dmaengine: Driver for Topcliff PCH DMA controller

Topcliff PCH is the platform controller hub that is going to
be used in Intel's upcoming general embedded platforms. This
adds the driver for Topcliff PCH DMA controller. The DMA
channels are strictly for device to host or host to device
transfers and cannot be used for generic memcpy.

Signed-off-by: Yong Wang <yong.y.wang@intel.com>
[kill GFP_ATOMIC, kill __raw_{read|write}l, locking fixlet]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

3 files changed, 965 insertions, 0 deletions

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 6a3e5bfa674..fed57634b6c 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -188,6 +188,13 @@ config PL330_DMA
 	  You need to provide platform specific settings via
 	  platform_data for a dma-pl330 device.
 
+config PCH_DMA
+	tristate "Topcliff PCH DMA support"
+	depends on PCI && X86
+	select DMA_ENGINE
+	help
+	  Enable support for the Topcliff PCH DMA engine.
+
 config DMA_ENGINE
 	bool
 
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 27b6c69ae63..72bd70384d8 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
 obj-$(CONFIG_TIMB_DMA) += timb_dma.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_PL330_DMA) += pl330.o
+obj-$(CONFIG_PCH_DMA) += pch_dma.o
diff --git a/drivers/dma/pch_dma.c b/drivers/dma/pch_dma.c
new file mode 100644
index 00000000000..37139ca496e
--- /dev/null
+++ b/drivers/dma/pch_dma.c
@@ -0,0 +1,957 @@
+/*
+ * Topcliff PCH DMA controller driver
+ * Copyright (c) 2010 Intel Corporation
+ *
+ * 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.
+ *
+ * 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.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pch_dma.h>
+
+#define DRV_NAME "pch-dma"
+
+#define DMA_CTL0_DISABLE		0x0
+#define DMA_CTL0_SG			0x1
+#define DMA_CTL0_ONESHOT		0x2
+#define DMA_CTL0_MODE_MASK_BITS		0x3
+#define DMA_CTL0_DIR_SHIFT_BITS		2
+#define DMA_CTL0_BITS_PER_CH		4
+
+#define DMA_CTL2_START_SHIFT_BITS	8
+#define DMA_CTL2_IRQ_ENABLE_MASK	((1UL << DMA_CTL2_START_SHIFT_BITS) - 1)
+
+#define DMA_STATUS_IDLE			0x0
+#define DMA_STATUS_DESC_READ		0x1
+#define DMA_STATUS_WAIT			0x2
+#define DMA_STATUS_ACCESS		0x3
+#define DMA_STATUS_BITS_PER_CH		2
+#define DMA_STATUS_MASK_BITS		0x3
+#define DMA_STATUS_SHIFT_BITS		16
+#define DMA_STATUS_IRQ(x)		(0x1 << (x))
+#define DMA_STATUS_ERR(x)		(0x1 << ((x) + 8))
+
+#define DMA_DESC_WIDTH_SHIFT_BITS	12
+#define DMA_DESC_WIDTH_1_BYTE		(0x3 << DMA_DESC_WIDTH_SHIFT_BITS)
+#define DMA_DESC_WIDTH_2_BYTES		(0x2 << DMA_DESC_WIDTH_SHIFT_BITS)
+#define DMA_DESC_WIDTH_4_BYTES		(0x0 << DMA_DESC_WIDTH_SHIFT_BITS)
+#define DMA_DESC_MAX_COUNT_1_BYTE	0x3FF
+#define DMA_DESC_MAX_COUNT_2_BYTES	0x3FF
+#define DMA_DESC_MAX_COUNT_4_BYTES	0x7FF
+#define DMA_DESC_END_WITHOUT_IRQ	0x0
+#define DMA_DESC_END_WITH_IRQ		0x1
+#define DMA_DESC_FOLLOW_WITHOUT_IRQ	0x2
+#define DMA_DESC_FOLLOW_WITH_IRQ	0x3
+
+#define MAX_CHAN_NR			8
+
+static unsigned int init_nr_desc_per_channel = 64;
+module_param(init_nr_desc_per_channel, uint, 0644);
+MODULE_PARM_DESC(init_nr_desc_per_channel,
+		 "initial descriptors per channel (default: 64)");
+
+struct pch_dma_desc_regs {
+	u32	dev_addr;
