xref: /drivers/dma/intel_mid_dma.c

/*
 *  intel_mid_dma.c - Intel Langwell DMA Drivers
 *
 *  Copyright (C) 2008-10 Intel Corp
 *  Author: Vinod Koul <vinod.koul@intel.com>
 *  The driver design is based on dw_dmac driver
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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; version 2 of the License.
 *
 *  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.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *
 */
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/pm_runtime.h>
#include <linux/intel_mid_dma.h>

#define MAX_CHAN	4 /*max ch across controllers*/
#include "intel_mid_dma_regs.h"

#define INTEL_MID_DMAC1_ID		0x0814
#define INTEL_MID_DMAC2_ID		0x0813
#define INTEL_MID_GP_DMAC2_ID		0x0827
#define INTEL_MFLD_DMAC1_ID		0x0830
#define LNW_PERIPHRAL_MASK_BASE		0xFFAE8008
#define LNW_PERIPHRAL_MASK_SIZE		0x10
#define LNW_PERIPHRAL_STATUS		0x0
#define LNW_PERIPHRAL_MASK		0x8

struct intel_mid_dma_probe_info {
	u8 max_chan;
	u8 ch_base;
	u16 block_size;
	u32 pimr_mask;
};

#define INFO(_max_chan, _ch_base, _block_size, _pimr_mask) \
	((kernel_ulong_t)&(struct intel_mid_dma_probe_info) {	\
		.max_chan = (_max_chan),			\
		.ch_base = (_ch_base),				\
		.block_size = (_block_size),			\
		.pimr_mask = (_pimr_mask),			\
	})

/*****************************************************************************
Utility Functions*/
/**
 * get_ch_index	-	convert status to channel
 * @status: status mask
 * @base: dma ch base value
 *
 * Modify the status mask and return the channel index needing
 * attention (or -1 if neither)
 */
static int get_ch_index(int *status, unsigned int base)
{
	int i;
	for (i = 0; i < MAX_CHAN; i++) {
		if (*status & (1 << (i + base))) {
			*status = *status & ~(1 << (i + base));
			pr_debug("MDMA: index %d New status %x\n", i, *status);
			return i;
		}
	}
	return -1;
}

/**
 * get_block_ts	-	calculates dma transaction length
 * @len: dma transfer length
 * @tx_width: dma transfer src width
 * @block_size: dma controller max block size
 *
 * Based on src width calculate the DMA trsaction length in data items
 * return data items or FFFF if exceeds max length for block
 */
static int get_block_ts(int len, int tx_width, int block_size)
{
	int byte_width = 0, block_ts = 0;

	switch (tx_width) {
	case LNW_DMA_WIDTH_8BIT:
		byte_width = 1;
		break;
	case LNW_DMA_WIDTH_16BIT:
		byte_width = 2;
		break;
	case LNW_DMA_WIDTH_32BIT:
	default:
		byte_width = 4;
		break;
	}

	block_ts = len/byte_width;
	if (block_ts > block_size)
		block_ts = 0xFFFF;
	return block_ts;
}

/*****************************************************************************
DMAC1 interrupt Functions*/

/**
 * dmac1_mask_periphral_intr -	mask the periphral interrupt
 * @midc: dma channel for which masking is required
 *
 * Masks the DMA periphral interrupt
 * this is valid for DMAC1 family controllers only
 * This controller should have periphral mask registers already mapped
 */
static void dmac1_mask_periphral_intr(struct intel_mid_dma_chan *midc)
{
	u32 pimr;
	struct middma_device *mid = to_middma_device(midc->chan.device);

	if (mid->pimr_mask) {
		pimr = readl(mid->mask_reg + LNW_PERIPHRAL_MASK);
		pimr |= mid->pimr_mask;
		writel(pimr, mid->mask_reg + LNW_PERIPHRAL_MASK);
	}
	return;
}

/**
 * dmac1_unmask_periphral_intr -	unmask the periphral interrupt
 * @midc: dma channel for which masking is required
 *
 * UnMasks the DMA periphral interrupt,
 * this is valid for DMAC1 family controllers only
 * This controller should have periphral mask registers already mapped
 */
static void dmac1_unmask_periphral_intr(struct intel_mid_dma_chan *midc)
{
	u32 pimr;
	struct middma_device *mid = to_middma_device(midc->chan.device);

	if (mid->pimr_mask) {
		pimr = readl(mid->mask_reg + LNW_PERIPHRAL_MASK);
		pimr &= ~mid->pimr_mask;
		writel(pimr, mid->mask_reg + LNW_PERIPHRAL_MASK);
	}
	return;
}

/**
 * enable_dma_interrupt -	enable the periphral interrupt
 * @midc: dma channel for which enable interrupt is required
 *
 * Enable the DMA periphral interrupt,
 * this is valid for DMAC1 family controllers only
 * This controller should have periphral mask registers already mapped
 */
static void enable_dma_interrupt(struct intel_mid_dma_chan *midc)
{
	dmac1_unmask_periphral_intr(midc);

	/*en ch interrupts*/
	iowrite32(UNMASK_INTR_REG(midc->ch_id), midc->dma_base + MASK_TFR);
	iowrite32(UNMASK_INTR_REG(midc->ch_id), midc->dma_base + MASK_ERR);
	return;
}

