[alsa-devel] [PATCH 1/7 v2] dmaengine: add a simple dma library
Guennadi Liakhovetski
g.liakhovetski at gmx.de
Thu Jan 26 15:56:18 CET 2012
This patch adds a library of functions, helping to implement dmaengine
drivers for hardware, unable to handle scatter-gather lists natively.
The first version of this driver only supports memcpy and slave DMA
operation.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
---
v2:
1. switch from using a tasklet to threaded IRQ, which allowed to
2. remove lock / unlock inline functions
3. remove __devinit, __devexit annotations
drivers/dma/Kconfig | 3 +
drivers/dma/Makefile | 1 +
drivers/dma/dma-simple.c | 873 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/dma-simple.h | 124 +++++++
4 files changed, 1001 insertions(+), 0 deletions(-)
create mode 100644 drivers/dma/dma-simple.c
create mode 100644 include/linux/dma-simple.h
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index f1a2749..f7c583e 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -149,6 +149,9 @@ config TXX9_DMAC
Support the TXx9 SoC internal DMA controller. This can be
integrated in chips such as the Toshiba TX4927/38/39.
+config DMA_SIMPLE
+ tristate
+
config SH_DMAE
tristate "Renesas SuperH DMAC support"
depends on (SUPERH && SH_DMA) || (ARM && ARCH_SHMOBILE)
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 009a222..d63f773 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -2,6 +2,7 @@ ccflags-$(CONFIG_DMADEVICES_DEBUG) := -DDEBUG
ccflags-$(CONFIG_DMADEVICES_VDEBUG) += -DVERBOSE_DEBUG
obj-$(CONFIG_DMA_ENGINE) += dmaengine.o
+obj-$(CONFIG_DMA_SIMPLE) += dma-simple.o
obj-$(CONFIG_NET_DMA) += iovlock.o
obj-$(CONFIG_INTEL_MID_DMAC) += intel_mid_dma.o
obj-$(CONFIG_DMATEST) += dmatest.o
diff --git a/drivers/dma/dma-simple.c b/drivers/dma/dma-simple.c
new file mode 100644
index 0000000..49d8f7d
--- /dev/null
+++ b/drivers/dma/dma-simple.c
@@ -0,0 +1,873 @@
+/*
+ * Simple dmaengine driver library
+ *
+ * extracted from shdma.c
+ *
+ * Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski at gmx.de>
+ * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro at renesas.com>
+ * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
+ * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/delay.h>
+#include <linux/dma-simple.h>
+#include <linux/dmaengine.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+/* DMA descriptor control */
+enum simple_desc_status {
+ DESC_IDLE,
+ DESC_PREPARED,
+ DESC_SUBMITTED,
+ DESC_COMPLETED, /* completed, have to call callback */
+ DESC_WAITING, /* callback called, waiting for ack / re-submit */
+};
+
+#define NR_DESCS_PER_CHANNEL 32
+
+#define to_simple_chan(c) container_of(c, struct dma_simple_chan, dma_chan)
+#define to_simple_dev(d) container_of(d, struct dma_simple_dev, dma_dev)
+
+/*
+ * For slave DMA we assume, that there is a finite number of DMA slaves in the
+ * system, and that each such slave can only use a finite number of channels.
+ * We use slave channel IDs to make sure, that no such slave channel ID is
+ * allocated more than once.
+ */
+static unsigned int slave_num = 256;
+module_param(slave_num, uint, 0444);
+
+/* A bitmask with slave_num bits */
+static unsigned long *simple_slave_used;
+
+/* Called under spin_lock_irq(&schan->chan_lock") */
+static void simple_chan_xfer_ld_queue(struct dma_simple_chan *schan)
+{
+ struct dma_simple_dev *sdev = to_simple_dev(schan->dma_chan.device);
+ const struct dma_simple_ops *ops = sdev->ops;
+ struct dma_simple_desc *sdesc;
+
+ /* DMA work check */
+ if (ops->channel_busy(schan))
