linux/drivers/dma/dmaengine.c
Dave Jiang 0821009445 dmaengine: fix channel index enumeration
When the channel register code was changed to allow hotplug operations,
dynamic indexing wasn't taken into account. When channels are randomly
plugged and unplugged out of order, the serial indexing breaks. Convert
channel indexing to using IDA tracking in order to allow dynamic
assignment. The previous code does not cause any regression bug for
existing channel allocation besides idxd driver since the hotplug usage
case is only used by idxd at this point.

With this change, the chan->idr_ref is also not needed any longer. We can
have a device with no channels registered due to hot plug. The channel
device release code no longer should attempt to free the dma device id on
the last channel release.

Fixes: e81274cd6b ("dmaengine: add support to dynamic register/unregister of channels")

Reported-by: Yixin Zhang <yixin.zhang@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Yixin Zhang <yixin.zhang@intel.com>
Link: https://lore.kernel.org/r/158679961260.7674.8485924270472851852.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2020-04-27 21:26:23 +05:30

1657 lines
41 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
*/
/*
* 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/driver-api/dmaengine for more details
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/platform_device.h>
#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>
#include <linux/numa.h>
static DEFINE_MUTEX(dma_list_mutex);
static DEFINE_IDA(dma_ida);
static LIST_HEAD(dma_device_list);
static long dmaengine_ref_count;
/* --- debugfs implementation --- */
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
static struct dentry *rootdir;
static void dmaengine_debug_register(struct dma_device *dma_dev)
{
dma_dev->dbg_dev_root = debugfs_create_dir(dev_name(dma_dev->dev),
rootdir);
if (IS_ERR(dma_dev->dbg_dev_root))
dma_dev->dbg_dev_root = NULL;
}
static void dmaengine_debug_unregister(struct dma_device *dma_dev)
{
debugfs_remove_recursive(dma_dev->dbg_dev_root);
dma_dev->dbg_dev_root = NULL;
}
static void dmaengine_dbg_summary_show(struct seq_file *s,
struct dma_device *dma_dev)
{
struct dma_chan *chan;
list_for_each_entry(chan, &dma_dev->channels, device_node) {
if (chan->client_count) {
seq_printf(s, " %-13s| %s", dma_chan_name(chan),
chan->dbg_client_name ?: "in-use");
if (chan->router)
seq_printf(s, " (via router: %s)\n",
dev_name(chan->router->dev));
else
seq_puts(s, "\n");
}
}
}
static int dmaengine_summary_show(struct seq_file *s, void *data)
{
struct dma_device *dma_dev = NULL;
mutex_lock(&dma_list_mutex);
list_for_each_entry(dma_dev, &dma_device_list, global_node) {
seq_printf(s, "dma%d (%s): number of channels: %u\n",
dma_dev->dev_id, dev_name(dma_dev->dev),
dma_dev->chancnt);
if (dma_dev->dbg_summary_show)
dma_dev->dbg_summary_show(s, dma_dev);
else
dmaengine_dbg_summary_show(s, dma_dev);
if (!list_is_last(&dma_dev->global_node, &dma_device_list))
seq_puts(s, "\n");
}
mutex_unlock(&dma_list_mutex);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(dmaengine_summary);
static void __init dmaengine_debugfs_init(void)
{
rootdir = debugfs_create_dir("dmaengine", NULL);
/* /sys/kernel/debug/dmaengine/summary */
debugfs_create_file("summary", 0444, rootdir, NULL,
&dmaengine_summary_fops);
}
#else
static inline void dmaengine_debugfs_init(void) { }
static inline int dmaengine_debug_register(struct dma_device *dma_dev)
{
return 0;
}