/**
 * disable_dma_interrupt -	disable the periphral interrupt
 * @midc: dma channel for which disable interrupt is required
 *
 * Disable the DMA periphral interrupt,
 * this is valid for DMAC1 family controllers only
 * This controller should have periphral mask registers already mapped
 */
static void disable_dma_interrupt(struct intel_mid_dma_chan *midc)
{
	/*Check LPE PISR, make sure fwd is disabled*/
	dmac1_mask_periphral_intr(midc);
	iowrite32(MASK_INTR_REG(midc->ch_id), midc->dma_base + MASK_BLOCK);
	iowrite32(MASK_INTR_REG(midc->ch_id), midc->dma_base + MASK_TFR);
	iowrite32(MASK_INTR_REG(midc->ch_id), midc->dma_base + MASK_ERR);
	return;
}

/*****************************************************************************
DMA channel helper Functions*/
/**
 * mid_desc_get		-	get a descriptor
 * @midc: dma channel for which descriptor is required
 *
 * Obtain a descriptor for the channel. Returns NULL if none are free.
 * Once the descriptor is returned it is private until put on another
 * list or freed
 */
static struct intel_mid_dma_desc *midc_desc_get(struct intel_mid_dma_chan *midc)
{
	struct intel_mid_dma_desc *desc, *_desc;
	struct intel_mid_dma_desc *ret = NULL;

	spin_lock_bh(&midc->lock);
	list_for_each_entry_safe(desc, _desc, &midc->free_list, desc_node) {
		if (async_tx_test_ack(&desc->txd)) {
			list_del(&desc->desc_node);
			ret = desc;
			break;
		}
	}
	spin_unlock_bh(&midc->lock);
	return ret;
}

/**
 * mid_desc_put		-	put a descriptor
 * @midc: dma channel for which descriptor is required
 * @desc: descriptor to put
 *
 * Return a descriptor from lwn_desc_get back to the free pool
 */
static void midc_desc_put(struct intel_mid_dma_chan *midc,
			struct intel_mid_dma_desc *desc)
{
	if (desc) {
		spin_lock_bh(&midc->lock);
		list_add_tail(&desc->desc_node, &midc->free_list);
		spin_unlock_bh(&midc->lock);
	}
}
/**
 * midc_dostart		-		begin a DMA transaction
 * @midc: channel for which txn is to be started
 * @first: first descriptor of series
 *
 * Load a transaction into the engine. This must be called with midc->lock
 * held and bh disabled.
 */
static void midc_dostart(struct intel_mid_dma_chan *midc,
			struct intel_mid_dma_desc *first)
{
	struct middma_device *mid = to_middma_device(midc->chan.device);

	/*  channel is idle */
	if (midc->busy && test_ch_en(midc->dma_base, midc->ch_id)) {
		/*error*/
		pr_err("ERR_MDMA: channel is busy in start\n");
		/* The tasklet will hopefully advance the queue... */
		return;
	}
	midc->busy = true;
	/*write registers and en*/
	iowrite32(first->sar, midc->ch_regs + SAR);
	iowrite32(first->dar, midc->ch_regs + DAR);
	iowrite32(first->cfg_hi, midc->ch_regs + CFG_HIGH);
	iowrite32(first->cfg_lo, midc->ch_regs + CFG_LOW);
	iowrite32(first->ctl_lo, midc->ch_regs + CTL_LOW);
	iowrite32(first->ctl_hi, midc->ch_regs + CTL_HIGH);
	pr_debug("MDMA:TX SAR %x,DAR %x,CFGL %x,CFGH %x,CTLH %x, CTLL %x\n",
		(int)first->sar, (int)first->dar, first->cfg_hi,
		first->cfg_lo, first->ctl_hi, first->ctl_lo);

	iowrite32(ENABLE_CHANNEL(midc->ch_id), mid->dma_base + DMA_CHAN_EN);
	first->status = DMA_IN_PROGRESS;
}

/**
 * midc_descriptor_complete	-	process completed descriptor
 * @midc: channel owning the descriptor
 * @desc: the descriptor itself
 *
 * Process a completed descriptor and perform any callbacks upon
 * the completion. The completion handling drops the lock during the
 * callbacks but must be called with the lock held.
 */
static void midc_descriptor_complete(struct intel_mid_dma_chan *midc,
	       struct intel_mid_dma_desc *desc)
{
	struct dma_async_tx_descriptor	*txd = &desc->txd;
	dma_async_tx_callback callback_txd = NULL;
	void *param_txd = NULL;

	midc->completed = txd->cookie;
	callback_txd = txd->callback;
	param_txd = txd->callback_param;

	list_move(&desc->desc_node, &midc->free_list);
	midc->busy = false;
	spin_unlock_bh(&midc->lock);
	if (callback_txd) {
		pr_debug("MDMA: TXD callback set ... calling\n");
		callback_txd(param_txd);
		spin_lock_bh(&midc->lock);
		return;
	}
	spin_lock_bh(&midc->lock);

}
/**
 * midc_scan_descriptors -		check the descriptors in channel
 *					mark completed when tx is completete
 * @mid: device
 * @midc: channel to scan
 *
 * Walk the descriptor chain for the device and process any entries
 * that are complete.
 */
static void midc_scan_descriptors(struct middma_device *mid,
				struct intel_mid_dma_chan *midc)
{
	struct intel_mid_dma_desc *desc = NULL, *_desc = NULL;

	/*tx is complete*/
	list_for_each_entry_safe(desc, _desc, &midc->active_list, desc_node) {
		if (desc->status == DMA_IN_PROGRESS)  {
			desc->status = DMA_SUCCESS;
			midc_descriptor_complete(midc, desc);
		}
	}
	return;
}

