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Message-Id: <20211202113553.238011-19-manivannan.sadhasivam@linaro.org>
Date: Thu, 2 Dec 2021 17:05:50 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: mhi@...ts.linux.dev
Cc: hemantk@...eaurora.org, bbhatt@...eaurora.org,
quic_jhugo@...cinc.com, vinod.koul@...aro.org,
bjorn.andersson@...aro.org, dmitry.baryshkov@...aro.org,
skananth@...eaurora.org, vpernami@...eaurora.org,
vbadigan@...eaurora.org, linux-arm-msm@...r.kernel.org,
linux-kernel@...r.kernel.org,
Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Subject: [PATCH 18/20] bus: mhi: ep: Add support for queueing SKBs over MHI bus
Add support for queueing SKBs over MHI bus in the MHI endpoint stack.
The mhi_ep_queue_skb() API will be used by the client networking drivers
to queue the SKBs to the host over MHI.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---
drivers/bus/mhi/ep/main.c | 132 ++++++++++++++++++++++++++++++++++++++
include/linux/mhi_ep.h | 12 ++++
2 files changed, 144 insertions(+)
diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 26d551eb63ce..cc3da846ed36 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -522,6 +522,138 @@ int mhi_ep_process_tre_ring(struct mhi_ep_ring *ring, struct mhi_ep_ring_element
return ret;
}
+static void skip_to_next_td(struct mhi_ep_chan *mhi_chan, struct mhi_ep_ring *ring)
+{
+ struct mhi_ep_ring_element *el;
+ u32 td_boundary_reached = 0;
+
+ mhi_chan->skip_td = 1;
+ el = &ring->ring_cache[ring->rd_offset];
+ while (ring->rd_offset != ring->wr_offset) {
+ if (td_boundary_reached) {
+ mhi_chan->skip_td = 0;
+ break;
+ }
+
+ if (!MHI_EP_TRE_GET_CHAIN(el))
+ td_boundary_reached = 1;
+
+ mhi_ep_ring_inc_index(ring);
+ el = &ring->ring_cache[ring->rd_offset];
+ }
+}
+
+int mhi_ep_queue_skb(struct mhi_ep_device *mhi_dev, enum dma_data_direction dir,
+ struct sk_buff *skb, size_t len, enum mhi_flags mflags)
+{
+ struct mhi_ep_chan *mhi_chan = (dir == DMA_FROM_DEVICE) ? mhi_dev->dl_chan :
+ mhi_dev->ul_chan;
+ struct mhi_ep_cntrl *mhi_cntrl = mhi_dev->mhi_cntrl;
+ enum mhi_ev_ccs code = MHI_EV_CC_INVALID;
+ struct mhi_ep_ring_element *el;
+ u64 write_to_loc, skip_tre = 0;
+ struct mhi_ep_ring *ring;
+ size_t bytes_to_write;
+ void __iomem *tre_buf;
+ phys_addr_t tre_phys;
+ void *read_from_loc;
+ u32 buf_remaining;
+ u32 tre_len;
+ int ret = 0;
+
+ if (dir == DMA_TO_DEVICE)
+ return -EINVAL;
+
+ buf_remaining = len;
+ ring = &mhi_cntrl->mhi_chan[mhi_chan->chan].ring;
+
+ mutex_lock(&mhi_chan->lock);
+ if (mhi_chan->skip_td)
+ skip_to_next_td(mhi_chan, ring);
+
+ do {
+ /* Don't process the transfer ring if the channel is not in RUNNING state */
+ if (mhi_chan->state != MHI_CH_STATE_RUNNING) {
+ dev_err(&mhi_chan->mhi_dev->dev, "Channel not available");
+ ret = -ENODEV;
+ goto err_exit;
+ }
+
+ if (mhi_ep_queue_is_empty(mhi_dev, dir)) {
+ dev_err(&mhi_chan->mhi_dev->dev, "TRE not available!\n");
