sw_desc: linked list of free SW descriptors
+ * @dmadev: dma device
+ * @dmachan: dma channel
+ * @hw_desq: HW descriptors queue
+ * @hw_desq_virt: virtual address of DESCQ
+ * @sw_desq: SW descriptors queue
+ * @desc_size: HW descriptor size
+ * @npendings: number of pending descriptors (for which tx_submit has
+ * been called, but not yet issue_pending)
+ */
+struct mv_xor_v2_device {
+	spinlock_t lock;
+	void __iomem *dma_base;
+	void __iomem *glob_base;
+	struct clk *clk;
+	struct tasklet_struct irq_tasklet;
+	struct list_head free_sw_desc;
+	struct dma_device dmadev;
+	struct dma_chan	dmachan;
+	dma_addr_t hw_desq;
+	struct mv_xor_v2_descriptor *hw_desq_virt;
+	struct mv_xor_v2_sw_desc *sw_desq;
+	int desc_size;
+	unsigned int npendings;
+};
+
+/**
+ * struct mv_xor_v2_sw_desc - implements a xor SW descriptor
+ * @idx: descriptor index
+ * @async_tx: support for the async_tx api
+ * @hw_desc: assosiated HW descriptor
+ * @free_list: node of the free SW descriprots list
+*/
+struct mv_xor_v2_sw_desc {
+	int idx;
+	struct dma_async_tx_descriptor async_tx;
+	struct mv_xor_v2_descriptor hw_desc;
+	struct list_head free_list;
+};
+
+/*
+ * Fill the data buffers to a HW descriptor
+ */
+static void mv_xor_v2_set_data_buffers(struct mv_xor_v2_device *xor_dev,
+					struct mv_xor_v2_descriptor *desc,
+					dma_addr_t src, int index)
+{
+	int arr_index = ((index >> 1) * 3);
+
+	/*
+	 * Fill the buffer's addresses to the descriptor.
+	 *
+	 * The format of the buffers address for 2 sequential buffers
+	 * X and X + 1:
+	 *
+	 *  First word:  Buffer-DX-Address-Low[31:0]
+	 *  Second word: Buffer-DX+1-Address-Low[31:0]
+	 *  Third word:  DX+1-Buffer-Address-High[47:32] [31:16]
+	 *		 DX-Buffer-Address-High[47:32] [15:0]
+	 */
+	if ((index & 0x1) == 0) {
+		desc->data_buff_addr[arr_index] = lower_32_bits(src);
+
+		desc->data_buff_addr[arr_index + 2] &= ~0xFFFF;
+		desc->data_buff_addr[arr_index + 2] |=
+			upper_32_bits(src) & 0xFFFF;
+	} else {
+		desc->data_buff_addr[arr_index + 1] =
+			lower_32_bits(src);
+
+		desc->data_buff_addr[arr_index + 2] &= ~0xFFFF0000;
+		desc->data_buff_addr[arr_index + 2] |=
+			(upper_32_bits(src) & 0xFFFF) << 16;
+	}
+}
+
+/*
+ * Return the next available index in the DESQ.
+ */
+static int mv_xor_v2_get_desq_write_ptr(struct mv_xor_v2_device *xor_dev)
+{
+	/* read the index for the next available descriptor in the DESQ */
+	u32 reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ALLOC_OFF);
+
+	return ((reg >> MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_SHIFT)
+		& MV_XOR_V2_DMA_DESQ_ALLOC_WRPTR_MASK);
+}
+
+/*
+ * notify the engine of new descriptors, and update the available index.
