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dmaengine: add an shdma-base library

Browse source 
This patch extracts code from shdma.c, that does not directly deal with
hardware implementation details and can be re-used with diverse DMA
controller variants, found on SH-based SoCs.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
This commit is contained in:
Guennadi Liakhovetski 2012-05-09 17:09:13 +02:00 • committed by Vinod Koul
commit 9a7b8e002e
3 changed files with 992 additions and 0 deletions
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1
drivers/dma/sh/Makefile
View file

@ -1 +1,2 @@
obj-$(CONFIG_SH_DMAE) += shdma-base.o
obj-$(CONFIG_SH_DMAE) += shdma.o

868
drivers/dma/sh/shdma-base.c Normal file
View file

@ -0,0 +1,868 @@
/*
* Dmaengine driver base library for DMA controllers, found on SH-based SoCs
*
* extracted from shdma.c
*
* Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
* Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@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/shdma-base.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>
#include "../dmaengine.h"
/* DMA descriptor control */
enum shdma_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_shdma_chan(c) container_of(c, struct shdma_chan, dma_chan)
#define to_shdma_dev(d) container_of(d, struct shdma_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 *shdma_slave_used;
/* Called under spin_lock_irq(&schan->chan_lock") */
static void shdma_chan_xfer_ld_queue(struct shdma_chan *schan)
{
struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
const struct shdma_ops *ops = sdev->ops;
struct shdma_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 shdma_tx_submit(struct dma_async_tx_descriptor *tx)
{
struct shdma_desc *chunk, *c, *desc =
container_of(tx, struct shdma_desc, async_tx),
*last = desc;
struct shdma_chan *schan = to_shdma_chan(tx->chan);
struct shdma_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 = dma_cookie_assign(tx);
/* 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 = SHDMA_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 != SHDMA_PM_ESTABLISHED) {
struct shdma_dev *sdev =
to_shdma_dev(schan->dma_chan.device);
const struct shdma_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 == SHDMA_PM_PENDING)
shdma_chan_xfer_ld_queue(schan);
schan->pm_state = SHDMA_PM_ESTABLISHED;
}
} else {
/*
* Tell .device_issue_pending() not to run the queue, interrupts
* will do it anyway
*/
schan->pm_state = SHDMA_PM_PENDING;
}
spin_unlock_irq(&schan->chan_lock);
return cookie;
}
/* Called with desc_lock held */
static struct shdma_desc *shdma_get_desc(struct shdma_chan *schan)
{
struct shdma_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 shdma_alloc_chan_resources(struct dma_chan *chan)
{
struct shdma_chan *schan = to_shdma_chan(chan);
struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
const struct shdma_ops *ops = sdev->ops;
struct shdma_desc *desc;
struct shdma_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 (slave->slave_id >= slave_num) {
ret = -EINVAL;
goto evalid;
}
if (test_and_set_bit(slave->slave_id, shdma_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 = shdma_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, shdma_slave_used);
etestused:
evalid:
chan->private = NULL;
return ret;
}
static dma_async_tx_callback __ld_cleanup(struct shdma_chan *schan, bool all)
{
struct shdma_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->dma_chan.completed_cookie != desc->cookie - 1)
dev_dbg(schan->dev,
"Completing cookie %d, expected %d\n",
desc->cookie,
schan->dma_chan.completed_cookie + 1);
schan->dma_chan.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 = SHDMA_PM_ESTABLISHED;
}
}
}
if (all && !callback)
/*
* Terminating and the loop completed normally: forgive
* uncompleted cookies
*/
schan->dma_chan.completed_cookie = schan->dma_chan.cookie;
spin_unlock_irqrestore(&schan->chan_lock, flags);
if (callback)
callback(param);
return callback;
}
/*
* shdma_chan_ld_cleanup - Clean up link descriptors
*
* Clean up the ld_queue of DMA channel.
*/
static void shdma_chan_ld_cleanup(struct shdma_chan *schan, bool all)
{
while (__ld_cleanup(schan, all))
;
}
/*
* shdma_free_chan_resources - Free all resources of the channel.
*/
static void shdma_free_chan_resources(struct dma_chan *chan)
{
struct shdma_chan *schan = to_shdma_chan(chan);
struct shdma_dev *sdev = to_shdma_dev(chan->device);
const struct shdma_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))
shdma_chan_ld_cleanup(schan, true);
if (chan->private) {
/* The caller is holding dma_list_mutex */
struct shdma_slave *slave = chan->private;
clear_bit(slave->slave_id, shdma_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);
}
/**
* shdma_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 shdma_desc *shdma_add_desc(struct shdma_chan *schan,
unsigned long flags, dma_addr_t *dst, dma_addr_t *src, size_t *len,
struct shdma_desc **first, enum dma_transfer_direction direction)
{
struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
const struct shdma_ops *ops = sdev->ops;
struct shdma_desc *new;
size_t copy_size = *len;
