Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1430 insertions, 0 deletions

diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c
new file mode 100644
index 000000000..f8459cc53
--- /dev/null
+++ b/drivers/dma/fsldma.c
@@ -0,0 +1,1430 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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.
+ */
+
+#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)
+{
+	FSL_DMA_OUT(chan, &chan->regs->sr, val, 32);
+}
+
+static u32 get_sr(struct fsldma_chan *chan)
+{
+	return FSL_DMA_IN(chan, &chan->regs->sr, 32);
+}
+
+static void set_mr(struct fsldma_chan *chan, u32 val)
+{
+	FSL_DMA_OUT(chan, &chan->regs->mr, val, 32);
+}
+
+static u32 get_mr(struct fsldma_chan *chan)
+{
+	return FSL_DMA_IN(chan, &chan->regs->mr, 32);
+}
+
+static void set_cdar(struct fsldma_chan *chan, dma_addr_t addr)
+{
+	FSL_DMA_OUT(chan, &chan->regs->cdar, addr | FSL_DMA_SNEN, 64);
+}
+
+static dma_addr_t get_cdar(struct fsldma_chan *chan)
+{
+	return FSL_DMA_IN(chan, &chan->regs->cdar, 64) & ~FSL_DMA_SNEN;
+}
+
+static void set_bcr(struct fsldma_chan *chan, u32 val)
+{
+	FSL_DMA_OUT(chan, &chan->regs->bcr, val, 32);
+}
+
+static u32 get_bcr(struct fsldma_chan *chan)
+{
+	return FSL_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_SAHTS_MASK;
+		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_DAHTS_MASK;
+		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 &= ~FSL_DMA_MR_BWC_MASK;
+	mode |= (__ilog2(size) << 24) & FSL_DMA_MR_BWC_MASK;
+
+	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_zalloc(chan->desc_pool, GFP_ATOMIC, &pdesc);
+	if (!desc) {
+		chan_dbg(chan, "out of memory for link descriptor\n");
+		return NULL;
+	}
+
+	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;
+
+		dma_descriptor_unmap(txd);
+		/* Run the link descriptor callback function */
+		dmaengine_desc_get_callback_invoke(txd, NULL);
+	}
+
+	/* 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 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(struct tasklet_struct *t)
+{
+	struct fsldma_chan *chan = from_tasklet(chan, t, tasklet);
+
+	chan_dbg(chan, "tasklet entry\n");
+
+	spin_lock(&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(&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) {
+		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) {
+			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) {
+		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) {
+			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)
+			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) {
+		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_setup(&chan->tasklet, dma_do_tasklet);
+	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;
+		fallthrough;
+	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 ? 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;
+	unsigned int i;
+	int err;
+
+	fdev = kzalloc(sizeof(*fdev), GFP_KERNEL);
+	if (!fdev) {
+		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;
+	}
+
+	/* 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_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_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:
+	for (i = 0; i < FSL_DMA_MAX_CHANS_PER_DEVICE; i++) {
+		if (fdev->chan[i])
+			fsl_dma_chan_remove(fdev->chan[i]);
+	}
+	irq_dispose_mapping(fdev->irq);
+	iounmap(fdev->regs);
+out_free:
+	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]);
+	}
+	irq_dispose_mapping(fdev->irq);
+
+	iounmap(fdev->regs);
+	kfree(fdev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int fsldma_suspend_late(struct device *dev)
+{
+	struct fsldma_device *fdev = dev_get_drvdata(dev);
+	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 fsldma_device *fdev = dev_get_drvdata(dev);
+	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", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, fsldma_of_ids);
+
+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");