static inline void dmaengine_debug_unregister(struct dma_device *dma_dev) { }
#endif /* DEBUG_FS */
/* --- sysfs implementation --- */
#define DMA_SLAVE_NAME "slave"
/**
* dev_to_dma_chan - convert a device pointer to 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);
kfree(chan_dev);
}
static struct class dma_devclass = {
.name = "dma",
.dev_groups = dma_dev_groups,
.dev_release = chan_dev_release,
};
/* --- client and device registration --- */
/**
* 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("dmaengine dma_channel_table_init failure: %d\n", err);
for_each_dma_cap_mask(cap, dma_cap_mask_all)
free_percpu(channel_table[cap]);
}
return err;
}
arch_initcall(dma_channel_table_init);
/**
* 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 == NUMA_NO_NODE ||
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 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->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++;
}
}
static void dma_device_release(struct kref *ref)
{
struct dma_device *device = container_of(ref, struct dma_device, ref);
list_del_rcu(&device->global_node);
dma_channel_rebalance();
if (device->device_release)
device->device_release(device);
}
static void dma_device_put(struct dma_device *device)
{
lockdep_assert_held(&dma_list_mutex);
kref_put(&device->ref, dma_device_release);
}
/**
* 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)
{
struct module *owner = dma_chan_to_owner(chan);
int ret;
/* The channel is already in use, update client count */
if (chan->client_count) {
__module_get(owner);
goto out;
}
if (!try_module_get(owner))
return -ENODEV;
ret = kref_get_unless_zero(&chan->device->ref);
if (!ret) {
ret = -ENODEV;
goto module_put_out;
}
/* allocate upon first client reference */
if (chan->device->device_alloc_chan_resources) {
ret = chan->device->device_alloc_chan_resources(chan);
if (ret < 0)
goto err_out;
}
if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
balance_ref_count(chan);
out:
chan->client_count++;
return 0;
err_out:
dma_device_put(chan->device);
module_put_out:
module_put(owner);
return ret;
}
/**
* 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)
{
/* This channel is not in use, bail out */
if (!chan->client_count)
return;
chan->client_count--;
/* This channel is not in use anymore, free it */
if (!chan->client_count && chan->device->device_free_chan_resources) {
/* Make sure all operations have completed */
dmaengine_synchronize(chan);
chan->device->device_free_chan_resources(chan);
}
/* If the channel is used via a DMA request router, free the mapping */
if (chan->router && chan->router->route_free) {
chan->router->route_free(chan->router->dev, chan->route_data);
chan->router = NULL;
chan->route_data = NULL;
}
dma_device_put(chan->device);
module_put(dma_chan_to_owner(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)) {
dev_err(chan->device->dev, "%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_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);
/**
* 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);
int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
{
struct dma_device *device;
if (!chan || !caps)
return -EINVAL;
device = chan->device;
/* check if the channel supports slave transactions */
if (!(test_bit(DMA_SLAVE, device->cap_mask.bits) ||
test_bit(DMA_CYCLIC, device->cap_mask.bits)))
return -ENXIO;
/*
* Check whether it reports it uses the generic slave
* capabilities, if not, that means it doesn't support any
* kind of slave capabilities reporting.