+	u32	mem_addr;
+	u32	size;
+	u32	next;
+};
+
+struct pch_dma_regs {
+	u32	dma_ctl0;
+	u32	dma_ctl1;
+	u32	dma_ctl2;
+	u32	reserved1;
+	u32	dma_sts0;
+	u32	dma_sts1;
+	u32	reserved2;
+	u32	reserved3;
+	struct pch_dma_desc_regs desc[0];
+};
+
+struct pch_dma_desc {
+	struct pch_dma_desc_regs regs;
+	struct dma_async_tx_descriptor txd;
+	struct list_head	desc_node;
+	struct list_head	tx_list;
+};
+
+struct pch_dma_chan {
+	struct dma_chan		chan;
+	void __iomem *membase;
+	enum dma_data_direction	dir;
+	struct tasklet_struct	tasklet;
+	unsigned long		err_status;
+
+	spinlock_t		lock;
+
+	dma_cookie_t		completed_cookie;
+	struct list_head	active_list;
+	struct list_head	queue;
+	struct list_head	free_list;
+	unsigned int		descs_allocated;
+};
+
+#define PDC_DEV_ADDR	0x00
+#define PDC_MEM_ADDR	0x04
+#define PDC_SIZE	0x08
+#define PDC_NEXT	0x0C
+
+#define channel_readl(pdc, name) \
+	readl((pdc)->membase + PDC_##name)
+#define channel_writel(pdc, name, val) \
+	writel((val), (pdc)->membase + PDC_##name)
+
+struct pch_dma {
+	struct dma_device	dma;
+	void __iomem *membase;
+	struct pci_pool		*pool;
+	struct pch_dma_regs	regs;
+	struct pch_dma_desc_regs ch_regs[MAX_CHAN_NR];
+	struct pch_dma_chan	channels[0];
+};
+
+#define PCH_DMA_CTL0	0x00
+#define PCH_DMA_CTL1	0x04
+#define PCH_DMA_CTL2	0x08
+#define PCH_DMA_STS0	0x10
+#define PCH_DMA_STS1	0x14
+
+#define dma_readl(pd, name) \
+	__raw_readl((pd)->membase + PCH_DMA_##name)
+#define dma_writel(pd, name, val) \
+	__raw_writel((val), (pd)->membase + PCH_DMA_##name)
+
+static inline struct pch_dma_desc *to_pd_desc(struct dma_async_tx_descriptor *txd)
+{
+	return container_of(txd, struct pch_dma_desc, txd);
+}
+
+static inline struct pch_dma_chan *to_pd_chan(struct dma_chan *chan)
+{
+	return container_of(chan, struct pch_dma_chan, chan);
+}
+
+static inline struct pch_dma *to_pd(struct dma_device *ddev)
+{
+	return container_of(ddev, struct pch_dma, dma);
+}
+
+static inline struct device *chan2dev(struct dma_chan *chan)
+{
+	return &chan->dev->device;
+}
+
+static inline struct device *chan2parent(struct dma_chan *chan)
+{
+	return chan->dev->device.parent;
+}
+
+static inline struct pch_dma_desc *pdc_first_active(struct pch_dma_chan *pd_chan)
+{
+	return list_first_entry(&pd_chan->active_list,
+				struct pch_dma_desc, desc_node);
+}
+
+static inline struct pch_dma_desc *pdc_first_queued(struct pch_dma_chan *pd_chan)
+{
+	return list_first_entry(&pd_chan->queue,
+				struct pch_dma_desc, desc_node);
+}
+
+static void pdc_enable_irq(struct dma_chan *chan, int enable)
+{
+	struct pch_dma *pd = to_pd(chan->device);
+	u32 val;
+
+	val = dma_readl(pd, CTL2);
+
+	if (enable)
+		val |= 0x1 << chan->chan_id;
+	else
+		val &= ~(0x1 << chan->chan_id);
+
+	dma_writel(pd, CTL2, val);
+
+	dev_dbg(chan2dev(chan), "pdc_enable_irq: chan %d -> %x\n",
+		chan->chan_id, val);
+}
+
+static void pdc_set_dir(struct dma_chan *chan)
+{
+	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
+	struct pch_dma *pd = to_pd(chan->device);
+	u32 val;
+
+	val = dma_readl(pd, CTL0);
+
+	if (pd_chan->dir == DMA_TO_DEVICE)
+		val |= 0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
+			       DMA_CTL0_DIR_SHIFT_BITS);