+ */
+static void mv_xor_v2_add_desc_to_desq(struct mv_xor_v2_device *xor_dev,
+				       int num_of_desc)
+{
+	/* write the number of new descriptors in the DESQ. */
+	writel(num_of_desc, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ADD_OFF);
+}
+
+/*
+ * free HW descriptors
+ */
+static void mv_xor_v2_free_desc_from_desq(struct mv_xor_v2_device *xor_dev,
+					  int num_of_desc)
+{
+	/* write the number of new descriptors in the DESQ. */
+	writel(num_of_desc, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_DEALLOC_OFF);
+}
+
+/*
+ * Set descriptor size
+ * Return the HW descriptor size in bytes
+ */
+static int mv_xor_v2_set_desc_size(struct mv_xor_v2_device *xor_dev)
+{
+	writel(MV_XOR_V2_DMA_DESQ_CTRL_128B,
+	       xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_CTRL_OFF);
+
+	return MV_XOR_V2_EXT_DESC_SIZE;
+}
+
+/*
+ * Set the IMSG threshold
+ */
+static inline
+void mv_xor_v2_set_imsg_thrd(struct mv_xor_v2_device *xor_dev, int thrd_val)
+{
+	u32 reg;
+
+	reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);
+
+	reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK << MV_XOR_V2_DMA_IMSG_THRD_SHIFT);
+	reg |= (thrd_val << MV_XOR_V2_DMA_IMSG_THRD_SHIFT);
+
+	writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF);
+}
+
+static irqreturn_t mv_xor_v2_interrupt_handler(int irq, void *data)
+{
+	struct mv_xor_v2_device *xor_dev = data;
+	unsigned int ndescs;
+	u32 reg;
+
+	reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_DONE_OFF);
+
+	ndescs = ((reg >> MV_XOR_V2_DMA_DESQ_DONE_PENDING_SHIFT) &
+		  MV_XOR_V2_DMA_DESQ_DONE_PENDING_MASK);
+
+	/* No descriptors to process */
+	if (!ndescs)
+		return IRQ_NONE;
+
+	/*
+	 * Update IMSG threshold, to disable new IMSG interrupts until
+	 * end of the tasklet
+	 */
+	mv_xor_v2_set_imsg_thrd(xor_dev, MV_XOR_V2_DESC_NUM);
+
+	/* schedule a tasklet to handle descriptors callbacks */
+	tasklet_schedule(&xor_dev->irq_tasklet);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * submit a descriptor to the DMA engine
+ */
+static dma_cookie_t
+mv_xor_v2_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	int desq_ptr;
+	void *dest_hw_desc;
+	dma_cookie_t cookie;
+	struct mv_xor_v2_sw_desc *sw_desc =
+		container_of(tx, struct mv_xor_v2_sw_desc, async_tx);
+	struct mv_xor_v2_device *xor_dev =
+		container_of(tx->chan, struct mv_xor_v2_device, dmachan);
+
+	dev_dbg(xor_dev->dmadev.dev,
+		"%s sw_desc %p: async_tx %p\n",
+		__func__, sw_desc, &sw_desc->async_tx);
+
+	/* assign coookie */
+	spin_lock_bh(&xor_dev->lock);
+	cookie = dma_cookie_assign(tx);
+
+	/* get the next available slot in the DESQ */
+	desq_ptr = mv_xor_v2_get_desq_write_ptr(xor_dev);
+
+	/* copy the HW descriptor from the SW descriptor to the DESQ */
+	dest_hw_desc = xor_dev->hw_desq_virt + desq_ptr;
+
+	memcpy(dest_hw_desc, &sw_desc->hw_desc, xor_dev->desc_size);
+
+	xor_dev->npendings++;
+
+	spin_unlock_bh(&xor_dev->lock);
+
+	return cookie;
+}
+
+/*
+ * Prepare a SW descriptor
+ */
+static struct mv_xor_v2_sw_desc	*
+mv_xor_v2_prep_sw_desc(struct mv_xor_v2_device *xor_dev)
+{
+	struct mv_xor_v2_sw_desc *sw_desc;
+
+	/* Lock the channel */
+	spin_lock_bh(&xor_dev->lock);
+
+	if (list_empty(&xor_dev->free_sw_desc)) {
+		spin_unlock_bh(&xor_dev->lock);
+		/* schedule tasklet to free some descriptors */
+		tasklet_schedule(&xor_dev->irq_tasklet);
+		return NULL;
+	}
+
+	/* get a free SW descriptor from the SW DESQ */
+	sw_desc = list_first_entry(&xor_dev->free_sw_desc,
+				   struct mv_xor_v2_sw_desc, free_list);
