- 根目录:
- drivers
- dma
- dmaengine.c
/*
* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* The full GNU General Public License is included in this distribution in the
* file called COPYING.
*/
/*
* This code implements the DMA subsystem. It provides a HW-neutral interface
* for other kernel code to use asynchronous memory copy capabilities,
* if present, and allows different HW DMA drivers to register as providing
* this capability.
*
* Due to the fact we are accelerating what is already a relatively fast
* operation, the code goes to great lengths to avoid additional overhead,
* such as locking.
*
* LOCKING:
*
* The subsystem keeps a global list of dma_device structs it is protected by a
* mutex, dma_list_mutex.
*
* A subsystem can get access to a channel by calling dmaengine_get() followed
* by dma_find_channel(), or if it has need for an exclusive channel it can call
* dma_request_channel(). Once a channel is allocated a reference is taken
* against its corresponding driver to disable removal.
*
* Each device has a channels list, which runs unlocked but is never modified
* once the device is registered, it's just setup by the driver.
*
* See Documentation/dmaengine.txt for more details
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/hardirq.h>
#include <linux/spinlock.h>
#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
#include <linux/rculist.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/acpi_dma.h>
#include <linux/of_dma.h>
#include <linux/mempool.h>
static DEFINE_MUTEX(dma_list_mutex);
static DEFINE_IDR(dma_idr);
static LIST_HEAD(dma_device_list);
static long dmaengine_ref_count;
/* --- sysfs implementation --- */
/**
* dev_to_dma_chan - convert a device pointer to the its sysfs container object
* @dev - device node
*
* Must be called under dma_list_mutex
*/
static struct dma_chan *dev_to_dma_chan(struct device *dev)
{
struct dma_chan_dev *chan_dev;
chan_dev = container_of(dev, typeof(*chan_dev), device);
return chan_dev->chan;
}
static ssize_t memcpy_count_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct dma_chan *chan;
unsigned long count = 0;
int i;
int err;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan) {
for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->memcpy_count;
err = sprintf(buf, "%lu\n", count);
} else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);
return err;
}
static DEVICE_ATTR_RO(memcpy_count);
static ssize_t bytes_transferred_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct dma_chan *chan;
unsigned long count = 0;
int i;
int err;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan) {
for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->bytes_transferred;
err = sprintf(buf, "%lu\n", count);
} else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);
return err;
}
static DEVICE_ATTR_RO(bytes_transferred);
static ssize_t in_use_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct dma_chan *chan;
int err;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan)
err = sprintf(buf, "%d\n", chan->client_count);
else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);
return err;
}
static DEVICE_ATTR_RO(in_use);
static struct attribute *dma_dev_attrs[] = {
&dev_attr_memcpy_count.attr,
&dev_attr_bytes_transferred.attr,
&dev_attr_in_use.attr,
NULL,
};
ATTRIBUTE_GROUPS(dma_dev);
static void chan_dev_release(struct device *dev)
{
struct dma_chan_dev *chan_dev;
chan_dev = container_of(dev, typeof(*chan_dev), device);
if (atomic_dec_and_test(chan_dev->idr_ref)) {
mutex_lock(&dma_list_mutex);
idr_remove(&dma_idr, chan_dev->dev_id);
mutex_unlock(&dma_list_mutex);
kfree(chan_dev->idr_ref);
}
kfree(chan_dev);
}
static struct class dma_devclass = {
.name = "dma",
.dev_groups = dma_dev_groups,
.dev_release = chan_dev_release,
};
/* --- client and device registration --- */
#define dma_device_satisfies_mask(device, mask) \
__dma_device_satisfies_mask((device), &(mask))
static int
__dma_device_satisfies_mask(struct dma_device *device,
const dma_cap_mask_t *want)
{
dma_cap_mask_t has;
bitmap_and(has.bits, want->bits, device->cap_mask.bits,
DMA_TX_TYPE_END);
return bitmap_equal(want->bits, has.bits, DMA_TX_TYPE_END);
}
static struct module *dma_chan_to_owner(struct dma_chan *chan)
{
return chan->device->dev->driver->owner;
}
/**
* balance_ref_count - catch up the channel reference count
* @chan - channel to balance ->client_count versus dmaengine_ref_count
*
* balance_ref_count must be called under dma_list_mutex
*/
static void balance_ref_count(struct dma_chan *chan)
{
struct module *owner = dma_chan_to_owner(chan);
