Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / dma / fsldma.c
diff --git a/kernel/drivers/dma/fsldma.c b/kernel/drivers/dma/fsldma.c
new file mode 100644 (file)
index 0000000..300f821
--- /dev/null
@@ -0,0 +1,1547 @@
+/*
+ * Freescale MPC85xx, MPC83xx DMA Engine support
+ *
+ * Copyright (C) 2007-2010 Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * Author:
+ *   Zhang Wei <wei.zhang@freescale.com>, Jul 2007
+ *   Ebony Zhu <ebony.zhu@freescale.com>, May 2007
+ *
+ * Description:
+ *   DMA engine driver for Freescale MPC8540 DMA controller, which is
+ *   also fit for MPC8560, MPC8555, MPC8548, MPC8641, and etc.
+ *   The support for MPC8349 DMA controller is also added.
+ *
+ * This driver instructs the DMA controller to issue the PCI Read Multiple
+ * command for PCI read operations, instead of using the default PCI Read Line
+ * command. Please be aware that this setting may result in read pre-fetching
+ * on some platforms.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/dmaengine.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/fsldma.h>
+#include "dmaengine.h"
+#include "fsldma.h"
+
+#define chan_dbg(chan, fmt, arg...)                                    \
+       dev_dbg(chan->dev, "%s: " fmt, chan->name, ##arg)
+#define chan_err(chan, fmt, arg...)                                    \
+       dev_err(chan->dev, "%s: " fmt, chan->name, ##arg)
+
+static const char msg_ld_oom[] = "No free memory for link descriptor";
+
+/*
+ * Register Helpers
+ */
+
+static void set_sr(struct fsldma_chan *chan, u32 val)
+{
+       DMA_OUT(chan, &chan->regs->sr, val, 32);
+}
+
+static u32 get_sr(struct fsldma_chan *chan)
+{
+       return DMA_IN(chan, &chan->regs->sr, 32);
+}
+
+static void set_mr(struct fsldma_chan *chan, u32 val)
+{
+       DMA_OUT(chan, &chan->regs->mr, val, 32);
+}
+
+static u32 get_mr(struct fsldma_chan *chan)
+{
+       return DMA_IN(chan, &chan->regs->mr, 32);
+}
+
+static void set_cdar(struct fsldma_chan *chan, dma_addr_t addr)
+{
+       DMA_OUT(chan, &chan->regs->cdar, addr | FSL_DMA_SNEN, 64);
+}
+
+static dma_addr_t get_cdar(struct fsldma_chan *chan)
+{
+       return DMA_IN(chan, &chan->regs->cdar, 64) & ~FSL_DMA_SNEN;
+}
+
+static void set_bcr(struct fsldma_chan *chan, u32 val)
+{
+       DMA_OUT(chan, &chan->regs->bcr, val, 32);
+}
+
+static u32 get_bcr(struct fsldma_chan *chan)
+{
+       return DMA_IN(chan, &chan->regs->bcr, 32);
+}
+
+/*
+ * Descriptor Helpers
+ */
+
+static void set_desc_cnt(struct fsldma_chan *chan,
+                               struct fsl_dma_ld_hw *hw, u32 count)
+{
+       hw->count = CPU_TO_DMA(chan, count, 32);
+}
+
+static void set_desc_src(struct fsldma_chan *chan,
+                        struct fsl_dma_ld_hw *hw, dma_addr_t src)
+{
+       u64 snoop_bits;
+
+       snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX)
+               ? ((u64)FSL_DMA_SATR_SREADTYPE_SNOOP_READ << 32) : 0;
+       hw->src_addr = CPU_TO_DMA(chan, snoop_bits | src, 64);
+}
+
+static void set_desc_dst(struct fsldma_chan *chan,
+                        struct fsl_dma_ld_hw *hw, dma_addr_t dst)
+{
+       u64 snoop_bits;
+
+       snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX)
+               ? ((u64)FSL_DMA_DATR_DWRITETYPE_SNOOP_WRITE << 32) : 0;
+       hw->dst_addr = CPU_TO_DMA(chan, snoop_bits | dst, 64);
+}
+
+static void set_desc_next(struct fsldma_chan *chan,
+                         struct fsl_dma_ld_hw *hw, dma_addr_t next)
+{
+       u64 snoop_bits;
+
+       snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_83XX)
+               ? FSL_DMA_SNEN : 0;
+       hw->next_ln_addr = CPU_TO_DMA(chan, snoop_bits | next, 64);
+}
+
+static void set_ld_eol(struct fsldma_chan *chan, struct fsl_desc_sw *desc)
+{
+       u64 snoop_bits;
+
+       snoop_bits = ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_83XX)
+               ? FSL_DMA_SNEN : 0;
+
+       desc->hw.next_ln_addr = CPU_TO_DMA(chan,
+               DMA_TO_CPU(chan, desc->hw.next_ln_addr, 64) | FSL_DMA_EOL
+                       | snoop_bits, 64);
+}
+
+/*
+ * DMA Engine Hardware Control Helpers
+ */
+
+static void dma_init(struct fsldma_chan *chan)
+{
+       /* Reset the channel */
+       set_mr(chan, 0);
+
+       switch (chan->feature & FSL_DMA_IP_MASK) {
+       case FSL_DMA_IP_85XX:
+               /* Set the channel to below modes:
+                * EIE - Error interrupt enable
+                * EOLNIE - End of links interrupt enable
+                * BWC - Bandwidth sharing among channels
+                */
+               set_mr(chan, FSL_DMA_MR_BWC | FSL_DMA_MR_EIE
+                       | FSL_DMA_MR_EOLNIE);
+               break;
+       case FSL_DMA_IP_83XX:
+               /* Set the channel to below modes:
+                * EOTIE - End-of-transfer interrupt enable
+                * PRC_RM - PCI read multiple
+                */
+               set_mr(chan, FSL_DMA_MR_EOTIE | FSL_DMA_MR_PRC_RM);
+               break;
+       }
+}
+
+static int dma_is_idle(struct fsldma_chan *chan)
+{
+       u32 sr = get_sr(chan);
+       return (!(sr & FSL_DMA_SR_CB)) || (sr & FSL_DMA_SR_CH);
+}
+
+/*
+ * Start the DMA controller
+ *
+ * Preconditions:
+ * - the CDAR register must point to the start descriptor
+ * - the MRn[CS] bit must be cleared
+ */
+static void dma_start(struct fsldma_chan *chan)
+{
+       u32 mode;
+
+       mode = get_mr(chan);
+
+       if (chan->feature & FSL_DMA_CHAN_PAUSE_EXT) {
+               set_bcr(chan, 0);
+               mode |= FSL_DMA_MR_EMP_EN;
+       } else {
+               mode &= ~FSL_DMA_MR_EMP_EN;
+       }
+
+       if (chan->feature & FSL_DMA_CHAN_START_EXT) {
+               mode |= FSL_DMA_MR_EMS_EN;
+       } else {
+               mode &= ~FSL_DMA_MR_EMS_EN;
+               mode |= FSL_DMA_MR_CS;
+       }
+
+       set_mr(chan, mode);
+}
+
+static void dma_halt(struct fsldma_chan *chan)
+{
+       u32 mode;
+       int i;
+
+       /* read the mode register */
+       mode = get_mr(chan);
+
+       /*
+        * The 85xx controller supports channel abort, which will stop
+        * the current transfer. On 83xx, this bit is the transfer error
+        * mask bit, which should not be changed.
