soc: qcom: smd: Support opening additional channels

With the qcom_smd_open_channel() API we allow SMD devices to open
additional SMD channels, to allow implementation of multi-channel SMD
devices - like Bluetooth.

Channels are opened from the same edge as the calling SMD device is tied
to.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>

diff --git a/drivers/soc/qcom/smd.c b/drivers/soc/qcom/smd.c
index 091d23c0e49f271f522787d7332eb2e9c9a95687..1ce0c7e406aefbc09ac90805a260b62cd2617f3d 100644 (file)
--- a/drivers/soc/qcom/smd.c
+++ b/drivers/soc/qcom/smd.c
@@ -129,6 +129,8 @@ struct qcom_smd_edge {
 
        unsigned smem_available;
 
+       wait_queue_head_t new_channel_event;
+
        struct work_struct scan_work;
        struct work_struct state_work;
 };
@@ -981,6 +983,76 @@ void qcom_smd_driver_unregister(struct qcom_smd_driver *qsdrv)
 }
 EXPORT_SYMBOL(qcom_smd_driver_unregister);
 
+static struct qcom_smd_channel *
+qcom_smd_find_channel(struct qcom_smd_edge *edge, const char *name)
+{
+       struct qcom_smd_channel *channel;
+       struct qcom_smd_channel *ret = NULL;
+       unsigned state;
+
+       read_lock(&edge->channels_lock);
+       list_for_each_entry(channel, &edge->channels, list) {
+               if (strcmp(channel->name, name))
+                       continue;
+
+               state = GET_RX_CHANNEL_INFO(channel, state);
+               if (state != SMD_CHANNEL_OPENING &&
+                   state != SMD_CHANNEL_OPENED)
+                       continue;
+
+               ret = channel;
+               break;
+       }
+       read_unlock(&edge->channels_lock);
+
+       return ret;
+}
+
+/**
+ * qcom_smd_open_channel() - claim additional channels on the same edge
+ * @sdev:      smd_device handle
+ * @name:      channel name
+ * @cb:                callback method to use for incoming data
+ *
+ * Returns a channel handle on success, or -EPROBE_DEFER if the channel isn't
+ * ready.
+ */
+struct qcom_smd_channel *qcom_smd_open_channel(struct qcom_smd_device *sdev,
+                                              const char *name,
+                                              qcom_smd_cb_t cb)
+{
+       struct qcom_smd_channel *channel;
+       struct qcom_smd_edge *edge = sdev->channel->edge;
+       int ret;
+
+       /* Wait up to HZ for the channel to appear */
+       ret = wait_event_interruptible_timeout(edge->new_channel_event,
+                       (channel = qcom_smd_find_channel(edge, name)) != NULL,
+                       HZ);
+       if (!ret)
+               return ERR_PTR(-ETIMEDOUT);
+
+       if (channel->state != SMD_CHANNEL_CLOSED) {
+               dev_err(&sdev->dev, "channel %s is busy\n", channel->name);
+               return ERR_PTR(-EBUSY);
+       }
+
+       channel->qsdev = sdev;
+       ret = qcom_smd_channel_open(channel, cb);
+       if (ret) {
+               channel->qsdev = NULL;
+               return ERR_PTR(ret);
+       }
+
+       /*
+        * Append the list of channel to the channels associated with the sdev
+        */
+       list_add_tail(&channel->dev_list, &sdev->channel->dev_list);
+
+       return channel;
+}
+EXPORT_SYMBOL(qcom_smd_open_channel);
+
 /*
  * Allocate the qcom_smd_channel object for a newly found smd channel,
  * retrieving and validating the smem items involved.
@@ -1117,6 +1189,8 @@ static void qcom_channel_scan_worker(struct work_struct *work)
 
                        dev_dbg(smd->dev, "new channel found: '%s'\n", channel->name);
                        set_bit(i, edge->allocated[tbl]);
+
+                       wake_up_interruptible(&edge->new_channel_event);
                }
        }
 
@@ -1283,6 +1357,7 @@ static int qcom_smd_probe(struct platform_device *pdev)
        for_each_available_child_of_node(pdev->dev.of_node, node) {
                edge = &smd->edges[i++];
                edge->smd = smd;
+               init_waitqueue_head(&edge->new_channel_event);
 
                ret = qcom_smd_parse_edge(&pdev->dev, node, edge);
                if (ret)

diff --git a/include/linux/soc/qcom/smd.h b/include/linux/soc/qcom/smd.h
index cccf2b17c077ad90b3a9ae66b5d6dfb20dd11ab7..49764d94ef4f74349737f6e5406f427a92e2b3d1 100644 (file)
--- a/include/linux/soc/qcom/smd.h
+++ b/include/linux/soc/qcom/smd.h
@@ -120,4 +120,8 @@ void qcom_smd_driver_unregister(struct qcom_smd_driver *drv);
 
 int qcom_smd_send(struct qcom_smd_channel *channel, const void *data, int len);
 
+struct qcom_smd_channel *qcom_smd_open_channel(struct qcom_smd_device *sdev,
+                                              const char *name,
+                                              qcom_smd_cb_t cb);
+
 #endif