+	else
+		val &= ~(0x1 << (DMA_CTL0_BITS_PER_CH * chan->chan_id +
+				 DMA_CTL0_DIR_SHIFT_BITS));
+
+	dma_writel(pd, CTL0, val);
+
+	dev_dbg(chan2dev(chan), "pdc_set_dir: chan %d -> %x\n",
+		chan->chan_id, val);
+}
+
+static void pdc_set_mode(struct dma_chan *chan, u32 mode)
+{
+	struct pch_dma *pd = to_pd(chan->device);
+	u32 val;
+
+	val = dma_readl(pd, CTL0);
+
+	val &= ~(DMA_CTL0_MODE_MASK_BITS <<
+		(DMA_CTL0_BITS_PER_CH * chan->chan_id));
+	val |= mode << (DMA_CTL0_BITS_PER_CH * chan->chan_id);
+
+	dma_writel(pd, CTL0, val);
+
+	dev_dbg(chan2dev(chan), "pdc_set_mode: chan %d -> %x\n",
+		chan->chan_id, val);
+}
+
+static u32 pdc_get_status(struct pch_dma_chan *pd_chan)
+{
+	struct pch_dma *pd = to_pd(pd_chan->chan.device);
+	u32 val;
+
+	val = dma_readl(pd, STS0);
+	return DMA_STATUS_MASK_BITS & (val >> (DMA_STATUS_SHIFT_BITS +
+			DMA_STATUS_BITS_PER_CH * pd_chan->chan.chan_id));
+}
+
+static bool pdc_is_idle(struct pch_dma_chan *pd_chan)
+{
+	if (pdc_get_status(pd_chan) == DMA_STATUS_IDLE)
+		return true;
+	else
+		return false;
+}
+
+static void pdc_dostart(struct pch_dma_chan *pd_chan, struct pch_dma_desc* desc)
+{
+	struct pch_dma *pd = to_pd(pd_chan->chan.device);
+	u32 val;
+
+	if (!pdc_is_idle(pd_chan)) {
+		dev_err(chan2dev(&pd_chan->chan),
+			"BUG: Attempt to start non-idle channel\n");
+		return;
+	}
+
+	channel_writel(pd_chan, DEV_ADDR, desc->regs.dev_addr);
+	channel_writel(pd_chan, MEM_ADDR, desc->regs.mem_addr);
+	channel_writel(pd_chan, SIZE, desc->regs.size);
+	channel_writel(pd_chan, NEXT, desc->regs.next);
+
+	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> dev_addr: %x\n",
+		pd_chan->chan.chan_id, desc->regs.dev_addr);
+	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> mem_addr: %x\n",
+		pd_chan->chan.chan_id, desc->regs.mem_addr);
+	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> size: %x\n",
+		pd_chan->chan.chan_id, desc->regs.size);
+	dev_dbg(chan2dev(&pd_chan->chan), "chan %d -> next: %x\n",
+		pd_chan->chan.chan_id, desc->regs.next);
+
+	if (list_empty(&desc->tx_list))
+		pdc_set_mode(&pd_chan->chan, DMA_CTL0_ONESHOT);
+	else
+		pdc_set_mode(&pd_chan->chan, DMA_CTL0_SG);
+
+	val = dma_readl(pd, CTL2);
+	val |= 1 << (DMA_CTL2_START_SHIFT_BITS + pd_chan->chan.chan_id);
+	dma_writel(pd, CTL2, val);
+}
+
+static void pdc_chain_complete(struct pch_dma_chan *pd_chan,
+			       struct pch_dma_desc *desc)
+{
+	struct dma_async_tx_descriptor *txd = &desc->txd;
+	dma_async_tx_callback callback = txd->callback;
+	void *param = txd->callback_param;
+
+	list_splice_init(&desc->tx_list, &pd_chan->free_list);
+	list_move(&desc->desc_node, &pd_chan->free_list);
+
+	if (callback)
+		callback(param);
+}
+
+static void pdc_complete_all(struct pch_dma_chan *pd_chan)
+{
+	struct pch_dma_desc *desc, *_d;
+	LIST_HEAD(list);
+
+	BUG_ON(!pdc_is_idle(pd_chan));
+
+	if (!list_empty(&pd_chan->queue))
+		pdc_dostart(pd_chan, pdc_first_queued(pd_chan));
+
+	list_splice_init(&pd_chan->active_list, &list);
+	list_splice_init(&pd_chan->queue, &pd_chan->active_list);
+
+	list_for_each_entry_safe(desc, _d, &list, desc_node)
+		pdc_chain_complete(pd_chan, desc);
+}
+
+static void pdc_handle_error(struct pch_dma_chan *pd_chan)
