[PATCH v13 1/4] bus: mhi: core: Add helper API to return number of free TREs
From: Hemant Kumar <hidden>
Date: 2020-11-28 04:16:30
Also in:
linux-arm-msm, lkml
Subsystem:
mhi bus, the rest · Maintainers:
Manivannan Sadhasivam, Linus Torvalds
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 <redacted> Reviewed-by: Jeffrey Hugo <redacted> Reviewed-by: Manivannan Sadhasivam <redacted> --- 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 4eb93d8..defd579a 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c@@ -260,6 +260,18 @@ 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 d31efcf..b3bc966 100644
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h@@ -597,6 +597,15 @@ 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
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