+	list_del(&sw_desc->free_list);
+
+	/* Release the channel */
+	spin_unlock_bh(&xor_dev->lock);
+
+	/* set the async tx descriptor */
+	dma_async_tx_descriptor_init(&sw_desc->async_tx, &xor_dev->dmachan);
+	sw_desc->async_tx.tx_submit = mv_xor_v2_tx_submit;
+	async_tx_ack(&sw_desc->async_tx);
+
+	return sw_desc;
+}
+
+/*
+ * Prepare a HW descriptor for a memcpy operation
+ */
+static struct dma_async_tx_descriptor *
+mv_xor_v2_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
+			  dma_addr_t src, size_t len, unsigned long flags)
+{
+	struct mv_xor_v2_sw_desc *sw_desc;
+	struct mv_xor_v2_descriptor *hw_descriptor;
+	struct mv_xor_v2_device	*xor_dev;
+
+	xor_dev = container_of(chan, struct mv_xor_v2_device, dmachan);
+
+	dev_dbg(xor_dev->dmadev.dev,
+		"%s len: %zu src %pad dest %pad flags: %ld\n",
+		__func__, len, &src, &dest, flags);
+
+	sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
+
+	sw_desc->async_tx.flags = flags;
+
+	/* set the HW descriptor */
+	hw_descriptor = &sw_desc->hw_desc;
+
+	/* save the SW descriptor ID to restore when operation is done */
+	hw_descriptor->desc_id = sw_desc->idx;
+
+	/* Set the MEMCPY control word */
+	hw_descriptor->desc_ctrl =
+		DESC_OP_MODE_MEMCPY << DESC_OP_MODE_SHIFT;
+
+	if (flags & DMA_PREP_INTERRUPT)
+		hw_descriptor->desc_ctrl |= DESC_IOD;
+
+	/* Set source address */
+	hw_descriptor->fill_pattern_src_addr[0] = lower_32_bits(src);
+	hw_descriptor->fill_pattern_src_addr[1] =
+		upper_32_bits(src) & 0xFFFF;
+
+	/* Set Destination address */
+	hw_descriptor->fill_pattern_src_addr[2] = lower_32_bits(dest);
+	hw_descriptor->fill_pattern_src_addr[3] =
+		upper_32_bits(dest) & 0xFFFF;
+
+	/* Set buffers size */
+	hw_descriptor->buff_size = len;
+
+	/* return the async tx descriptor */
+	return &sw_desc->async_tx;
+}
+
+/*
+ * Prepare a HW descriptor for a XOR operation
+ */
+static struct dma_async_tx_descriptor *
+mv_xor_v2_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
+		       unsigned int src_cnt, size_t len, unsigned long flags)
+{
+	struct mv_xor_v2_sw_desc *sw_desc;
+	struct mv_xor_v2_descriptor *hw_descriptor;
+	struct mv_xor_v2_device	*xor_dev =
+		container_of(chan, struct mv_xor_v2_device, dmachan);
+	int i;
+
+	if (src_cnt > MV_XOR_V2_CMD_LINE_NUM_MAX_D_BUF || src_cnt < 1)
+		return NULL;
+
+	dev_dbg(xor_dev->dmadev.dev,
+		"%s src_cnt: %d len: %zu dest %pad flags: %ld\n",
+		__func__, src_cnt, len, &dest, flags);
+
+	sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
+
+	sw_desc->async_tx.flags = flags;
+
+	/* set the HW descriptor */
+	hw_descriptor = &sw_desc->hw_desc;
+
+	/* save the SW descriptor ID to restore when operation is done */
+	hw_descriptor->desc_id = sw_desc->idx;
+
+	/* Set the XOR control word */
+	hw_descriptor->desc_ctrl =
+		DESC_OP_MODE_XOR << DESC_OP_MODE_SHIFT;
+	hw_descriptor->desc_ctrl |= DESC_P_BUFFER_ENABLE;
+
+	if (flags & DMA_PREP_INTERRUPT)
+		hw_descriptor->desc_ctrl |= DESC_IOD;
+
+	/* Set the data buffers */
+	for (i = 0; i < src_cnt; i++)
+		mv_xor_v2_set_data_buffers(xor_dev, hw_descriptor, src[i], i);
+
+	hw_descriptor->desc_ctrl |=
+		src_cnt << DESC_NUM_ACTIVE_D_BUF_SHIFT;
+
+	/* Set Destination address */
+	hw_descriptor->fill_pattern_src_addr[2] = lower_32_bits(dest);
+	hw_descriptor->fill_pattern_src_addr[3] =
+		upper_32_bits(dest) & 0xFFFF;
+
+	/* Set buffers size */
+	hw_descriptor->buff_size = len;
+
+	/* return the async tx descriptor */
+	return &sw_desc->async_tx;
+}
+
+/*
+ * Prepare a HW descriptor for interrupt operation.