+{
+	struct pch_dma_desc *bad_desc;
+
+	bad_desc = pdc_first_active(pd_chan);
+	list_del(&bad_desc->desc_node);
+
+	list_splice_init(&pd_chan->queue, pd_chan->active_list.prev);
+
+	if (!list_empty(&pd_chan->active_list))
+		pdc_dostart(pd_chan, pdc_first_active(pd_chan));
+
+	dev_crit(chan2dev(&pd_chan->chan), "Bad descriptor submitted\n");
+	dev_crit(chan2dev(&pd_chan->chan), "descriptor cookie: %d\n",
+		 bad_desc->txd.cookie);
+
+	pdc_chain_complete(pd_chan, bad_desc);
+}
+
+static void pdc_advance_work(struct pch_dma_chan *pd_chan)
+{
+	if (list_empty(&pd_chan->active_list) ||
+		list_is_singular(&pd_chan->active_list)) {
+		pdc_complete_all(pd_chan);
+	} else {
+		pdc_chain_complete(pd_chan, pdc_first_active(pd_chan));
+		pdc_dostart(pd_chan, pdc_first_active(pd_chan));
+	}
+}
+
+static dma_cookie_t pdc_assign_cookie(struct pch_dma_chan *pd_chan,
+				      struct pch_dma_desc *desc)
+{
+	dma_cookie_t cookie = pd_chan->chan.cookie;
+
+	if (++cookie < 0)
+		cookie = 1;
+
+	pd_chan->chan.cookie = cookie;
+	desc->txd.cookie = cookie;
+
+	return cookie;
+}
+
+static dma_cookie_t pd_tx_submit(struct dma_async_tx_descriptor *txd)
+{
+	struct pch_dma_desc *desc = to_pd_desc(txd);
+	struct pch_dma_chan *pd_chan = to_pd_chan(txd->chan);
+	dma_cookie_t cookie;
+
+	spin_lock_bh(&pd_chan->lock);
+	cookie = pdc_assign_cookie(pd_chan, desc);
+
+	if (list_empty(&pd_chan->active_list)) {
+		list_add_tail(&desc->desc_node, &pd_chan->active_list);
+		pdc_dostart(pd_chan, desc);
+	} else {
+		list_add_tail(&desc->desc_node, &pd_chan->queue);
+	}
+
+	spin_unlock_bh(&pd_chan->lock);
+	return 0;
+}
+
+static struct pch_dma_desc *pdc_alloc_desc(struct dma_chan *chan, gfp_t flags)
+{
+	struct pch_dma_desc *desc = NULL;
+	struct pch_dma *pd = to_pd(chan->device);
+	dma_addr_t addr;
+
+	desc = pci_pool_alloc(pd->pool, GFP_KERNEL, &addr);
+	if (desc) {
+		memset(desc, 0, sizeof(struct pch_dma_desc));
+		INIT_LIST_HEAD(&desc->tx_list);
+		dma_async_tx_descriptor_init(&desc->txd, chan);
+		desc->txd.tx_submit = pd_tx_submit;
+		desc->txd.flags = DMA_CTRL_ACK;
+		desc->txd.phys = addr;
+	}
+
+	return desc;
+}
+
+static struct pch_dma_desc *pdc_desc_get(struct pch_dma_chan *pd_chan)
+{
+	struct pch_dma_desc *desc, *_d;
+	struct pch_dma_desc *ret = NULL;
+	int i;
+
+	spin_lock_bh(&pd_chan->lock);
+	list_for_each_entry_safe(desc, _d, &pd_chan->free_list, desc_node) {
+		i++;
+		if (async_tx_test_ack(&desc->txd)) {
+			list_del(&desc->desc_node);
+			ret = desc;
+			break;
+		}
+		dev_dbg(chan2dev(&pd_chan->chan), "desc %p not ACKed\n", desc);
+	}
+	spin_unlock_bh(&pd_chan->lock);
+	dev_dbg(chan2dev(&pd_chan->chan), "scanned %d descriptors\n", i);
+
+	if (!ret) {
+		ret = pdc_alloc_desc(&pd_chan->chan, GFP_NOIO);
+		if (ret) {
+			spin_lock_bh(&pd_chan->lock);
+			pd_chan->descs_allocated++;
+			spin_unlock_bh(&pd_chan->lock);
+		} else {
+			dev_err(chan2dev(&pd_chan->chan),
+				"failed to alloc desc\n");
+		}
+	}
+
+	return ret;
+}
+
+static void pdc_desc_put(struct pch_dma_chan *pd_chan,
+			 struct pch_dma_desc *desc)
+{
+	if (desc) {
+		spin_lock_bh(&pd_chan->lock);
+		list_splice_init(&desc->tx_list, &pd_chan->free_list);