while (chan->client_count < dmaengine_ref_count) {
__module_get(owner);
chan->client_count++;
}
}
/**
* dma_chan_get - try to grab a dma channel's parent driver module
* @chan - channel to grab
*
* Must be called under dma_list_mutex
*/
static int dma_chan_get(struct dma_chan *chan)
{
int err = -ENODEV;
struct module *owner = dma_chan_to_owner(chan);
if (chan->client_count) {
__module_get(owner);
err = 0;
} else if (try_module_get(owner))
err = 0;
if (err == 0)
chan->client_count++;
/* allocate upon first client reference */
if (chan->client_count == 1 && err == 0) {
int desc_cnt = chan->device->device_alloc_chan_resources(chan);
if (desc_cnt < 0) {
err = desc_cnt;
chan->client_count = 0;
module_put(owner);
} else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
balance_ref_count(chan);
}
return err;
}
/**
* dma_chan_put - drop a reference to a dma channel's parent driver module
* @chan - channel to release
*
* Must be called under dma_list_mutex
*/
static void dma_chan_put(struct dma_chan *chan)
{
if (!chan->client_count)
return; /* this channel failed alloc_chan_resources */
chan->client_count--;
module_put(dma_chan_to_owner(chan));
if (chan->client_count == 0)
chan->device->device_free_chan_resources(chan);
}
enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
{
enum dma_status status;
unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
dma_async_issue_pending(chan);
do {
status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
pr_err("%s: timeout!\n", __func__);
return DMA_ERROR;
}
if (status != DMA_IN_PROGRESS)
break;
cpu_relax();
} while (1);
return status;
}
EXPORT_SYMBOL(dma_sync_wait);
/**
* dma_cap_mask_all - enable iteration over all operation types
*/
static dma_cap_mask_t dma_cap_mask_all;
/**
* dma_chan_tbl_ent - tracks channel allocations per core/operation
* @chan - associated channel for this entry
*/
struct dma_chan_tbl_ent {
struct dma_chan *chan;
};
/**
* channel_table - percpu lookup table for memory-to-memory offload providers
*/
static struct dma_chan_tbl_ent __percpu *channel_table[DMA_TX_TYPE_END];
static int __init dma_channel_table_init(void)
{
enum dma_transaction_type cap;
int err = 0;
bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END);
/* 'interrupt', 'private', and 'slave' are channel capabilities,
* but are not associated with an operation so they do not need
* an entry in the channel_table
*/
clear_bit(DMA_INTERRUPT, dma_cap_mask_all.bits);
clear_bit(DMA_PRIVATE, dma_cap_mask_all.bits);
clear_bit(DMA_SLAVE, dma_cap_mask_all.bits);
for_each_dma_cap_mask(cap, dma_cap_mask_all) {
channel_table[cap] = alloc_percpu(struct dma_chan_tbl_ent);
if (!channel_table[cap]) {
err = -ENOMEM;
break;
}
}
if (err) {
pr_err("initialization failure\n");
for_each_dma_cap_mask(cap, dma_cap_mask_all)
if (channel_table[cap])
free_percpu(channel_table[cap]);
}
return err;
}
arch_initcall(dma_channel_table_init);
/**
* dma_find_channel - find a channel to carry out the operation
* @tx_type: transaction type
*/
struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type)
{
return this_cpu_read(channel_table[tx_type]->chan);
}
EXPORT_SYMBOL(dma_find_channel);
/*
* net_dma_find_channel - find a channel for net_dma
* net_dma has alignment requirements
*/
struct dma_chan *net_dma_find_channel(void)
{
struct dma_chan *chan = dma_find_channel(DMA_MEMCPY);
if (chan && !is_dma_copy_aligned(chan->device, 1, 1, 1))
return NULL;
return chan;
}
EXPORT_SYMBOL(net_dma_find_channel);
/**
* dma_issue_pending_all - flush all pending operations across all channels
*/
void dma_issue_pending_all(void)
{
struct dma_device *device;
struct dma_chan *chan;
rcu_read_lock();
list_for_each_entry_rcu(device, &dma_device_list, global_node) {
if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
continue;
list_for_each_entry(chan, &device->channels, device_node)
if (chan->client_count)
device->device_issue_pending(chan);
}
rcu_read_unlock();
}
EXPORT_SYMBOL(dma_issue_pending_all);
/**
* dma_chan_is_local - returns true if the channel is in the same numa-node as the cpu
*/
static bool dma_chan_is_local(struct dma_chan *chan, int cpu)
{
int node = dev_to_node(chan->device->dev);
return node == -1 || cpumask_test_cpu(cpu, cpumask_of_node(node));
}
/**
* min_chan - returns the channel with min count and in the same numa-node as the cpu
* @cap: capability to match
* @cpu: cpu index which the channel should be close to
*
* If some channels are close to the given cpu, the one with the lowest
* reference count is returned. Otherwise, cpu is ignored and only the
* reference count is taken into account.