*/
if (!device->directions)
return -ENXIO;
caps->src_addr_widths = device->src_addr_widths;
caps->dst_addr_widths = device->dst_addr_widths;
caps->directions = device->directions;
caps->max_burst = device->max_burst;
caps->residue_granularity = device->residue_granularity;
caps->descriptor_reuse = device->descriptor_reuse;
caps->cmd_pause = !!device->device_pause;
caps->cmd_resume = !!device->device_resume;
caps->cmd_terminate = !!device->device_terminate_all;
return 0;
}
EXPORT_SYMBOL_GPL(dma_get_slave_caps);
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 (mask && !dma_device_satisfies_mask(dev, mask)) {
dev_dbg(dev->dev, "%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) {
dev_dbg(dev->dev, "%s: %s busy\n",
__func__, dma_chan_name(chan));
continue;
}
if (fn && !fn(chan, fn_param)) {
dev_dbg(dev->dev, "%s: %s filter said false\n",
__func__, dma_chan_name(chan));
continue;
}
return chan;
}
return NULL;
}
static struct dma_chan *find_candidate(struct dma_device *device,
const dma_cap_mask_t *mask,
dma_filter_fn fn, void *fn_param)
{
struct dma_chan *chan = private_candidate(mask, device, fn, fn_param);
int err;
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) {
if (err == -ENODEV) {
dev_dbg(device->dev, "%s: %s module removed\n",
__func__, dma_chan_name(chan));
list_del_rcu(&device->global_node);
} else
dev_dbg(device->dev,
"%s: failed to get %s: (%d)\n",
__func__, dma_chan_name(chan), err);
if (--device->privatecnt == 0)
dma_cap_clear(DMA_PRIVATE, device->cap_mask);
chan = ERR_PTR(err);
}
}
return chan ? chan : ERR_PTR(-EPROBE_DEFER);
}
/**
* dma_get_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) {
struct dma_device *device = chan->device;
dma_cap_set(DMA_PRIVATE, device->cap_mask);
device->privatecnt++;
err = dma_chan_get(chan);
if (err) {
dev_dbg(chan->device->dev,
"%s: failed to get %s: (%d)\n",
__func__, dma_chan_name(chan), err);
chan = NULL;
if (--device->privatecnt == 0)
dma_cap_clear(DMA_PRIVATE, device->cap_mask);
}
} 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;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
/* lock against __dma_request_channel */
mutex_lock(&dma_list_mutex);
chan = find_candidate(device, &mask, NULL, NULL);
mutex_unlock(&dma_list_mutex);
return IS_ERR(chan) ? NULL : 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
* @np: device node to look for DMA channels
*
* 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 device_node *np)
{
struct dma_device *device, *_d;
struct dma_chan *chan = NULL;
/* Find a channel */
mutex_lock(&dma_list_mutex);
list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
/* Finds a DMA controller with matching device node */
if (np && device->dev->of_node && np != device->dev->of_node)
continue;
chan = find_candidate(device, mask, fn, fn_param);
if (!IS_ERR(chan))
break;
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);
static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
const char *name,
struct device *dev)
{
int i;
if (!device->filter.mapcnt)
return NULL;
for (i = 0; i < device->filter.mapcnt; i++) {
const struct dma_slave_map *map = &device->filter.map[i];
if (!strcmp(map->devname, dev_name(dev)) &&
!strcmp(map->slave, name))
return map;
}
return NULL;
}
/**
* dma_request_chan - 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_chan(struct device *dev, const char *name)
{
struct dma_device *d, *_d;
struct dma_chan *chan = NULL;
/* If device-tree is present get slave info from here */
if (dev->of_node)
chan = of_dma_request_slave_channel(dev->of_node, name);
/* If device was enumerated by ACPI get slave info from here */
if (has_acpi_companion(dev) && !chan)
chan = acpi_dma_request_slave_chan_by_name(dev, name);
if (PTR_ERR(chan) == -EPROBE_DEFER)
return chan;
if (!IS_ERR_OR_NULL(chan))
goto found;
/* Try to find the channel via the DMA filter map(s) */
mutex_lock(&dma_list_mutex);
list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
dma_cap_mask_t mask;
const struct dma_slave_map *map = dma_filter_match(d, name, dev);
if (!map)
continue;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
chan = find_candidate(d, &mask, d->filter.fn, map->param);
if (!IS_ERR(chan))
break;
}
mutex_unlock(&dma_list_mutex);
if (IS_ERR_OR_NULL(chan))
return chan ? chan : ERR_PTR(-EPROBE_DEFER);
found:
#ifdef CONFIG_DEBUG_FS
chan->dbg_client_name = kasprintf(GFP_KERNEL, "%s:%s", dev_name(dev),
name);
#endif
chan->name = kasprintf(GFP_KERNEL, "dma:%s", name);
if (!chan->name)
return chan;
chan->slave = dev;
if (sysfs_create_link(&chan->dev->device.kobj, &dev->kobj,
DMA_SLAVE_NAME))
dev_warn(dev, "Cannot create DMA %s symlink\n", DMA_SLAVE_NAME);
if (sysfs_create_link(&dev->kobj, &chan->dev->device.kobj, chan->name))
dev_warn(dev, "Cannot create DMA %s symlink\n", chan->name);
return chan;
}
EXPORT_SYMBOL_GPL(dma_request_chan);
/**
* 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_chan(dev, name);
if (IS_ERR(ch))
return NULL;
return ch;
}
EXPORT_SYMBOL_GPL(dma_request_slave_channel);
/**
* dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
* @mask: capabilities that the channel must satisfy
*
* Returns pointer to appropriate DMA channel on success or an error pointer.