+		list_add(&desc->desc_node, &pd_chan->free_list);
+		spin_unlock_bh(&pd_chan->lock);
+	}
+}
+
+static int pd_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
+	struct pch_dma_desc *desc;
+	LIST_HEAD(tmp_list);
+	int i;
+
+	if (!pdc_is_idle(pd_chan)) {
+		dev_dbg(chan2dev(chan), "DMA channel not idle ?\n");
+		return -EIO;
+	}
+
+	if (!list_empty(&pd_chan->free_list))
+		return pd_chan->descs_allocated;
+
+	for (i = 0; i < init_nr_desc_per_channel; i++) {
+		desc = pdc_alloc_desc(chan, GFP_KERNEL);
+
+		if (!desc) {
+			dev_warn(chan2dev(chan),
+				"Only allocated %d initial descriptors\n", i);
+			break;
+		}
+
+		list_add_tail(&desc->desc_node, &tmp_list);
+	}
+
+	spin_lock_bh(&pd_chan->lock);
+	list_splice(&tmp_list, &pd_chan->free_list);
+	pd_chan->descs_allocated = i;
+	pd_chan->completed_cookie = chan->cookie = 1;
+	spin_unlock_bh(&pd_chan->lock);
+
+	pdc_enable_irq(chan, 1);
+	pdc_set_dir(chan);
+
+	return pd_chan->descs_allocated;
+}
+
+static void pd_free_chan_resources(struct dma_chan *chan)
+{
+	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
+	struct pch_dma *pd = to_pd(chan->device);
+	struct pch_dma_desc *desc, *_d;
+	LIST_HEAD(tmp_list);
+
+	BUG_ON(!pdc_is_idle(pd_chan));
+	BUG_ON(!list_empty(&pd_chan->active_list));
+	BUG_ON(!list_empty(&pd_chan->queue));
+
+	spin_lock_bh(&pd_chan->lock);
+	list_splice_init(&pd_chan->free_list, &tmp_list);
+	pd_chan->descs_allocated = 0;
+	spin_unlock_bh(&pd_chan->lock);
+
+	list_for_each_entry_safe(desc, _d, &tmp_list, desc_node)
+		pci_pool_free(pd->pool, desc, desc->txd.phys);
+
+	pdc_enable_irq(chan, 0);
+}
+
+static enum dma_status pd_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
+				    struct dma_tx_state *txstate)
+{
+	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
+	dma_cookie_t last_used;
+	dma_cookie_t last_completed;
+	int ret;
+
+	spin_lock_bh(&pd_chan->lock);
+	last_completed = pd_chan->completed_cookie;
+	last_used = chan->cookie;
+	spin_unlock_bh(&pd_chan->lock);
+
+	ret = dma_async_is_complete(cookie, last_completed, last_used);
+
+	dma_set_tx_state(txstate, last_completed, last_used, 0);
+
+	return ret;
+}
+
+static void pd_issue_pending(struct dma_chan *chan)
+{
+	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
+
+	if (pdc_is_idle(pd_chan)) {
+		spin_lock_bh(&pd_chan->lock);
+		pdc_advance_work(pd_chan);
+		spin_unlock_bh(&pd_chan->lock);
+	}
+}
+
+static struct dma_async_tx_descriptor *pd_prep_slave_sg(struct dma_chan *chan,
+			struct scatterlist *sgl, unsigned int sg_len,
+			enum dma_data_direction direction, unsigned long flags)
+{
+	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
+	struct pch_dma_slave *pd_slave = chan->private;
+	struct pch_dma_desc *first = NULL;
+	struct pch_dma_desc *prev = NULL;
+	struct pch_dma_desc *desc = NULL;
+	struct scatterlist *sg;
+	dma_addr_t reg;
+	int i;
+
+	if (unlikely(!sg_len)) {
+		dev_info(chan2dev(chan), "prep_slave_sg: length is zero!\n");
+		return NULL;
+	}
+
+	if (direction == DMA_FROM_DEVICE)
+		reg = pd_slave->rx_reg;
+	else if (direction == DMA_TO_DEVICE)
+		reg = pd_slave->tx_reg;
+	else
+		return NULL;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		desc = pdc_desc_get(pd_chan);