+        */
+       if ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX) {
+               mode |= FSL_DMA_MR_CA;
+               set_mr(chan, mode);
+
+               mode &= ~FSL_DMA_MR_CA;
+       }
+
+       /* stop the DMA controller */
+       mode &= ~(FSL_DMA_MR_CS | FSL_DMA_MR_EMS_EN);
+       set_mr(chan, mode);
+
+       /* wait for the DMA controller to become idle */
+       for (i = 0; i < 100; i++) {
+               if (dma_is_idle(chan))
+                       return;
+
+               udelay(10);
+       }
+
+       if (!dma_is_idle(chan))
+               chan_err(chan, "DMA halt timeout!\n");
+}
+
+/**
+ * fsl_chan_set_src_loop_size - Set source address hold transfer size
+ * @chan : Freescale DMA channel
+ * @size     : Address loop size, 0 for disable loop
+ *
+ * The set source address hold transfer size. The source
+ * address hold or loop transfer size is when the DMA transfer
+ * data from source address (SA), if the loop size is 4, the DMA will
+ * read data from SA, SA + 1, SA + 2, SA + 3, then loop back to SA,
+ * SA + 1 ... and so on.
+ */
+static void fsl_chan_set_src_loop_size(struct fsldma_chan *chan, int size)
+{
+       u32 mode;
+
+       mode = get_mr(chan);
+
+       switch (size) {
+       case 0:
+               mode &= ~FSL_DMA_MR_SAHE;
+               break;
+       case 1:
+       case 2:
+       case 4:
+       case 8:
+               mode |= FSL_DMA_MR_SAHE | (__ilog2(size) << 14);
+               break;
+       }
+
+       set_mr(chan, mode);
+}
+
+/**
+ * fsl_chan_set_dst_loop_size - Set destination address hold transfer size
+ * @chan : Freescale DMA channel
+ * @size     : Address loop size, 0 for disable loop
+ *
+ * The set destination address hold transfer size. The destination
+ * address hold or loop transfer size is when the DMA transfer
+ * data to destination address (TA), if the loop size is 4, the DMA will
+ * write data to TA, TA + 1, TA + 2, TA + 3, then loop back to TA,
+ * TA + 1 ... and so on.
+ */
+static void fsl_chan_set_dst_loop_size(struct fsldma_chan *chan, int size)
+{
+       u32 mode;
+
+       mode = get_mr(chan);
+
+       switch (size) {
+       case 0:
+               mode &= ~FSL_DMA_MR_DAHE;
+               break;
+       case 1:
+       case 2:
+       case 4:
+       case 8:
+               mode |= FSL_DMA_MR_DAHE | (__ilog2(size) << 16);
+               break;
+       }
+
+       set_mr(chan, mode);
+}
+
+/**
+ * fsl_chan_set_request_count - Set DMA Request Count for external control
+ * @chan : Freescale DMA channel
+ * @size     : Number of bytes to transfer in a single request
+ *
+ * The Freescale DMA channel can be controlled by the external signal DREQ#.
+ * The DMA request count is how many bytes are allowed to transfer before
+ * pausing the channel, after which a new assertion of DREQ# resumes channel
+ * operation.
+ *
+ * A size of 0 disables external pause control. The maximum size is 1024.
+ */
+static void fsl_chan_set_request_count(struct fsldma_chan *chan, int size)
+{
+       u32 mode;
+
+       BUG_ON(size > 1024);
+
+       mode = get_mr(chan);
+       mode |= (__ilog2(size) << 24) & 0x0f000000;
+
+       set_mr(chan, mode);
+}
+
+/**
+ * fsl_chan_toggle_ext_pause - Toggle channel external pause status
+ * @chan : Freescale DMA channel
+ * @enable   : 0 is disabled, 1 is enabled.
+ *
+ * The Freescale DMA channel can be controlled by the external signal DREQ#.
+ * The DMA Request Count feature should be used in addition to this feature
+ * to set the number of bytes to transfer before pausing the channel.
+ */
+static void fsl_chan_toggle_ext_pause(struct fsldma_chan *chan, int enable)
+{
+       if (enable)
+               chan->feature |= FSL_DMA_CHAN_PAUSE_EXT;
+       else
+               chan->feature &= ~FSL_DMA_CHAN_PAUSE_EXT;
+}
+
+/**
+ * fsl_chan_toggle_ext_start - Toggle channel external start status
+ * @chan : Freescale DMA channel
+ * @enable   : 0 is disabled, 1 is enabled.
+ *
+ * If enable the external start, the channel can be started by an
+ * external DMA start pin. So the dma_start() does not start the
+ * transfer immediately. The DMA channel will wait for the
+ * control pin asserted.
+ */
+static void fsl_chan_toggle_ext_start(struct fsldma_chan *chan, int enable)
+{
+       if (enable)
+               chan->feature |= FSL_DMA_CHAN_START_EXT;
+       else
+               chan->feature &= ~FSL_DMA_CHAN_START_EXT;
+}
+
+int fsl_dma_external_start(struct dma_chan *dchan, int enable)
+{
+       struct fsldma_chan *chan;
+
+       if (!dchan)
+               return -EINVAL;
+
+       chan = to_fsl_chan(dchan);
+
+       fsl_chan_toggle_ext_start(chan, enable);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(fsl_dma_external_start);
+
+static void append_ld_queue(struct fsldma_chan *chan, struct fsl_desc_sw *desc)
+{
+       struct fsl_desc_sw *tail = to_fsl_desc(chan->ld_pending.prev);
+
+       if (list_empty(&chan->ld_pending))
+               goto out_splice;
+
+       /*
+        * Add the hardware descriptor to the chain of hardware descriptors
+        * that already exists in memory.
