v4.19.13 snapshot.
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
new file mode 100644
index 0000000..f1a441a
--- /dev/null
+++ b/drivers/dma/dmaengine.c
@@ -0,0 +1,1381 @@
+/*
+ * 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.
+ *
+ * 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/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>
+
+static DEFINE_MUTEX(dma_list_mutex);
+static DEFINE_IDA(dma_ida);
+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)) {
+ ida_free(&dma_ida, chan_dev->dev_id);
+ 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)
+{
+ 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;
+
+ /* 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:
+ 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--;
+ module_put(dma_chan_to_owner(chan));
+
+ /* 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;
+ }
+}
+
+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_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)
+ 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);
+
+/**
+ * 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;
+ }
+}
+
+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
+ *
+ * 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;
+
+ /* Find a channel */
+ mutex_lock(&dma_list_mutex);
+ list_for_each_entry_safe(device, _d, &dma_device_list, global_node) {
+ 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 (chan) {
+ /* Valid channel found or requester need to be deferred */
+ if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
+ return chan;
+ }
+
+ /* 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);
+
+ return chan ? chan : ERR_PTR(-EPROBE_DEFER);
+}
+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);
+ 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);
+ 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;
+ 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 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;
+}
+
+/**
+ * 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 */
+ if (!device->dev) {
+ pr_err("DMAdevice must have dev\n");
+ return -EIO;
+ }
+
+ 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;
+ }
+
+ /* 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;
+ }
+
+ if (!chancnt) {
+ dev_err(device->dev, "%s: device has no channels!\n", __func__);
+ rc = -ENODEV;
+ goto err_out;
+ }
+
+ 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) {
+ ida_free(&dma_ida, device->dev_id);
+ 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);
+
+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);
+
+/* 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;
+ return class_register(&dma_devclass);
+}
+arch_initcall(dma_bus_init);
+
+