Re: [PATCH 09/11] bus: mhi: host: Get total descriptor count

On Thu, Dec 11, 2025 at 01:37:41PM +0530, Sivareddy Surasani wrote:
> From: Vivek Pernamitta <[email protected]>
> 
> Introduce a new API to retrieve the length of a transfer ring.
> This API allows clients to query the ring length.
> 

What about mhi_get_free_desc_count()?

- Mani

> Signed-off-by: Vivek Pernamitta <[email protected]>
> Signed-off-by: Sivareddy Surasani <[email protected]>
> ---
>  drivers/bus/mhi/host/main.c | 11 +++++++++++
>  include/linux/mhi.h         |  9 +++++++++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
> index 9772fb13400c..6be15297829d 100644
> --- a/drivers/bus/mhi/host/main.c
> +++ b/drivers/bus/mhi/host/main.c
> @@ -345,6 +345,17 @@ int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
>  }
>  EXPORT_SYMBOL_GPL(mhi_get_free_desc_count);
>  
> +int mhi_get_total_descriptors(struct mhi_device *mhi_dev,
> +			      enum dma_data_direction dir)
> +{
> +	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 tre_ring->elements;
> +}
> +EXPORT_SYMBOL(mhi_get_total_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 66fd83bed306..013bc2d82196 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -620,6 +620,15 @@ void mhi_notify(struct mhi_device *mhi_dev, enum mhi_callback cb_reason);
>  int mhi_get_free_desc_count(struct mhi_device *mhi_dev,
>  				enum dma_data_direction dir);
>  
> +/**
> + * mhi_get_total_descriptors - Get total transfer ring length
> + * Get # of TD available to queue buffers
> + * @mhi_dev: Device associated with the channels
> + * @dir: Direction of the channel
> + */
> +int mhi_get_total_descriptors(struct mhi_device *mhi_dev,
> +			      enum dma_data_direction dir);
> +
>  /**
>   * mhi_prepare_for_power_up - Do pre-initialization before power up.
>   *                            This is optional, call this before power up if
> 
> -- 
> 2.34.1
> 

-- 
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