*/
struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
{
struct dma_chan *chan;
if (!mask)
return ERR_PTR(-ENODEV);
chan = __dma_request_channel(mask, NULL, NULL, NULL);
if (!chan) {
mutex_lock(&dma_list_mutex);
if (list_empty(&dma_device_list))
chan = ERR_PTR(-EPROBE_DEFER);
else
chan = ERR_PTR(-ENODEV);
mutex_unlock(&dma_list_mutex);
}
return chan;
}
EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
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);
if (chan->slave) {
sysfs_remove_link(&chan->dev->device.kobj, DMA_SLAVE_NAME);
sysfs_remove_link(&chan->slave->kobj, chan->name);
kfree(chan->name);
chan->name = NULL;
chan->slave = NULL;
}
#ifdef CONFIG_DEBUG_FS
kfree(chan->dbg_client_name);
chan->dbg_client_name = NULL;
#endif
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)
dev_dbg(chan->device->dev,
"%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, *_d;
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_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)
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 IS_ENABLED(CONFIG_ASYNC_MEMCPY)
if (!dma_has_cap(DMA_MEMCPY, device->cap_mask))
return false;
#endif
#if IS_ENABLED(CONFIG_ASYNC_XOR)
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 IS_ENABLED(CONFIG_ASYNC_PQ)
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 = ida_alloc(&dma_ida, GFP_KERNEL);
if (rc < 0)
return rc;
device->dev_id = rc;
return 0;
}
static int __dma_async_device_channel_register(struct dma_device *device,
struct dma_chan *chan)
{
int rc = 0;
chan->local = alloc_percpu(typeof(*chan->local));
if (!chan->local)
goto err_out;
chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
if (!chan->dev) {
free_percpu(chan->local);
chan->local = NULL;
goto err_out;
}
/*
* When the chan_id is a negative value, we are dynamically adding
* the channel. Otherwise we are static enumerating.
*/
mutex_lock(&device->chan_mutex);
chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL);
mutex_unlock(&device->chan_mutex);
if (chan->chan_id < 0) {
pr_err("%s: unable to alloc ida for chan: %d\n",
__func__, chan->chan_id);
goto err_out;
}
chan->dev->device.class = &dma_devclass;
chan->dev->device.parent = device->dev;
chan->dev->chan = chan;
chan->dev->dev_id = device->dev_id;
dev_set_name(&chan->dev->device, "dma%dchan%d",
device->dev_id, chan->chan_id);
rc = device_register(&chan->dev->device);
if (rc)
goto err_out_ida;
chan->client_count = 0;
device->chancnt++;
return 0;
err_out_ida:
mutex_lock(&device->chan_mutex);
ida_free(&device->chan_ida, chan->chan_id);
mutex_unlock(&device->chan_mutex);
err_out:
free_percpu(chan->local);
kfree(chan->dev);
return rc;
}
int dma_async_device_channel_register(struct dma_device *device,
struct dma_chan *chan)
{
int rc;
rc = __dma_async_device_channel_register(device, chan);
if (rc < 0)
return rc;
dma_channel_rebalance();
return 0;
}
EXPORT_SYMBOL_GPL(dma_async_device_channel_register);
static void __dma_async_device_channel_unregister(struct dma_device *device,
struct dma_chan *chan)
{
WARN_ONCE(!device->device_release && chan->client_count,
"%s called while %d clients hold a reference\n",
__func__, chan->client_count);
mutex_lock(&dma_list_mutex);
list_del(&chan->device_node);
device->chancnt--;
chan->dev->chan = NULL;
mutex_unlock(&dma_list_mutex);
mutex_lock(&device->chan_mutex);
ida_free(&device->chan_ida, chan->chan_id);
mutex_unlock(&device->chan_mutex);
device_unregister(&chan->dev->device);
free_percpu(chan->local);
}
void dma_async_device_channel_unregister(struct dma_device *device,
struct dma_chan *chan)
{
__dma_async_device_channel_unregister(device, chan);
dma_channel_rebalance();
}
EXPORT_SYMBOL_GPL(dma_async_device_channel_unregister);
/**
* dma_async_device_register - registers DMA devices found
* @device: &dma_device
*
* After calling this routine the structure should not be freed except in the
* device_release() callback which will be called after
* dma_async_device_unregister() is called and no further references are taken.