* Must be called under dma_list_mutex.
*/
static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu)
{
struct dma_device *device;
struct dma_chan *chan;
struct dma_chan *min = NULL;
struct dma_chan *localmin = NULL;
list_for_each_entry(device, &dma_device_list, global_node) {
if (!dma_has_cap(cap, device->cap_mask) ||
dma_has_cap(DMA_PRIVATE, device->cap_mask))
continue;
list_for_each_entry(chan, &device->channels, device_node) {
if (!chan->client_count)
continue;
if (!min || chan->table_count < min->table_count)
min = chan;
if (dma_chan_is_local(chan, cpu))
if (!localmin ||
chan->table_count < localmin->table_count)
localmin = chan;
}
}
chan = localmin ? localmin : min;
if (chan)
chan->table_count++;
return chan;
}
/**
* dma_channel_rebalance - redistribute the available channels
*
* Optimize for cpu isolation (each cpu gets a dedicated channel for an
* operation type) in the SMP case, and operation isolation (avoid
* multi-tasking channels) in the non-SMP case. Must be called under
* dma_list_mutex.
*/
static void dma_channel_rebalance(void)
{
struct dma_chan *chan;
struct dma_device *device;
int cpu;
int cap;
/* undo the last distribution */
for_each_dma_cap_mask(cap, dma_cap_mask_all)
for_each_possible_cpu(cpu)
per_cpu_ptr(channel_table[cap], cpu)->chan = NULL;
list_for_each_entry(device, &dma_device_list, global_node) {
if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
continue;
list_for_each_entry(chan, &device->channels, device_node)
chan->table_count = 0;
}
/* don't populate the channel_table if no clients are available */
if (!dmaengine_ref_count)
return;
/* redistribute available channels */
for_each_dma_cap_mask(cap, dma_cap_mask_all)
for_each_online_cpu(cpu) {
chan = min_chan(cap, cpu);
per_cpu_ptr(channel_table[cap], cpu)->chan = chan;
}
}
static struct dma_chan *private_candidate(const dma_cap_mask_t *mask,
struct dma_device *dev,
dma_filter_fn fn, void *fn_param)
{
struct dma_chan *chan;
if (!__dma_device_satisfies_mask(dev, mask)) {
pr_debug("%s: wrong capabilities\n", __func__);
return NULL;
}
/* devices with multiple channels need special handling as we need to
* ensure that all channels are either private or public.