+        *
+        * This will un-set the EOL bit of the existing transaction, and the
+        * last link in this transaction will become the EOL descriptor.
+        */
+       set_desc_next(chan, &tail->hw, desc->async_tx.phys);
+
+       /*
+        * Add the software descriptor and all children to the list
+        * of pending transactions
+        */
+out_splice:
+       list_splice_tail_init(&desc->tx_list, &chan->ld_pending);
+}
+
+static dma_cookie_t fsl_dma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+       struct fsldma_chan *chan = to_fsl_chan(tx->chan);
+       struct fsl_desc_sw *desc = tx_to_fsl_desc(tx);
+       struct fsl_desc_sw *child;
+       dma_cookie_t cookie = -EINVAL;
+
+       spin_lock_bh(&chan->desc_lock);
+
+#ifdef CONFIG_PM
+       if (unlikely(chan->pm_state != RUNNING)) {
+               chan_dbg(chan, "cannot submit due to suspend\n");
+               spin_unlock_bh(&chan->desc_lock);
+               return -1;
+       }
+#endif
+
+       /*
+        * assign cookies to all of the software descriptors
+        * that make up this transaction
+        */
+       list_for_each_entry(child, &desc->tx_list, node) {
+               cookie = dma_cookie_assign(&child->async_tx);
+       }
+
+       /* put this transaction onto the tail of the pending queue */
+       append_ld_queue(chan, desc);
+
+       spin_unlock_bh(&chan->desc_lock);
+
+       return cookie;
+}
+
+/**
+ * fsl_dma_free_descriptor - Free descriptor from channel's DMA pool.
+ * @chan : Freescale DMA channel
+ * @desc: descriptor to be freed
+ */
+static void fsl_dma_free_descriptor(struct fsldma_chan *chan,
+               struct fsl_desc_sw *desc)
+{
+       list_del(&desc->node);
+       chan_dbg(chan, "LD %p free\n", desc);
+       dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
+}
+
+/**
+ * fsl_dma_alloc_descriptor - Allocate descriptor from channel's DMA pool.
+ * @chan : Freescale DMA channel
+ *
+ * Return - The descriptor allocated. NULL for failed.
+ */
+static struct fsl_desc_sw *fsl_dma_alloc_descriptor(struct fsldma_chan *chan)
+{
+       struct fsl_desc_sw *desc;
+       dma_addr_t pdesc;
+
+       desc = dma_pool_alloc(chan->desc_pool, GFP_ATOMIC, &pdesc);
+       if (!desc) {
+               chan_dbg(chan, "out of memory for link descriptor\n");
+               return NULL;
+       }
+
+       memset(desc, 0, sizeof(*desc));
+       INIT_LIST_HEAD(&desc->tx_list);
+       dma_async_tx_descriptor_init(&desc->async_tx, &chan->common);
+       desc->async_tx.tx_submit = fsl_dma_tx_submit;
+       desc->async_tx.phys = pdesc;
+
+       chan_dbg(chan, "LD %p allocated\n", desc);
+
+       return desc;
+}
+
+/**
+ * fsldma_clean_completed_descriptor - free all descriptors which
+ * has been completed and acked
+ * @chan: Freescale DMA channel
+ *
+ * This function is used on all completed and acked descriptors.
+ * All descriptors should only be freed in this function.
+ */
+static void fsldma_clean_completed_descriptor(struct fsldma_chan *chan)
+{
+       struct fsl_desc_sw *desc, *_desc;
+
+       /* Run the callback for each descriptor, in order */
+       list_for_each_entry_safe(desc, _desc, &chan->ld_completed, node)
+               if (async_tx_test_ack(&desc->async_tx))
+                       fsl_dma_free_descriptor(chan, desc);
+}
+
+/**
+ * fsldma_run_tx_complete_actions - cleanup a single link descriptor
+ * @chan: Freescale DMA channel
+ * @desc: descriptor to cleanup and free
+ * @cookie: Freescale DMA transaction identifier
+ *
+ * This function is used on a descriptor which has been executed by the DMA
+ * controller. It will run any callbacks, submit any dependencies.
+ */
+static dma_cookie_t fsldma_run_tx_complete_actions(struct fsldma_chan *chan,
+               struct fsl_desc_sw *desc, dma_cookie_t cookie)
+{
+       struct dma_async_tx_descriptor *txd = &desc->async_tx;
+       dma_cookie_t ret = cookie;
+
+       BUG_ON(txd->cookie < 0);
+
+       if (txd->cookie > 0) {
+               ret = txd->cookie;
+
+               /* Run the link descriptor callback function */
+               if (txd->callback) {
+                       chan_dbg(chan, "LD %p callback\n", desc);
+                       txd->callback(txd->callback_param);
+               }
+       }
+
+       /* Run any dependencies */
+       dma_run_dependencies(txd);
+
+       return ret;
+}
+
+/**
+ * fsldma_clean_running_descriptor - move the completed descriptor from
+ * ld_running to ld_completed
+ * @chan: Freescale DMA channel
+ * @desc: the descriptor which is completed
+ *
+ * Free the descriptor directly if acked by async_tx api, or move it to
+ * queue ld_completed.
+ */
+static void fsldma_clean_running_descriptor(struct fsldma_chan *chan,
+               struct fsl_desc_sw *desc)
+{
+       /* Remove from the list of transactions */
+       list_del(&desc->node);
+
+       /*
+        * the client is allowed to attach dependent operations
+        * until 'ack' is set
+        */
+       if (!async_tx_test_ack(&desc->async_tx)) {
+               /*
+                * Move this descriptor to the list of descriptors which is
+                * completed, but still awaiting the 'ack' bit to be set.