+ return;
+
+ /* Find the first not transferred descriptor */
+ list_for_each_entry(sdesc, &schan->ld_queue, node)
+ if (sdesc->mark == DESC_SUBMITTED) {
+ ops->start_xfer(schan, sdesc);
+ break;
+ }
+}
+
+static dma_cookie_t simple_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+ struct dma_simple_desc *chunk, *c, *desc =
+ container_of(tx, struct dma_simple_desc, async_tx),
+ *last = desc;
+ struct dma_simple_chan *schan = to_simple_chan(tx->chan);
+ struct dma_simple_slave *slave = tx->chan->private;
+ dma_async_tx_callback callback = tx->callback;
+ dma_cookie_t cookie;
+ bool power_up;
+
+ spin_lock_irq(&schan->chan_lock);
+
+ power_up = list_empty(&schan->ld_queue);
+
+ cookie = schan->dma_chan.cookie + 1;
+ if (cookie < 0)
+ cookie = 1;
+
+ schan->dma_chan.cookie = cookie;
+ tx->cookie = cookie;
+
+ /* Mark all chunks of this descriptor as submitted, move to the queue */
+ list_for_each_entry_safe(chunk, c, desc->node.prev, node) {
+ /*
+ * All chunks are on the global ld_free, so, we have to find
+ * the end of the chain ourselves
+ */
+ if (chunk != desc && (chunk->mark == DESC_IDLE ||
+ chunk->async_tx.cookie > 0 ||
+ chunk->async_tx.cookie == -EBUSY ||
+ &chunk->node == &schan->ld_free))
+ break;
+ chunk->mark = DESC_SUBMITTED;
+ /* Callback goes to the last chunk */
+ chunk->async_tx.callback = NULL;
+ chunk->cookie = cookie;
+ list_move_tail(&chunk->node, &schan->ld_queue);
+ last = chunk;
+
+ dev_dbg(schan->dev, "submit #%d@%p on %d\n",
+ tx->cookie, &last->async_tx, schan->id);
+ }
+
+ last->async_tx.callback = callback;
+ last->async_tx.callback_param = tx->callback_param;
+
+ if (power_up) {
+ int ret;
+ schan->pm_state = DMA_SIMPLE_PM_BUSY;
+
+ ret = pm_runtime_get(schan->dev);
+
+ spin_unlock_irq(&schan->chan_lock);
+ if (ret < 0)
+ dev_err(schan->dev, "%s(): GET = %d\n", __func__, ret);
+
+ pm_runtime_barrier(schan->dev);
+
+ spin_lock_irq(&schan->chan_lock);
+
+ /* Have we been reset, while waiting? */
+ if (schan->pm_state != DMA_SIMPLE_PM_ESTABLISHED) {
+ struct dma_simple_dev *sdev =
+ to_simple_dev(schan->dma_chan.device);
+ const struct dma_simple_ops *ops = sdev->ops;
+ dev_dbg(schan->dev, "Bring up channel %d\n",
+ schan->id);
+ /*
+ * TODO: .xfer_setup() might fail on some platforms.
+ * Make it int then, on error remove chunks from the
+ * queue again
+ */
+ ops->setup_xfer(schan, slave);
+
+ if (schan->pm_state == DMA_SIMPLE_PM_PENDING)
+ simple_chan_xfer_ld_queue(schan);
+ schan->pm_state = DMA_SIMPLE_PM_ESTABLISHED;
+ }
+ } else {
+ /*
+ * Tell .device_issue_pending() not to run the queue, interrupts
+ * will do it anyway
+ */
+ schan->pm_state = DMA_SIMPLE_PM_PENDING;
+ }
+
+ spin_unlock_irq(&schan->chan_lock);
+
+ return cookie;
+}
+
+/* Called with desc_lock held */
+static struct dma_simple_desc *simple_get_desc(struct dma_simple_chan *schan)
+{
+ struct dma_simple_desc *sdesc;
+
+ list_for_each_entry(sdesc, &schan->ld_free, node)
+ if (sdesc->mark != DESC_PREPARED) {
+ BUG_ON(sdesc->mark != DESC_IDLE);
+ list_del(&sdesc->node);
+ return sdesc;
+ }
+
+ return NULL;
+}
+
+static int simple_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct dma_simple_chan *schan = to_simple_chan(chan);
+ struct dma_simple_dev *sdev = to_simple_dev(schan->dma_chan.device);
+ const struct dma_simple_ops *ops = sdev->ops;
+ struct dma_simple_desc *desc;
+ struct dma_simple_slave *slave = chan->private;
+ int ret, i;
+
+ /*
+ * This relies on the guarantee from dmaengine that alloc_chan_resources
+ * never runs concurrently with itself or free_chan_resources.