*/
int dma_async_device_register(struct dma_device *device)
{
int rc;
struct dma_chan* chan;
if (!device)
return -ENODEV;
/* validate device routines */
if (!device->dev) {
pr_err("DMAdevice must have dev\n");
return -EIO;
}
device->owner = device->dev->driver->owner;
if (dma_has_cap(DMA_MEMCPY, device->cap_mask) && !device->device_prep_dma_memcpy) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_MEMCPY");
return -EIO;
}
if (dma_has_cap(DMA_XOR, device->cap_mask) && !device->device_prep_dma_xor) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_XOR");
return -EIO;
}
if (dma_has_cap(DMA_XOR_VAL, device->cap_mask) && !device->device_prep_dma_xor_val) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_XOR_VAL");
return -EIO;
}
if (dma_has_cap(DMA_PQ, device->cap_mask) && !device->device_prep_dma_pq) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_PQ");
return -EIO;
}
if (dma_has_cap(DMA_PQ_VAL, device->cap_mask) && !device->device_prep_dma_pq_val) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_PQ_VAL");
return -EIO;
}
if (dma_has_cap(DMA_MEMSET, device->cap_mask) && !device->device_prep_dma_memset) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_MEMSET");
return -EIO;
}
if (dma_has_cap(DMA_INTERRUPT, device->cap_mask) && !device->device_prep_dma_interrupt) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_INTERRUPT");
return -EIO;
}
if (dma_has_cap(DMA_CYCLIC, device->cap_mask) && !device->device_prep_dma_cyclic) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_CYCLIC");
return -EIO;
}
if (dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && !device->device_prep_interleaved_dma) {
dev_err(device->dev,
"Device claims capability %s, but op is not defined\n",
"DMA_INTERLEAVE");
return -EIO;
}
if (!device->device_tx_status) {
dev_err(device->dev, "Device tx_status is not defined\n");
return -EIO;
}
if (!device->device_issue_pending) {
dev_err(device->dev, "Device issue_pending is not defined\n");
return -EIO;
}
if (!device->device_release)
dev_dbg(device->dev,
"WARN: Device release is not defined so it is not safe to unbind this driver while in use\n");
kref_init(&device->ref);
/* 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);
rc = get_dma_id(device);
if (rc != 0)
return rc;
mutex_init(&device->chan_mutex);
ida_init(&device->chan_ida);
/* represent channels in sysfs. Probably want devs too */
list_for_each_entry(chan, &device->channels, device_node) {
rc = __dma_async_device_channel_register(device, chan);
if (rc < 0)
goto err_out;
}
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);
dmaengine_debug_register(device);
return 0;
err_out:
/* if we never registered a channel just release the idr */
if (!device->chancnt) {
ida_free(&dma_ida, device->dev_id);
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, *n;
dmaengine_debug_unregister(device);
list_for_each_entry_safe(chan, n, &device->channels, device_node)
__dma_async_device_channel_unregister(device, chan);
mutex_lock(&dma_list_mutex);
/*
* setting DMA_PRIVATE ensures the device being torn down will not
* be used in the channel_table
*/
dma_cap_set(DMA_PRIVATE, device->cap_mask);
dma_channel_rebalance();
ida_free(&dma_ida, device->dev_id);
dma_device_put(device);
mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL(dma_async_device_unregister);
static void dmam_device_release(struct device *dev, void *res)
{
struct dma_device *device;
device = *(struct dma_device **)res;
dma_async_device_unregister(device);
}
/**
* dmaenginem_async_device_register - registers DMA devices found
* @device: &dma_device
*
* The operation is managed and will be undone on driver detach.