+                */
+               list_add_tail(&desc->node, &chan->ld_completed);
+               return;
+       }
+
+       dma_pool_free(chan->desc_pool, desc, desc->async_tx.phys);
+}
+
+/**
+ * fsl_chan_xfer_ld_queue - transfer any pending transactions
+ * @chan : Freescale DMA channel
+ *
+ * HARDWARE STATE: idle
+ * LOCKING: must hold chan->desc_lock
+ */
+static void fsl_chan_xfer_ld_queue(struct fsldma_chan *chan)
+{
+       struct fsl_desc_sw *desc;
+
+       /*
+        * If the list of pending descriptors is empty, then we
+        * don't need to do any work at all
+        */
+       if (list_empty(&chan->ld_pending)) {
+               chan_dbg(chan, "no pending LDs\n");
+               return;
+       }
+
+       /*
+        * The DMA controller is not idle, which means that the interrupt
+        * handler will start any queued transactions when it runs after
+        * this transaction finishes
+        */
+       if (!chan->idle) {
+               chan_dbg(chan, "DMA controller still busy\n");
+               return;
+       }
+
+       /*
+        * If there are some link descriptors which have not been
+        * transferred, we need to start the controller
+        */
+
+       /*
+        * Move all elements from the queue of pending transactions
+        * onto the list of running transactions
+        */
+       chan_dbg(chan, "idle, starting controller\n");
+       desc = list_first_entry(&chan->ld_pending, struct fsl_desc_sw, node);
+       list_splice_tail_init(&chan->ld_pending, &chan->ld_running);
+
+       /*
+        * The 85xx DMA controller doesn't clear the channel start bit
+        * automatically at the end of a transfer. Therefore we must clear
+        * it in software before starting the transfer.
+        */
+       if ((chan->feature & FSL_DMA_IP_MASK) == FSL_DMA_IP_85XX) {
+               u32 mode;
+
+               mode = get_mr(chan);
+               mode &= ~FSL_DMA_MR_CS;
+               set_mr(chan, mode);
+       }
+
+       /*
+        * Program the descriptor's address into the DMA controller,
+        * then start the DMA transaction
+        */
+       set_cdar(chan, desc->async_tx.phys);
+       get_cdar(chan);
+
+       dma_start(chan);
+       chan->idle = false;
+}
+
+/**
+ * fsldma_cleanup_descriptors - cleanup link descriptors which are completed
+ * and move them to ld_completed to free until flag 'ack' is set
+ * @chan: Freescale DMA channel
+ *
+ * This function is used on descriptors which have been executed by the DMA
+ * controller. It will run any callbacks, submit any dependencies, then
+ * free these descriptors if flag 'ack' is set.
+ */
+static void fsldma_cleanup_descriptors(struct fsldma_chan *chan)
+{
+       struct fsl_desc_sw *desc, *_desc;
+       dma_cookie_t cookie = 0;
+       dma_addr_t curr_phys = get_cdar(chan);
+       int seen_current = 0;
+
+       fsldma_clean_completed_descriptor(chan);
+
+       /* Run the callback for each descriptor, in order */
+       list_for_each_entry_safe(desc, _desc, &chan->ld_running, node) {
+               /*
+                * do not advance past the current descriptor loaded into the
+                * hardware channel, subsequent descriptors are either in
+                * process or have not been submitted
+                */
+               if (seen_current)
+                       break;
+
+               /*
+                * stop the search if we reach the current descriptor and the
+                * channel is busy
+                */
+               if (desc->async_tx.phys == curr_phys) {
+                       seen_current = 1;
+                       if (!dma_is_idle(chan))
+                               break;
+               }
+
+               cookie = fsldma_run_tx_complete_actions(chan, desc, cookie);
+
+               fsldma_clean_running_descriptor(chan, desc);
+       }
+
+       /*
+        * Start any pending transactions automatically
+        *
+        * In the ideal case, we keep the DMA controller busy while we go
+        * ahead and free the descriptors below.
+        */
+       fsl_chan_xfer_ld_queue(chan);
+
+       if (cookie > 0)
+               chan->common.completed_cookie = cookie;
+}
+
+/**
+ * fsl_dma_alloc_chan_resources - Allocate resources for DMA channel.
+ * @chan : Freescale DMA channel
+ *
+ * This function will create a dma pool for descriptor allocation.
+ *
+ * Return - The number of descriptors allocated.
+ */
+static int fsl_dma_alloc_chan_resources(struct dma_chan *dchan)
+{
+       struct fsldma_chan *chan = to_fsl_chan(dchan);
+
+       /* Has this channel already been allocated? */
+       if (chan->desc_pool)
+               return 1;
+
+       /*
+        * We need the descriptor to be aligned to 32bytes
+        * for meeting FSL DMA specification requirement.
+        */
+       chan->desc_pool = dma_pool_create(chan->name, chan->dev,
+                                         sizeof(struct fsl_desc_sw),
+                                         __alignof__(struct fsl_desc_sw), 0);
+       if (!chan->desc_pool) {
+               chan_err(chan, "unable to allocate descriptor pool\n");
+               return -ENOMEM;
+       }
+
+       /* there is at least one descriptor free to be allocated */
+       return 1;
+}
+
+/**
+ * fsldma_free_desc_list - Free all descriptors in a queue
+ * @chan: Freescae DMA channel
+ * @list: the list to free
+ *
+ * LOCKING: must hold chan->desc_lock
+ */
+static void fsldma_free_desc_list(struct fsldma_chan *chan,
+                                 struct list_head *list)
+{
+       struct fsl_desc_sw *desc, *_desc;
+
+       list_for_each_entry_safe(desc, _desc, list, node)
+               fsl_dma_free_descriptor(chan, desc);
+}
+
+static void fsldma_free_desc_list_reverse(struct fsldma_chan *chan,
+                                         struct list_head *list)
+{
+       struct fsl_desc_sw *desc, *_desc;
+
+       list_for_each_entry_safe_reverse(desc, _desc, list, node)
+               fsl_dma_free_descriptor(chan, desc);
+}
+
+/**
+ * fsl_dma_free_chan_resources - Free all resources of the channel.
