/*
   * DMA controller driver for CSR SiRFprimaII
   *
   * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
   *
   * Licensed under GPLv2 or later.
   */
  
  #include <linux/module.h>
  #include <linux/dmaengine.h>
  #include <linux/dma-mapping.h>
  #include <linux/pm_runtime.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  #include <linux/of_irq.h>
  #include <linux/of_address.h>
  #include <linux/of_device.h>
  #include <linux/of_platform.h>
  #include <linux/clk.h>
  #include <linux/sirfsoc_dma.h>
  
  #include "dmaengine.h"
  
  #define SIRFSOC_DMA_DESCRIPTORS                 16
  #define SIRFSOC_DMA_CHANNELS                    16
  
  #define SIRFSOC_DMA_CH_ADDR                     0x00
  #define SIRFSOC_DMA_CH_XLEN                     0x04
  #define SIRFSOC_DMA_CH_YLEN                     0x08
  #define SIRFSOC_DMA_CH_CTRL                     0x0C
  
  #define SIRFSOC_DMA_WIDTH_0                     0x100
  #define SIRFSOC_DMA_CH_VALID                    0x140
  #define SIRFSOC_DMA_CH_INT                      0x144
  #define SIRFSOC_DMA_INT_EN                      0x148
  #define SIRFSOC_DMA_INT_EN_CLR			0x14C
  #define SIRFSOC_DMA_CH_LOOP_CTRL                0x150
  #define SIRFSOC_DMA_CH_LOOP_CTRL_CLR            0x15C
  
  #define SIRFSOC_DMA_MODE_CTRL_BIT               4
  #define SIRFSOC_DMA_DIR_CTRL_BIT                5
  
  /* xlen and dma_width register is in 4 bytes boundary */
  #define SIRFSOC_DMA_WORD_LEN			4
  
  struct sirfsoc_dma_desc {
  	struct dma_async_tx_descriptor	desc;
  	struct list_head		node;
  
  	/* SiRFprimaII 2D-DMA parameters */
  
  	int             xlen;           /* DMA xlen */
  	int             ylen;           /* DMA ylen */
  	int             width;          /* DMA width */
  	int             dir;
  	bool            cyclic;         /* is loop DMA? */
  	u32             addr;		/* DMA buffer address */
  };
  
  struct sirfsoc_dma_chan {
  	struct dma_chan			chan;
  	struct list_head		free;
  	struct list_head		prepared;
  	struct list_head		queued;
  	struct list_head		active;
  	struct list_head		completed;
  	unsigned long			happened_cyclic;
  	unsigned long			completed_cyclic;
  
  	/* Lock for this structure */
  	spinlock_t			lock;
  
  	int				mode;
  };
  
  struct sirfsoc_dma_regs {
  	u32				ctrl[SIRFSOC_DMA_CHANNELS];
  	u32				interrupt_en;
  };
  
  struct sirfsoc_dma {
  	struct dma_device		dma;
  	struct tasklet_struct		tasklet;
  	struct sirfsoc_dma_chan		channels[SIRFSOC_DMA_CHANNELS];
  	void __iomem			*base;
  	int				irq;
  	struct clk			*clk;
  	bool				is_marco;
  	struct sirfsoc_dma_regs		regs_save;
  };
  
  #define DRV_NAME	"sirfsoc_dma"
  
  static int sirfsoc_dma_runtime_suspend(struct device *dev);
  
  /* Convert struct dma_chan to struct sirfsoc_dma_chan */
  static inline
  struct sirfsoc_dma_chan *dma_chan_to_sirfsoc_dma_chan(struct dma_chan *c)
  {
  	return container_of(c, struct sirfsoc_dma_chan, chan);
  }
  
  /* Convert struct dma_chan to struct sirfsoc_dma */
  static inline struct sirfsoc_dma *dma_chan_to_sirfsoc_dma(struct dma_chan *c)
  {
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(c);
  	return container_of(schan, struct sirfsoc_dma, channels[c->chan_id]);
  }
  
