dmaengine: DMA engine driver for Marvell XOR engine

The XOR engine found in Marvell's SoCs and system controllers
provides XOR and DMA operation, iSCSI CRC32C calculation, memory
initialization, and memory ECC error cleanup operation support.

This driver implements the DMA engine API and supports the following
capabilities:
- memcpy
- xor
- memset

The XOR engine can be used by DMA engine clients implemented in the
kernel, one of those clients is the RAID module.  In that case, I
observed 20% improvement in the raid5 write throughput, and 40%
decrease in the CPU utilization when doing array construction, those
results obtained on an 5182 running at 500Mhz.

When enabling the NET DMA client, the performance decreased, so
meanwhile it is recommended to keep this client off.

Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 183 insertions, 0 deletions

diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h
new file mode 100644
index 0000000..06cafe1
--- /dev/null
+++ b/drivers/dma/mv_xor.h
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2007, 2008, Marvell International Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MV_XOR_H
+#define MV_XOR_H
+
+#include <linux/types.h>
+#include <linux/io.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+
+#define USE_TIMER
+#define MV_XOR_SLOT_SIZE		64
+#define MV_XOR_THRESHOLD		1
+
+#define XOR_OPERATION_MODE_XOR		0
+#define XOR_OPERATION_MODE_MEMCPY	2
+#define XOR_OPERATION_MODE_MEMSET	4
+
+#define XOR_CURR_DESC(chan)	(chan->mmr_base + 0x210 + (chan->idx * 4))
+#define XOR_NEXT_DESC(chan)	(chan->mmr_base + 0x200 + (chan->idx * 4))
+#define XOR_BYTE_COUNT(chan)	(chan->mmr_base + 0x220 + (chan->idx * 4))
+#define XOR_DEST_POINTER(chan)	(chan->mmr_base + 0x2B0 + (chan->idx * 4))
+#define XOR_BLOCK_SIZE(chan)	(chan->mmr_base + 0x2C0 + (chan->idx * 4))
+#define XOR_INIT_VALUE_LOW(chan)	(chan->mmr_base + 0x2E0)
+#define XOR_INIT_VALUE_HIGH(chan)	(chan->mmr_base + 0x2E4)
+
+#define XOR_CONFIG(chan)	(chan->mmr_base + 0x10 + (chan->idx * 4))
+#define XOR_ACTIVATION(chan)	(chan->mmr_base + 0x20 + (chan->idx * 4))
+#define XOR_INTR_CAUSE(chan)	(chan->mmr_base + 0x30)
+#define XOR_INTR_MASK(chan)	(chan->mmr_base + 0x40)
+#define XOR_ERROR_CAUSE(chan)	(chan->mmr_base + 0x50)
+#define XOR_ERROR_ADDR(chan)	(chan->mmr_base + 0x60)
+#define XOR_INTR_MASK_VALUE	0x3F5
+
+#define WINDOW_BASE(w)		(0x250 + ((w) << 2))
+#define WINDOW_SIZE(w)		(0x270 + ((w) << 2))
+#define WINDOW_REMAP_HIGH(w)	(0x290 + ((w) << 2))
+#define WINDOW_BAR_ENABLE(chan)	(0x240 + ((chan) << 2))
+
+struct mv_xor_shared_private {
+	void __iomem	*xor_base;
+	void __iomem	*xor_high_base;
+};
+
+
+/**
+ * struct mv_xor_device - internal representation of a XOR device
+ * @pdev: Platform device
+ * @id: HW XOR Device selector
+ * @dma_desc_pool: base of DMA descriptor region (DMA address)
+ * @dma_desc_pool_virt: base of DMA descriptor region (CPU address)
+ * @common: embedded struct dma_device
+ */
+struct mv_xor_device {
+	struct platform_device		*pdev;
+	int				id;
+	dma_addr_t			dma_desc_pool;
+	void				*dma_desc_pool_virt;
+	struct dma_device		common;
+	struct mv_xor_shared_private	*shared;
+};
+
+/**
+ * struct mv_xor_chan - internal representation of a XOR channel
+ * @pending: allows batching of hardware operations
+ * @completed_cookie: identifier for the most recently completed operation
+ * @lock: serializes enqueue/dequeue operations to the descriptors pool