+ * @chan : Freescale DMA channel
+ */
+static void fsl_dma_free_chan_resources(struct dma_chan *dchan)
+{
+       struct fsldma_chan *chan = to_fsl_chan(dchan);
+
+       chan_dbg(chan, "free all channel resources\n");
+       spin_lock_bh(&chan->desc_lock);
+       fsldma_cleanup_descriptors(chan);
+       fsldma_free_desc_list(chan, &chan->ld_pending);
+       fsldma_free_desc_list(chan, &chan->ld_running);
+       fsldma_free_desc_list(chan, &chan->ld_completed);
+       spin_unlock_bh(&chan->desc_lock);
+
+       dma_pool_destroy(chan->desc_pool);
+       chan->desc_pool = NULL;
+}
+
+static struct dma_async_tx_descriptor *
+fsl_dma_prep_memcpy(struct dma_chan *dchan,
+       dma_addr_t dma_dst, dma_addr_t dma_src,
+       size_t len, unsigned long flags)
+{
+       struct fsldma_chan *chan;
+       struct fsl_desc_sw *first = NULL, *prev = NULL, *new;
+       size_t copy;
+
+       if (!dchan)
+               return NULL;
+
+       if (!len)
+               return NULL;
+
+       chan = to_fsl_chan(dchan);
+
+       do {
+
+               /* Allocate the link descriptor from DMA pool */
+               new = fsl_dma_alloc_descriptor(chan);
+               if (!new) {
+                       chan_err(chan, "%s\n", msg_ld_oom);
+                       goto fail;
+               }
+
+               copy = min(len, (size_t)FSL_DMA_BCR_MAX_CNT);
+
+               set_desc_cnt(chan, &new->hw, copy);
+               set_desc_src(chan, &new->hw, dma_src);
+               set_desc_dst(chan, &new->hw, dma_dst);
+
+               if (!first)
+                       first = new;
+               else
+                       set_desc_next(chan, &prev->hw, new->async_tx.phys);
+
+               new->async_tx.cookie = 0;
+               async_tx_ack(&new->async_tx);
+
+               prev = new;
+               len -= copy;
+               dma_src += copy;
+               dma_dst += copy;
+
+               /* Insert the link descriptor to the LD ring */
+               list_add_tail(&new->node, &first->tx_list);
+       } while (len);
+
+       new->async_tx.flags = flags; /* client is in control of this ack */
+       new->async_tx.cookie = -EBUSY;
+
+       /* Set End-of-link to the last link descriptor of new list */
+       set_ld_eol(chan, new);
+
+       return &first->async_tx;
+
+fail:
+       if (!first)
+               return NULL;
+
+       fsldma_free_desc_list_reverse(chan, &first->tx_list);
+       return NULL;
+}
+
+static struct dma_async_tx_descriptor *fsl_dma_prep_sg(struct dma_chan *dchan,
+       struct scatterlist *dst_sg, unsigned int dst_nents,
+       struct scatterlist *src_sg, unsigned int src_nents,
+       unsigned long flags)
+{
+       struct fsl_desc_sw *first = NULL, *prev = NULL, *new = NULL;
+       struct fsldma_chan *chan = to_fsl_chan(dchan);
+       size_t dst_avail, src_avail;
+       dma_addr_t dst, src;
+       size_t len;
+
+       /* basic sanity checks */
+       if (dst_nents == 0 || src_nents == 0)
+               return NULL;
+
+       if (dst_sg == NULL || src_sg == NULL)
+               return NULL;
+
+       /*
+        * TODO: should we check that both scatterlists have the same
+        * TODO: number of bytes in total? Is that really an error?
+        */
+
+       /* get prepared for the loop */
+       dst_avail = sg_dma_len(dst_sg);
+       src_avail = sg_dma_len(src_sg);
+
+       /* run until we are out of scatterlist entries */
+       while (true) {
+
+               /* create the largest transaction possible */
+               len = min_t(size_t, src_avail, dst_avail);
+               len = min_t(size_t, len, FSL_DMA_BCR_MAX_CNT);
+               if (len == 0)
+                       goto fetch;
+
+               dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - dst_avail;
+               src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - src_avail;
+
+               /* allocate and populate the descriptor */
+               new = fsl_dma_alloc_descriptor(chan);
+               if (!new) {
+                       chan_err(chan, "%s\n", msg_ld_oom);
+                       goto fail;
+               }
+
+               set_desc_cnt(chan, &new->hw, len);
+               set_desc_src(chan, &new->hw, src);
+               set_desc_dst(chan, &new->hw, dst);
+
+               if (!first)
+                       first = new;
+               else
+                       set_desc_next(chan, &prev->hw, new->async_tx.phys);
+
+               new->async_tx.cookie = 0;
+               async_tx_ack(&new->async_tx);
+               prev = new;
+
+               /* Insert the link descriptor to the LD ring */
+               list_add_tail(&new->node, &first->tx_list);
+
+               /* update metadata */
+               dst_avail -= len;
+               src_avail -= len;
+
+fetch:
+               /* fetch the next dst scatterlist entry */
+               if (dst_avail == 0) {
+
+                       /* no more entries: we're done */
+                       if (dst_nents == 0)
+                               break;
+
+                       /* fetch the next entry: if there are no more: done */
+                       dst_sg = sg_next(dst_sg);
+                       if (dst_sg == NULL)
+                               break;
+
+                       dst_nents--;
+                       dst_avail = sg_dma_len(dst_sg);
+               }
+
+               /* fetch the next src scatterlist entry */
+               if (src_avail == 0) {
+
+                       /* no more entries: we're done */
+                       if (src_nents == 0)
+                               break;
+
+                       /* fetch the next entry: if there are no more: done */
+                       src_sg = sg_next(src_sg);
+                       if (src_sg == NULL)
+                               break;
+
+                       src_nents--;
+                       src_avail = sg_dma_len(src_sg);
+               }
+       }
+
+       new->async_tx.flags = flags; /* client is in control of this ack */
+       new->async_tx.cookie = -EBUSY;
+
+       /* Set End-of-link to the last link descriptor of new list */
+       set_ld_eol(chan, new);
+
+       return &first->async_tx;
+
+fail:
+       if (!first)
+               return NULL;
+
+       fsldma_free_desc_list_reverse(chan, &first->tx_list);
+       return NULL;
+}
+
+static int fsl_dma_device_terminate_all(struct dma_chan *dchan)
+{
+       struct fsldma_chan *chan;
+
+       if (!dchan)
+               return -EINVAL;
+
+       chan = to_fsl_chan(dchan);
+
+       spin_lock_bh(&chan->desc_lock);
+
+       /* Halt the DMA engine */
+       dma_halt(chan);
+
+       /* Remove and free all of the descriptors in the LD queue */
+       fsldma_free_desc_list(chan, &chan->ld_pending);
+       fsldma_free_desc_list(chan, &chan->ld_running);
+       fsldma_free_desc_list(chan, &chan->ld_completed);