/*****************************************************************************
DMA engine callback Functions*/
/**
 * intel_mid_dma_tx_submit -	callback to submit DMA transaction
 * @tx: dma engine descriptor
 *
 * Submit the DMA trasaction for this descriptor, start if ch idle
 */
static dma_cookie_t intel_mid_dma_tx_submit(struct dma_async_tx_descriptor *tx)
{
	struct intel_mid_dma_desc	*desc = to_intel_mid_dma_desc(tx);
	struct intel_mid_dma_chan	*midc = to_intel_mid_dma_chan(tx->chan);
	dma_cookie_t		cookie;

	spin_lock_bh(&midc->lock);
	cookie = midc->chan.cookie;

	if (++cookie < 0)
		cookie = 1;

	midc->chan.cookie = cookie;
	desc->txd.cookie = cookie;


	if (list_empty(&midc->active_list)) {
		midc_dostart(midc, desc);
		list_add_tail(&desc->desc_node, &midc->active_list);
	} else {
		list_add_tail(&desc->desc_node, &midc->queue);
	}
	spin_unlock_bh(&midc->lock);

	return cookie;
}

/**
 * intel_mid_dma_issue_pending -	callback to issue pending txn
 * @chan: chan where pending trascation needs to be checked and submitted
 *
 * Call for scan to issue pending descriptors
 */
static void intel_mid_dma_issue_pending(struct dma_chan *chan)
{
	struct intel_mid_dma_chan	*midc = to_intel_mid_dma_chan(chan);

	spin_lock_bh(&midc->lock);
	if (!list_empty(&midc->queue))
		midc_scan_descriptors(to_middma_device(chan->device), midc);
	spin_unlock_bh(&midc->lock);
}

/**
 * intel_mid_dma_tx_status -	Return status of txn
 * @chan: chan for where status needs to be checked
 * @cookie: cookie for txn
 * @txstate: DMA txn state
 *
 * Return status of DMA txn
 */
static enum dma_status intel_mid_dma_tx_status(struct dma_chan *chan,
						dma_cookie_t cookie,
						struct dma_tx_state *txstate)
{
	struct intel_mid_dma_chan	*midc = to_intel_mid_dma_chan(chan);
	dma_cookie_t		last_used;
	dma_cookie_t		last_complete;
	int				ret;

	last_complete = midc->completed;
	last_used = chan->cookie;

	ret = dma_async_is_complete(cookie, last_complete, last_used);
	if (ret != DMA_SUCCESS) {
		midc_scan_descriptors(to_middma_device(chan->device), midc);

		last_complete = midc->completed;
		last_used = chan->cookie;

		ret = dma_async_is_complete(cookie, last_complete, last_used);
	}

	if (txstate) {
		txstate->last = last_complete;
		txstate->used = last_used;
		txstate->residue = 0;
	}
	return ret;
}

/**
 * intel_mid_dma_device_control -	DMA device control
 * @chan: chan for DMA control
 * @cmd: control cmd
 * @arg: cmd arg value
 *
 * Perform DMA control command
 */
static int intel_mid_dma_device_control(struct dma_chan *chan,
			enum dma_ctrl_cmd cmd, unsigned long arg)
{
	struct intel_mid_dma_chan	*midc = to_intel_mid_dma_chan(chan);
	struct middma_device	*mid = to_middma_device(chan->device);
	struct intel_mid_dma_desc	*desc, *_desc;
	LIST_HEAD(list);

	if (cmd != DMA_TERMINATE_ALL)
		return -ENXIO;

	spin_lock_bh(&midc->lock);
	if (midc->busy == false) {
		spin_unlock_bh(&midc->lock);
		return 0;
	}
	list_splice_init(&midc->free_list, &list);
	midc->descs_allocated = 0;
	midc->slave = NULL;

	/* Disable interrupts */
	disable_dma_interrupt(midc);

	spin_unlock_bh(&midc->lock);
	list_for_each_entry_safe(desc, _desc, &list, desc_node) {
		pr_debug("MDMA: freeing descriptor %p\n", desc);
		pci_pool_free(mid->dma_pool, desc, desc->txd.phys);
	}
	return 0;
}

/**
 * intel_mid_dma_prep_slave_sg -	Prep slave sg txn
 * @chan: chan for DMA transfer
 * @sgl: scatter gather list
 * @sg_len: length of sg txn
 * @direction: DMA transfer dirtn
 * @flags: DMA flags
 *
 * Do DMA sg txn: NOT supported now
 */
static struct dma_async_tx_descriptor *intel_mid_dma_prep_slave_sg(
			struct dma_chan *chan, struct scatterlist *sgl,
			unsigned int sg_len, enum dma_data_direction direction,
			unsigned long flags)
{
	/*not supported now*/
	return NULL;
}

/**
 * intel_mid_dma_prep_memcpy -	Prep memcpy txn
 * @chan: chan for DMA transfer
 * @dest: destn address
 * @src: src address
 * @len: DMA transfer len
 * @flags: DMA flags
 *
 * Perform a DMA memcpy. Note we support slave periphral DMA transfers only
 * The periphral txn details should be filled in slave structure properly
 * Returns the descriptor for this txn
 */
static struct dma_async_tx_descriptor *intel_mid_dma_prep_memcpy(
			struct dma_chan *chan, dma_addr_t dest,
			dma_addr_t src, size_t len, unsigned long flags)
{
	struct intel_mid_dma_chan *midc;
	struct intel_mid_dma_desc *desc = NULL;
	struct intel_mid_dma_slave *mids;
	union intel_mid_dma_ctl_lo ctl_lo;
	union intel_mid_dma_ctl_hi ctl_hi;
	union intel_mid_dma_cfg_lo cfg_lo;
	union intel_mid_dma_cfg_hi cfg_hi;
	enum intel_mid_dma_width width = 0;

	pr_debug("MDMA: Prep for memcpy\n");
	WARN_ON(!chan);
	if (!len)
		return NULL;

	mids = chan->private;
	WARN_ON(!mids);

	midc = to_intel_mid_dma_chan(chan);
	WARN_ON(!midc);

	pr_debug("MDMA:called for DMA %x CH %d Length %zu\n",
				midc->dma->pci_id, midc->ch_id, len);
	pr_debug("MDMA:Cfg passed Mode %x, Dirn %x, HS %x, Width %x\n",
		mids->cfg_mode, mids->dirn, mids->hs_mode, mids->src_width);