+ * @mmr_base: memory mapped register base
+ * @idx: the index of the xor channel
+ * @chain: device chain view of the descriptors
+ * @completed_slots: slots completed by HW but still need to be acked
+ * @device: parent device
+ * @common: common dmaengine channel object members
+ * @last_used: place holder for allocation to continue from where it left off
+ * @all_slots: complete domain of slots usable by the channel
+ * @slots_allocated: records the actual size of the descriptor slot pool
+ * @irq_tasklet: bottom half where mv_xor_slot_cleanup runs
+ */
+struct mv_xor_chan {
+	int			pending;
+	dma_cookie_t		completed_cookie;
+	spinlock_t		lock; /* protects the descriptor slot pool */
+	void __iomem		*mmr_base;
+	unsigned int		idx;
+	enum dma_transaction_type	current_type;
+	struct list_head	chain;
+	struct list_head	completed_slots;
+	struct mv_xor_device	*device;
+	struct dma_chan		common;
+	struct mv_xor_desc_slot	*last_used;
+	struct list_head	all_slots;
+	int			slots_allocated;
+	struct tasklet_struct	irq_tasklet;
+#ifdef USE_TIMER
+	unsigned long		cleanup_time;
+	u32			current_on_last_cleanup;
+	dma_cookie_t		is_complete_cookie;
+#endif
+};
+
+/**
+ * struct mv_xor_desc_slot - software descriptor
+ * @slot_node: node on the mv_xor_chan.all_slots list
+ * @chain_node: node on the mv_xor_chan.chain list
+ * @completed_node: node on the mv_xor_chan.completed_slots list
+ * @hw_desc: virtual address of the hardware descriptor chain
+ * @phys: hardware address of the hardware descriptor chain
+ * @group_head: first operation in a transaction
+ * @slot_cnt: total slots used in an transaction (group of operations)
+ * @slots_per_op: number of slots per operation
+ * @idx: pool index
+ * @unmap_src_cnt: number of xor sources
+ * @unmap_len: transaction bytecount
+ * @async_tx: support for the async_tx api
+ * @group_list: list of slots that make up a multi-descriptor transaction
+ *	for example transfer lengths larger than the supported hw max
+ * @xor_check_result: result of zero sum
+ * @crc32_result: result crc calculation
+ */
+struct mv_xor_desc_slot {
+	struct list_head	slot_node;
+	struct list_head	chain_node;
+	struct list_head	completed_node;
+	enum dma_transaction_type	type;
+	void			*hw_desc;
+	struct mv_xor_desc_slot	*group_head;
+	u16			slot_cnt;
+	u16			slots_per_op;
+	u16			idx;
+	u16			unmap_src_cnt;
+	u32			value;
+	size_t			unmap_len;
+	struct dma_async_tx_descriptor	async_tx;
+	union {
+		u32		*xor_check_result;
+		u32		*crc32_result;
+	};
+#ifdef USE_TIMER
+	unsigned long		arrival_time;
+	struct timer_list	timeout;
+#endif
+};
+
+/* This structure describes XOR descriptor size 64bytes	*/
+struct mv_xor_desc {
+	u32 status;		/* descriptor execution status */
+	u32 crc32_result;	/* result of CRC-32 calculation */
+	u32 desc_command;	/* type of operation to be carried out */
+	u32 phy_next_desc;	/* next descriptor address pointer */
+	u32 byte_count;		/* size of src/dst blocks in bytes */
+	u32 phy_dest_addr;	/* destination block address */
+	u32 phy_src_addr[8];	/* source block addresses */
+	u32 reserved0;
+	u32 reserved1;
+};
+
+#define to_mv_sw_desc(addr_hw_desc)		\
+	container_of(addr_hw_desc, struct mv_xor_desc_slot, hw_desc)
+
+#define mv_hw_desc_slot_idx(hw_desc, idx)	\
+	((void *)(((unsigned long)hw_desc) + ((idx) << 5)))
+
+#define MV_XOR_MIN_BYTE_COUNT	(128)
+#define XOR_MAX_BYTE_COUNT	((16 * 1024 * 1024) - 1)
+#define MV_XOR_MAX_BYTE_COUNT	XOR_MAX_BYTE_COUNT
+
+
+#endif