Re: [PATCH v3 1/4] bus: mhi: core: Add helper API to return number of free TREs

Manivannan Sadhasivam
2020-06-19T05:31:35Z

On Thu, Jun 11, 2020 at 11:13:41AM -0700, Hemant Kumar wrote:
> Introduce mhi_get_no_free_descriptors() API to return number
> of TREs available to queue buffer. MHI clients can use this
> API to know before hand if ring is full without calling queue
> API.
>
> Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
> ---
> drivers/bus/mhi/core/main.c | 12 ++++++++++++
> include/linux/mhi.h | 9 +++++++++
> 2 files changed, 21 insertions(+)
>
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index d25f321..1bd3b1e 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -258,6 +258,18 @@ int mhi_destroy_device(struct device *dev, void *data)
> return 0;
> }
>
> +int mhi_get_no_free_descriptors(struct mhi_device *mhi_dev,
> + enum dma_data_direction dir)

How about "mhi_get_nr_free_descriptors"? Also align with '('

> +{
> + struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
> + struct mhi_chan *mhi_chan = (dir == DMA_TO_DEVICE) ?
> + mhi_dev->ul_chan : mhi_dev->dl_chan;
> + struct mhi_ring *tre_ring = &mhi_chan->tre_ring;
> +
> + return get_nr_avail_ring_elements(mhi_cntrl, tre_ring);
> +}
> +EXPORT_SYMBOL_GPL(mhi_get_no_free_descriptors);
> +
> void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason)
> {
> struct mhi_driver *mhi_drv;
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index 6af6bd6..a39b77d 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -602,6 +602,15 @@ void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl,
> void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
>
> /**
> + * mhi_get_no_free_descriptors - Get transfer ring length

Is the description correct? I'd suggest to just use the below one.

> + * Get # of TD available to queue buffers

How about, "Get # of available TREs to queue buffers"?

> + * @mhi_dev: Device associated with the channels
> + * @dir: Direction of the channel
> + */
> +int mhi_get_no_free_descriptors(struct mhi_device *mhi_dev,
> + enum dma_data_direction dir);

Align this with '('

Thanks,
Mani

> +
> +/**
> * mhi_prepare_for_power_up - Do pre-initialization before power up.
> * This is optional, call this before power up if
> * the controller does not want bus framework to
> --
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> a Linux Foundation Collaborative Project
>