+ */
+ if (slave) {
+ if (test_and_set_bit(slave->slave_id, simple_slave_used)) {
+ ret = -EBUSY;
+ goto etestused;
+ }
+
+ ret = ops->set_slave(schan, slave);
+ if (ret < 0)
+ goto esetslave;
+ }
+
+ schan->desc = kcalloc(NR_DESCS_PER_CHANNEL,
+ sdev->desc_size, GFP_KERNEL);
+ if (!schan->desc) {
+ ret = -ENOMEM;
+ goto edescalloc;
+ }
+ schan->desc_num = NR_DESCS_PER_CHANNEL;
+
+ for (i = 0; i < NR_DESCS_PER_CHANNEL; i++) {
+ desc = ops->embedded_desc(schan->desc, i);
+ dma_async_tx_descriptor_init(&desc->async_tx,
+ &schan->dma_chan);
+ desc->async_tx.tx_submit = simple_tx_submit;
+ desc->mark = DESC_IDLE;
+
+ list_add(&desc->node, &schan->ld_free);
+ }
+
+ return NR_DESCS_PER_CHANNEL;
+
+edescalloc:
+ if (slave)
+esetslave:
+ clear_bit(slave->slave_id, simple_slave_used);
+etestused:
+ chan->private = NULL;
+ return ret;
+}
+
+static dma_async_tx_callback __ld_cleanup(struct dma_simple_chan *schan, bool all)
+{
+ struct dma_simple_desc *desc, *_desc;
+ /* Is the "exposed" head of a chain acked? */
+ bool head_acked = false;
+ dma_cookie_t cookie = 0;
+ dma_async_tx_callback callback = NULL;
+ void *param = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&schan->chan_lock, flags);
+ list_for_each_entry_safe(desc, _desc, &schan->ld_queue, node) {
+ struct dma_async_tx_descriptor *tx = &desc->async_tx;
+
+ BUG_ON(tx->cookie > 0 && tx->cookie != desc->cookie);
+ BUG_ON(desc->mark != DESC_SUBMITTED &&
+ desc->mark != DESC_COMPLETED &&
+ desc->mark != DESC_WAITING);
+
+ /*
+ * queue is ordered, and we use this loop to (1) clean up all
+ * completed descriptors, and to (2) update descriptor flags of
+ * any chunks in a (partially) completed chain
+ */
+ if (!all && desc->mark == DESC_SUBMITTED &&
+ desc->cookie != cookie)
+ break;
+
+ if (tx->cookie > 0)
+ cookie = tx->cookie;
+
+ if (desc->mark == DESC_COMPLETED && desc->chunks == 1) {
+ if (schan->completed_cookie != desc->cookie - 1)
+ dev_dbg(schan->dev,
+ "Completing cookie %d, expected %d\n",
+ desc->cookie,
+ schan->completed_cookie + 1);
+ schan->completed_cookie = desc->cookie;
+ }
+
+ /* Call callback on the last chunk */
+ if (desc->mark == DESC_COMPLETED && tx->callback) {
+ desc->mark = DESC_WAITING;
+ callback = tx->callback;
+ param = tx->callback_param;
+ dev_dbg(schan->dev, "descriptor #%d@%p on %d callback\n",
+ tx->cookie, tx, schan->id);
+ BUG_ON(desc->chunks != 1);
+ break;
+ }
+
+ if (tx->cookie > 0 || tx->cookie == -EBUSY) {
+ if (desc->mark == DESC_COMPLETED) {
+ BUG_ON(tx->cookie < 0);
+ desc->mark = DESC_WAITING;
+ }
+ head_acked = async_tx_test_ack(tx);
+ } else {
+ switch (desc->mark) {
+ case DESC_COMPLETED:
+ desc->mark = DESC_WAITING;
+ /* Fall through */
+ case DESC_WAITING:
+ if (head_acked)
+ async_tx_ack(&desc->async_tx);
+ }
+ }
+
+ dev_dbg(schan->dev, "descriptor %p #%d completed.\n",
+ tx, tx->cookie);
+
+ if (((desc->mark == DESC_COMPLETED ||
+ desc->mark == DESC_WAITING) &&
+ async_tx_test_ack(&desc->async_tx)) || all) {
+ /* Remove from ld_queue list */
+ desc->mark = DESC_IDLE;
+
+ list_move(&desc->node, &schan->ld_free);
+
+ if (list_empty(&schan->ld_queue)) {
+ dev_dbg(schan->dev, "Bring down channel %d\n", schan->id);
+ pm_runtime_put(schan->dev);
+ schan->pm_state = DMA_SIMPLE_PM_ESTABLISHED;
+ }
+ }
+ }
+
+ if (all && !callback)
+ /*
+ * Terminating and the loop completed normally: forgive
+ * uncompleted cookies
+ */
+ schan->completed_cookie = schan->dma_chan.cookie;
+
+ spin_unlock_irqrestore(&schan->chan_lock, flags);
+
+ if (callback)
+ callback(param);
+
+ return callback;
+}
+
+/*
+ * simple_chan_ld_cleanup - Clean up link descriptors
+ *
+ * Clean up the ld_queue of DMA channel.
+ */
+static void simple_chan_ld_cleanup(struct dma_simple_chan *schan, bool all)
+{
+ while (__ld_cleanup(schan, all))
+ ;
+}
+
+/*
+ * simple_free_chan_resources - Free all resources of the channel.