  /* Execute all queued DMA descriptors */
  static void sirfsoc_dma_execute(struct sirfsoc_dma_chan *schan)
  {
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
  	int cid = schan->chan.chan_id;
  	struct sirfsoc_dma_desc *sdesc = NULL;
  
  	/*
  	 * lock has been held by functions calling this, so we don't hold
  	 * lock again
  	 */
  
  	sdesc = list_first_entry(&schan->queued, struct sirfsoc_dma_desc,
  		node);
  	/* Move the first queued descriptor to active list */
  	list_move_tail(&sdesc->node, &schan->active);
  
  	/* Start the DMA transfer */
  	writel_relaxed(sdesc->width, sdma->base + SIRFSOC_DMA_WIDTH_0 +
  		cid * 4);
  	writel_relaxed(cid | (schan->mode << SIRFSOC_DMA_MODE_CTRL_BIT) |
  		(sdesc->dir << SIRFSOC_DMA_DIR_CTRL_BIT),
  		sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_CTRL);
  	writel_relaxed(sdesc->xlen, sdma->base + cid * 0x10 +
  		SIRFSOC_DMA_CH_XLEN);
  	writel_relaxed(sdesc->ylen, sdma->base + cid * 0x10 +
  		SIRFSOC_DMA_CH_YLEN);
  	writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN) |
  		(1 << cid), sdma->base + SIRFSOC_DMA_INT_EN);
  
  	/*
  	 * writel has an implict memory write barrier to make sure data is
  	 * flushed into memory before starting DMA
  	 */
  	writel(sdesc->addr >> 2, sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_ADDR);
  
  	if (sdesc->cyclic) {
  		writel((1 << cid) | 1 << (cid + 16) |
  			readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL),
  			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
  		schan->happened_cyclic = schan->completed_cyclic = 0;
  	}
  }
  
  /* Interrupt handler */
  static irqreturn_t sirfsoc_dma_irq(int irq, void *data)
  {
  	struct sirfsoc_dma *sdma = data;
  	struct sirfsoc_dma_chan *schan;
  	struct sirfsoc_dma_desc *sdesc = NULL;
  	u32 is;
  	int ch;
  
  	is = readl(sdma->base + SIRFSOC_DMA_CH_INT);
  	while ((ch = fls(is) - 1) >= 0) {
  		is &= ~(1 << ch);
  		writel_relaxed(1 << ch, sdma->base + SIRFSOC_DMA_CH_INT);
  		schan = &sdma->channels[ch];
  
  		spin_lock(&schan->lock);
  
  		sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
  			node);
  		if (!sdesc->cyclic) {
  			/* Execute queued descriptors */
  			list_splice_tail_init(&schan->active, &schan->completed);
  			if (!list_empty(&schan->queued))
  				sirfsoc_dma_execute(schan);
  		} else
  			schan->happened_cyclic++;
  
  		spin_unlock(&schan->lock);
  	}
  
  	/* Schedule tasklet */
  	tasklet_schedule(&sdma->tasklet);
  
  	return IRQ_HANDLED;
  }
  
  /* process completed descriptors */
  static void sirfsoc_dma_process_completed(struct sirfsoc_dma *sdma)
  {
  	dma_cookie_t last_cookie = 0;
  	struct sirfsoc_dma_chan *schan;
  	struct sirfsoc_dma_desc *sdesc;
  	struct dma_async_tx_descriptor *desc;
  	unsigned long flags;
  	unsigned long happened_cyclic;
  	LIST_HEAD(list);
  	int i;
  
  	for (i = 0; i < sdma->dma.chancnt; i++) {
  		schan = &sdma->channels[i];
  
  		/* Get all completed descriptors */
  		spin_lock_irqsave(&schan->lock, flags);
  		if (!list_empty(&schan->completed)) {
  			list_splice_tail_init(&schan->completed, &list);
  			spin_unlock_irqrestore(&schan->lock, flags);
  
