diff options
| -rw-r--r-- | drivers/dma/dmaengine.c | 155 | ||||
| -rw-r--r-- | include/linux/dmaengine.h | 16 |
2 files changed, 155 insertions, 16 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 418eca2..7a0594f 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -134,14 +134,14 @@ static struct class dma_devclass = { /* --- client and device registration --- */ -#define dma_chan_satisfies_mask(chan, mask) \ - __dma_chan_satisfies_mask((chan), &(mask)) +#define dma_device_satisfies_mask(device, mask) \ + __dma_device_satisfies_mask((device), &(mask)) static int -__dma_chan_satisfies_mask(struct dma_chan *chan, dma_cap_mask_t *want) +__dma_device_satisfies_mask(struct dma_device *device, dma_cap_mask_t *want) { dma_cap_mask_t has; - bitmap_and(has.bits, want->bits, chan->device->cap_mask.bits, + 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); } @@ -195,7 +195,7 @@ static int dma_chan_get(struct dma_chan *chan) err = desc_cnt; chan->client_count = 0; module_put(owner); - } else + } else if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask)) balance_ref_count(chan); } @@ -232,14 +232,16 @@ static void dma_client_chan_alloc(struct dma_client *client) /* Find a channel */ list_for_each_entry(device, &dma_device_list, global_node) { + if (dma_has_cap(DMA_PRIVATE, device->cap_mask)) + continue; /* Does the client require a specific DMA controller? */ if (client->slave && client->slave->dma_dev && client->slave->dma_dev != device->dev) continue; + if (!dma_device_satisfies_mask(device, client->cap_mask)) + continue; list_for_each_entry(chan, &device->channels, device_node) { - if (!dma_chan_satisfies_mask(chan, client->cap_mask)) - continue; if (!chan->client_count) continue; ack = client->event_callback(client, chan, @@ -320,11 +322,12 @@ static int __init dma_channel_table_init(void) bitmap_fill(dma_cap_mask_all.bits, DMA_TX_TYPE_END); - /* 'interrupt' and 'slave' are channel capabilities, but are not - * associated with an operation so they do not need an entry in the - * channel_table + /* '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) { @@ -378,10 +381,13 @@ void dma_issue_pending_all(void) "client called %s without a reference", __func__); rcu_read_lock(); - list_for_each_entry_rcu(device, &dma_device_list, global_node) + 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); @@ -403,7 +409,8 @@ static struct dma_chan *nth_chan(enum dma_transaction_type cap, int n) struct dma_chan *min = NULL; list_for_each_entry(device, &dma_device_list, global_node) { - if (!dma_has_cap(cap, device->cap_mask)) + 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) @@ -452,9 +459,12 @@ static void dma_channel_rebalance(void) for_each_possible_cpu(cpu) per_cpu_ptr(channel_table[cap], cpu)->chan = NULL; - list_for_each_entry(device, &dma_device_list, global_node) + 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) @@ -473,6 +483,111 @@ static void dma_channel_rebalance(void) } } +static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_device *dev) +{ + struct dma_chan *chan; + struct dma_chan *ret = NULL; + + 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__, dev_name(&chan->dev)); + continue; + } + ret = chan; + break; + } + + return ret; +} + +/** + * 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 + */ +struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param) +{ + struct dma_device *device, *_d; + struct dma_chan *chan = NULL; + enum dma_state_client ack; + 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); + if (!chan) + continue; + + if (fn) + ack = fn(chan, fn_param); + else + ack = DMA_ACK; + + if (ack == DMA_ACK) { + /* 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); + err = dma_chan_get(chan); + + if (err == -ENODEV) { + pr_debug("%s: %s module removed\n", __func__, + dev_name(&chan->dev)); + list_del_rcu(&device->global_node); + } else if (err) + pr_err("dmaengine: failed to get %s: (%d)\n", + dev_name(&chan->dev), err); + else + break; + } else if (ack == DMA_DUP) { + pr_debug("%s: %s filter said DMA_DUP\n", + __func__, dev_name(&chan->dev)); + } else if (ack == DMA_NAK) { + pr_debug("%s: %s filter said DMA_NAK\n", + __func__, dev_name(&chan->dev)); + break; + } else + WARN_ONCE(1, "filter_fn: unknown response?\n"); + chan = NULL; + } + mutex_unlock(&dma_list_mutex); + + pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail", + chan ? dev_name(&chan->dev) : NULL); + + return chan; +} +EXPORT_SYMBOL_GPL(__dma_request_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); + mutex_unlock(&dma_list_mutex); +} +EXPORT_SYMBOL_GPL(dma_release_channel); + /** * dma_chans_notify_available - broadcast available channels to the clients */ @@ -506,7 +621,9 @@ void dma_async_client_register(struct dma_client *client) dmaengine_ref_count++; /* try to grab channels */ - list_for_each_entry_safe(device, _d, &dma_device_list, global_node) + 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) { @@ -517,6 +634,7 @@ void dma_async_client_register(struct dma_client *client) pr_err("dmaengine: failed to get %s: (%d)\n", dev_name(&chan->dev), err); } + } /* if this is the first reference and there were channels * waiting we need to rebalance to get those channels @@ -547,9 +665,12 @@ void dma_async_client_unregister(struct dma_client *client) dmaengine_ref_count--; BUG_ON(dmaengine_ref_count < 0); /* drop channel references */ - list_for_each_entry(device, &dma_device_list, global_node) + 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); + } list_del(&client->global_node); mutex_unlock(&dma_list_mutex); @@ -639,9 +760,11 @@ int dma_async_device_register(struct dma_device *device) chan->slow_ref = 0; INIT_RCU_HEAD(&chan->rcu); } + device->chancnt = chancnt; mutex_lock(&dma_list_mutex); - if (dmaengine_ref_count) + /* 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 diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 57a43ad..fe40bc0 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -89,6 +89,7 @@ enum dma_transaction_type { DMA_MEMSET, DMA_MEMCPY_CRC32C, DMA_INTERRUPT, + DMA_PRIVATE, DMA_SLAVE, }; @@ -224,6 +225,18 @@ typedef enum dma_state_client (*dma_event_callback) (struct dma_client *client, struct dma_chan *chan, enum dma_state state); /** + * typedef dma_filter_fn - callback filter for dma_request_channel + * @chan: channel to be reviewed + * @filter_param: opaque parameter passed through dma_request_channel + * + * When this optional parameter is specified in a call to dma_request_channel a + * suitable channel is passed to this routine for further dispositioning before + * being returned. Where 'suitable' indicates a non-busy channel that + * satisfies the given capability mask. + */ +typedef enum dma_state_client (*dma_filter_fn)(struct dma_chan *chan, void *filter_param); + +/** * struct dma_client - info on the entity making use of DMA services * @event_callback: func ptr to call when something happens * @cap_mask: only return channels that satisfy the requested capabilities @@ -472,6 +485,9 @@ void dma_async_device_unregister(struct dma_device *device); void dma_run_dependencies(struct dma_async_tx_descriptor *tx); struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type); void dma_issue_pending_all(void); +#define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y) +struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param); +void dma_release_channel(struct dma_chan *chan); /* --- Helper iov-locking functions --- */ |