if (!copy_size)
return NULL;
/* Allocate the link descriptor from the free list */
new = shdma_get_desc(schan);
if (!new) {
dev_err(schan->dev, "No free link descriptor available\n");
return NULL;
}
ops->desc_setup(schan, new, *src, *dst, &copy_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;
}
/*
* shdma_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 *shdma_prep_sg(struct shdma_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 shdma_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 = shdma_add_desc(schan, flags,
&sg_addr, addr, &len, &first,
direction);
else
new = shdma_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 *shdma_prep_memcpy(
struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
size_t len, unsigned long flags)
{
struct shdma_chan *schan = to_shdma_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 shdma_prep_sg(schan, &sg, 1, &dma_dest, DMA_MEM_TO_MEM, flags);
}
static struct dma_async_tx_descriptor *shdma_prep_slave_sg(
struct dma_chan *chan, struct scatterlist *sgl, unsigned int sg_len,
enum dma_transfer_direction direction, unsigned long flags, void *context)
{
struct shdma_chan *schan = to_shdma_chan(chan);
struct shdma_dev *sdev = to_shdma_dev(schan->dma_chan.device);
const struct shdma_ops *ops = sdev->ops;
struct shdma_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 shdma_prep_sg(schan, sgl, sg_len, &slave_addr,
direction, flags);
}
static int shdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
unsigned long arg)
{
struct shdma_chan *schan = to_shdma_chan(chan);
struct shdma_dev *sdev = to_shdma_dev(chan->device);
const struct shdma_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);
shdma_chan_ld_cleanup(schan, true);
return 0;
}
static void shdma_issue_pending(struct dma_chan *chan)
{
struct shdma_chan *schan = to_shdma_chan(chan);
spin_lock_irq(&schan->chan_lock);
if (schan->pm_state == SHDMA_PM_ESTABLISHED)
shdma_chan_xfer_ld_queue(schan);
else
schan->pm_state = SHDMA_PM_PENDING;
spin_unlock_irq(&schan->chan_lock);
}
static enum dma_status shdma_tx_status(struct dma_chan *chan,
dma_cookie_t cookie,
struct dma_tx_state *txstate)
{
struct shdma_chan *schan = to_shdma_chan(chan);
enum dma_status status;
unsigned long flags;
shdma_chan_ld_cleanup(schan, false);
spin_lock_irqsave(&schan->chan_lock, flags);
status = dma_cookie_status(chan, cookie, txstate);
/*
* If we don't find cookie on the queue, it has been aborted and we have
* to report error
*/
if (status != DMA_SUCCESS) {
struct shdma_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 shdma_reset(struct shdma_dev *sdev)
{
const struct shdma_ops *ops = sdev->ops;
struct shdma_chan *schan;
unsigned int handled = 0;
int i;
/* Reset all channels */
shdma_for_each_chan(schan, sdev, i) {
struct shdma_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 = SHDMA_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(shdma_reset);
static irqreturn_t chan_irq(int irq, void *dev)
{
struct shdma_chan *schan = dev;
const struct shdma_ops *ops =
to_shdma_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 shdma_chan *schan = dev;
const struct shdma_ops *ops =
to_shdma_dev(schan->dma_chan.device)->ops;
struct shdma_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 */
shdma_chan_xfer_ld_queue(schan);
spin_unlock_irq(&schan->chan_lock);
shdma_chan_ld_cleanup(schan, false);
return IRQ_HANDLED;
}
int shdma_request_irq(struct shdma_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(shdma_request_irq);
void shdma_free_irq(struct shdma_chan *schan)
{
if (schan->irq >= 0)
free_irq(schan->irq, schan);
}
EXPORT_SYMBOL(shdma_free_irq);
void shdma_chan_probe(struct shdma_dev *sdev,
struct shdma_chan *schan, int id)
{
schan->pm_state = SHDMA_PM_ESTABLISHED;
/* reference struct dma_device */
schan->dma_chan.device = &sdev->dma_dev;
dma_cookie_init(&schan->dma_chan);
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(shdma_chan_probe);
void shdma_chan_remove(struct shdma_chan *schan)
{
list_del(&schan->dma_chan.device_node);
}
EXPORT_SYMBOL(shdma_chan_remove);
int shdma_init(struct device *dev, struct shdma_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
= shdma_alloc_chan_resources;
dma_dev->device_free_chan_resources = shdma_free_chan_resources;
dma_dev->device_prep_dma_memcpy = shdma_prep_memcpy;
dma_dev->device_tx_status = shdma_tx_status;
dma_dev->device_issue_pending = shdma_issue_pending;
/* Compulsory for DMA_SLAVE fields */
dma_dev->device_prep_slave_sg = shdma_prep_slave_sg;
dma_dev->device_control = shdma_control;
dma_dev->dev = dev;
return 0;
}
EXPORT_SYMBOL(shdma_init);
void shdma_cleanup(struct shdma_dev *sdev)
{
kfree(sdev->schan);
}
EXPORT_SYMBOL(shdma_cleanup);
static int __init shdma_enter(void)
{
shdma_slave_used = kzalloc(DIV_ROUND_UP(slave_num, BITS_PER_LONG) *
sizeof(long), GFP_KERNEL);
if (!shdma_slave_used)
return -ENOMEM;
return 0;
}
module_init(shdma_enter);
static void __exit shdma_exit(void)
{
kfree(shdma_slave_used);
}
module_exit(shdma_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("SH-DMA driver base library");
MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");