+       chan->idle = true;
+
+       spin_unlock_bh(&chan->desc_lock);
+       return 0;
+}
+
+static int fsl_dma_device_config(struct dma_chan *dchan,
+                                struct dma_slave_config *config)
+{
+       struct fsldma_chan *chan;
+       int size;
+
+       if (!dchan)
+               return -EINVAL;
+
+       chan = to_fsl_chan(dchan);
+
+       /* make sure the channel supports setting burst size */
+       if (!chan->set_request_count)
+               return -ENXIO;
+
+       /* we set the controller burst size depending on direction */
+       if (config->direction == DMA_MEM_TO_DEV)
+               size = config->dst_addr_width * config->dst_maxburst;
+       else
+               size = config->src_addr_width * config->src_maxburst;
+
+       chan->set_request_count(chan, size);
+       return 0;
+}
+
+
+/**
+ * fsl_dma_memcpy_issue_pending - Issue the DMA start command
+ * @chan : Freescale DMA channel
+ */
+static void fsl_dma_memcpy_issue_pending(struct dma_chan *dchan)
+{
+       struct fsldma_chan *chan = to_fsl_chan(dchan);
+
+       spin_lock_bh(&chan->desc_lock);
+       fsl_chan_xfer_ld_queue(chan);
+       spin_unlock_bh(&chan->desc_lock);
+}
+
+/**
+ * fsl_tx_status - Determine the DMA status
+ * @chan : Freescale DMA channel
+ */
+static enum dma_status fsl_tx_status(struct dma_chan *dchan,
+                                       dma_cookie_t cookie,
+                                       struct dma_tx_state *txstate)
+{
+       struct fsldma_chan *chan = to_fsl_chan(dchan);
+       enum dma_status ret;
+
+       ret = dma_cookie_status(dchan, cookie, txstate);
+       if (ret == DMA_COMPLETE)
+               return ret;
+
+       spin_lock_bh(&chan->desc_lock);
+       fsldma_cleanup_descriptors(chan);
+       spin_unlock_bh(&chan->desc_lock);
+
+       return dma_cookie_status(dchan, cookie, txstate);
+}
+
+/*----------------------------------------------------------------------------*/
+/* Interrupt Handling                                                         */
+/*----------------------------------------------------------------------------*/
+
+static irqreturn_t fsldma_chan_irq(int irq, void *data)
+{
+       struct fsldma_chan *chan = data;
+       u32 stat;
+
+       /* save and clear the status register */
+       stat = get_sr(chan);
+       set_sr(chan, stat);
+       chan_dbg(chan, "irq: stat = 0x%x\n", stat);
+
+       /* check that this was really our device */
+       stat &= ~(FSL_DMA_SR_CB | FSL_DMA_SR_CH);
+       if (!stat)
+               return IRQ_NONE;
+
+       if (stat & FSL_DMA_SR_TE)
+               chan_err(chan, "Transfer Error!\n");
+
+       /*
+        * Programming Error
+        * The DMA_INTERRUPT async_tx is a NULL transfer, which will
+        * trigger a PE interrupt.
+        */
+       if (stat & FSL_DMA_SR_PE) {
+               chan_dbg(chan, "irq: Programming Error INT\n");
+               stat &= ~FSL_DMA_SR_PE;
+               if (get_bcr(chan) != 0)
+                       chan_err(chan, "Programming Error!\n");
+       }
+
+       /*
+        * For MPC8349, EOCDI event need to update cookie
+        * and start the next transfer if it exist.
+        */
+       if (stat & FSL_DMA_SR_EOCDI) {
+               chan_dbg(chan, "irq: End-of-Chain link INT\n");
+               stat &= ~FSL_DMA_SR_EOCDI;
+       }
+
+       /*
+        * If it current transfer is the end-of-transfer,
+        * we should clear the Channel Start bit for
+        * prepare next transfer.
+        */
+       if (stat & FSL_DMA_SR_EOLNI) {
+               chan_dbg(chan, "irq: End-of-link INT\n");
+               stat &= ~FSL_DMA_SR_EOLNI;
+       }
+
+       /* check that the DMA controller is really idle */
+       if (!dma_is_idle(chan))
+               chan_err(chan, "irq: controller not idle!\n");
+
+       /* check that we handled all of the bits */
+       if (stat)
+               chan_err(chan, "irq: unhandled sr 0x%08x\n", stat);
+
+       /*
+        * Schedule the tasklet to handle all cleanup of the current
+        * transaction. It will start a new transaction if there is
+        * one pending.
+        */
+       tasklet_schedule(&chan->tasklet);
+       chan_dbg(chan, "irq: Exit\n");
+       return IRQ_HANDLED;
+}
+
+static void dma_do_tasklet(unsigned long data)
+{
+       struct fsldma_chan *chan = (struct fsldma_chan *)data;
+
+       chan_dbg(chan, "tasklet entry\n");
+
+       spin_lock_bh(&chan->desc_lock);
+
+       /* the hardware is now idle and ready for more */
+       chan->idle = true;
+
+       /* Run all cleanup for descriptors which have been completed */
+       fsldma_cleanup_descriptors(chan);
+
+       spin_unlock_bh(&chan->desc_lock);
+
+       chan_dbg(chan, "tasklet exit\n");
+}
+
+static irqreturn_t fsldma_ctrl_irq(int irq, void *data)
+{
+       struct fsldma_device *fdev = data;
+       struct fsldma_chan *chan;
+       unsigned int handled = 0;
+       u32 gsr, mask;
+       int i;
+
+       gsr = (fdev->feature & FSL_DMA_BIG_ENDIAN) ? in_be32(fdev->regs)
+                                                  : in_le32(fdev->regs);
+       mask = 0xff000000;
+       dev_dbg(fdev->dev, "IRQ: gsr 0x%.8x\n", gsr);
+
+       for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+               chan = fdev->chan[i];
+               if (!chan)
+                       continue;
+
+               if (gsr & mask) {
+                       dev_dbg(fdev->dev, "IRQ: chan %d\n", chan->id);
+                       fsldma_chan_irq(irq, chan);
+                       handled++;
+               }
+
+               gsr &= ~mask;
+               mask >>= 8;
+       }
+
+       return IRQ_RETVAL(handled);
+}
+
+static void fsldma_free_irqs(struct fsldma_device *fdev)
+{
+       struct fsldma_chan *chan;
+       int i;
+
+       if (fdev->irq != NO_IRQ) {
+               dev_dbg(fdev->dev, "free per-controller IRQ\n");
+               free_irq(fdev->irq, fdev);
+               return;
+       }
+
+       for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+               chan = fdev->chan[i];
+               if (chan && chan->irq != NO_IRQ) {
+                       chan_dbg(chan, "free per-channel IRQ\n");
+                       free_irq(chan->irq, chan);
+               }
+       }
+}
+
+static int fsldma_request_irqs(struct fsldma_device *fdev)
+{
+       struct fsldma_chan *chan;
+       int ret;
+       int i;
+
+       /* if we have a per-controller IRQ, use that */
+       if (fdev->irq != NO_IRQ) {
+               dev_dbg(fdev->dev, "request per-controller IRQ\n");
+               ret = request_irq(fdev->irq, fsldma_ctrl_irq, IRQF_SHARED,
+                                 "fsldma-controller", fdev);
+               return ret;
+       }
+
+       /* no per-controller IRQ, use the per-channel IRQs */