+ */
+static struct dma_async_tx_descriptor *
+mv_xor_v2_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags)
+{
+	struct mv_xor_v2_sw_desc *sw_desc;
+	struct mv_xor_v2_descriptor *hw_descriptor;
+	struct mv_xor_v2_device	*xor_dev =
+		container_of(chan, struct mv_xor_v2_device, dmachan);
+
+	sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
+
+	/* set the HW descriptor */
+	hw_descriptor = &sw_desc->hw_desc;
+
+	/* save the SW descriptor ID to restore when operation is done */
+	hw_descriptor->desc_id = sw_desc->idx;
+
+	/* Set the INTERRUPT control word */
+	hw_descriptor->desc_ctrl =
+		DESC_OP_MODE_NOP << DESC_OP_MODE_SHIFT;
+	hw_descriptor->desc_ctrl |= DESC_IOD;
+
+	/* return the async tx descriptor */
+	return &sw_desc->async_tx;
+}
+
+/*
+ * push pending transactions to hardware
+ */
+static void mv_xor_v2_issue_pending(struct dma_chan *chan)
+{
+	struct mv_xor_v2_device *xor_dev =
+		container_of(chan, struct mv_xor_v2_device, dmachan);
+
+	spin_lock_bh(&xor_dev->lock);
+
+	/*
+	 * update the engine with the number of descriptors to
+	 * process
+	 */
+	mv_xor_v2_add_desc_to_desq(xor_dev, xor_dev->npendings);
+	xor_dev->npendings = 0;
+
+	/* Activate the channel */
+	writel(0, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_STOP_OFF);
+
+	spin_unlock_bh(&xor_dev->lock);
+}
+
+static inline
+int mv_xor_v2_get_pending_params(struct mv_xor_v2_device *xor_dev,
+				 int *pending_ptr)
+{
+	u32 reg;
+
+	reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_DONE_OFF);
+
+	/* get the next pending descriptor index */
+	*pending_ptr = ((reg >> MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_SHIFT) &
+			MV_XOR_V2_DMA_DESQ_DONE_READ_PTR_MASK);
+
+	/* get the number of descriptors pending handle */
+	return ((reg >> MV_XOR_V2_DMA_DESQ_DONE_PENDING_SHIFT) &
+		MV_XOR_V2_DMA_DESQ_DONE_PENDING_MASK);
+}
+
+/*
+ * handle the descriptors after HW process
+ */
+static void mv_xor_v2_tasklet(unsigned long data)
+{
+	struct mv_xor_v2_device *xor_dev = (struct mv_xor_v2_device *) data;
+	int pending_ptr, num_of_pending, i;
+	struct mv_xor_v2_descriptor *next_pending_hw_desc = NULL;
+	struct mv_xor_v2_sw_desc *next_pending_sw_desc = NULL;
+
+	dev_dbg(xor_dev->dmadev.dev, "%s %d\n", __func__, __LINE__);
+
+	/* get the pending descriptors parameters */
+	num_of_pending = mv_xor_v2_get_pending_params(xor_dev, &pending_ptr);
+
+	/* next HW descriptor */
+	next_pending_hw_desc = xor_dev->hw_desq_virt + pending_ptr;
+
+	/* loop over free descriptors */
+	for (i = 0; i < num_of_pending; i++) {
+
+		if (pending_ptr > MV_XOR_V2_DESC_NUM)
+			pending_ptr = 0;
+
+		if (next_pending_sw_desc != NULL)
+			next_pending_hw_desc++;
+
+		/* get the SW descriptor related to the HW descriptor */
+		next_pending_sw_desc =
+			&xor_dev->sw_desq[next_pending_hw_desc->desc_id];
+
+		/* call the callback */
+		if (next_pending_sw_desc->async_tx.cookie > 0) {
+			/*
+			 * update the channel's completed cookie - no
+			 * lock is required the IMSG threshold provide
+			 * the locking
+			 */