+ */
+static void simple_free_chan_resources(struct dma_chan *chan)
+{
+ struct dma_simple_chan *schan = to_simple_chan(chan);
+ struct dma_simple_dev *sdev = to_simple_dev(chan->device);
+ const struct dma_simple_ops *ops = sdev->ops;
+ LIST_HEAD(list);
+
+ /* Protect against ISR */
+ spin_lock_irq(&schan->chan_lock);
+ ops->halt_channel(schan);
+ spin_unlock_irq(&schan->chan_lock);
+
+ /* Now no new interrupts will occur */
+
+ /* Prepared and not submitted descriptors can still be on the queue */
+ if (!list_empty(&schan->ld_queue))
+ simple_chan_ld_cleanup(schan, true);
+
+ if (chan->private) {
+ /* The caller is holding dma_list_mutex */
+ struct dma_simple_slave *slave = chan->private;
+ clear_bit(slave->slave_id, simple_slave_used);
+ chan->private = NULL;
+ }
+
+ spin_lock_irq(&schan->chan_lock);
+
+ list_splice_init(&schan->ld_free, &list);
+ schan->desc_num = 0;
+
+ spin_unlock_irq(&schan->chan_lock);
+
+ kfree(schan->desc);
+}
+
+/**
+ * simple_add_desc - get, set up and return one transfer descriptor
+ * @schan: DMA channel
+ * @flags: DMA transfer flags
+ * @dst: destination DMA address, incremented when direction equals
+ * DMA_DEV_TO_MEM or DMA_MEM_TO_MEM
+ * @src: source DMA address, incremented when direction equals
+ * DMA_MEM_TO_DEV or DMA_MEM_TO_MEM
+ * @len: DMA transfer length
+ * @first: if NULL, set to the current descriptor and cookie set to -EBUSY
+ * @direction: needed for slave DMA to decide which address to keep constant,
+ * equals DMA_MEM_TO_MEM for MEMCPY
+ * Returns 0 or an error
+ * Locks: called with desc_lock held
+ */
+static struct dma_simple_desc *simple_add_desc(struct dma_simple_chan *schan,
+ unsigned long flags, dma_addr_t *dst, dma_addr_t *src, size_t *len,
+ struct dma_simple_desc **first, enum dma_transfer_direction direction)
+{
+ struct dma_simple_dev *sdev = to_simple_dev(schan->dma_chan.device);
+ const struct dma_simple_ops *ops = sdev->ops;
+ struct dma_simple_desc *new;
+ size_t copy_size = *len;
+
+ if (!copy_size)
+ return NULL;
+
+ /* Allocate the link descriptor from the free list */
+ new = simple_get_desc(schan);
+ if (!new) {
+ dev_err(schan->dev, "No free link descriptor available\n");
+ return NULL;
+ }
+
+ ops->desc_setup(schan, new, *src, *dst, ©_size);
+
+ if (!*first) {
+ /* First desc */
+ new->async_tx.cookie = -EBUSY;
+ *first = new;
+ } else {
+ /* Other desc - invisible to the user */
+ new->async_tx.cookie = -EINVAL;
+ }
+
+ dev_dbg(schan->dev,
+ "chaining (%u/%u)@%x -> %x with %p, cookie %d\n",
+ copy_size, *len, *src, *dst, &new->async_tx,
+ new->async_tx.cookie);
+
+ new->mark = DESC_PREPARED;
+ new->async_tx.flags = flags;
+ new->direction = direction;
+
+ *len -= copy_size;
+ if (direction == DMA_MEM_TO_MEM || direction == DMA_MEM_TO_DEV)
+ *src += copy_size;
+ if (direction == DMA_MEM_TO_MEM || direction == DMA_DEV_TO_MEM)
+ *dst += copy_size;
+
+ return new;
+}
+
+/*
+ * simple_prep_sg - prepare transfer descriptors from an SG list
+ *
+ * Common routine for public (MEMCPY) and slave DMA. The MEMCPY case is also
+ * converted to scatter-gather to guarantee consistent locking and a correct
+ * list manipulation. For slave DMA direction carries the usual meaning, and,
+ * logically, the SG list is RAM and the addr variable contains slave address,
+ * e.g., the FIFO I/O register. For MEMCPY direction equals DMA_MEM_TO_MEM
+ * and the SG list contains only one element and points at the source buffer.