	/*calculate CFG_LO*/
	if (mids->hs_mode == LNW_DMA_SW_HS) {
		cfg_lo.cfg_lo = 0;
		cfg_lo.cfgx.hs_sel_dst = 1;
		cfg_lo.cfgx.hs_sel_src = 1;
	} else if (mids->hs_mode == LNW_DMA_HW_HS)
		cfg_lo.cfg_lo = 0x00000;

	/*calculate CFG_HI*/
	if (mids->cfg_mode == LNW_DMA_MEM_TO_MEM) {
		/*SW HS only*/
		cfg_hi.cfg_hi = 0;
	} else {
		cfg_hi.cfg_hi = 0;
		if (midc->dma->pimr_mask) {
			cfg_hi.cfgx.protctl = 0x0; /*default value*/
			cfg_hi.cfgx.fifo_mode = 1;
			if (mids->dirn == DMA_TO_DEVICE) {
				cfg_hi.cfgx.src_per = 0;
				if (mids->device_instance == 0)
					cfg_hi.cfgx.dst_per = 3;
				if (mids->device_instance == 1)
					cfg_hi.cfgx.dst_per = 1;
			} else if (mids->dirn == DMA_FROM_DEVICE) {
				if (mids->device_instance == 0)
					cfg_hi.cfgx.src_per = 2;
				if (mids->device_instance == 1)
					cfg_hi.cfgx.src_per = 0;
				cfg_hi.cfgx.dst_per = 0;
			}
		} else {
			cfg_hi.cfgx.protctl = 0x1; /*default value*/
			cfg_hi.cfgx.src_per = cfg_hi.cfgx.dst_per =
					midc->ch_id - midc->dma->chan_base;
		}
	}

	/*calculate CTL_HI*/
	ctl_hi.ctlx.reser = 0;
	width = mids->src_width;

	ctl_hi.ctlx.block_ts = get_block_ts(len, width, midc->dma->block_size);
	pr_debug("MDMA:calc len %d for block size %d\n",
				ctl_hi.ctlx.block_ts, midc->dma->block_size);
	/*calculate CTL_LO*/
	ctl_lo.ctl_lo = 0;
	ctl_lo.ctlx.int_en = 1;
	ctl_lo.ctlx.dst_tr_width = mids->dst_width;
	ctl_lo.ctlx.src_tr_width = mids->src_width;
	ctl_lo.ctlx.dst_msize = mids->src_msize;
	ctl_lo.ctlx.src_msize = mids->dst_msize;

	if (mids->cfg_mode == LNW_DMA_MEM_TO_MEM) {
		ctl_lo.ctlx.tt_fc = 0;
		ctl_lo.ctlx.sinc = 0;
		ctl_lo.ctlx.dinc = 0;
	} else {
		if (mids->dirn == DMA_TO_DEVICE) {
			ctl_lo.ctlx.sinc = 0;
			ctl_lo.ctlx.dinc = 2;
			ctl_lo.ctlx.tt_fc = 1;
		} else if (mids->dirn == DMA_FROM_DEVICE) {
			ctl_lo.ctlx.sinc = 2;
			ctl_lo.ctlx.dinc = 0;
			ctl_lo.ctlx.tt_fc = 2;
		}
	}

	pr_debug("MDMA:Calc CTL LO %x, CTL HI %x, CFG LO %x, CFG HI %x\n",
		ctl_lo.ctl_lo, ctl_hi.ctl_hi, cfg_lo.cfg_lo, cfg_hi.cfg_hi);

	enable_dma_interrupt(midc);

	desc = midc_desc_get(midc);
	if (desc == NULL)
		goto err_desc_get;
	desc->sar = src;
	desc->dar = dest ;
	desc->len = len;
	desc->cfg_hi = cfg_hi.cfg_hi;
	desc->cfg_lo = cfg_lo.cfg_lo;
	desc->ctl_lo = ctl_lo.ctl_lo;
	desc->ctl_hi = ctl_hi.ctl_hi;
	desc->width = width;
	desc->dirn = mids->dirn;
	return &desc->txd;

err_desc_get:
	pr_err("ERR_MDMA: Failed to get desc\n");
	midc_desc_put(midc, desc);
	return NULL;
}