  			/* Execute callbacks and run dependencies */
  			list_for_each_entry(sdesc, &list, node) {
  				desc = &sdesc->desc;
  
  				if (desc->callback)
  					desc->callback(desc->callback_param);
  
  				last_cookie = desc->cookie;
  				dma_run_dependencies(desc);
  			}
  
  			/* Free descriptors */
  			spin_lock_irqsave(&schan->lock, flags);
  			list_splice_tail_init(&list, &schan->free);
  			schan->chan.completed_cookie = last_cookie;
  			spin_unlock_irqrestore(&schan->lock, flags);
  		} else {
  			/* for cyclic channel, desc is always in active list */
  			sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
  				node);
  
  			if (!sdesc || (sdesc && !sdesc->cyclic)) {
  				/* without active cyclic DMA */
  				spin_unlock_irqrestore(&schan->lock, flags);
  				continue;
  			}
  
  			/* cyclic DMA */
  			happened_cyclic = schan->happened_cyclic;
  			spin_unlock_irqrestore(&schan->lock, flags);
  
  			desc = &sdesc->desc;
  			while (happened_cyclic != schan->completed_cyclic) {
  				if (desc->callback)
  					desc->callback(desc->callback_param);
  				schan->completed_cyclic++;
  			}
  		}
  	}
  }
  
  /* DMA Tasklet */
  static void sirfsoc_dma_tasklet(unsigned long data)
  {
  	struct sirfsoc_dma *sdma = (void *)data;
  
  	sirfsoc_dma_process_completed(sdma);
  }
  
  /* Submit descriptor to hardware */
  static dma_cookie_t sirfsoc_dma_tx_submit(struct dma_async_tx_descriptor *txd)
  {
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(txd->chan);
  	struct sirfsoc_dma_desc *sdesc;
  	unsigned long flags;
  	dma_cookie_t cookie;
  
  	sdesc = container_of(txd, struct sirfsoc_dma_desc, desc);
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	/* Move descriptor to queue */
  	list_move_tail(&sdesc->node, &schan->queued);
  
  	cookie = dma_cookie_assign(txd);
  
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	return cookie;
  }
  
  static int sirfsoc_dma_slave_config(struct sirfsoc_dma_chan *schan,
  	struct dma_slave_config *config)
  {
  	unsigned long flags;
  
  	if ((config->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) ||
  		(config->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES))
  		return -EINVAL;
  
  	spin_lock_irqsave(&schan->lock, flags);
  	schan->mode = (config->src_maxburst == 4 ? 1 : 0);
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	return 0;
  }
  
  static int sirfsoc_dma_terminate_all(struct sirfsoc_dma_chan *schan)
  {
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
  	int cid = schan->chan.chan_id;
  	unsigned long flags;
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	if (!sdma->is_marco) {
  		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN) &
  			~(1 << cid), sdma->base + SIRFSOC_DMA_INT_EN);
  		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL)
  			& ~((1 << cid) | 1 << (cid + 16)),
  			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
  	} else {
  		writel_relaxed(1 << cid, sdma->base + SIRFSOC_DMA_INT_EN_CLR);
  		writel_relaxed((1 << cid) | 1 << (cid + 16),
  			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL_CLR);
  	}
  
  	writel_relaxed(1 << cid, sdma->base + SIRFSOC_DMA_CH_VALID);
  
  	list_splice_tail_init(&schan->active, &schan->free);
  	list_splice_tail_init(&schan->queued, &schan->free);
  
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	return 0;
  }
  
  static int sirfsoc_dma_pause_chan(struct sirfsoc_dma_chan *schan)
  {
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
  	int cid = schan->chan.chan_id;
  	unsigned long flags;
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	if (!sdma->is_marco)
  		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL)
  			& ~((1 << cid) | 1 << (cid + 16)),
  			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
  	else
  		writel_relaxed((1 << cid) | 1 << (cid + 16),
  			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL_CLR);
  
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	return 0;
  }
  
  static int sirfsoc_dma_resume_chan(struct sirfsoc_dma_chan *schan)
  {
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
  	int cid = schan->chan.chan_id;
  	unsigned long flags;
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	if (!sdma->is_marco)
  		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL)
  			| ((1 << cid) | 1 << (cid + 16)),
  			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
  	else
  		writel_relaxed((1 << cid) | 1 << (cid + 16),
  			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
  
