Messages in this thread Patch in this message | | | From | Hemant Kumar <> | Subject | [PATCH v2 1/3] bus: mhi: core: Add helper API to return number of free TREs | Date | Thu, 21 May 2020 19:51:28 -0700 |
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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) +{ + 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 + * Get # of TD available 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); + +/** * 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 -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
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