/**
 * intel_mid_dma_free_chan_resources -	Frees dma resources
 * @chan: chan requiring attention
 *
 * Frees the allocated resources on this DMA chan
 */
static void intel_mid_dma_free_chan_resources(struct dma_chan *chan)
{
	struct intel_mid_dma_chan	*midc = to_intel_mid_dma_chan(chan);
	struct middma_device	*mid = to_middma_device(chan->device);
	struct intel_mid_dma_desc	*desc, *_desc;

	if (true == midc->busy) {
		/*trying to free ch in use!!!!!*/
		pr_err("ERR_MDMA: trying to free ch in use\n");
	}
	pm_runtime_put(&mid->pdev->dev);
	spin_lock_bh(&midc->lock);
	midc->descs_allocated = 0;
	list_for_each_entry_safe(desc, _desc, &midc->active_list, desc_node) {
		list_del(&desc->desc_node);
		pci_pool_free(mid->dma_pool, desc, desc->txd.phys);
	}
	list_for_each_entry_safe(desc, _desc, &midc->free_list, desc_node) {
		list_del(&desc->desc_node);
		pci_pool_free(mid->dma_pool, desc, desc->txd.phys);
	}
	list_for_each_entry_safe(desc, _desc, &midc->queue, desc_node) {
		list_del(&desc->desc_node);
		pci_pool_free(mid->dma_pool, desc, desc->txd.phys);
	}
	spin_unlock_bh(&midc->lock);
	midc->in_use = false;
	midc->busy = false;
	/* Disable CH interrupts */
	iowrite32(MASK_INTR_REG(midc->ch_id), mid->dma_base + MASK_BLOCK);
	iowrite32(MASK_INTR_REG(midc->ch_id), mid->dma_base + MASK_ERR);
}

/**
 * intel_mid_dma_alloc_chan_resources -	Allocate dma resources
 * @chan: chan requiring attention
 *
 * Allocates DMA resources on this chan
 * Return the descriptors allocated
 */
static int intel_mid_dma_alloc_chan_resources(struct dma_chan *chan)
{
	struct intel_mid_dma_chan	*midc = to_intel_mid_dma_chan(chan);
	struct middma_device	*mid = to_middma_device(chan->device);
	struct intel_mid_dma_desc	*desc;
	dma_addr_t		phys;
	int	i = 0;

	pm_runtime_get_sync(&mid->pdev->dev);

	if (mid->state == SUSPENDED) {
		if (dma_resume(mid->pdev)) {
			pr_err("ERR_MDMA: resume failed");
			return -EFAULT;
		}
	}

	/* ASSERT:  channel is idle */
	if (test_ch_en(mid->dma_base, midc->ch_id)) {
		/*ch is not idle*/
		pr_err("ERR_MDMA: ch not idle\n");
		pm_runtime_put(&mid->pdev->dev);
		return -EIO;
	}
	midc->completed = chan->cookie = 1;

	spin_lock_bh(&midc->lock);
	while (midc->descs_allocated < DESCS_PER_CHANNEL) {
		spin_unlock_bh(&midc->lock);
		desc = pci_pool_alloc(mid->dma_pool, GFP_KERNEL, &phys);
		if (!desc) {
			pr_err("ERR_MDMA: desc failed\n");
			pm_runtime_put(&mid->pdev->dev);
			return -ENOMEM;
			/*check*/
		}
		dma_async_tx_descriptor_init(&desc->txd, chan);
		desc->txd.tx_submit = intel_mid_dma_tx_submit;
		desc->txd.flags = DMA_CTRL_ACK;
		desc->txd.phys = phys;
		spin_lock_bh(&midc->lock);
		i = ++midc->descs_allocated;
		list_add_tail(&desc->desc_node, &midc->free_list);
	}
	spin_unlock_bh(&midc->lock);
	midc->in_use = true;
	midc->busy = false;
	pr_debug("MID_DMA: Desc alloc done ret: %d desc\n", i);
	return i;
}

/**
 * midc_handle_error -	Handle DMA txn error
 * @mid: controller where error occured
 * @midc: chan where error occured
 *
 * Scan the descriptor for error
 */
static void midc_handle_error(struct middma_device *mid,
		struct intel_mid_dma_chan *midc)
{
	midc_scan_descriptors(mid, midc);
}

/**
 * dma_tasklet -	DMA interrupt tasklet
 * @data: tasklet arg (the controller structure)
 *
 * Scan the controller for interrupts for completion/error
 * Clear the interrupt and call for handling completion/error
 */
static void dma_tasklet(unsigned long data)
{
	struct middma_device *mid = NULL;
	struct intel_mid_dma_chan *midc = NULL;
	u32 status;
	int i;

	mid = (struct middma_device *)data;
	if (mid == NULL) {
		pr_err("ERR_MDMA: tasklet Null param\n");
		return;
	}
	pr_debug("MDMA: in tasklet for device %x\n", mid->pci_id);
	status = ioread32(mid->dma_base + RAW_TFR);
	pr_debug("MDMA:RAW_TFR %x\n", status);
	status &= mid->intr_mask;
	while (status) {
		/*txn interrupt*/
		i = get_ch_index(&status, mid->chan_base);
		if (i < 0) {
			pr_err("ERR_MDMA:Invalid ch index %x\n", i);
			return;
		}
		midc = &mid->ch[i];
		if (midc == NULL) {
			pr_err("ERR_MDMA:Null param midc\n");
			return;
		}
		pr_debug("MDMA:Tx complete interrupt %x, Ch No %d Index %d\n",
				status, midc->ch_id, i);
		/*clearing this interrupts first*/
		iowrite32((1 << midc->ch_id), mid->dma_base + CLEAR_TFR);
		iowrite32((1 << midc->ch_id), mid->dma_base + CLEAR_BLOCK);

		spin_lock_bh(&midc->lock);
		midc_scan_descriptors(mid, midc);
		pr_debug("MDMA:Scan of desc... complete, unmasking\n");
		iowrite32(UNMASK_INTR_REG(midc->ch_id),
				mid->dma_base + MASK_TFR);
		spin_unlock_bh(&midc->lock);
	}

