diff options
| author | Hemant Kumar <hemantk@codeaurora.org> | 2020-10-16 21:04:14 -0700 |
|---|---|---|
| committer | Loic Poulain <loic.poulain@linaro.org> | 2021-01-18 15:06:28 +0100 |
| commit | f6177eac81d3575b0f707be833b86900f19d711b (patch) | |
| tree | 399505e80be6d30434d4dd6e22f11ad619c2f12e | |
| parent | 7541f3ecae85bed7d148d3b6c2a0b70aa037fd18 (diff) | |
bus: mhi: core: Add helper API to return number of free TREs
Introduce mhi_get_free_desc_count() 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>
Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
| -rw-r--r-- | drivers/bus/mhi/core/main.c | 12 | ||||
| -rw-r--r-- | include/linux/mhi.h | 9 |
2 files changed, 21 insertions, 0 deletions
diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c index 8576b0f03f2c..6780f53f16c9 100644 --- a/drivers/bus/mhi/core/main.c +++ b/drivers/bus/mhi/core/main.c @@ -280,6 +280,18 @@ int mhi_destroy_device(struct device *dev, void *data) return 0; } +int mhi_get_free_desc_count(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_free_desc_count); + 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 fe6555496e27..d26acc8b21cd 100644 --- a/include/linux/mhi.h +++ b/include/linux/mhi.h @@ -603,6 +603,15 @@ 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_free_desc_count - 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_free_desc_count(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 |