mhi: core: add support for bounce buffer transfer

Not all MHI capable devices can access entire host DDR. If an MHI client provide a transfer packet that’s outside of supported address range, copy the packet to a local bounce buffer prior to transfer. CRs-Fixed 1110280 Change-Id: Ie7292a2c89cc6608d5360f8a330d78635d913c29 Signed-off-by: Sujeev Dias <sdias@codeaurora.org>
2017-01-19 12:19:55 -08:00 · 2017-01-19 12:19:55 -08:00 · 5ce3f182b8
commit 5ce3f182b8
parent 75edc331a7
4 changed files with 161 additions and 93 deletions
--- a/Documentation/devicetree/bindings/mhi/msm_mhi.txt
+++ b/Documentation/devicetree/bindings/mhi/msm_mhi.txt
@ -120,6 +120,13 @@ Main node properties:
  Value type: <u32>
  Definition: Segment size in bytes for each segment in bytes.

+- qcom,mhi-bb-required
+  Usage: optional
+  Value type: bool
+  Definition: Determine whether MHI device require bounce buffer
+	during active transfer.  If true, during channel open host
+	will pre-allocate transfer buffers.
+
 ========
 Example:
 ========
--- a/drivers/platform/msm/mhi/mhi.h
+++ b/drivers/platform/msm/mhi/mhi.h
@ -1,4 +1,4 @@
-/* Copyright (c) 2014-2016, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
@ -348,6 +348,7 @@ struct mhi_ring {
 	u32 msi_disable_cntr;
 	u32 msi_enable_cntr;
 	spinlock_t ring_lock;
+	struct dma_pool *dma_pool;
 };

 enum MHI_CMD_STATUS {
@ -446,9 +447,12 @@ struct mhi_state_work_queue {

 struct mhi_buf_info {
 	dma_addr_t bb_p_addr;
+	dma_addr_t pre_alloc_p_addr;
 	void *bb_v_addr;
+	void *pre_alloc_v_addr;
 	void *client_buf;
 	size_t buf_len;
+	size_t pre_alloc_len;
 	size_t filled_size;
 	enum dma_data_direction dir;
 	int bb_active;
@ -479,6 +483,7 @@ struct mhi_flags {
 	u32 kill_threads;
 	u32 ev_thread_stopped;
 	u32 st_thread_stopped;
+	bool bb_required;
 };

 struct mhi_wait_queues {
--- a/drivers/platform/msm/mhi/mhi_iface.c
+++ b/drivers/platform/msm/mhi/mhi_iface.c
@ -1,4 +1,4 @@
-/* Copyright (c) 2014-2016, The Linux Foundation. All rights reserved.
+/* Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
@ -456,6 +456,10 @@ static int mhi_plat_probe(struct platform_device *pdev)
 		INIT_WORK(&bhi_ctxt->fw_load_work, bhi_firmware_download);
 	}

+	mhi_dev_ctxt->flags.bb_required =
+		of_property_read_bool(pdev->dev.of_node,
+				      "qcom,mhi-bb-required");
+
 	mhi_dev_ctxt->plat_dev = pdev;
 	platform_set_drvdata(pdev, mhi_dev_ctxt);

--- a/drivers/platform/msm/mhi/mhi_main.c
+++ b/drivers/platform/msm/mhi/mhi_main.c
@ -32,9 +32,18 @@

 static int reset_chan_cmd(struct mhi_device_ctxt *mhi_dev_ctxt,
 			  union mhi_cmd_pkt *cmd_pkt);
+static void disable_bb_ctxt(struct mhi_device_ctxt *mhi_dev_ctxt,
+			    struct mhi_ring *bb_ctxt);