*/
if (dev->chancnt > 1 && !dma_has_cap(DMA_PRIVATE, dev->cap_mask))
list_for_each_entry(chan, &dev->channels, device_node) {
/* some channels are already publicly allocated */
if (chan->client_count)
return NULL;
}
list_for_each_entry(chan, &dev->channels, device_node) {
if (chan->client_count) {
pr_debug("%s: %s busy\n",
__func__, dma_chan_name(chan));
continue;
}
if (fn && !fn(chan, fn_param)) {
pr_debug("%s: %s filter said false\n",
__func__, dma_chan_name(chan));
continue;
}
return chan;
}
return NULL;
}
/**
* dma_request_slave_channel - try to get specific channel exclusively
* @chan: target channel
*/
struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
{
int err = -EBUSY;
/* lock against __dma_request_channel */
mutex_lock(&dma_list_mutex);
if (chan->client_count == 0) {
err = dma_chan_get(chan);
if (err)
pr_debug("%s: failed to get %s: (%d)\n",
__func__, dma_chan_name(chan), err);
} else
chan = NULL;
mutex_unlock(&dma_list_mutex);
return chan;
}
EXPORT_SYMBOL_GPL(dma_get_slave_channel);
struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
{
dma_cap_mask_t mask;
struct dma_chan *chan;
int err;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
/* lock against __dma_request_channel */
mutex_lock(&dma_list_mutex);
chan = private_candidate(&mask, device, NULL, NULL);
if (chan) {
err = dma_chan_get(chan);
if (err) {
pr_debug("%s: failed to get %s: (%d)\n",
__func__, dma_chan_name(chan), err);
chan = NULL;
}
}
mutex_unlock(&dma_list_mutex);
return chan;
}
EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
/**
* __dma_request_channel - try to allocate an exclusive channel
* @mask: capabilities that the channel must satisfy
* @fn: optional callback to disposition available channels
* @fn_param: opaque parameter to pass to dma_filter_fn
*
* Returns pointer to appropriate DMA channel on success or NULL.
*/
struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
dma_filter_fn fn, void *fn_param)
{
struct dma_device *device, *_d;
struct dma_chan *chan = NULL;
int err;
/* Find a channel */
mutex_lock(&dma_list_mutex);
list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
chan = private_candidate(mask, device, fn, fn_param);
if (chan) {
/* Found a suitable channel, try to grab, prep, and
* return it. We first set DMA_PRIVATE to disable
* balance_ref_count as this channel will not be
* published in the general-purpose allocator
*/
dma_cap_set(DMA_PRIVATE, device->cap_mask);
device->privatecnt++;
err = dma_chan_get(chan);
if (err == -ENODEV) {
pr_debug("%s: %s module removed\n",
__func__, dma_chan_name(chan));
list_del_rcu(&device->global_node);
} else if (err)
pr_debug("%s: failed to get %s: (%d)\n",
__func__, dma_chan_name(chan), err);
else
break;
if (--device->privatecnt == 0)
dma_cap_clear(DMA_PRIVATE, device->cap_mask);
chan = NULL;
}
}
mutex_unlock(&dma_list_mutex);
pr_debug("%s: %s (%s)\n",
__func__,
chan ? "success" : "fail",
chan ? dma_chan_name(chan) : NULL);
return chan;
}
EXPORT_SYMBOL_GPL(__dma_request_channel);
/**
* dma_request_slave_channel - try to allocate an exclusive slave channel
* @dev: pointer to client device structure
* @name: slave channel name
*
* Returns pointer to appropriate DMA channel on success or an error pointer.
*/
struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
const char *name)
{
struct dma_chan *chan;
/* If device-tree is present get slave info from here */
if (dev->of_node)
return of_dma_request_slave_channel(dev->of_node, name);
/* If device was enumerated by ACPI get slave info from here */
if (ACPI_HANDLE(dev)) {
chan = acpi_dma_request_slave_chan_by_name(dev, name);
if (chan)
return chan;
}
return ERR_PTR(-ENODEV);
}
EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
/**
* dma_request_slave_channel - try to allocate an exclusive slave channel
* @dev: pointer to client device structure
* @name: slave channel name
*
* Returns pointer to appropriate DMA channel on success or NULL.