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include/linux/shdma-base.h Normal file
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/*
* Dmaengine driver base library for DMA controllers, found on SH-based SoCs
*
* extracted from shdma.c and headers
*
* Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
* Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@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 SHDMA_BASE_H
#define SHDMA_BASE_H
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/types.h>
/**
* shdma_pm_state - DMA channel PM state
* SHDMA_PM_ESTABLISHED: either idle or during data transfer
* SHDMA_PM_BUSY: during the transfer preparation, when we have to
* drop the lock temporarily
* SHDMA_PM_PENDING: transfers pending
*/
enum shdma_pm_state {
SHDMA_PM_ESTABLISHED,
SHDMA_PM_BUSY,
SHDMA_PM_PENDING,
};
struct device;
/*
* Drivers, using this library are expected to embed struct shdma_dev,
* struct shdma_chan, struct shdma_desc, and struct shdma_slave
* in their respective device, channel, descriptor and slave objects.
*/
struct shdma_slave {
unsigned int slave_id;
};
struct shdma_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 shdma_chan {
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 shdma_pm_state pm_state;
};
/**
* struct shdma_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 shdma_desc pointer from the
* descriptor array
* chan_irq: process channel IRQ, return true if a transfer has
* completed (atomic)
*/
struct shdma_ops {
bool (*desc_completed)(struct shdma_chan *, struct shdma_desc *);
void (*halt_channel)(struct shdma_chan *);
bool (*channel_busy)(struct shdma_chan *);
dma_addr_t (*slave_addr)(struct shdma_chan *);
int (*desc_setup)(struct shdma_chan *, struct shdma_desc *,
dma_addr_t, dma_addr_t, size_t *);
int (*set_slave)(struct shdma_chan *, struct shdma_slave *);
void (*setup_xfer)(struct shdma_chan *, struct shdma_slave *);
void (*start_xfer)(struct shdma_chan *, struct shdma_desc *);
struct shdma_desc *(*embedded_desc)(void *, int);
bool (*chan_irq)(struct shdma_chan *, int);
};
struct shdma_dev {
struct dma_device dma_dev;
struct shdma_chan **schan;
const struct shdma_ops *ops;
size_t desc_size;
};
#define shdma_for_each_chan(c, d, i) for (i = 0, c = (d)->schan[0]; \
i < (d)->dma_dev.chancnt; c = (d)->schan[++i])
int shdma_request_irq(struct shdma_chan *, int,
unsigned long, const char *);
void shdma_free_irq(struct shdma_chan *);
bool shdma_reset(struct shdma_dev *sdev);
void shdma_chan_probe(struct shdma_dev *sdev,
struct shdma_chan *schan, int id);
void shdma_chan_remove(struct shdma_chan *schan);
int shdma_init(struct device *dev, struct shdma_dev *sdev,
int chan_num);
void shdma_cleanup(struct shdma_dev *sdev);
#endif