-static int enable_bb_ctxt(struct mhi_ring *bb_ctxt, int nr_el)
+static int enable_bb_ctxt(struct mhi_device_ctxt *mhi_dev_ctxt,
+			  struct mhi_ring *bb_ctxt,
+			  int nr_el,
+			  int chan,
+			  size_t max_payload)
 {
+	int i;
+	struct mhi_buf_info *mhi_buf_info;
+
 	bb_ctxt->el_size = sizeof(struct mhi_buf_info);
 	bb_ctxt->len     = bb_ctxt->el_size * nr_el;
 	bb_ctxt->base    = kzalloc(bb_ctxt->len, GFP_KERNEL);
@ -43,7 +52,46 @@ static int enable_bb_ctxt(struct mhi_ring *bb_ctxt, int nr_el)
 	bb_ctxt->ack_rp  = bb_ctxt->base;
 	if (!bb_ctxt->base)
 		return -ENOMEM;
+
+	if (mhi_dev_ctxt->flags.bb_required) {
+		char pool_name[32];
+
+		snprintf(pool_name, sizeof(pool_name), "mhi%d_%d",
+			 mhi_dev_ctxt->plat_dev->id, chan);
+
+		mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
+			"Creating pool %s for chan:%d payload: 0x%lx\n",
+			pool_name, chan, max_payload);
+
+		bb_ctxt->dma_pool = dma_pool_create(pool_name,
+			&mhi_dev_ctxt->plat_dev->dev, max_payload, 0, 0);
+		if (unlikely(!bb_ctxt->dma_pool))
+			goto dma_pool_error;
+
+		mhi_buf_info = (struct mhi_buf_info *)bb_ctxt->base;
+		for (i = 0; i < nr_el; i++, mhi_buf_info++) {
+			mhi_buf_info->pre_alloc_v_addr =
+				dma_pool_alloc(bb_ctxt->dma_pool, GFP_KERNEL,
+					       &mhi_buf_info->pre_alloc_p_addr);
+			if (unlikely(!mhi_buf_info->pre_alloc_v_addr))
+				goto dma_alloc_error;
+			mhi_buf_info->pre_alloc_len = max_payload;
+		}
+	}
+
 	return 0;
+
+dma_alloc_error:
+	for (--i, --mhi_buf_info; i >= 0; i--, mhi_buf_info--)
+		dma_pool_free(bb_ctxt->dma_pool, mhi_buf_info->pre_alloc_v_addr,
+			      mhi_buf_info->pre_alloc_p_addr);
+
+	dma_pool_destroy(bb_ctxt->dma_pool);
+	bb_ctxt->dma_pool = NULL;
+dma_pool_error:
+	kfree(bb_ctxt->base);
+	bb_ctxt->base = NULL;
+	return -ENOMEM;
 }

 static void mhi_write_db(struct mhi_device_ctxt *mhi_dev_ctxt,
@ -207,11 +255,9 @@ int mhi_release_chan_ctxt(struct mhi_device_ctxt *mhi_dev_ctxt,
 	return 0;
 }

-void free_tre_ring(struct mhi_client_config *client_config)
+void free_tre_ring(struct mhi_device_ctxt *mhi_dev_ctxt, int chan)
 {
 	struct mhi_chan_ctxt *chan_ctxt;
-	struct mhi_device_ctxt *mhi_dev_ctxt = client_config->mhi_dev_ctxt;
-	int chan = client_config->chan_info.chan_nr;
 	int r;

 	chan_ctxt = &mhi_dev_ctxt->dev_space.ring_ctxt.cc_list[chan];
@ -276,11 +322,6 @@ int mhi_open_channel(struct mhi_client_handle *client_handle)
 		return -EINVAL;

 	mhi_dev_ctxt = client_config->mhi_dev_ctxt;
-	ret_val = get_chan_props(mhi_dev_ctxt,
-			    client_config->chan_info.chan_nr,
-			   &client_config->chan_info);
-	if (ret_val)
-		return ret_val;