	status = ioread32(mid->dma_base + RAW_ERR);
	status &= mid->intr_mask;
	while (status) {
		/*err interrupt*/
		i = get_ch_index(&status, mid->chan_base);
		if (i < 0) {
			pr_err("ERR_MDMA:Invalid ch index %x\n", i);
			return;
		}
		midc = &mid->ch[i];
		if (midc == NULL) {
			pr_err("ERR_MDMA:Null param midc\n");
			return;
		}
		pr_debug("MDMA:Tx complete interrupt %x, Ch No %d Index %d\n",
				status, midc->ch_id, i);

		iowrite32((1 << midc->ch_id), mid->dma_base + CLEAR_ERR);
		spin_lock_bh(&midc->lock);
		midc_handle_error(mid, midc);
		iowrite32(UNMASK_INTR_REG(midc->ch_id),
				mid->dma_base + MASK_ERR);
		spin_unlock_bh(&midc->lock);
	}
	pr_debug("MDMA:Exiting takslet...\n");
	return;
}

static void dma_tasklet1(unsigned long data)
{
	pr_debug("MDMA:in takslet1...\n");
	return dma_tasklet(data);
}

static void dma_tasklet2(unsigned long data)
{
	pr_debug("MDMA:in takslet2...\n");
	return dma_tasklet(data);
}

/**
 * intel_mid_dma_interrupt -	DMA ISR
 * @irq: IRQ where interrupt occurred
 * @data: ISR cllback data (the controller structure)
 *
 * See if this is our interrupt if so then schedule the tasklet
 * otherwise ignore
 */
static irqreturn_t intel_mid_dma_interrupt(int irq, void *data)
{
	struct middma_device *mid = data;
	u32 tfr_status, err_status;
	int call_tasklet = 0;

	tfr_status = ioread32(mid->dma_base + RAW_TFR);
	err_status = ioread32(mid->dma_base + RAW_ERR);
	if (!tfr_status && !err_status)
		return IRQ_NONE;

	/*DMA Interrupt*/
	pr_debug("MDMA:Got an interrupt on irq %d\n", irq);
	if (!mid) {
		pr_err("ERR_MDMA:null pointer mid\n");
		return -EINVAL;
	}

	pr_debug("MDMA: Status %x, Mask %x\n", tfr_status, mid->intr_mask);
	tfr_status &= mid->intr_mask;
	if (tfr_status) {
		/*need to disable intr*/
		iowrite32((tfr_status << 8), mid->dma_base + MASK_TFR);
		pr_debug("MDMA: Calling tasklet %x\n", tfr_status);
		call_tasklet = 1;
	}
	err_status &= mid->intr_mask;
	if (err_status) {
		iowrite32(MASK_INTR_REG(err_status), mid->dma_base + MASK_ERR);
		call_tasklet = 1;
	}
	if (call_tasklet)
		tasklet_schedule(&mid->tasklet);

	return IRQ_HANDLED;
}

static irqreturn_t intel_mid_dma_interrupt1(int irq, void *data)
{
	return intel_mid_dma_interrupt(irq, data);
}

static irqreturn_t intel_mid_dma_interrupt2(int irq, void *data)
{
	return intel_mid_dma_interrupt(irq, data);
}

/**
 * mid_setup_dma -	Setup the DMA controller
 * @pdev: Controller PCI device structure
 *
 * Initilize the DMA controller, channels, registers with DMA engine,
 * ISR. Initilize DMA controller channels.
 */
static int mid_setup_dma(struct pci_dev *pdev)
{
	struct middma_device *dma = pci_get_drvdata(pdev);
	int err, i;

	/* DMA coherent memory pool for DMA descriptor allocations */
	dma->dma_pool = pci_pool_create("intel_mid_dma_desc_pool", pdev,
					sizeof(struct intel_mid_dma_desc),
					32, 0);
	if (NULL == dma->dma_pool) {
		pr_err("ERR_MDMA:pci_pool_create failed\n");
		err = -ENOMEM;
		kfree(dma);
		goto err_dma_pool;
	}

	INIT_LIST_HEAD(&dma->common.channels);
	dma->pci_id = pdev->device;
	if (dma->pimr_mask) {
		dma->mask_reg = ioremap(LNW_PERIPHRAL_MASK_BASE,
					LNW_PERIPHRAL_MASK_SIZE);
		if (dma->mask_reg == NULL) {
			pr_err("ERR_MDMA:Cant map periphral intr space !!\n");
			return -ENOMEM;
		}
	} else
		dma->mask_reg = NULL;

	pr_debug("MDMA:Adding %d channel for this controller\n", dma->max_chan);
	/*init CH structures*/
	dma->intr_mask = 0;
	dma->state = RUNNING;
	for (i = 0; i < dma->max_chan; i++) {
		struct intel_mid_dma_chan *midch = &dma->ch[i];

		midch->chan.device = &dma->common;
		midch->chan.cookie =  1;
		midch->chan.chan_id = i;
		midch->ch_id = dma->chan_base + i;
		pr_debug("MDMA:Init CH %d, ID %d\n", i, midch->ch_id);

		midch->dma_base = dma->dma_base;
		midch->ch_regs = dma->dma_base + DMA_CH_SIZE * midch->ch_id;
		midch->dma = dma;
		dma->intr_mask |= 1 << (dma->chan_base + i);
		spin_lock_init(&midch->lock);