+       for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+               chan = fdev->chan[i];
+               if (!chan)
+                       continue;
+
+               if (chan->irq == NO_IRQ) {
+                       chan_err(chan, "interrupts property missing in device tree\n");
+                       ret = -ENODEV;
+                       goto out_unwind;
+               }
+
+               chan_dbg(chan, "request per-channel IRQ\n");
+               ret = request_irq(chan->irq, fsldma_chan_irq, IRQF_SHARED,
+                                 "fsldma-chan", chan);
+               if (ret) {
+                       chan_err(chan, "unable to request per-channel IRQ\n");
+                       goto out_unwind;
+               }
+       }
+
+       return 0;
+
+out_unwind:
+       for (/* none */; i >= 0; i--) {
+               chan = fdev->chan[i];
+               if (!chan)
+                       continue;
+
+               if (chan->irq == NO_IRQ)
+                       continue;
+
+               free_irq(chan->irq, chan);
+       }
+
+       return ret;
+}
+
+/*----------------------------------------------------------------------------*/
+/* OpenFirmware Subsystem                                                     */
+/*----------------------------------------------------------------------------*/
+
+static int fsl_dma_chan_probe(struct fsldma_device *fdev,
+       struct device_node *node, u32 feature, const char *compatible)
+{
+       struct fsldma_chan *chan;
+       struct resource res;
+       int err;
+
+       /* alloc channel */
+       chan = kzalloc(sizeof(*chan), GFP_KERNEL);
+       if (!chan) {
+               dev_err(fdev->dev, "no free memory for DMA channels!\n");
+               err = -ENOMEM;
+               goto out_return;
+       }
+
+       /* ioremap registers for use */
+       chan->regs = of_iomap(node, 0);
+       if (!chan->regs) {
+               dev_err(fdev->dev, "unable to ioremap registers\n");
+               err = -ENOMEM;
+               goto out_free_chan;
+       }
+
+       err = of_address_to_resource(node, 0, &res);
+       if (err) {
+               dev_err(fdev->dev, "unable to find 'reg' property\n");
+               goto out_iounmap_regs;
+       }
+
+       chan->feature = feature;
+       if (!fdev->feature)
+               fdev->feature = chan->feature;
+
+       /*
+        * If the DMA device's feature is different than the feature
+        * of its channels, report the bug
+        */
+       WARN_ON(fdev->feature != chan->feature);
+
+       chan->dev = fdev->dev;
+       chan->id = (res.start & 0xfff) < 0x300 ?
+                  ((res.start - 0x100) & 0xfff) >> 7 :
+                  ((res.start - 0x200) & 0xfff) >> 7;
+       if (chan->id >= FSL_DMA_MAX_CHANS_PER_DEVICE) {
+               dev_err(fdev->dev, "too many channels for device\n");
+               err = -EINVAL;
+               goto out_iounmap_regs;
+       }
+
+       fdev->chan[chan->id] = chan;
+       tasklet_init(&chan->tasklet, dma_do_tasklet, (unsigned long)chan);
+       snprintf(chan->name, sizeof(chan->name), "chan%d", chan->id);
+
+       /* Initialize the channel */
+       dma_init(chan);
+
+       /* Clear cdar registers */
+       set_cdar(chan, 0);
+
+       switch (chan->feature & FSL_DMA_IP_MASK) {
+       case FSL_DMA_IP_85XX:
+               chan->toggle_ext_pause = fsl_chan_toggle_ext_pause;
+       case FSL_DMA_IP_83XX:
+               chan->toggle_ext_start = fsl_chan_toggle_ext_start;
+               chan->set_src_loop_size = fsl_chan_set_src_loop_size;
+               chan->set_dst_loop_size = fsl_chan_set_dst_loop_size;
+               chan->set_request_count = fsl_chan_set_request_count;
+       }
+
+       spin_lock_init(&chan->desc_lock);
+       INIT_LIST_HEAD(&chan->ld_pending);
+       INIT_LIST_HEAD(&chan->ld_running);
+       INIT_LIST_HEAD(&chan->ld_completed);
+       chan->idle = true;
+#ifdef CONFIG_PM
+       chan->pm_state = RUNNING;
+#endif
+
+       chan->common.device = &fdev->common;
+       dma_cookie_init(&chan->common);
+
+       /* find the IRQ line, if it exists in the device tree */
+       chan->irq = irq_of_parse_and_map(node, 0);
+
+       /* Add the channel to DMA device channel list */
+       list_add_tail(&chan->common.device_node, &fdev->common.channels);
+
+       dev_info(fdev->dev, "#%d (%s), irq %d\n", chan->id, compatible,
+                chan->irq != NO_IRQ ? chan->irq : fdev->irq);
+
+       return 0;
+
+out_iounmap_regs:
+       iounmap(chan->regs);
+out_free_chan:
+       kfree(chan);
+out_return:
+       return err;
+}
+
+static void fsl_dma_chan_remove(struct fsldma_chan *chan)
+{
+       irq_dispose_mapping(chan->irq);
+       list_del(&chan->common.device_node);
+       iounmap(chan->regs);
+       kfree(chan);
+}
+
+static int fsldma_of_probe(struct platform_device *op)
+{
+       struct fsldma_device *fdev;
+       struct device_node *child;
+       int err;
+
+       fdev = kzalloc(sizeof(*fdev), GFP_KERNEL);
+       if (!fdev) {
+               dev_err(&op->dev, "No enough memory for 'priv'\n");
+               err = -ENOMEM;
+               goto out_return;
+       }
+
+       fdev->dev = &op->dev;
+       INIT_LIST_HEAD(&fdev->common.channels);
+
+       /* ioremap the registers for use */
+       fdev->regs = of_iomap(op->dev.of_node, 0);
+       if (!fdev->regs) {
+               dev_err(&op->dev, "unable to ioremap registers\n");
+               err = -ENOMEM;
+               goto out_free_fdev;
+       }
+
+       /* map the channel IRQ if it exists, but don't hookup the handler yet */
+       fdev->irq = irq_of_parse_and_map(op->dev.of_node, 0);
+
+       dma_cap_set(DMA_MEMCPY, fdev->common.cap_mask);
+       dma_cap_set(DMA_SG, fdev->common.cap_mask);
+       dma_cap_set(DMA_SLAVE, fdev->common.cap_mask);
+       fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources;
+       fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources;
+       fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy;
+       fdev->common.device_prep_dma_sg = fsl_dma_prep_sg;
+       fdev->common.device_tx_status = fsl_tx_status;
+       fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending;
+       fdev->common.device_config = fsl_dma_device_config;
+       fdev->common.device_terminate_all = fsl_dma_device_terminate_all;
+       fdev->common.dev = &op->dev;
+
+       fdev->common.src_addr_widths = FSL_DMA_BUSWIDTHS;
+       fdev->common.dst_addr_widths = FSL_DMA_BUSWIDTHS;
+       fdev->common.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+       fdev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+
+       dma_set_mask(&(op->dev), DMA_BIT_MASK(36));
+
+       platform_set_drvdata(op, fdev);
+
+       /*
+        * We cannot use of_platform_bus_probe() because there is no
+        * of_platform_bus_remove(). Instead, we manually instantiate every DMA
+        * channel object.
