+EXPORT_SYMBOL(get_dma_residue);
+
+static int search_cap(const char **haystack, const char *needle)
+{
+ const char **p;
+
+ for (p = haystack; *p; p++)
+ if (strcmp(*p, needle) == 0)
+ return 1;
+
+ return 0;
+}
+
+/**
+ * request_dma_bycap - Allocate a DMA channel based on its capabilities
+ * @dmac: List of DMA controllers to search
+ * @caps: List of capabilites
+ *
+ * Search all channels of all DMA controllers to find a channel which
+ * matches the requested capabilities. The result is the channel
+ * number if a match is found, or %-ENODEV if no match is found.
+ *
+ * Note that not all DMA controllers export capabilities, in which
+ * case they can never be allocated using this API, and so
+ * request_dma() must be used specifying the channel number.
+ */
+int request_dma_bycap(const char **dmac, const char **caps, const char *dev_id)
+{
+ unsigned int found = 0;
+ struct dma_info *info;
+ const char **p;
+ int i;
+
+ BUG_ON(!dmac || !caps);
+
+ list_for_each_entry(info, ®istered_dmac_list, list)
+ if (strcmp(*dmac, info->name) == 0) {
+ found = 1;
+ break;
+ }
+
+ if (!found)
+ return -ENODEV;
+
+ for (i = 0; i < info->nr_channels; i++) {
+ struct dma_channel *channel = &info->channels[i];
+
+ if (unlikely(!channel->caps))
+ continue;
+
+ for (p = caps; *p; p++) {
+ if (!search_cap(channel->caps, *p))
+ break;
+ if (request_dma(channel->chan, dev_id) == 0)
+ return channel->chan;
+ }
+ }
+
+ return -EINVAL;
+}
+EXPORT_SYMBOL(request_dma_bycap);
+
+int dmac_search_free_channel(const char *dev_id)
+{
+ struct dma_channel *channel = { 0 };
+ struct dma_info *info = get_dma_info(0);
+ int i;
+
+ for (i = 0; i < info->nr_channels; i++) {
+ channel = &info->channels[i];
+ if (unlikely(!channel))
+ return -ENODEV;
+
+ if (atomic_read(&channel->busy) == 0)
+ break;
+ }
+
+ if (info->ops->request) {
+ int result = info->ops->request(channel);
+ if (result)
+ return result;
+
+ atomic_set(&channel->busy, 1);
+ return channel->chan;
+ }
+
+ return -ENOSYS;
+}