*/
int dmaenginem_async_device_register(struct dma_device *device)
{
void *p;
int ret;
p = devres_alloc(dmam_device_release, sizeof(void *), GFP_KERNEL);
if (!p)
return -ENOMEM;
ret = dma_async_device_register(device);
if (!ret) {
*(struct dma_device **)p = device;
devres_add(device->dev, p);
} else {
devres_free(p);
}
return ret;
}
EXPORT_SYMBOL(dmaenginem_async_device_register);
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];
#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
case 2 ... 4:
return &unmap_pool[1];
case 5 ... 7:
return &unmap_pool[2];
case 8:
return &unmap_pool[3];
#endif
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);
}
cnt = unmap->map_cnt;
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];
mempool_destroy(p->pool);
p->pool = NULL;
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;
unmap->map_cnt = nr;
return unmap;
}
EXPORT_SYMBOL(dmaengine_get_unmap_data);
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);
static inline int desc_check_and_set_metadata_mode(
struct dma_async_tx_descriptor *desc, enum dma_desc_metadata_mode mode)
{
/* Make sure that the metadata mode is not mixed */
if (!desc->desc_metadata_mode) {
if (dmaengine_is_metadata_mode_supported(desc->chan, mode))
desc->desc_metadata_mode = mode;
else
return -ENOTSUPP;
} else if (desc->desc_metadata_mode != mode) {
return -EINVAL;
}
return 0;
}
int dmaengine_desc_attach_metadata(struct dma_async_tx_descriptor *desc,
void *data, size_t len)
{
int ret;
if (!desc)
return -EINVAL;
ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_CLIENT);
if (ret)
return ret;
if (!desc->metadata_ops || !desc->metadata_ops->attach)
return -ENOTSUPP;
return desc->metadata_ops->attach(desc, data, len);
}
EXPORT_SYMBOL_GPL(dmaengine_desc_attach_metadata);
void *dmaengine_desc_get_metadata_ptr(struct dma_async_tx_descriptor *desc,
size_t *payload_len, size_t *max_len)
{
int ret;
if (!desc)
return ERR_PTR(-EINVAL);
ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_ENGINE);
if (ret)
return ERR_PTR(ret);
if (!desc->metadata_ops || !desc->metadata_ops->get_ptr)
return ERR_PTR(-ENOTSUPP);
return desc->metadata_ops->get_ptr(desc, payload_len, max_len);
}
EXPORT_SYMBOL_GPL(dmaengine_desc_get_metadata_ptr);
int dmaengine_desc_set_metadata_len(struct dma_async_tx_descriptor *desc,
size_t payload_len)
{
int ret;
if (!desc)
return -EINVAL;
ret = desc_check_and_set_metadata_mode(desc, DESC_METADATA_ENGINE);
if (ret)
return ret;
if (!desc->metadata_ops || !desc->metadata_ops->set_len)
return -ENOTSUPP;
return desc->metadata_ops->set_len(desc, payload_len);
}
EXPORT_SYMBOL_GPL(dmaengine_desc_set_metadata_len);
/* 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)) {
dev_err(tx->chan->device->dev,
"%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;
err = class_register(&dma_devclass);
if (!err)
dmaengine_debugfs_init();
return err;
}
arch_initcall(dma_bus_init);