Re: [PATCH v2 5/7] soc: qcom: smd: Support opening additional channels

[yfw <fengwei.yin@linaro.org>]

Hi Bjorn,

On 2015/10/10 4:48, Bjorn Andersson wrote:
> 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>
> ---
>
> Changes since v1:
> - New patch
>
>   drivers/soc/qcom/smd.c       | 75 ++++++++++++++++++++++++++++++++++++++++++++
>   include/linux/soc/qcom/smd.h |  4 +++
>   2 files changed, 79 insertions(+)
>
> diff --git a/drivers/soc/qcom/smd.c b/drivers/soc/qcom/smd.c
> index 4c55708aac50..3257ba488d3d 100644
> --- 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;
>   };
> @@ -1042,6 +1044,76 @@ 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);
> +
Do we need qcom_smd_close_channel API here?

Regards
Yin, Fengwei

>   /*
>    * Allocate the qcom_smd_channel object for a newly found smd channel,
>    * retrieving and validating the smem items involved.
> @@ -1178,6 +1250,8 @@ 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);
>   		}
>   	}
>
> @@ -1340,6 +1414,7 @@ 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 65a64fcdb1aa..bd51c8a9d807 100644
> --- a/include/linux/soc/qcom/smd.h
> +++ b/include/linux/soc/qcom/smd.h
> @@ -56,4 +56,8 @@ 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
>