*/
struct dma_chan *dma_request_slave_channel(struct device *dev,
const char *name)
{
struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
if (IS_ERR(ch))
return NULL;
return ch;
}
EXPORT_SYMBOL_GPL(dma_request_slave_channel);
void dma_release_channel(struct dma_chan *chan)
{
mutex_lock(&dma_list_mutex);
WARN_ONCE(chan->client_count != 1,
"chan reference count %d != 1\n", chan->client_count);
dma_chan_put(chan);
/* drop PRIVATE cap enabled by __dma_request_channel() */
if (--chan->device->privatecnt == 0)
dma_cap_clear(DMA_PRIVATE, chan->device->cap_mask);
mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL_GPL(dma_release_channel);
/**
* dmaengine_get - register interest in dma_channels
*/
void dmaengine_get(void)
{
struct dma_device *device, *_d;
struct dma_chan *chan;
int err;
mutex_lock(&dma_list_mutex);
dmaengine_ref_count++;
/* try to grab channels */
list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
continue;
list_for_each_entry(chan, &device->channels, device_node) {
err = dma_chan_get(chan);
if (err == -ENODEV) {
/* module removed before we could use it */
list_del_rcu(&device->global_node);
break;
} else if (err)
pr_debug("%s: failed to get %s: (%d)\n",
__func__, dma_chan_name(chan), err);
}
}
/* if this is the first reference and there were channels
* waiting we need to rebalance to get those channels
* incorporated into the channel table
*/
if (dmaengine_ref_count == 1)
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL(dmaengine_get);
/**
* dmaengine_put - let dma drivers be removed when ref_count == 0
*/
void dmaengine_put(void)
{
struct dma_device *device;
struct dma_chan *chan;
mutex_lock(&dma_list_mutex);
dmaengine_ref_count--;
BUG_ON(dmaengine_ref_count < 0);
/* drop channel references */
list_for_each_entry(device, &dma_device_list, global_node) {
if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
continue;
list_for_each_entry(chan, &device->channels, device_node)
dma_chan_put(chan);
}
mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL(dmaengine_put);
static bool device_has_all_tx_types(struct dma_device *device)
{
/* A device that satisfies this test has channels that will never cause
* an async_tx channel switch event as all possible operation types can
* be handled.
*/
#ifdef CONFIG_ASYNC_TX_DMA
if (!dma_has_cap(DMA_INTERRUPT, device->cap_mask))
return false;
#endif
#if defined(CONFIG_ASYNC_MEMCPY) || defined(CONFIG_ASYNC_MEMCPY_MODULE)
if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
return false;
#endif
#if defined(CONFIG_ASYNC_XOR) || defined(CONFIG_ASYNC_XOR_MODULE)
if (!dma_has_cap(DMA_XOR, device->cap_mask))
return false;
#ifndef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA
if (!dma_has_cap(DMA_XOR_VAL, device->cap_mask))
return false;
#endif
#endif
#if defined(CONFIG_ASYNC_PQ) || defined(CONFIG_ASYNC_PQ_MODULE)
if (!dma_has_cap(DMA_PQ, device->cap_mask))
return false;
#ifndef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA
if (!dma_has_cap(DMA_PQ_VAL, device->cap_mask))
return false;
#endif
#endif
return true;
}
static int get_dma_id(struct dma_device *device)
{
int rc;
mutex_lock(&dma_list_mutex);
rc = idr_alloc(&dma_idr, NULL, 0, 0, GFP_KERNEL);
if (rc >= 0)
device->dev_id = rc;
mutex_unlock(&dma_list_mutex);
return rc < 0 ? rc : 0;
}
/**
* dma_async_device_register - registers DMA devices found
* @device: &dma_device
*/
int dma_async_device_register(struct dma_device *device)
{
int chancnt = 0, rc;
struct dma_chan* chan;
atomic_t *idr_ref;
if (!device)
return -ENODEV;
/* validate device routines */
BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
!device->device_prep_dma_memcpy);
BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
!device->device_prep_dma_xor);
BUG_ON(dma_has_cap(DMA_XOR_VAL, device->cap_mask) &&
!device->device_prep_dma_xor_val);
BUG_ON(dma_has_cap(DMA_PQ, device->cap_mask) &&
!device->device_prep_dma_pq);
BUG_ON(dma_has_cap(DMA_PQ_VAL, device->cap_mask) &&
!device->device_prep_dma_pq_val);
BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
!device->device_prep_dma_interrupt);
BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) &&
!device->device_prep_dma_sg);
BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) &&
!device->device_prep_dma_cyclic);
BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
!device->device_control);
BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) &&
!device->device_prep_interleaved_dma);
BUG_ON(!device->device_alloc_chan_resources);
BUG_ON(!device->device_free_chan_resources);
BUG_ON(!device->device_tx_status);
BUG_ON(!device->device_issue_pending);
BUG_ON(!device->dev);
/* note: this only matters in the
* CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
*/
if (device_has_all_tx_types(device))
dma_cap_set(DMA_ASYNC_TX, device->cap_mask);
idr_ref = kmalloc(sizeof(*idr_ref), GFP_KERNEL);
if (!idr_ref)
return -ENOMEM;
rc = get_dma_id(device);
if (rc != 0) {
kfree(idr_ref);
return rc;
}
atomic_set(idr_ref, 0);
/* represent channels in sysfs. Probably want devs too */
list_for_each_entry(chan, &device->channels, device_node) {
rc = -ENOMEM;
chan->local = alloc_percpu(typeof(*chan->local));
if (chan->local == NULL)
goto err_out;
chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
if (chan->dev == NULL) {
free_percpu(chan->local);
chan->local = NULL;
goto err_out;
}
chan->chan_id = chancnt++;
chan->dev->device.class = &dma_devclass;
chan->dev->device.parent = device->dev;
chan->dev->chan = chan;
chan->dev->idr_ref = idr_ref;
chan->dev->dev_id = device->dev_id;
atomic_inc(idr_ref);
dev_set_name(&chan->dev->device, "dma%dchan%d",
device->dev_id, chan->chan_id);
rc = device_register(&chan->dev->device);
if (rc) {
free_percpu(chan->local);
chan->local = NULL;
kfree(chan->dev);
atomic_dec(idr_ref);
goto err_out;
}
chan->client_count = 0;
}
device->chancnt = chancnt;
mutex_lock(&dma_list_mutex);
/* take references on public channels */
if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
list_for_each_entry(chan, &device->channels, device_node) {
/* if clients are already waiting for channels we need
* to take references on their behalf
*/
if (dma_chan_get(chan) == -ENODEV) {
/* note we can only get here for the first
* channel as the remaining channels are
* guaranteed to get a reference
*/
rc = -ENODEV;
mutex_unlock(&dma_list_mutex);
goto err_out;
}
}
list_add_tail_rcu(&device->global_node, &dma_device_list);
if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
device->privatecnt++; /* Always private */
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
return 0;
err_out:
/* if we never registered a channel just release the idr */
if (atomic_read(idr_ref) == 0) {
mutex_lock(&dma_list_mutex);
idr_remove(&dma_idr, device->dev_id);
mutex_unlock(&dma_list_mutex);
kfree(idr_ref);
return rc;
}
list_for_each_entry(chan, &device->channels, device_node) {
if (chan->local == NULL)
continue;
mutex_lock(&dma_list_mutex);
chan->dev->chan = NULL;
mutex_unlock(&dma_list_mutex);
device_unregister(&chan->dev->device);
free_percpu(chan->local);
}
return rc;
}
EXPORT_SYMBOL(dma_async_device_register);
/**
* dma_async_device_unregister - unregister a DMA device
* @device: &dma_device
*
* This routine is called by dma driver exit routines, dmaengine holds module
* references to prevent it being called while channels are in use.