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	return 0;
  }
  
  static int sirfsoc_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
  	unsigned long arg)
  {
  	struct dma_slave_config *config;
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
  
  	switch (cmd) {
  	case DMA_PAUSE:
  		return sirfsoc_dma_pause_chan(schan);
  	case DMA_RESUME:
  		return sirfsoc_dma_resume_chan(schan);
  	case DMA_TERMINATE_ALL:
  		return sirfsoc_dma_terminate_all(schan);
  	case DMA_SLAVE_CONFIG:
  		config = (struct dma_slave_config *)arg;
  		return sirfsoc_dma_slave_config(schan, config);
  
  	default:
  		break;
  	}
  
  	return -ENOSYS;
  }
  
  /* Alloc channel resources */
  static int sirfsoc_dma_alloc_chan_resources(struct dma_chan *chan)
  {
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
  	struct sirfsoc_dma_desc *sdesc;
  	unsigned long flags;
  	LIST_HEAD(descs);
  	int i;
  
  	pm_runtime_get_sync(sdma->dma.dev);
  
  	/* Alloc descriptors for this channel */
  	for (i = 0; i < SIRFSOC_DMA_DESCRIPTORS; i++) {
  		sdesc = kzalloc(sizeof(*sdesc), GFP_KERNEL);
  		if (!sdesc) {
  			dev_notice(sdma->dma.dev, "Memory allocation error. "
  				"Allocated only %u descriptors
  ", i);
  			break;
  		}
  
  		dma_async_tx_descriptor_init(&sdesc->desc, chan);
  		sdesc->desc.flags = DMA_CTRL_ACK;
  		sdesc->desc.tx_submit = sirfsoc_dma_tx_submit;
  
  		list_add_tail(&sdesc->node, &descs);
  	}
  
  	/* Return error only if no descriptors were allocated */
  	if (i == 0)
  		return -ENOMEM;
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	list_splice_tail_init(&descs, &schan->free);
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	return i;
  }
  
  /* Free channel resources */
  static void sirfsoc_dma_free_chan_resources(struct dma_chan *chan)
  {
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
  	struct sirfsoc_dma_desc *sdesc, *tmp;
  	unsigned long flags;
  	LIST_HEAD(descs);
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	/* Channel must be idle */
  	BUG_ON(!list_empty(&schan->prepared));
  	BUG_ON(!list_empty(&schan->queued));
  	BUG_ON(!list_empty(&schan->active));
  	BUG_ON(!list_empty(&schan->completed));
  
  	/* Move data */
  	list_splice_tail_init(&schan->free, &descs);
  
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	/* Free descriptors */
  	list_for_each_entry_safe(sdesc, tmp, &descs, node)
  		kfree(sdesc);
  
  	pm_runtime_put(sdma->dma.dev);
  }
  
  /* Send pending descriptor to hardware */
  static void sirfsoc_dma_issue_pending(struct dma_chan *chan)
  {
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
  	unsigned long flags;
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	if (list_empty(&schan->active) && !list_empty(&schan->queued))
  		sirfsoc_dma_execute(schan);
  
  	spin_unlock_irqrestore(&schan->lock, flags);
  }
  
  /* Check request completion status */
  static enum dma_status
  sirfsoc_dma_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
  	struct dma_tx_state *txstate)
  {
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
  	unsigned long flags;
  	enum dma_status ret;
  	struct sirfsoc_dma_desc *sdesc;
  	int cid = schan->chan.chan_id;
  	unsigned long dma_pos;
  	unsigned long dma_request_bytes;
  	unsigned long residue;
  
  	spin_lock_irqsave(&schan->lock, flags);
  
  	sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
  			node);
  	dma_request_bytes = (sdesc->xlen + 1) * (sdesc->ylen + 1) *
  		(sdesc->width * SIRFSOC_DMA_WORD_LEN);
  