+ */
+static struct dma_async_tx_descriptor *simple_prep_sg(struct dma_simple_chan *schan,
+ struct scatterlist *sgl, unsigned int sg_len, dma_addr_t *addr,
+ enum dma_transfer_direction direction, unsigned long flags)
+{
+ struct scatterlist *sg;
+ struct dma_simple_desc *first = NULL, *new = NULL /* compiler... */;
+ LIST_HEAD(tx_list);
+ int chunks = 0;
+ unsigned long irq_flags;
+ int i;
+
+ for_each_sg(sgl, sg, sg_len, i)
+ chunks += DIV_ROUND_UP(sg_dma_len(sg), schan->max_xfer_len);
+
+ /* Have to lock the whole loop to protect against concurrent release */
+ spin_lock_irqsave(&schan->chan_lock, irq_flags);
+
+ /*
+ * Chaining:
+ * first descriptor is what user is dealing with in all API calls, its
+ * cookie is at first set to -EBUSY, at tx-submit to a positive
+ * number
+ * if more than one chunk is needed further chunks have cookie = -EINVAL
+ * the last chunk, if not equal to the first, has cookie = -ENOSPC
+ * all chunks are linked onto the tx_list head with their .node heads
+ * only during this function, then they are immediately spliced
+ * back onto the free list in form of a chain
+ */
+ for_each_sg(sgl, sg, sg_len, i) {
+ dma_addr_t sg_addr = sg_dma_address(sg);
+ size_t len = sg_dma_len(sg);
+
+ if (!len)
+ goto err_get_desc;
+
+ do {
+ dev_dbg(schan->dev, "Add SG #%d@%p[%d], dma %llx\n",
+ i, sg, len, (unsigned long long)sg_addr);
+
+ if (direction == DMA_DEV_TO_MEM)
+ new = simple_add_desc(schan, flags,
+ &sg_addr, addr, &len, &first,
+ direction);
+ else
+ new = simple_add_desc(schan, flags,
+ addr, &sg_addr, &len, &first,
+ direction);
+ if (!new)
+ goto err_get_desc;
+
+ new->chunks = chunks--;
+ list_add_tail(&new->node, &tx_list);
+ } while (len);
+ }
+
+ if (new != first)
+ new->async_tx.cookie = -ENOSPC;
+
+ /* Put them back on the free list, so, they don't get lost */
+ list_splice_tail(&tx_list, &schan->ld_free);
+
+ spin_unlock_irqrestore(&schan->chan_lock, irq_flags);
+
+ return &first->async_tx;
+
+err_get_desc:
+ list_for_each_entry(new, &tx_list, node)
+ new->mark = DESC_IDLE;
+ list_splice(&tx_list, &schan->ld_free);
+
+ spin_unlock_irqrestore(&schan->chan_lock, irq_flags);
+
+ return NULL;
+}
+
+static struct dma_async_tx_descriptor *simple_prep_memcpy(
+ struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
+ size_t len, unsigned long flags)
+{
+ struct dma_simple_chan *schan = to_simple_chan(chan);
+ struct scatterlist sg;
+
+ if (!chan || !len)
+ return NULL;
+
+ BUG_ON(!schan->desc_num);
+
+ sg_init_table(&sg, 1);
+ sg_set_page(&sg, pfn_to_page(PFN_DOWN(dma_src)), len,
+ offset_in_page(dma_src));
+ sg_dma_address(&sg) = dma_src;
+ sg_dma_len(&sg) = len;
+
+ return simple_prep_sg(schan, &sg, 1, &dma_dest, DMA_MEM_TO_MEM, flags);
+}
+
+static struct dma_async_tx_descriptor *simple_prep_slave_sg(
+ struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
+ enum dma_transfer_direction direction, unsigned long flags)
+{
+ struct dma_simple_chan *schan = to_simple_chan(chan);
+ struct dma_simple_dev *sdev = to_simple_dev(schan->dma_chan.device);
+ const struct dma_simple_ops *ops = sdev->ops;
+ struct dma_simple_slave *slave = chan->private;
+ dma_addr_t slave_addr;
+
+ if (!chan)
+ return NULL;
+
+ BUG_ON(!schan->desc_num);
+
+ /* Someone calling slave DMA on a generic channel? */
+ if (!slave || !sg_len) {
+ dev_warn(schan->dev, "%s: bad parameter: %p, %d, %d\n",
+ __func__, slave, sg_len, slave ? slave->slave_id : -1);
+ return NULL;
+ }
+
+ slave_addr = ops->slave_addr(schan);
+
+ return simple_prep_sg(schan, sgl, sg_len, &slave_addr,
+ direction, flags);
+}
+
+static int simple_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+ unsigned long arg)
+{
+ struct dma_simple_chan *schan = to_simple_chan(chan);
+ struct dma_simple_dev *sdev = to_simple_dev(chan->device);
+ const struct dma_simple_ops *ops = sdev->ops;
+ unsigned long flags;
+
+ /* Only supports DMA_TERMINATE_ALL */
+ if (cmd != DMA_TERMINATE_ALL)
+ return -ENXIO;
+
+ if (!chan)
+ return -EINVAL;
+
+ spin_lock_irqsave(&schan->chan_lock, flags);
+
+ ops->halt_channel(schan);