		INIT_LIST_HEAD(&midch->active_list);
		INIT_LIST_HEAD(&midch->queue);
		INIT_LIST_HEAD(&midch->free_list);
		/*mask interrupts*/
		iowrite32(MASK_INTR_REG(midch->ch_id),
			dma->dma_base + MASK_BLOCK);
		iowrite32(MASK_INTR_REG(midch->ch_id),
			dma->dma_base + MASK_SRC_TRAN);
		iowrite32(MASK_INTR_REG(midch->ch_id),
			dma->dma_base + MASK_DST_TRAN);
		iowrite32(MASK_INTR_REG(midch->ch_id),
			dma->dma_base + MASK_ERR);
		iowrite32(MASK_INTR_REG(midch->ch_id),
			dma->dma_base + MASK_TFR);

		disable_dma_interrupt(midch);
		list_add_tail(&midch->chan.device_node, &dma->common.channels);
	}
	pr_debug("MDMA: Calc Mask as %x for this controller\n", dma->intr_mask);

	/*init dma structure*/
	dma_cap_zero(dma->common.cap_mask);
	dma_cap_set(DMA_MEMCPY, dma->common.cap_mask);
	dma_cap_set(DMA_SLAVE, dma->common.cap_mask);
	dma_cap_set(DMA_PRIVATE, dma->common.cap_mask);
	dma->common.dev = &pdev->dev;
	dma->common.chancnt = dma->max_chan;

	dma->common.device_alloc_chan_resources =
					intel_mid_dma_alloc_chan_resources;
	dma->common.device_free_chan_resources =
					intel_mid_dma_free_chan_resources;

	dma->common.device_tx_status = intel_mid_dma_tx_status;
	dma->common.device_prep_dma_memcpy = intel_mid_dma_prep_memcpy;
	dma->common.device_issue_pending = intel_mid_dma_issue_pending;
	dma->common.device_prep_slave_sg = intel_mid_dma_prep_slave_sg;
	dma->common.device_control = intel_mid_dma_device_control;

	/*enable dma cntrl*/
	iowrite32(REG_BIT0, dma->dma_base + DMA_CFG);

	/*register irq */
	if (dma->pimr_mask) {
		pr_debug("MDMA:Requesting irq shared for DMAC1\n");
		err = request_irq(pdev->irq, intel_mid_dma_interrupt1,
			IRQF_SHARED, "INTEL_MID_DMAC1", dma);
		if (0 != err)
			goto err_irq;
	} else {
		dma->intr_mask = 0x03;
		pr_debug("MDMA:Requesting irq for DMAC2\n");
		err = request_irq(pdev->irq, intel_mid_dma_interrupt2,
			IRQF_SHARED, "INTEL_MID_DMAC2", dma);
		if (0 != err)
			goto err_irq;
	}
	/*register device w/ engine*/
	err = dma_async_device_register(&dma->common);
	if (0 != err) {
		pr_err("ERR_MDMA:device_register failed: %d\n", err);
		goto err_engine;
	}
	if (dma->pimr_mask) {
		pr_debug("setting up tasklet1 for DMAC1\n");
		tasklet_init(&dma->tasklet, dma_tasklet1, (unsigned long)dma);
	} else {
		pr_debug("setting up tasklet2 for DMAC2\n");
		tasklet_init(&dma->tasklet, dma_tasklet2, (unsigned long)dma);
	}
	return 0;

err_engine:
	free_irq(pdev->irq, dma);
err_irq:
	pci_pool_destroy(dma->dma_pool);
	kfree(dma);
err_dma_pool:
	pr_err("ERR_MDMA:setup_dma failed: %d\n", err);
	return err;

}

/**
 * middma_shutdown -	Shutdown the DMA controller
 * @pdev: Controller PCI device structure
 *
 * Called by remove
 * Unregister DMa controller, clear all structures and free interrupt
 */
static void middma_shutdown(struct pci_dev *pdev)
{
	struct middma_device *device = pci_get_drvdata(pdev);

	dma_async_device_unregister(&device->common);
	pci_pool_destroy(device->dma_pool);
	if (device->mask_reg)
		iounmap(device->mask_reg);
	if (device->dma_base)
		iounmap(device->dma_base);
	free_irq(pdev->irq, device);
	return;
}

/**
 * intel_mid_dma_probe -	PCI Probe
 * @pdev: Controller PCI device structure
 * @id: pci device id structure
 *
 * Initilize the PCI device, map BARs, query driver data.
 * Call setup_dma to complete contoller and chan initilzation
 */
static int __devinit intel_mid_dma_probe(struct pci_dev *pdev,
					const struct pci_device_id *id)
{
	struct middma_device *device;
	u32 base_addr, bar_size;
	struct intel_mid_dma_probe_info *info;
	int err;

	pr_debug("MDMA: probe for %x\n", pdev->device);
	info = (void *)id->driver_data;
	pr_debug("MDMA: CH %d, base %d, block len %d, Periphral mask %x\n",
				info->max_chan, info->ch_base,
				info->block_size, info->pimr_mask);

	err = pci_enable_device(pdev);
	if (err)
		goto err_enable_device;

	err = pci_request_regions(pdev, "intel_mid_dmac");
	if (err)
		goto err_request_regions;

	err = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
	if (err)
		goto err_set_dma_mask;

	err = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
	if (err)
		goto err_set_dma_mask;

	device = kzalloc(sizeof(*device), GFP_KERNEL);
	if (!device) {
		pr_err("ERR_MDMA:kzalloc failed probe\n");
		err = -ENOMEM;
		goto err_kzalloc;
	}
	device->pdev = pci_dev_get(pdev);

	base_addr = pci_resource_start(pdev, 0);
	bar_size  = pci_resource_len(pdev, 0);
	device->dma_base = ioremap_nocache(base_addr, DMA_REG_SIZE);
	if (!device->dma_base) {
		pr_err("ERR_MDMA:ioremap failed\n");
		err = -ENOMEM;
		goto err_ioremap;
	}
	pci_set_drvdata(pdev, device);
	pci_set_master(pdev);
	device->max_chan = info->max_chan;
	device->chan_base = info->ch_base;
	device->block_size = info->block_size;
	device->pimr_mask = info->pimr_mask;

	err = mid_setup_dma(pdev);
	if (err)
		goto err_dma;