  	ret = dma_cookie_status(chan, cookie, txstate);
  	dma_pos = readl_relaxed(sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_ADDR)
  		<< 2;
  	residue = dma_request_bytes - (dma_pos - sdesc->addr);
  	dma_set_residue(txstate, residue);
  
  	spin_unlock_irqrestore(&schan->lock, flags);
  
  	return ret;
  }
  
  static struct dma_async_tx_descriptor *sirfsoc_dma_prep_interleaved(
  	struct dma_chan *chan, struct dma_interleaved_template *xt,
  	unsigned long flags)
  {
  	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
  	struct sirfsoc_dma_desc *sdesc = NULL;
  	unsigned long iflags;
  	int ret;
  
  	if ((xt->dir != DMA_MEM_TO_DEV) && (xt->dir != DMA_DEV_TO_MEM)) {
  		ret = -EINVAL;
  		goto err_dir;
  	}
  
  	/* Get free descriptor */
  	spin_lock_irqsave(&schan->lock, iflags);
  	if (!list_empty(&schan->free)) {
  		sdesc = list_first_entry(&schan->free, struct sirfsoc_dma_desc,
  			node);
  		list_del(&sdesc->node);
  	}
  	spin_unlock_irqrestore(&schan->lock, iflags);
  
  	if (!sdesc) {
  		/* try to free completed descriptors */
  		sirfsoc_dma_process_completed(sdma);
  		ret = 0;
  		goto no_desc;
  	}
  
  	/* Place descriptor in prepared list */
  	spin_lock_irqsave(&schan->lock, iflags);
  
  	/*
  	 * Number of chunks in a frame can only be 1 for prima2
  	 * and ylen (number of frame - 1) must be at least 0
  	 */
  	if ((xt->frame_size == 1) && (xt->numf > 0)) {
  		sdesc->cyclic = 0;
  		sdesc->xlen = xt->sgl[0].size / SIRFSOC_DMA_WORD_LEN;
  		sdesc->width = (xt->sgl[0].size + xt->sgl[0].icg) /
  				SIRFSOC_DMA_WORD_LEN;
  		sdesc->ylen = xt->numf - 1;
  		if (xt->dir == DMA_MEM_TO_DEV) {
  			sdesc->addr = xt->src_start;
  			sdesc->dir = 1;
  		} else {
  			sdesc->addr = xt->dst_start;
  			sdesc->dir = 0;
  		}
  
  		list_add_tail(&sdesc->node, &schan->prepared);
  	} else {
  		pr_err("sirfsoc DMA Invalid xfer
  ");
  		ret = -EINVAL;
  		goto err_xfer;
  	}
  	spin_unlock_irqrestore(&schan->lock, iflags);
  
  	return &sdesc->desc;
  err_xfer:
  	spin_unlock_irqrestore(&schan->lock, iflags);
  no_desc:
  err_dir:
  	return ERR_PTR(ret);
  }
  
  static struct dma_async_tx_descriptor *
  sirfsoc_dma_prep_cyclic(struct dma_chan *chan, dma_addr_t addr,
  	size_t buf_len, size_t period_len,
  	enum dma_transfer_direction direction, unsigned long flags, void *context)
  {
  	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
  	struct sirfsoc_dma_desc *sdesc = NULL;
  	unsigned long iflags;
  
  	/*
  	 * we only support cycle transfer with 2 period
  	 * If the X-length is set to 0, it would be the loop mode.
  	 * The DMA address keeps increasing until reaching the end of a loop
  	 * area whose size is defined by (DMA_WIDTH x (Y_LENGTH + 1)). Then
  	 * the DMA address goes back to the beginning of this area.
  	 * In loop mode, the DMA data region is divided into two parts, BUFA
  	 * and BUFB. DMA controller generates interrupts twice in each loop:
  	 * when the DMA address reaches the end of BUFA or the end of the
  	 * BUFB
  	 */
  	if (buf_len !=  2 * period_len)
  		return ERR_PTR(-EINVAL);
  