*/
void dma_async_device_unregister(struct dma_device *device)
{
struct dma_chan *chan;
mutex_lock(&dma_list_mutex);
list_del_rcu(&device->global_node);
dma_channel_rebalance();
mutex_unlock(&dma_list_mutex);
list_for_each_entry(chan, &device->channels, device_node) {
WARN_ONCE(chan->client_count,
"%s called while %d clients hold a reference\n",
__func__, chan->client_count);
mutex_lock(&dma_list_mutex);
chan->dev->chan = NULL;
mutex_unlock(&dma_list_mutex);
device_unregister(&chan->dev->device);
free_percpu(chan->local);
}
}
EXPORT_SYMBOL(dma_async_device_unregister);
struct dmaengine_unmap_pool {
struct kmem_cache *cache;
const char *name;
mempool_t *pool;
size_t size;
};
#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
static struct dmaengine_unmap_pool unmap_pool[] = {
__UNMAP_POOL(2),
#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
__UNMAP_POOL(16),
__UNMAP_POOL(128),
__UNMAP_POOL(256),
#endif
};
static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
{
int order = get_count_order(nr);
switch (order) {
case 0 ... 1:
return &unmap_pool[0];
case 2 ... 4:
return &unmap_pool[1];
case 5 ... 7:
return &unmap_pool[2];
case 8:
return &unmap_pool[3];
default:
BUG();
return NULL;
}
}
static void dmaengine_unmap(struct kref *kref)
{
struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
struct device *dev = unmap->dev;
int cnt, i;
cnt = unmap->to_cnt;
for (i = 0; i < cnt; i++)
dma_unmap_page(dev, unmap->addr[i], unmap->len,
DMA_TO_DEVICE);
cnt += unmap->from_cnt;
for (; i < cnt; i++)
dma_unmap_page(dev, unmap->addr[i], unmap->len,
DMA_FROM_DEVICE);
cnt += unmap->bidi_cnt;
for (; i < cnt; i++) {
if (unmap->addr[i] == 0)
continue;
dma_unmap_page(dev, unmap->addr[i], unmap->len,
DMA_BIDIRECTIONAL);
}
mempool_free(unmap, __get_unmap_pool(cnt)->pool);
}
void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
{
if (unmap)
kref_put(&unmap->kref, dmaengine_unmap);
}
EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
static void dmaengine_destroy_unmap_pool(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
struct dmaengine_unmap_pool *p = &unmap_pool[i];
if (p->pool)
mempool_destroy(p->pool);
p->pool = NULL;
if (p->cache)
kmem_cache_destroy(p->cache);
p->cache = NULL;
}
}
static int __init dmaengine_init_unmap_pool(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
struct dmaengine_unmap_pool *p = &unmap_pool[i];
size_t size;
size = sizeof(struct dmaengine_unmap_data) +
sizeof(dma_addr_t) * p->size;
p->cache = kmem_cache_create(p->name, size, 0,
SLAB_HWCACHE_ALIGN, NULL);
if (!p->cache)
break;
p->pool = mempool_create_slab_pool(1, p->cache);
if (!p->pool)
break;
}
if (i == ARRAY_SIZE(unmap_pool))
return 0;
dmaengine_destroy_unmap_pool();
return -ENOMEM;
}
struct dmaengine_unmap_data *
dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
{
struct dmaengine_unmap_data *unmap;
unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
if (!unmap)
return NULL;
memset(unmap, 0, sizeof(*unmap));
kref_init(&unmap->kref);
unmap->dev = dev;
return unmap;
}
EXPORT_SYMBOL(dmaengine_get_unmap_data);
/**
* dma_async_memcpy_pg_to_pg - offloaded copy from page to page
* @chan: DMA channel to offload copy to
* @dest_pg: destination page
* @dest_off: offset in page to copy to
* @src_pg: source page
* @src_off: offset in page to copy from
* @len: length
*
* Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
* address according to the DMA mapping API rules for streaming mappings.
* Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
* (kernel memory or locked user space pages).
*/
dma_cookie_t
dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
unsigned int dest_off, struct page *src_pg, unsigned int src_off,
size_t len)
{
struct dma_device *dev = chan->device;
struct dma_async_tx_descriptor *tx;
struct dmaengine_unmap_data *unmap;
dma_cookie_t cookie;
unsigned long flags;
unmap = dmaengine_get_unmap_data(dev->dev, 2, GFP_NOWAIT);
if (!unmap)
return -ENOMEM;
unmap->to_cnt = 1;
unmap->from_cnt = 1;
unmap->addr[0] = dma_map_page(dev->dev, src_pg, src_off, len,
DMA_TO_DEVICE);
unmap->addr[1] = dma_map_page(dev->dev, dest_pg, dest_off, len,
DMA_FROM_DEVICE);
unmap->len = len;
flags = DMA_CTRL_ACK;
tx = dev->device_prep_dma_memcpy(chan, unmap->addr[1], unmap->addr[0],
len, flags);
if (!tx) {
dmaengine_unmap_put(unmap);
return -ENOMEM;
}
dma_set_unmap(tx, unmap);
cookie = tx->tx_submit(tx);
dmaengine_unmap_put(unmap);
preempt_disable();
__this_cpu_add(chan->local->bytes_transferred, len);
__this_cpu_inc(chan->local->memcpy_count);
preempt_enable();
return cookie;
}
EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);
/**
* dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
* @chan: DMA channel to offload copy to
* @dest: destination address (virtual)
* @src: source address (virtual)
* @len: length
*
* Both @dest and @src must be mappable to a bus address according to the
* DMA mapping API rules for streaming mappings.