+			dma_cookie_complete(&next_pending_sw_desc->async_tx);
+
+			if (next_pending_sw_desc->async_tx.callback)
+				next_pending_sw_desc->async_tx.callback(
+				next_pending_sw_desc->async_tx.callback_param);
+
+			dma_descriptor_unmap(&next_pending_sw_desc->async_tx);
+		}
+
+		dma_run_dependencies(&next_pending_sw_desc->async_tx);
+
+		/* Lock the channel */
+		spin_lock_bh(&xor_dev->lock);
+
+		/* add the SW descriptor to the free descriptors list */
+		list_add(&next_pending_sw_desc->free_list,
+			 &xor_dev->free_sw_desc);
+
+		/* Release the channel */
+		spin_unlock_bh(&xor_dev->lock);
+
+		/* increment the next descriptor */
+		pending_ptr++;
+	}
+
+	if (num_of_pending != 0) {
+		/* free the descriptores */
+		mv_xor_v2_free_desc_from_desq(xor_dev, num_of_pending);
+	}
+
+	/* Update IMSG threshold, to enable new IMSG interrupts */
+	mv_xor_v2_set_imsg_thrd(xor_dev, 0);
+}
+
+/*
+ *	Set DMA Interrupt-message (IMSG) parameters
+ */
+static void mv_xor_v2_set_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct mv_xor_v2_device *xor_dev = dev_get_drvdata(desc->dev);
+
+	writel(msg->address_lo,
+	       xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_BALR_OFF);
+	writel(msg->address_hi & 0xFFFF,
+	       xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_BAHR_OFF);
+	writel(msg->data,
+	       xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_CDAT_OFF);
+}
+
+static int mv_xor_v2_descq_init(struct mv_xor_v2_device *xor_dev)
+{
+	u32 reg;
+
+	/* write the DESQ size to the DMA engine */
+	writel(MV_XOR_V2_DESC_NUM,
+	       xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_SIZE_OFF);
+
+	/* write the DESQ address to the DMA enngine*/
+	writel(xor_dev->hw_desq & 0xFFFFFFFF,
+	       xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_BALR_OFF);
+	writel((xor_dev->hw_desq & 0xFFFF00000000) >> 32,
+	       xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_BAHR_OFF);
+
+	/* enable the DMA engine */
+	writel(0, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_STOP_OFF);
+
+	/*
+	 * This is a temporary solution, until we activate the
+	 * SMMU. Set the attributes for reading & writing data buffers
+	 * & descriptors to:
+	 *
+	 *  - OuterShareable - Snoops will be performed on CPU caches
+	 *  - Enable cacheable - Bufferable, Modifiable, Other Allocate
+	 *    and Allocate
+	 */
+	reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ARATTR_OFF);
+	reg &= ~MV_XOR_V2_DMA_DESQ_ATTR_CACHE_MASK;
+	reg |= MV_XOR_V2_DMA_DESQ_ATTR_OUTER_SHAREABLE |
+		MV_XOR_V2_DMA_DESQ_ATTR_CACHEABLE;
+	writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_ARATTR_OFF);
+
+	reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_AWATTR_OFF);
+	reg &= ~MV_XOR_V2_DMA_DESQ_ATTR_CACHE_MASK;
+	reg |= MV_XOR_V2_DMA_DESQ_ATTR_OUTER_SHAREABLE |
+		MV_XOR_V2_DMA_DESQ_ATTR_CACHEABLE;
+	writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_DESQ_AWATTR_OFF);
+
+	/* BW CTRL - set values to optimize the XOR performance:
+	 *
+	 *  - Set WrBurstLen & RdBurstLen - the unit will issue
+	 *    maximum of 256B write/read transactions.
