diff options
Diffstat (limited to 'drivers/dma/dmaengine.c')
| -rw-r--r-- | drivers/dma/dmaengine.c | 109 |
1 files changed, 70 insertions, 39 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 9e56745f87bf..9162ac80c18f 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -87,7 +87,8 @@ static struct dma_chan *dev_to_dma_chan(struct device *dev) return chan_dev->chan; } -static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf) +static ssize_t memcpy_count_show(struct device *dev, + struct device_attribute *attr, char *buf) { struct dma_chan *chan; unsigned long count = 0; @@ -106,9 +107,10 @@ static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *at return err; } +static DEVICE_ATTR_RO(memcpy_count); -static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr, - char *buf) +static ssize_t bytes_transferred_show(struct device *dev, + struct device_attribute *attr, char *buf) { struct dma_chan *chan; unsigned long count = 0; @@ -127,8 +129,10 @@ static ssize_t show_bytes_transferred(struct device *dev, struct device_attribut return err; } +static DEVICE_ATTR_RO(bytes_transferred); -static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf) +static ssize_t in_use_show(struct device *dev, struct device_attribute *attr, + char *buf) { struct dma_chan *chan; int err; @@ -143,13 +147,15 @@ static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, ch return err; } +static DEVICE_ATTR_RO(in_use); -static struct device_attribute dma_attrs[] = { - __ATTR(memcpy_count, S_IRUGO, show_memcpy_count, NULL), - __ATTR(bytes_transferred, S_IRUGO, show_bytes_transferred, NULL), - __ATTR(in_use, S_IRUGO, show_in_use, NULL), - __ATTR_NULL +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) { @@ -167,7 +173,7 @@ static void chan_dev_release(struct device *dev) static struct class dma_devclass = { .name = "dma", - .dev_attrs = dma_attrs, + .dev_groups = dma_dev_groups, .dev_release = chan_dev_release, }; @@ -376,20 +382,30 @@ void dma_issue_pending_all(void) EXPORT_SYMBOL(dma_issue_pending_all); /** - * nth_chan - returns the nth channel of the given capability + * 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 - * @n: nth channel desired + * @cpu: cpu index which the channel should be close to * - * Defaults to returning the channel with the desired capability and the - * lowest reference count when 'n' cannot be satisfied. Must be called - * under dma_list_mutex. + * 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 *nth_chan(enum dma_transaction_type cap, int n) +static struct dma_chan *min_chan(enum dma_transaction_type cap, int cpu) { struct dma_device *device; struct dma_chan *chan; - struct dma_chan *ret = NULL; 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) || @@ -398,27 +414,22 @@ static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n) list_for_each_entry(chan, &device->channels, device_node) { if (!chan->client_count) continue; - if (!min) - min = chan; - else if (chan->table_count < min->table_count) + if (!min || chan->table_count < min->table_count) min = chan; - if (n-- == 0) { - ret = chan; - break; /* done */ - } + if (dma_chan_is_local(chan, cpu)) + if (!localmin || + chan->table_count < localmin->table_count) + localmin = chan; } - if (ret) - break; /* done */ } - if (!ret) - ret = min; + chan = localmin ? localmin : min; - if (ret) - ret->table_count++; + if (chan) + chan->table_count++; - return ret; + return chan; } /** @@ -435,7 +446,6 @@ static void dma_channel_rebalance(void) struct dma_device *device; int cpu; int cap; - int n; /* undo the last distribution */ for_each_dma_cap_mask(cap, dma_cap_mask_all) @@ -454,14 +464,9 @@ static void dma_channel_rebalance(void) return; /* redistribute available channels */ - n = 0; for_each_dma_cap_mask(cap, dma_cap_mask_all) for_each_online_cpu(cpu) { - if (num_possible_cpus() > 1) - chan = nth_chan(cap, n++); - else - chan = nth_chan(cap, -1); - + chan = min_chan(cap, cpu); per_cpu_ptr(channel_table[cap], cpu)->chan = chan; } } @@ -504,7 +509,33 @@ static struct dma_chan *private_candidate(const dma_cap_mask_t *mask, } /** - * dma_request_channel - try to allocate an exclusive channel + * 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); + +/** + * __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 |