* Both @dest and @src must stay memory resident (kernel memory or locked
* user space pages).
*/
dma_cookie_t
dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
void *src, size_t len)
{
return dma_async_memcpy_pg_to_pg(chan, virt_to_page(dest),
(unsigned long) dest & ~PAGE_MASK,
virt_to_page(src),
(unsigned long) src & ~PAGE_MASK, len);
}
EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);
/**
* dma_async_memcpy_buf_to_pg - offloaded copy from address to page
* @chan: DMA channel to offload copy to
* @page: destination page
* @offset: offset in page to copy to
* @kdata: source address (virtual)
* @len: length
*
* Both @page/@offset and @kdata must be mappable to a bus address according
* to the DMA mapping API rules for streaming mappings.
* Both @page/@offset and @kdata must stay memory resident (kernel memory or
* locked user space pages)
*/
dma_cookie_t
dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
unsigned int offset, void *kdata, size_t len)
{
return dma_async_memcpy_pg_to_pg(chan, page, offset,
virt_to_page(kdata),
(unsigned long) kdata & ~PAGE_MASK, len);
}
EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);
void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
struct dma_chan *chan)
{
tx->chan = chan;
#ifdef CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH
spin_lock_init(&tx->lock);
#endif
}
EXPORT_SYMBOL(dma_async_tx_descriptor_init);
/* dma_wait_for_async_tx - spin wait for a transaction to complete
* @tx: in-flight transaction to wait on
*/
enum dma_status
dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
{
unsigned long dma_sync_wait_timeout = jiffies + msecs_to_jiffies(5000);
if (!tx)
return DMA_COMPLETE;
while (tx->cookie == -EBUSY) {
if (time_after_eq(jiffies, dma_sync_wait_timeout)) {
pr_err("%s timeout waiting for descriptor submission\n",
__func__);
return DMA_ERROR;
}
cpu_relax();
}
return dma_sync_wait(tx->chan, tx->cookie);
}
EXPORT_SYMBOL_GPL(dma_wait_for_async_tx);
/* dma_run_dependencies - helper routine for dma drivers to process
* (start) dependent operations on their target channel
* @tx: transaction with dependencies
*/
void dma_run_dependencies(struct dma_async_tx_descriptor *tx)
{
struct dma_async_tx_descriptor *dep = txd_next(tx);
struct dma_async_tx_descriptor *dep_next;
struct dma_chan *chan;
if (!dep)
return;
/* we'll submit tx->next now, so clear the link */
txd_clear_next(tx);
chan = dep->chan;
/* keep submitting up until a channel switch is detected
* in that case we will be called again as a result of
* processing the interrupt from async_tx_channel_switch
*/
for (; dep; dep = dep_next) {
txd_lock(dep);
txd_clear_parent(dep);
dep_next = txd_next(dep);
if (dep_next && dep_next->chan == chan)
txd_clear_next(dep); /* ->next will be submitted */
else
dep_next = NULL; /* submit current dep and terminate */
txd_unlock(dep);
dep->tx_submit(dep);
}
chan->device->device_issue_pending(chan);
}
EXPORT_SYMBOL_GPL(dma_run_dependencies);
static int __init dma_bus_init(void)
{
int err = dmaengine_init_unmap_pool();
if (err)
return err;
return class_register(&dma_devclass);
}
arch_initcall(dma_bus_init);