  	/* Get free descriptor */
  	spin_lock_irqsave(&schan->lock, iflags);
  	if (!list_empty(&schan->free)) {
  		sdesc = list_first_entry(&schan->free, struct sirfsoc_dma_desc,
  			node);
  		list_del(&sdesc->node);
  	}
  	spin_unlock_irqrestore(&schan->lock, iflags);
  
  	if (!sdesc)
  		return NULL;
  
  	/* Place descriptor in prepared list */
  	spin_lock_irqsave(&schan->lock, iflags);
  	sdesc->addr = addr;
  	sdesc->cyclic = 1;
  	sdesc->xlen = 0;
  	sdesc->ylen = buf_len / SIRFSOC_DMA_WORD_LEN - 1;
  	sdesc->width = 1;
  	list_add_tail(&sdesc->node, &schan->prepared);
  	spin_unlock_irqrestore(&schan->lock, iflags);
  
  	return &sdesc->desc;
  }
  
  /*
   * The DMA controller consists of 16 independent DMA channels.
   * Each channel is allocated to a different function
   */
  bool sirfsoc_dma_filter_id(struct dma_chan *chan, void *chan_id)
  {
  	unsigned int ch_nr = (unsigned int) chan_id;
  
  	if (ch_nr == chan->chan_id +
  		chan->device->dev_id * SIRFSOC_DMA_CHANNELS)
  		return true;
  
  	return false;
  }
  EXPORT_SYMBOL(sirfsoc_dma_filter_id);
  
  #define SIRFSOC_DMA_BUSWIDTHS \
  	(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
  	BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
  	BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
  	BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \
  	BIT(DMA_SLAVE_BUSWIDTH_8_BYTES))
  
  static int sirfsoc_dma_device_slave_caps(struct dma_chan *dchan,
  	struct dma_slave_caps *caps)
  {
  	caps->src_addr_widths = SIRFSOC_DMA_BUSWIDTHS;
  	caps->dstn_addr_widths = SIRFSOC_DMA_BUSWIDTHS;
  	caps->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
  	caps->cmd_pause = true;
  	caps->cmd_terminate = true;
  
  	return 0;
  }
  
  static int sirfsoc_dma_probe(struct platform_device *op)
  {
  	struct device_node *dn = op->dev.of_node;
  	struct device *dev = &op->dev;
  	struct dma_device *dma;
  	struct sirfsoc_dma *sdma;
  	struct sirfsoc_dma_chan *schan;
  	struct resource res;
  	ulong regs_start, regs_size;
  	u32 id;
  	int ret, i;
  
  	sdma = devm_kzalloc(dev, sizeof(*sdma), GFP_KERNEL);
  	if (!sdma) {
  		dev_err(dev, "Memory exhausted!
  ");
  		return -ENOMEM;
  	}
  
  	if (of_device_is_compatible(dn, "sirf,marco-dmac"))
  		sdma->is_marco = true;
  
  	if (of_property_read_u32(dn, "cell-index", &id)) {
  		dev_err(dev, "Fail to get DMAC index
  ");
  		return -ENODEV;
  	}
  
  	sdma->irq = irq_of_parse_and_map(dn, 0);
  	if (sdma->irq == NO_IRQ) {
  		dev_err(dev, "Error mapping IRQ!
  ");
  		return -EINVAL;
  	}
  
  	sdma->clk = devm_clk_get(dev, NULL);
  	if (IS_ERR(sdma->clk)) {
  		dev_err(dev, "failed to get a clock.
  ");
  		return PTR_ERR(sdma->clk);
  	}
  
  	ret = of_address_to_resource(dn, 0, &res);
  	if (ret) {
  		dev_err(dev, "Error parsing memory region!
  ");
  		goto irq_dispose;
  	}
  
  	regs_start = res.start;
  	regs_size = resource_size(&res);
  
  	sdma->base = devm_ioremap(dev, regs_start, regs_size);
  	if (!sdma->base) {
  		dev_err(dev, "Error mapping memory region!
  ");
  		ret = -ENOMEM;
  		goto irq_dispose;
  	}
  
  	ret = request_irq(sdma->irq, &sirfsoc_dma_irq, 0, DRV_NAME, sdma);
  	if (ret) {
  		dev_err(dev, "Error requesting IRQ!
  ");
  		ret = -EINVAL;
  		goto irq_dispose;
  	}
  