+
+		if (!desc)
+			goto err_desc_get;
+
+		desc->regs.dev_addr = reg;
+		desc->regs.mem_addr = sg_phys(sg);
+		desc->regs.size = sg_dma_len(sg);
+		desc->regs.next = DMA_DESC_FOLLOW_WITHOUT_IRQ;
+
+		switch (pd_slave->width) {
+		case PCH_DMA_WIDTH_1_BYTE:
+			if (desc->regs.size > DMA_DESC_MAX_COUNT_1_BYTE)
+				goto err_desc_get;
+			desc->regs.size |= DMA_DESC_WIDTH_1_BYTE;
+			break;
+		case PCH_DMA_WIDTH_2_BYTES:
+			if (desc->regs.size > DMA_DESC_MAX_COUNT_2_BYTES)
+				goto err_desc_get;
+			desc->regs.size |= DMA_DESC_WIDTH_2_BYTES;
+			break;
+		case PCH_DMA_WIDTH_4_BYTES:
+			if (desc->regs.size > DMA_DESC_MAX_COUNT_4_BYTES)
+				goto err_desc_get;
+			desc->regs.size |= DMA_DESC_WIDTH_4_BYTES;
+			break;
+		default:
+			goto err_desc_get;
+		}
+
+
+		if (!first) {
+			first = desc;
+		} else {
+			prev->regs.next |= desc->txd.phys;
+			list_add_tail(&desc->desc_node, &first->tx_list);
+		}
+
+		prev = desc;
+	}
+
+	if (flags & DMA_PREP_INTERRUPT)
+		desc->regs.next = DMA_DESC_END_WITH_IRQ;
+	else
+		desc->regs.next = DMA_DESC_END_WITHOUT_IRQ;
+
+	first->txd.cookie = -EBUSY;
+	desc->txd.flags = flags;
+
+	return &first->txd;
+
+err_desc_get:
+	dev_err(chan2dev(chan), "failed to get desc or wrong parameters\n");
+	pdc_desc_put(pd_chan, first);
+	return NULL;
+}
+
+static int pd_device_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+			     unsigned long arg)
+{
+	struct pch_dma_chan *pd_chan = to_pd_chan(chan);
+	struct pch_dma_desc *desc, *_d;
+	LIST_HEAD(list);
+
+	if (cmd != DMA_TERMINATE_ALL)
+		return -ENXIO;
+
+	spin_lock_bh(&pd_chan->lock);
+
+	pdc_set_mode(&pd_chan->chan, DMA_CTL0_DISABLE);
+
+	list_splice_init(&pd_chan->active_list, &list);
+	list_splice_init(&pd_chan->queue, &list);
+
+	list_for_each_entry_safe(desc, _d, &list, desc_node)
+		pdc_chain_complete(pd_chan, desc);
+
+	spin_unlock_bh(&pd_chan->lock);
+
+
+	return 0;
+}
+
+static void pdc_tasklet(unsigned long data)
+{
+	struct pch_dma_chan *pd_chan = (struct pch_dma_chan *)data;
+
+	if (!pdc_is_idle(pd_chan)) {
+		dev_err(chan2dev(&pd_chan->chan),
+			"BUG: handle non-idle channel in tasklet\n");
+		return;
+	}
+
+	spin_lock_bh(&pd_chan->lock);
+	if (test_and_clear_bit(0, &pd_chan->err_status))
+		pdc_handle_error(pd_chan);
+	else
+		pdc_advance_work(pd_chan);
+	spin_unlock_bh(&pd_chan->lock);
+}
+
+static irqreturn_t pd_irq(int irq, void *devid)
+{
+	struct pch_dma *pd = (struct pch_dma *)devid;
+	struct pch_dma_chan *pd_chan;
+	u32 sts0;
+	int i;
+	int ret = IRQ_NONE;
+
+	sts0 = dma_readl(pd, STS0);
+
+	dev_dbg(pd->dma.dev, "pd_irq sts0: %x\n", sts0);
+
+	for (i = 0; i < pd->dma.chancnt; i++) {
+		pd_chan = &pd->channels[i];
+
+		if (sts0 & DMA_STATUS_IRQ(i)) {
+			if (sts0 & DMA_STATUS_ERR(i))
+				set_bit(0, &pd_chan->err_status);
+
+			tasklet_schedule(&pd_chan->tasklet);
+			ret = IRQ_HANDLED;
+		}
+
+	}
+
+	/* clear interrupt bits in status register */
+	dma_writel(pd, STS0, sts0);
+
+	return ret;
+}
+
+static void pch_dma_save_regs(struct pch_dma *pd)
+{
+	struct pch_dma_chan *pd_chan;
+	struct dma_chan *chan, *_c;
+	int i = 0;
+
+	pd->regs.dma_ctl0 = dma_readl(pd, CTL0);
+	pd->regs.dma_ctl1 = dma_readl(pd, CTL1);
+	pd->regs.dma_ctl2 = dma_readl(pd, CTL2);