+        */
+       for_each_child_of_node(op->dev.of_node, child) {
+               if (of_device_is_compatible(child, "fsl,eloplus-dma-channel")) {
+                       fsl_dma_chan_probe(fdev, child,
+                               FSL_DMA_IP_85XX | FSL_DMA_BIG_ENDIAN,
+                               "fsl,eloplus-dma-channel");
+               }
+
+               if (of_device_is_compatible(child, "fsl,elo-dma-channel")) {
+                       fsl_dma_chan_probe(fdev, child,
+                               FSL_DMA_IP_83XX | FSL_DMA_LITTLE_ENDIAN,
+                               "fsl,elo-dma-channel");
+               }
+       }
+
+       /*
+        * Hookup the IRQ handler(s)
+        *
+        * If we have a per-controller interrupt, we prefer that to the
+        * per-channel interrupts to reduce the number of shared interrupt
+        * handlers on the same IRQ line
+        */
+       err = fsldma_request_irqs(fdev);
+       if (err) {
+               dev_err(fdev->dev, "unable to request IRQs\n");
+               goto out_free_fdev;
+       }
+
+       dma_async_device_register(&fdev->common);
+       return 0;
+
+out_free_fdev:
+       irq_dispose_mapping(fdev->irq);
+       kfree(fdev);
+out_return:
+       return err;
+}
+
+static int fsldma_of_remove(struct platform_device *op)
+{
+       struct fsldma_device *fdev;
+       unsigned int i;
+
+       fdev = platform_get_drvdata(op);
+       dma_async_device_unregister(&fdev->common);
+
+       fsldma_free_irqs(fdev);
+
+       for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+               if (fdev->chan[i])
+                       fsl_dma_chan_remove(fdev->chan[i]);
+       }
+
+       iounmap(fdev->regs);
+       kfree(fdev);
+
+       return 0;
+}
+
+#ifdef CONFIG_PM
+static int fsldma_suspend_late(struct device *dev)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct fsldma_device *fdev = platform_get_drvdata(pdev);
+       struct fsldma_chan *chan;
+       int i;
+
+       for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+               chan = fdev->chan[i];
+               if (!chan)
+                       continue;
+
+               spin_lock_bh(&chan->desc_lock);
+               if (unlikely(!chan->idle))
+                       goto out;
+               chan->regs_save.mr = get_mr(chan);
+               chan->pm_state = SUSPENDED;
+               spin_unlock_bh(&chan->desc_lock);
+       }
+       return 0;
+
+out:
+       for (; i >= 0; i--) {
+               chan = fdev->chan[i];
+               if (!chan)
+                       continue;
+               chan->pm_state = RUNNING;
+               spin_unlock_bh(&chan->desc_lock);
+       }
+       return -EBUSY;
+}
+
+static int fsldma_resume_early(struct device *dev)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct fsldma_device *fdev = platform_get_drvdata(pdev);
+       struct fsldma_chan *chan;
+       u32 mode;
+       int i;
+
+       for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+               chan = fdev->chan[i];
+               if (!chan)
+                       continue;
+
+               spin_lock_bh(&chan->desc_lock);
+               mode = chan->regs_save.mr
+                       & ~FSL_DMA_MR_CS & ~FSL_DMA_MR_CC & ~FSL_DMA_MR_CA;
+               set_mr(chan, mode);
+               chan->pm_state = RUNNING;
+               spin_unlock_bh(&chan->desc_lock);
+       }
+
+       return 0;
+}
+
+static const struct dev_pm_ops fsldma_pm_ops = {
+       .suspend_late   = fsldma_suspend_late,
+       .resume_early   = fsldma_resume_early,
+};
+#endif
+
+static const struct of_device_id fsldma_of_ids[] = {
+       { .compatible = "fsl,elo3-dma", },
+       { .compatible = "fsl,eloplus-dma", },
+       { .compatible = "fsl,elo-dma", },
+       {}
+};
+
+static struct platform_driver fsldma_of_driver = {
+       .driver = {
+               .name = "fsl-elo-dma",
+               .of_match_table = fsldma_of_ids,
+#ifdef CONFIG_PM
+               .pm = &fsldma_pm_ops,
+#endif
+       },
+       .probe = fsldma_of_probe,
+       .remove = fsldma_of_remove,
+};
+
+/*----------------------------------------------------------------------------*/
+/* Module Init / Exit                                                         */
+/*----------------------------------------------------------------------------*/
+
+static __init int fsldma_init(void)
+{
+       pr_info("Freescale Elo series DMA driver\n");
+       return platform_driver_register(&fsldma_of_driver);
+}
+
+static void __exit fsldma_exit(void)
+{
+       platform_driver_unregister(&fsldma_of_driver);
+}
+
+subsys_initcall(fsldma_init);
+module_exit(fsldma_exit);
+
+MODULE_DESCRIPTION("Freescale Elo series DMA driver");
+MODULE_LICENSE("GPL");