+
+ spin_unlock_irqrestore(&schan->chan_lock, flags);
+
+ simple_chan_ld_cleanup(schan, true);
+
+ return 0;
+}
+
+static void simple_issue_pending(struct dma_chan *chan)
+{
+ struct dma_simple_chan *schan = to_simple_chan(chan);
+
+ spin_lock_irq(&schan->chan_lock);
+ if (schan->pm_state == DMA_SIMPLE_PM_ESTABLISHED)
+ simple_chan_xfer_ld_queue(schan);
+ else
+ schan->pm_state = DMA_SIMPLE_PM_PENDING;
+ spin_unlock_irq(&schan->chan_lock);
+}
+
+static enum dma_status simple_tx_status(struct dma_chan *chan,
+ dma_cookie_t cookie,
+ struct dma_tx_state *txstate)
+{
+ struct dma_simple_chan *schan = to_simple_chan(chan);
+ dma_cookie_t last_used;
+ dma_cookie_t last_complete;
+ enum dma_status status;
+ unsigned long flags;
+
+ simple_chan_ld_cleanup(schan, false);
+
+ /* First read completed cookie to avoid a skew */
+ last_complete = schan->completed_cookie;
+ rmb();
+ last_used = chan->cookie;
+ BUG_ON(last_complete < 0);
+ dma_set_tx_state(txstate, last_complete, last_used, 0);
+
+ spin_lock_irqsave(&schan->chan_lock, flags);
+
+ status = dma_async_is_complete(cookie, last_complete, last_used);
+
+ /*
+ * If we don't find cookie on the queue, it has been aborted and we have
+ * to report error
+ */
+ if (status != DMA_SUCCESS) {
+ struct dma_simple_desc *sdesc;
+ status = DMA_ERROR;
+ list_for_each_entry(sdesc, &schan->ld_queue, node)
+ if (sdesc->cookie == cookie) {
+ status = DMA_IN_PROGRESS;
+ break;
+ }
+ }
+
+ spin_unlock_irqrestore(&schan->chan_lock, flags);
+
+ return status;
+}
+
+/* Called from error IRQ or NMI */
+bool dma_simple_reset(struct dma_simple_dev *sdev)
+{
+ const struct dma_simple_ops *ops = sdev->ops;
+ struct dma_simple_chan *schan;
+ unsigned int handled = 0;
+ int i;
+
+ /* Reset all channels */
+ dma_simple_for_each_chan(schan, sdev, i) {
+ struct dma_simple_desc *sdesc;
+ LIST_HEAD(dl);
+
+ if (!schan)
+ continue;
+
+ spin_lock(&schan->chan_lock);
+
+ /* Stop the channel */
+ ops->halt_channel(schan);
+
+ list_splice_init(&schan->ld_queue, &dl);
+
+ if (!list_empty(&dl)) {
+ dev_dbg(schan->dev, "Bring down channel %d\n", schan->id);
+ pm_runtime_put(schan->dev);
+ }
+ schan->pm_state = DMA_SIMPLE_PM_ESTABLISHED;
+
+ spin_unlock(&schan->chan_lock);
+
+ /* Complete all */
+ list_for_each_entry(sdesc, &dl, node) {
+ struct dma_async_tx_descriptor *tx = &sdesc->async_tx;
+ sdesc->mark = DESC_IDLE;
+ if (tx->callback)
+ tx->callback(tx->callback_param);
+ }
+
+ spin_lock(&schan->chan_lock);
+ list_splice(&dl, &schan->ld_free);
+ spin_unlock(&schan->chan_lock);
+
+ handled++;
+ }
+
+ return !!handled;
+}
+EXPORT_SYMBOL(dma_simple_reset);
+
+static irqreturn_t chan_irq(int irq, void *dev)
+{
+ struct dma_simple_chan *schan = dev;
+ const struct dma_simple_ops *ops =
+ to_simple_dev(schan->dma_chan.device)->ops;
+ irqreturn_t ret;
+
+ spin_lock(&schan->chan_lock);
+
+ ret = ops->chan_irq(schan, irq) ? IRQ_WAKE_THREAD : IRQ_NONE;
+
+ spin_unlock(&schan->chan_lock);
+
+ return ret;
+}
+
+static irqreturn_t chan_irqt(int irq, void *dev)
+{
+ struct dma_simple_chan *schan = dev;
+ const struct dma_simple_ops *ops =
+ to_simple_dev(schan->dma_chan.device)->ops;
+ struct dma_simple_desc *sdesc;
+
+ spin_lock_irq(&schan->chan_lock);
+ list_for_each_entry(sdesc, &schan->ld_queue, node) {
+ if (sdesc->mark == DESC_SUBMITTED &&
+ ops->desc_completed(schan, sdesc)) {
+ dev_dbg(schan->dev, "done #%d@%p\n",
+ sdesc->async_tx.cookie, &sdesc->async_tx);
+ sdesc->mark = DESC_COMPLETED;
+ break;
+ }
+ }
+ /* Next desc */
+ simple_chan_xfer_ld_queue(schan);
+ spin_unlock_irq(&schan->chan_lock);
+
+ simple_chan_ld_cleanup(schan, false);
+
+ return IRQ_HANDLED;
+}
+
+int dma_simple_request_irq(struct dma_simple_chan *schan, int irq,
+ unsigned long flags, const char *name)
+{
+ int ret = request_threaded_irq(irq, chan_irq, chan_irqt,
+ flags, name, schan);
+
+ schan->irq = ret < 0 ? ret : irq;
+
+ return ret;
+}
+EXPORT_SYMBOL(dma_simple_request_irq);
+
+void dma_simple_free_irq(struct dma_simple_chan *schan)
+{
+ if (schan->irq >= 0)
+ free_irq(schan->irq, schan);
+}