 	chan = client_config->chan_info.chan_nr;
 	cfg = &mhi_dev_ctxt->mhi_chan_cfg[chan];
@ -302,21 +343,11 @@ int mhi_open_channel(struct mhi_client_handle *client_handle)
 		mhi_log(mhi_dev_ctxt, MHI_MSG_ERROR,
 			"Failed to initialize tre ring chan %d ret %d\n",
 			chan, ret_val);
-		mutex_unlock(&cfg->chan_lock);
-		return ret_val;
+		goto error_tre_ring;
 	}
 	client_config->event_ring_index =
 		mhi_dev_ctxt->dev_space.ring_ctxt.
 				cc_list[chan].mhi_event_ring_index;
-	ret_val = enable_bb_ctxt(&mhi_dev_ctxt->chan_bb_list[chan],
-			client_config->chan_info.max_desc);
-	if (ret_val) {
-		mhi_log(mhi_dev_ctxt, MHI_MSG_ERROR,
-			"Failed to initialize bb ctxt chan %d ret %d\n",
-			chan, ret_val);
-		mutex_unlock(&cfg->chan_lock);
-		return ret_val;
-	}

 	client_config->msi_vec =
 		mhi_dev_ctxt->dev_space.ring_ctxt.ec_list[
@ -331,18 +362,13 @@ int mhi_open_channel(struct mhi_client_handle *client_handle)
 		mhi_log(mhi_dev_ctxt, MHI_MSG_ERROR,
 			"MHI State is disabled\n");
 		read_unlock_bh(&mhi_dev_ctxt->pm_xfer_lock);
-		mutex_unlock(&cfg->chan_lock);
-		return -EIO;
+		ret_val = -EIO;
+		goto error_pm_state;
 	}
-
-	WARN_ON(mhi_dev_ctxt->mhi_pm_state == MHI_PM_DISABLE);
 	mhi_dev_ctxt->assert_wake(mhi_dev_ctxt, false);
 	read_unlock_bh(&mhi_dev_ctxt->pm_xfer_lock);
 	mhi_dev_ctxt->runtime_get(mhi_dev_ctxt);

-	spin_lock_irq(&chan_ring->ring_lock);
-	chan_ring->ch_state = MHI_CHAN_STATE_ENABLED;
-	spin_unlock_irq(&chan_ring->ring_lock);
 	ret_val = mhi_send_cmd(client_config->mhi_dev_ctxt,
 			       MHI_COMMAND_START_CHAN,
 			       chan);
@ -377,16 +403,30 @@ int mhi_open_channel(struct mhi_client_handle *client_handle)
 		goto error_completion;
 	}

+	spin_lock_irq(&chan_ring->ring_lock);
+	chan_ring->ch_state = MHI_CHAN_STATE_ENABLED;
+	spin_unlock_irq(&chan_ring->ring_lock);
 	client_config->chan_status = 1;

-error_completion:
-
 	read_lock_bh(&mhi_dev_ctxt->pm_xfer_lock);
 	mhi_dev_ctxt->deassert_wake(mhi_dev_ctxt);
 	read_unlock_bh(&mhi_dev_ctxt->pm_xfer_lock);
 	mhi_dev_ctxt->runtime_put(mhi_dev_ctxt);
 	mutex_unlock(&cfg->chan_lock);

+	mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
+		"chan:%d opened successfully\n", chan);
+	return 0;
+
+error_completion:
+	read_lock_bh(&mhi_dev_ctxt->pm_xfer_lock);
+	mhi_dev_ctxt->deassert_wake(mhi_dev_ctxt);
+	read_unlock_bh(&mhi_dev_ctxt->pm_xfer_lock);
+	mhi_dev_ctxt->runtime_put(mhi_dev_ctxt);
+error_pm_state:
+	free_tre_ring(mhi_dev_ctxt, chan);
+error_tre_ring:
+	mutex_unlock(&cfg->chan_lock);
 	mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
 		"Exited chan 0x%x ret:%d\n", chan, ret_val);
 	return ret_val;
@ -431,6 +471,7 @@ int mhi_register_channel(struct mhi_client_handle **client_handle,
 	struct mhi_client_config *client_config;
 	const char *node_name;
 	enum MHI_CLIENT_CHANNEL chan;
+	int ret;

 	if (!client_info || client_info->dev->of_node == NULL)
 		return -EINVAL;
@ -489,6 +530,17 @@ int mhi_register_channel(struct mhi_client_handle **client_handle,
 	if (MHI_CLIENT_IP_HW_0_IN  == chan)
 		client_config->intmod_t = 10;