  	dma = &sdma->dma;
  	dma->dev = dev;
  	dma->chancnt = SIRFSOC_DMA_CHANNELS;
  
  	dma->device_alloc_chan_resources = sirfsoc_dma_alloc_chan_resources;
  	dma->device_free_chan_resources = sirfsoc_dma_free_chan_resources;
  	dma->device_issue_pending = sirfsoc_dma_issue_pending;
  	dma->device_control = sirfsoc_dma_control;
  	dma->device_tx_status = sirfsoc_dma_tx_status;
  	dma->device_prep_interleaved_dma = sirfsoc_dma_prep_interleaved;
  	dma->device_prep_dma_cyclic = sirfsoc_dma_prep_cyclic;
  	dma->device_slave_caps = sirfsoc_dma_device_slave_caps;
  
  	INIT_LIST_HEAD(&dma->channels);
  	dma_cap_set(DMA_SLAVE, dma->cap_mask);
  	dma_cap_set(DMA_CYCLIC, dma->cap_mask);
  	dma_cap_set(DMA_INTERLEAVE, dma->cap_mask);
  	dma_cap_set(DMA_PRIVATE, dma->cap_mask);
  
  	for (i = 0; i < dma->chancnt; i++) {
  		schan = &sdma->channels[i];
  
  		schan->chan.device = dma;
  		dma_cookie_init(&schan->chan);
  
  		INIT_LIST_HEAD(&schan->free);
  		INIT_LIST_HEAD(&schan->prepared);
  		INIT_LIST_HEAD(&schan->queued);
  		INIT_LIST_HEAD(&schan->active);
  		INIT_LIST_HEAD(&schan->completed);
  
  		spin_lock_init(&schan->lock);
  		list_add_tail(&schan->chan.device_node, &dma->channels);
  	}
  
  	tasklet_init(&sdma->tasklet, sirfsoc_dma_tasklet, (unsigned long)sdma);
  
  	/* Register DMA engine */
  	dev_set_drvdata(dev, sdma);
  
  	ret = dma_async_device_register(dma);
  	if (ret)
  		goto free_irq;
  
  	pm_runtime_enable(&op->dev);
  	dev_info(dev, "initialized SIRFSOC DMAC driver
  ");
  
  	return 0;
  
  free_irq:
  	free_irq(sdma->irq, sdma);
  irq_dispose:
  	irq_dispose_mapping(sdma->irq);
  	return ret;
  }
  
  static int sirfsoc_dma_remove(struct platform_device *op)
  {
  	struct device *dev = &op->dev;
  	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
  
  	dma_async_device_unregister(&sdma->dma);
  	free_irq(sdma->irq, sdma);
  	irq_dispose_mapping(sdma->irq);
  	pm_runtime_disable(&op->dev);
  	if (!pm_runtime_status_suspended(&op->dev))
  		sirfsoc_dma_runtime_suspend(&op->dev);
  
  	return 0;
  }
  
  static int sirfsoc_dma_runtime_suspend(struct device *dev)
  {
  	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
  
  	clk_disable_unprepare(sdma->clk);
  	return 0;
  }
  
  static int sirfsoc_dma_runtime_resume(struct device *dev)
  {
  	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
  	int ret;
  
  	ret = clk_prepare_enable(sdma->clk);
  	if (ret < 0) {
  		dev_err(dev, "clk_enable failed: %d
  ", ret);
  		return ret;
  	}
  	return 0;
  }
  
  static int sirfsoc_dma_pm_suspend(struct device *dev)
  {
  	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
  	struct sirfsoc_dma_regs *save = &sdma->regs_save;
  	struct sirfsoc_dma_desc *sdesc;
  	struct sirfsoc_dma_chan *schan;
  	int ch;
  	int ret;
  
  	/*
  	 * if we were runtime-suspended before, resume to enable clock
  	 * before accessing register
  	 */
  	if (pm_runtime_status_suspended(dev)) {
  		ret = sirfsoc_dma_runtime_resume(dev);
  		if (ret < 0)
  			return ret;
  	}
  