+EXPORT_SYMBOL(dma_simple_free_irq);
+
+void dma_simple_chan_probe(struct dma_simple_dev *sdev,
+ struct dma_simple_chan *schan, int id)
+{
+ schan->pm_state = DMA_SIMPLE_PM_ESTABLISHED;
+
+ /* reference struct dma_device */
+ schan->dma_chan.device = &sdev->dma_dev;
+
+ schan->dev = sdev->dma_dev.dev;
+ schan->id = id;
+
+ if (!schan->max_xfer_len)
+ schan->max_xfer_len = PAGE_SIZE;
+
+ spin_lock_init(&schan->chan_lock);
+
+ /* Init descripter manage list */
+ INIT_LIST_HEAD(&schan->ld_queue);
+ INIT_LIST_HEAD(&schan->ld_free);
+
+ /* Add the channel to DMA device channel list */
+ list_add_tail(&schan->dma_chan.device_node,
+ &sdev->dma_dev.channels);
+ sdev->schan[sdev->dma_dev.chancnt++] = schan;
+}
+EXPORT_SYMBOL(dma_simple_chan_probe);
+
+void dma_simple_chan_remove(struct dma_simple_chan *schan)
+{
+ list_del(&schan->dma_chan.device_node);
+}
+EXPORT_SYMBOL(dma_simple_chan_remove);
+
+int dma_simple_init(struct device *dev, struct dma_simple_dev *sdev,
+ int chan_num)
+{
+ struct dma_device *dma_dev = &sdev->dma_dev;
+
+ /*
+ * Require all call-backs for now, they can trivially be made optional
+ * later as required
+ */
+ if (!sdev->ops ||
+ !sdev->desc_size ||
+ !sdev->ops->embedded_desc ||
+ !sdev->ops->start_xfer ||
+ !sdev->ops->setup_xfer ||
+ !sdev->ops->set_slave ||
+ !sdev->ops->desc_setup ||
+ !sdev->ops->slave_addr ||
+ !sdev->ops->channel_busy ||
+ !sdev->ops->halt_channel ||
+ !sdev->ops->desc_completed)
+ return -EINVAL;
+
+ sdev->schan = kcalloc(chan_num, sizeof(*sdev->schan), GFP_KERNEL);
+ if (!sdev->schan)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&dma_dev->channels);
+
+ /* Common and MEMCPY operations */
+ dma_dev->device_alloc_chan_resources
+ = simple_alloc_chan_resources;
+ dma_dev->device_free_chan_resources = simple_free_chan_resources;
+ dma_dev->device_prep_dma_memcpy = simple_prep_memcpy;
+ dma_dev->device_tx_status = simple_tx_status;
+ dma_dev->device_issue_pending = simple_issue_pending;
+
+ /* Compulsory for DMA_SLAVE fields */
+ dma_dev->device_prep_slave_sg = simple_prep_slave_sg;
+ dma_dev->device_control = simple_control;
+
+ dma_dev->dev = dev;
+
+ return 0;
+}
+EXPORT_SYMBOL(dma_simple_init);
+
+void dma_simple_cleanup(struct dma_simple_dev *sdev)
+{
+ kfree(sdev->schan);
+}
+EXPORT_SYMBOL(dma_simple_cleanup);
+
+static int __init dma_simple_enter(void)
+{
+ simple_slave_used = kzalloc(DIV_ROUND_UP(slave_num, BITS_PER_LONG) *
+ sizeof(long), GFP_KERNEL);
+ if (!simple_slave_used)
+ return -ENOMEM;
+ return 0;
+}
+module_init(dma_simple_enter);
+
+static void __exit dma_simple_exit(void)
+{
+ kfree(simple_slave_used);
+}
+module_exit(dma_simple_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Simple dmaengine driver library");
+MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski at gmx.de>");
diff --git a/include/linux/dma-simple.h b/include/linux/dma-simple.h
new file mode 100644
index 0000000..5336674
--- /dev/null
+++ b/include/linux/dma-simple.h
@@ -0,0 +1,124 @@
+/*
+ * Simple dmaengine driver library
+ *
+ * extracted from shdma.c and headers
+ *
+ * Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski at gmx.de>
+ * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro at renesas.com>
+ * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
+ * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef DMA_SIMPLE_H
+#define DMA_SIMPLE_H
+
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/types.h>
+
+/**
+ * dma_simple_pm_state - DMA channel PM state
+ * DMA_SIMPLE_PM_ESTABLISHED: either idle or during data transfer
+ * DMA_SIMPLE_PM_BUSY: during the transfer preparation, when we have to
+ * drop the lock temporarily
+ * DMA_SIMPLE_PM_PENDING: transfers pending
+ */
+enum dma_simple_pm_state {
+ DMA_SIMPLE_PM_ESTABLISHED,
+ DMA_SIMPLE_PM_BUSY,
+ DMA_SIMPLE_PM_PENDING,
+};
+
+struct device;
+
+/*
+ * Drivers, using this library are expected to embed struct dma_simple_dev,
+ * struct dma_simple_chan, struct dma_simple_desc, and struct dma_simple_slave
+ * in their respective device, channel, descriptor and slave objects.