+	 * -  Limit the number of outstanding write & read data
+	 *    (OBB/IBB) requests to the maximal value.
+	*/
+	reg = ((MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_VAL <<
+		MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_RD_SHIFT) |
+	       (MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_VAL  <<
+		MV_XOR_V2_GLOB_BW_CTRL_NUM_OSTD_WR_SHIFT) |
+	       (MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_VAL <<
+		MV_XOR_V2_GLOB_BW_CTRL_RD_BURST_LEN_SHIFT) |
+	       (MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_VAL <<
+		MV_XOR_V2_GLOB_BW_CTRL_WR_BURST_LEN_SHIFT));
+	writel(reg, xor_dev->glob_base + MV_XOR_V2_GLOB_BW_CTRL);
+
+	/* Disable the AXI timer feature */
+	reg = readl(xor_dev->glob_base + MV_XOR_V2_GLOB_PAUSE);
+	reg |= MV_XOR_V2_GLOB_PAUSE_AXI_TIME_DIS_VAL;
+	writel(reg, xor_dev->glob_base + MV_XOR_V2_GLOB_PAUSE);
+
+	return 0;
+}
+
+static int mv_xor_v2_probe(struct platform_device *pdev)
+{
+	struct mv_xor_v2_device *xor_dev;
+	struct resource *res;
+	int i, ret = 0;
+	struct dma_device *dma_dev;
+	struct mv_xor_v2_sw_desc *sw_desc;
+	struct msi_desc *msi_desc;
+
+	BUILD_BUG_ON(sizeof(struct mv_xor_v2_descriptor) !=
+		     MV_XOR_V2_EXT_DESC_SIZE);
+
+	xor_dev = devm_kzalloc(&pdev->dev, sizeof(*xor_dev), GFP_KERNEL);
+	if (!xor_dev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	xor_dev->dma_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(xor_dev->dma_base))
+		return PTR_ERR(xor_dev->dma_base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	xor_dev->glob_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(xor_dev->glob_base))
+		return PTR_ERR(xor_dev->glob_base);
+
+	platform_set_drvdata(pdev, xor_dev);
+
+	xor_dev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(xor_dev->clk) && PTR_ERR(xor_dev->clk) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+	if (!IS_ERR(xor_dev->clk)) {
+		ret = clk_prepare_enable(xor_dev->clk);
+		if (ret)
+			return ret;
+	}
+
+	ret = platform_msi_domain_alloc_irqs(&pdev->dev, 1,
+					     mv_xor_v2_set_msi_msg);
+	if (ret)
+		goto disable_clk;
+
+	msi_desc = first_msi_entry(&pdev->dev);
+	if (!msi_desc)
+		goto free_msi_irqs;
+
+	ret = devm_request_irq(&pdev->dev, msi_desc->irq,
+			       mv_xor_v2_interrupt_handler, 0,
+			       dev_name(&pdev->dev), xor_dev);
+	if (ret)
+		goto free_msi_irqs;
+
+	tasklet_init(&xor_dev->irq_tasklet, mv_xor_v2_tasklet,
+		     (unsigned long) xor_dev);
+
+	xor_dev->desc_size = mv_xor_v2_set_desc_size(xor_dev);
+
+	dma_cookie_init(&xor_dev->dmachan);
+
+	/*
+	 * allocate coherent memory for hardware descriptors
+	 * note: writecombine gives slightly better performance, but
+	 * requires that we explicitly flush the writes
+	 */
+	xor_dev->hw_desq_virt =
+		dma_alloc_coherent(&pdev->dev,
+				   xor_dev->desc_size * MV_XOR_V2_DESC_NUM,