+ ret = -EINVAL;
+ goto err_exit;
+ }
+
+ el = &ring->ring_cache[ring->rd_offset];
+ tre_len = MHI_EP_TRE_GET_LEN(el);
+ if (skb->len > tre_len) {
+ dev_err(&mhi_chan->mhi_dev->dev, "Buffer size (%d) is too large!\n",
+ skb->len);
+ ret = -ENOMEM;
+ goto err_exit;
+ }
+
+ bytes_to_write = min(buf_remaining, tre_len);
+ read_from_loc = skb->data;
+ write_to_loc = MHI_EP_TRE_GET_PTR(el);
+
+ tre_buf = mhi_cntrl->alloc_addr(mhi_cntrl, &tre_phys, bytes_to_write);
+ if (!tre_buf) {
+ dev_err(&mhi_chan->mhi_dev->dev, "Failed to allocate TRE buffer\n");
+ ret = -ENOMEM;
+ goto err_exit;
+ }
+
+ ret = mhi_cntrl->map_addr(mhi_cntrl, tre_phys, write_to_loc, bytes_to_write);
+ if (ret) {
+ dev_err(&mhi_chan->mhi_dev->dev, "Failed to map TRE buffer\n");
+ goto err_tre_free;
+ }
+
+ dev_dbg(&mhi_chan->mhi_dev->dev, "Writing %d bytes", bytes_to_write);
+ memcpy_toio(tre_buf, read_from_loc, bytes_to_write);
+
+ mhi_cntrl->unmap_addr(mhi_cntrl, tre_phys);
+ mhi_cntrl->free_addr(mhi_cntrl, tre_phys, tre_buf, bytes_to_write);
+
+ buf_remaining -= bytes_to_write;
+ if (buf_remaining) {
+ if (!MHI_EP_TRE_GET_CHAIN(el))
+ code = MHI_EV_CC_OVERFLOW;
+ else if (MHI_EP_TRE_GET_IEOB(el))
+ code = MHI_EV_CC_EOB;
+ } else {
+ if (MHI_EP_TRE_GET_CHAIN(el))
+ skip_tre = 1;
+ code = MHI_EV_CC_EOT;
+ }
+
+ ret = mhi_ep_send_completion_event(mhi_cntrl, ring, bytes_to_write, code);
+ if (ret) {
+ dev_err(&mhi_chan->mhi_dev->dev, "Error sending completion event");
+ goto err_exit;
+ }
+
+ mhi_ep_ring_inc_index(ring);
+ } while (!skip_tre && buf_remaining);
+
+ if (skip_tre)
+ skip_to_next_td(mhi_chan, ring);
+
+ mutex_unlock(&mhi_chan->lock);
+
+ return 0;
+
+err_tre_free:
+ mhi_cntrl->free_addr(mhi_cntrl, tre_phys, tre_buf, bytes_to_write);
+err_exit:
+ mutex_unlock(&mhi_chan->lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(mhi_ep_queue_skb);
+
static int mhi_ep_cache_host_cfg(struct mhi_ep_cntrl *mhi_cntrl)
{
struct device *dev = &mhi_cntrl->mhi_dev->dev;
diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h
index 260a181d3fab..a7715f8066ed 100644
--- a/include/linux/mhi_ep.h
+++ b/include/linux/mhi_ep.h
@@ -274,4 +274,16 @@ void mhi_ep_power_down(struct mhi_ep_cntrl *mhi_cntrl);
*/
bool mhi_ep_queue_is_empty(struct mhi_ep_device *mhi_dev, enum dma_data_direction dir);
+/**
+ * mhi_ep_queue_skb - Send SKBs to host over MHI Endpoint
+ * @mhi_dev: Device associated with the channels
+ * @dir: DMA direction for the channel
+ * @skb: Buffer for holding SKBs
+ * @len: Buffer length
+ * @mflags: MHI Endpoint transfer flags used for the transfer
+ *
+ * Return: 0 if the SKBs has been sent successfully, a negative error code otherwise.
+ */
+int mhi_ep_queue_skb(struct mhi_ep_device *mhi_dev, enum dma_data_direction dir,
+ struct sk_buff *skb, size_t len, enum mhi_flags mflags);
#endif
--
2.25.1
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