+
+	list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
+		pd_chan = to_pd_chan(chan);
+
+		pd->ch_regs[i].dev_addr = channel_readl(pd_chan, DEV_ADDR);
+		pd->ch_regs[i].mem_addr = channel_readl(pd_chan, MEM_ADDR);
+		pd->ch_regs[i].size = channel_readl(pd_chan, SIZE);
+		pd->ch_regs[i].next = channel_readl(pd_chan, NEXT);
+
+		i++;
+	}
+}
+
+static void pch_dma_restore_regs(struct pch_dma *pd)
+{
+	struct pch_dma_chan *pd_chan;
+	struct dma_chan *chan, *_c;
+	int i = 0;
+
+	dma_writel(pd, CTL0, pd->regs.dma_ctl0);
+	dma_writel(pd, CTL1, pd->regs.dma_ctl1);
+	dma_writel(pd, CTL2, pd->regs.dma_ctl2);
+
+	list_for_each_entry_safe(chan, _c, &pd->dma.channels, device_node) {
+		pd_chan = to_pd_chan(chan);
+
+		channel_writel(pd_chan, DEV_ADDR, pd->ch_regs[i].dev_addr);
+		channel_writel(pd_chan, MEM_ADDR, pd->ch_regs[i].mem_addr);
+		channel_writel(pd_chan, SIZE, pd->ch_regs[i].size);
+		channel_writel(pd_chan, NEXT, pd->ch_regs[i].next);
+
+		i++;
+	}
+}
+
+static int pch_dma_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+	struct pch_dma *pd = pci_get_drvdata(pdev);
+
+	if (pd)
+		pch_dma_save_regs(pd);
+
+	pci_save_state(pdev);
+	pci_disable_device(pdev);
+	pci_set_power_state(pdev, pci_choose_state(pdev, state));
+
+	return 0;
+}
+
+static int pch_dma_resume(struct pci_dev *pdev)
+{
+	struct pch_dma *pd = pci_get_drvdata(pdev);
+	int err;
+
+	pci_set_power_state(pdev, PCI_D0);
+	pci_restore_state(pdev);
+
+	err = pci_enable_device(pdev);
+	if (err) {
+		dev_dbg(&pdev->dev, "failed to enable device\n");
+		return err;
+	}
+
+	if (pd)
+		pch_dma_restore_regs(pd);
+
+	return 0;
+}
+
+static int __devinit pch_dma_probe(struct pci_dev *pdev,
+				   const struct pci_device_id *id)
+{
+	struct pch_dma *pd;
+	struct pch_dma_regs *regs;
+	unsigned int nr_channels;
+	int err;
+	int i;
+
+	nr_channels = id->driver_data;
+	pd = kzalloc(sizeof(struct pch_dma)+
+		sizeof(struct pch_dma_chan) * nr_channels, GFP_KERNEL);
+	if (!pd)
+		return -ENOMEM;
+
+	pci_set_drvdata(pdev, pd);
+
+	err = pci_enable_device(pdev);
+	if (err) {
+		dev_err(&pdev->dev, "Cannot enable PCI device\n");
+		goto err_free_mem;
+	}
+
+	if (!(pci_resource_flags(pdev, 1) & IORESOURCE_MEM)) {
+		dev_err(&pdev->dev, "Cannot find proper base address\n");
+		goto err_disable_pdev;
+	}
+
+	err = pci_request_regions(pdev, DRV_NAME);
+	if (err) {
+		dev_err(&pdev->dev, "Cannot obtain PCI resources\n");
+		goto err_disable_pdev;
+	}
+
+	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+	if (err) {
+		dev_err(&pdev->dev, "Cannot set proper DMA config\n");
+		goto err_free_res;
+	}
+
+	regs = pd->membase = pci_iomap(pdev, 1, 0);
+	if (!pd->membase) {
+		dev_err(&pdev->dev, "Cannot map MMIO registers\n");
+		err = -ENOMEM;
+		goto err_free_res;
+	}
+
+	pci_set_master(pdev);
+
+	err = request_irq(pdev->irq, pd_irq, IRQF_SHARED, DRV_NAME, pd);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to request IRQ\n");
+		goto err_iounmap;
+	}
+
+	pd->pool = pci_pool_create("pch_dma_desc_pool", pdev,
+				   sizeof(struct pch_dma_desc), 4, 0);
+	if (!pd->pool) {
+		dev_err(&pdev->dev, "Failed to alloc DMA descriptors\n");
+		err = -ENOMEM;
+		goto err_free_irq;