+				   &xor_dev->hw_desq, GFP_KERNEL);
+	if (!xor_dev->hw_desq_virt) {
+		ret = -ENOMEM;
+		goto free_msi_irqs;
+	}
+
+	/* alloc memory for the SW descriptors */
+	xor_dev->sw_desq = devm_kzalloc(&pdev->dev, sizeof(*sw_desc) *
+					MV_XOR_V2_DESC_NUM, GFP_KERNEL);
+	if (!xor_dev->sw_desq) {
+		ret = -ENOMEM;
+		goto free_hw_desq;
+	}
+
+	spin_lock_init(&xor_dev->lock);
+
+	/* init the free SW descriptors list */
+	INIT_LIST_HEAD(&xor_dev->free_sw_desc);
+
+	/* add all SW descriptors to the free list */
+	for (i = 0; i < MV_XOR_V2_DESC_NUM; i++) {
+		xor_dev->sw_desq[i].idx = i;
+		list_add(&xor_dev->sw_desq[i].free_list,
+			 &xor_dev->free_sw_desc);
+	}
+
+	dma_dev = &xor_dev->dmadev;
+
+	/* set DMA capabilities */
+	dma_cap_zero(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_INTERRUPT, dma_dev->cap_mask);
+
+	/* init dma link list */
+	INIT_LIST_HEAD(&dma_dev->channels);
+
+	/* set base routines */
+	dma_dev->device_tx_status = dma_cookie_status;
+	dma_dev->device_issue_pending = mv_xor_v2_issue_pending;
+	dma_dev->dev = &pdev->dev;
+
+	dma_dev->device_prep_dma_memcpy = mv_xor_v2_prep_dma_memcpy;
+	dma_dev->device_prep_dma_interrupt = mv_xor_v2_prep_dma_interrupt;
+	dma_dev->max_xor = 8;
+	dma_dev->device_prep_dma_xor = mv_xor_v2_prep_dma_xor;
+
+	xor_dev->dmachan.device = dma_dev;
+
+	list_add_tail(&xor_dev->dmachan.device_node,
+		      &dma_dev->channels);
+
+	mv_xor_v2_descq_init(xor_dev);
+
+	ret = dma_async_device_register(dma_dev);
+	if (ret)
+		goto free_hw_desq;
+
+	dev_notice(&pdev->dev, "Marvell Version 2 XOR driver\n");
+
+	return 0;
+
+free_hw_desq:
+	dma_free_coherent(&pdev->dev,
+			  xor_dev->desc_size * MV_XOR_V2_DESC_NUM,
+			  xor_dev->hw_desq_virt, xor_dev->hw_desq);
+free_msi_irqs:
+	platform_msi_domain_free_irqs(&pdev->dev);
+disable_clk:
+	if (!IS_ERR(xor_dev->clk))
+		clk_disable_unprepare(xor_dev->clk);
+	return ret;
+}
+
+static int mv_xor_v2_remove(struct platform_device *pdev)
+{
+	struct mv_xor_v2_device *xor_dev = platform_get_drvdata(pdev);
+
+	dma_async_device_unregister(&xor_dev->dmadev);
+
+	dma_free_coherent(&pdev->dev,
+			  xor_dev->desc_size * MV_XOR_V2_DESC_NUM,
+			  xor_dev->hw_desq_virt, xor_dev->hw_desq);
+
+	platform_msi_domain_free_irqs(&pdev->dev);
+
+	clk_disable_unprepare(xor_dev->clk);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id mv_xor_v2_dt_ids[] = {
+	{ .compatible = "marvell,xor-v2", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, mv_xor_v2_dt_ids);
+#endif
+
+static struct platform_driver mv_xor_v2_driver = {
+	.probe		= mv_xor_v2_probe,
+	.remove		= mv_xor_v2_remove,
+	.driver		= {
+		.name	= "mv_xor_v2",
+		.of_match_table = of_match_ptr(mv_xor_v2_dt_ids),
+	},
+};
+
+module_platform_driver(mv_xor_v2_driver);
+
+MODULE_DESCRIPTION("DMA engine driver for Marvell's Version 2 of XOR engine");
+MODULE_LICENSE("GPL");
+