	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);
	pm_runtime_allow(&pdev->dev);
	return 0;

err_dma:
	iounmap(device->dma_base);
err_ioremap:
	pci_dev_put(pdev);
	kfree(device);
err_kzalloc:
err_set_dma_mask:
	pci_release_regions(pdev);
	pci_disable_device(pdev);
err_request_regions:
err_enable_device:
	pr_err("ERR_MDMA:Probe failed %d\n", err);
	return err;
}

/**
 * intel_mid_dma_remove -	PCI remove
 * @pdev: Controller PCI device structure
 *
 * Free up all resources and data
 * Call shutdown_dma to complete contoller and chan cleanup
 */
static void __devexit intel_mid_dma_remove(struct pci_dev *pdev)
{
	struct middma_device *device = pci_get_drvdata(pdev);
	middma_shutdown(pdev);
	pci_dev_put(pdev);
	kfree(device);
	pci_release_regions(pdev);
	pci_disable_device(pdev);
}

/* Power Management */
/*
* dma_suspend - PCI suspend function
*
* @pci: PCI device structure
* @state: PM message
*
* This function is called by OS when a power event occurs
*/
int dma_suspend(struct pci_dev *pci, pm_message_t state)
{
	int i;
	struct middma_device *device = pci_get_drvdata(pci);
	pr_debug("MDMA: dma_suspend called\n");

	for (i = 0; i < device->max_chan; i++) {
		if (device->ch[i].in_use)
			return -EAGAIN;
	}
	device->state = SUSPENDED;
	pci_set_drvdata(pci, device);
	pci_save_state(pci);
	pci_disable_device(pci);
	pci_set_power_state(pci, PCI_D3hot);
	return 0;
}

/**
* dma_resume - PCI resume function
*
* @pci:	PCI device structure
*
* This function is called by OS when a power event occurs
*/
int dma_resume(struct pci_dev *pci)
{
	int ret;
	struct middma_device *device = pci_get_drvdata(pci);

	pr_debug("MDMA: dma_resume called\n");
	pci_set_power_state(pci, PCI_D0);
	pci_restore_state(pci);
	ret = pci_enable_device(pci);
	if (ret) {
		pr_err("MDMA: device cant be enabled for %x\n", pci->device);
		return ret;
	}
	device->state = RUNNING;
	iowrite32(REG_BIT0, device->dma_base + DMA_CFG);
	pci_set_drvdata(pci, device);
	return 0;
}

static int dma_runtime_suspend(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	return dma_suspend(pci_dev, PMSG_SUSPEND);
}

static int dma_runtime_resume(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	return dma_resume(pci_dev);
}

static int dma_runtime_idle(struct device *dev)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct middma_device *device = pci_get_drvdata(pdev);
	int i;

	for (i = 0; i < device->max_chan; i++) {
		if (device->ch[i].in_use)
			return -EAGAIN;
	}

	return pm_schedule_suspend(dev, 0);
}

/******************************************************************************
* PCI stuff
*/
static struct pci_device_id intel_mid_dma_ids[] = {
	{ PCI_VDEVICE(INTEL, INTEL_MID_DMAC1_ID),	INFO(2, 6, 4095, 0x200020)},
	{ PCI_VDEVICE(INTEL, INTEL_MID_DMAC2_ID),	INFO(2, 0, 2047, 0)},
	{ PCI_VDEVICE(INTEL, INTEL_MID_GP_DMAC2_ID),	INFO(2, 0, 2047, 0)},
	{ PCI_VDEVICE(INTEL, INTEL_MFLD_DMAC1_ID),	INFO(4, 0, 4095, 0x400040)},
	{ 0, }
};
MODULE_DEVICE_TABLE(pci, intel_mid_dma_ids);

static const struct dev_pm_ops intel_mid_dma_pm = {
	.runtime_suspend = dma_runtime_suspend,
	.runtime_resume = dma_runtime_resume,
	.runtime_idle = dma_runtime_idle,
};

static struct pci_driver intel_mid_dma_pci = {
	.name		=	"Intel MID DMA",
	.id_table	=	intel_mid_dma_ids,
	.probe		=	intel_mid_dma_probe,
	.remove		=	__devexit_p(intel_mid_dma_remove),
#ifdef CONFIG_PM
	.suspend = dma_suspend,
	.resume = dma_resume,
	.driver = {
		.pm = &intel_mid_dma_pm,
	},
#endif
};

static int __init intel_mid_dma_init(void)
{
	pr_debug("INFO_MDMA: LNW DMA Driver Version %s\n",
			INTEL_MID_DMA_DRIVER_VERSION);
	return pci_register_driver(&intel_mid_dma_pci);
}
fs_initcall(intel_mid_dma_init);

static void __exit intel_mid_dma_exit(void)
{
	pci_unregister_driver(&intel_mid_dma_pci);
}
module_exit(intel_mid_dma_exit);

MODULE_AUTHOR("Vinod Koul <vinod.koul@intel.com>");
MODULE_DESCRIPTION("Intel (R) MID DMAC Driver");
MODULE_LICENSE("GPL v2");
MODULE_VERSION(INTEL_MID_DMA_DRIVER_VERSION);