+	}
+
+	pd->dma.dev = &pdev->dev;
+	pd->dma.chancnt = nr_channels;
+
+	INIT_LIST_HEAD(&pd->dma.channels);
+
+	for (i = 0; i < nr_channels; i++) {
+		struct pch_dma_chan *pd_chan = &pd->channels[i];
+
+		pd_chan->chan.device = &pd->dma;
+		pd_chan->chan.cookie = 1;
+		pd_chan->chan.chan_id = i;
+
+		pd_chan->membase = &regs->desc[i];
+
+		pd_chan->dir = (i % 2) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+
+		spin_lock_init(&pd_chan->lock);
+
+		INIT_LIST_HEAD(&pd_chan->active_list);
+		INIT_LIST_HEAD(&pd_chan->queue);
+		INIT_LIST_HEAD(&pd_chan->free_list);
+
+		tasklet_init(&pd_chan->tasklet, pdc_tasklet,
+			     (unsigned long)pd_chan);
+		list_add_tail(&pd_chan->chan.device_node, &pd->dma.channels);
+	}
+
+	dma_cap_zero(pd->dma.cap_mask);
+	dma_cap_set(DMA_PRIVATE, pd->dma.cap_mask);
+	dma_cap_set(DMA_SLAVE, pd->dma.cap_mask);
+
+	pd->dma.device_alloc_chan_resources = pd_alloc_chan_resources;
+	pd->dma.device_free_chan_resources = pd_free_chan_resources;
+	pd->dma.device_tx_status = pd_tx_status;
+	pd->dma.device_issue_pending = pd_issue_pending;
+	pd->dma.device_prep_slave_sg = pd_prep_slave_sg;
+	pd->dma.device_control = pd_device_control;
+
+	err = dma_async_device_register(&pd->dma);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to register DMA device\n");
+		goto err_free_pool;
+	}
+
+	return 0;
+
+err_free_pool:
+	pci_pool_destroy(pd->pool);
+err_free_irq:
+	free_irq(pdev->irq, pd);
+err_iounmap:
+	pci_iounmap(pdev, pd->membase);
+err_free_res:
+	pci_release_regions(pdev);
+err_disable_pdev:
+	pci_disable_device(pdev);
+err_free_mem:
+	return err;
+}
+
+static void __devexit pch_dma_remove(struct pci_dev *pdev)
+{
+	struct pch_dma *pd = pci_get_drvdata(pdev);
+	struct pch_dma_chan *pd_chan;
+	struct dma_chan *chan, *_c;
+
+	if (pd) {
+		dma_async_device_unregister(&pd->dma);
+
+		list_for_each_entry_safe(chan, _c, &pd->dma.channels,
+					 device_node) {
+			pd_chan = to_pd_chan(chan);
+
+			tasklet_disable(&pd_chan->tasklet);
+			tasklet_kill(&pd_chan->tasklet);
+		}
+
+		pci_pool_destroy(pd->pool);
+		free_irq(pdev->irq, pd);
+		pci_iounmap(pdev, pd->membase);
+		pci_release_regions(pdev);
+		pci_disable_device(pdev);
+		kfree(pd);
+	}
+}
+
+/* PCI Device ID of DMA device */
+#define PCI_DEVICE_ID_PCH_DMA_8CH        0x8810
+#define PCI_DEVICE_ID_PCH_DMA_4CH        0x8815
+
+static const struct pci_device_id pch_dma_id_table[] = {
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PCH_DMA_8CH), 8 },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_PCH_DMA_4CH), 4 },
+};
+
+static struct pci_driver pch_dma_driver = {
+	.name		= DRV_NAME,
+	.id_table	= pch_dma_id_table,
+	.probe		= pch_dma_probe,
+	.remove		= __devexit_p(pch_dma_remove),
+#ifdef CONFIG_PM
+	.suspend	= pch_dma_suspend,
+	.resume		= pch_dma_resume,
+#endif
+};
+
+static int __init pch_dma_init(void)
+{
+	return pci_register_driver(&pch_dma_driver);
+}
+
+static void __exit pch_dma_exit(void)
+{
+	pci_unregister_driver(&pch_dma_driver);
+}
+
+module_init(pch_dma_init);
+module_exit(pch_dma_exit);
+
+MODULE_DESCRIPTION("Topcliff PCH DMA controller driver");
+MODULE_AUTHOR("Yong Wang <yong.y.wang@intel.com>");
+MODULE_LICENSE("GPL v2");