  	/*
  	 * DMA controller will lose all registers while suspending
  	 * so we need to save registers for active channels
  	 */
  	for (ch = 0; ch < SIRFSOC_DMA_CHANNELS; ch++) {
  		schan = &sdma->channels[ch];
  		if (list_empty(&schan->active))
  			continue;
  		sdesc = list_first_entry(&schan->active,
  			struct sirfsoc_dma_desc,
  			node);
  		save->ctrl[ch] = readl_relaxed(sdma->base +
  			ch * 0x10 + SIRFSOC_DMA_CH_CTRL);
  	}
  	save->interrupt_en = readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN);
  
  	/* Disable clock */
  	sirfsoc_dma_runtime_suspend(dev);
  
  	return 0;
  }
  
  static int sirfsoc_dma_pm_resume(struct device *dev)
  {
  	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
  	struct sirfsoc_dma_regs *save = &sdma->regs_save;
  	struct sirfsoc_dma_desc *sdesc;
  	struct sirfsoc_dma_chan *schan;
  	int ch;
  	int ret;
  
  	/* Enable clock before accessing register */
  	ret = sirfsoc_dma_runtime_resume(dev);
  	if (ret < 0)
  		return ret;
  
  	writel_relaxed(save->interrupt_en, sdma->base + SIRFSOC_DMA_INT_EN);
  	for (ch = 0; ch < SIRFSOC_DMA_CHANNELS; ch++) {
  		schan = &sdma->channels[ch];
  		if (list_empty(&schan->active))
  			continue;
  		sdesc = list_first_entry(&schan->active,
  			struct sirfsoc_dma_desc,
  			node);
  		writel_relaxed(sdesc->width,
  			sdma->base + SIRFSOC_DMA_WIDTH_0 + ch * 4);
  		writel_relaxed(sdesc->xlen,
  			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_XLEN);
  		writel_relaxed(sdesc->ylen,
  			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_YLEN);
  		writel_relaxed(save->ctrl[ch],
  			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_CTRL);
  		writel_relaxed(sdesc->addr >> 2,
  			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_ADDR);
  	}
  
  	/* if we were runtime-suspended before, suspend again */
  	if (pm_runtime_status_suspended(dev))
  		sirfsoc_dma_runtime_suspend(dev);
  
  	return 0;
  }
  
  static const struct dev_pm_ops sirfsoc_dma_pm_ops = {
  	SET_RUNTIME_PM_OPS(sirfsoc_dma_runtime_suspend, sirfsoc_dma_runtime_resume, NULL)
  	SET_SYSTEM_SLEEP_PM_OPS(sirfsoc_dma_pm_suspend, sirfsoc_dma_pm_resume)
  };
  
  static struct of_device_id sirfsoc_dma_match[] = {
  	{ .compatible = "sirf,prima2-dmac", },
  	{ .compatible = "sirf,marco-dmac", },
  	{},
  };
  
  static struct platform_driver sirfsoc_dma_driver = {
  	.probe		= sirfsoc_dma_probe,
  	.remove		= sirfsoc_dma_remove,
  	.driver = {
  		.name = DRV_NAME,
  		.owner = THIS_MODULE,
  		.pm = &sirfsoc_dma_pm_ops,
  		.of_match_table	= sirfsoc_dma_match,
  	},
  };
  
  static __init int sirfsoc_dma_init(void)
  {
  	return platform_driver_register(&sirfsoc_dma_driver);
  }
  
  static void __exit sirfsoc_dma_exit(void)
  {
  	platform_driver_unregister(&sirfsoc_dma_driver);
  }
  
  subsys_initcall(sirfsoc_dma_init);
  module_exit(sirfsoc_dma_exit);
  
  MODULE_AUTHOR("Rongjun Ying <rongjun.ying@csr.com>, "
  	"Barry Song <baohua.song@csr.com>");
  MODULE_DESCRIPTION("SIRFSOC DMA control driver");
  MODULE_LICENSE("GPL v2");