+ */
+
+struct dma_simple_slave {
+ unsigned int slave_id;
+};
+
+struct dma_simple_desc {
+ struct list_head node;
+ struct dma_async_tx_descriptor async_tx;
+ enum dma_transfer_direction direction;
+ dma_cookie_t cookie;
+ int chunks;
+ int mark;
+};
+
+struct dma_simple_chan {
+ dma_cookie_t completed_cookie; /* The maximum cookie completed */
+ spinlock_t chan_lock; /* Channel operation lock */
+ struct list_head ld_queue; /* Link descriptors queue */
+ struct list_head ld_free; /* Free link descriptors */
+ struct dma_chan dma_chan; /* DMA channel */
+ struct device *dev; /* Channel device */
+ void *desc; /* buffer for descriptor array */
+ int desc_num; /* desc count */
+ size_t max_xfer_len; /* max transfer length */
+ int id; /* Raw id of this channel */
+ int irq; /* Channel IRQ */
+ enum dma_simple_pm_state pm_state;
+};
+
+/**
+ * struct dma_simple_ops - simple DMA driver operations
+ * desc_completed: return true, if this is the descriptor, that just has
+ * completed (atomic)
+ * halt_channel: stop DMA channel operation (atomic)
+ * channel_busy: return true, if the channel is busy (atomic)
+ * slave_addr: return slave DMA address
+ * desc_setup: set up the hardware specific descriptor portion (atomic)
+ * set_slave: bind channel to a slave
+ * setup_xfer: configure channel hardware for operation (atomic)
+ * start_xfer: start the DMA transfer (atomic)
+ * embedded_desc: return Nth struct dma_simple_desc pointer from the
+ * descriptor array
+ * chan_irq: process channel IRQ, return true if a transfer has
+ * completed (atomic)
+ */
+struct dma_simple_ops {
+ bool (*desc_completed)(struct dma_simple_chan *, struct dma_simple_desc *);
+ void (*halt_channel)(struct dma_simple_chan *);
+ bool (*channel_busy)(struct dma_simple_chan *);
+ dma_addr_t (*slave_addr)(struct dma_simple_chan *);
+ int (*desc_setup)(struct dma_simple_chan *, struct dma_simple_desc *,
+ dma_addr_t, dma_addr_t, size_t *);
+ int (*set_slave)(struct dma_simple_chan *, struct dma_simple_slave *);
+ void (*setup_xfer)(struct dma_simple_chan *, struct dma_simple_slave *);
+ void (*start_xfer)(struct dma_simple_chan *, struct dma_simple_desc *);
+ struct dma_simple_desc *(*embedded_desc)(void *, int);
+ bool (*chan_irq)(struct dma_simple_chan *, int);
+};
+
+struct dma_simple_dev {
+ struct dma_device dma_dev;
+ struct dma_simple_chan **schan;
+ const struct dma_simple_ops *ops;
+ size_t desc_size;
+};
+
+#define dma_simple_for_each_chan(c, d, i) for (i = 0, c = (d)->schan[0]; \
+ i < (d)->dma_dev.chancnt; c = (d)->schan[++i])
+
+int dma_simple_request_irq(struct dma_simple_chan *, int,
+ unsigned long, const char *);
+void dma_simple_free_irq(struct dma_simple_chan *);
+bool dma_simple_reset(struct dma_simple_dev *sdev);
+void dma_simple_chan_probe(struct dma_simple_dev *sdev,
+ struct dma_simple_chan *schan, int id);
+void dma_simple_chan_remove(struct dma_simple_chan *schan);
+int dma_simple_init(struct device *dev, struct dma_simple_dev *sdev,
+ int chan_num);
+void dma_simple_cleanup(struct dma_simple_dev *sdev);
+
+#endif
--
1.7.2.5
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