+	get_chan_props(mhi_dev_ctxt, chan, &client_config->chan_info);
+	ret = enable_bb_ctxt(mhi_dev_ctxt, &mhi_dev_ctxt->chan_bb_list[chan],
+			     client_config->chan_info.max_desc, chan,
+			     client_config->client_info.max_payload);
+	if (ret) {
+		kfree(mhi_dev_ctxt->client_handle_list[chan]->client_config);
+		kfree(mhi_dev_ctxt->client_handle_list[chan]);
+		mhi_dev_ctxt->client_handle_list[chan] =  NULL;
+		return -ENOMEM;
+	}
+
 	if (mhi_dev_ctxt->dev_exec_env == MHI_EXEC_ENV_AMSS &&
 	    mhi_dev_ctxt->flags.mhi_initialized) {
 		mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
@ -531,6 +583,14 @@ void mhi_close_channel(struct mhi_client_handle *client_handle)

 	/* No more processing events for this channel */
 	spin_lock_irq(&chan_ring->ring_lock);
+	if (chan_ring->ch_state != MHI_CHAN_STATE_ENABLED) {
+		mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
+			"Chan %d is not enabled, cur state:0x%x\n",
+			chan, chan_ring->ch_state);
+		spin_unlock_irq(&chan_ring->ring_lock);
+		mutex_unlock(&cfg->chan_lock);
+		return;
+	}
 	chan_ring->ch_state = MHI_CHAN_STATE_DISABLED;
 	spin_unlock_irq(&chan_ring->ring_lock);
 	init_completion(&cfg->cmd_complete);
@ -565,22 +625,30 @@ void mhi_close_channel(struct mhi_client_handle *client_handle)
 		mhi_log(mhi_dev_ctxt, MHI_MSG_ERROR,
 			"Error to receive event completion ev_cod:0x%x\n",
 			ev_code);
-		goto error_completion;
 	}

+error_completion:
 	ret_val = reset_chan_cmd(mhi_dev_ctxt, &cmd_pkt);
 	if (ret_val)
 		mhi_log(mhi_dev_ctxt, MHI_MSG_ERROR,
 			"Error resetting cmd ret:%d\n", ret_val);
-error_completion:

 	read_lock_bh(&mhi_dev_ctxt->pm_xfer_lock);
 	mhi_dev_ctxt->deassert_wake(mhi_dev_ctxt);
 	read_unlock_bh(&mhi_dev_ctxt->pm_xfer_lock);
 	mhi_dev_ctxt->runtime_put(mhi_dev_ctxt);
+	mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
+		"resetting bb_ring for chan 0x%x\n", chan);
+	mhi_dev_ctxt->chan_bb_list[chan].rp =
+		mhi_dev_ctxt->chan_bb_list[chan].base;
+	mhi_dev_ctxt->chan_bb_list[chan].wp =
+		mhi_dev_ctxt->chan_bb_list[chan].base;
+	mhi_dev_ctxt->chan_bb_list[chan].ack_rp =
+		mhi_dev_ctxt->chan_bb_list[chan].base;
+
 	mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
 		"Freeing ring for chan 0x%x\n", chan);
-	free_tre_ring(client_config);
+	free_tre_ring(mhi_dev_ctxt, chan);
 	mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
 		"Chan 0x%x confirmed closed.\n", chan);
 	client_config->chan_status = 0;
@ -639,6 +707,7 @@ static inline int mhi_queue_tre(struct mhi_device_ctxt
 	}
 	return 0;
 }
+
 static int create_bb(struct mhi_device_ctxt *mhi_dev_ctxt,
 		  int chan, void *buf, size_t buf_len,
 		  enum dma_data_direction dir, struct mhi_buf_info **bb)
@ -674,6 +743,7 @@ static int create_bb(struct mhi_device_ctxt *mhi_dev_ctxt,
 					bb_info->client_buf,
 					bb_info->buf_len,
 					bb_info->dir);
+	bb_info->bb_active = 0;
 	if (!VALID_BUF(bb_info->bb_p_addr, bb_info->buf_len, mhi_dev_ctxt)) {
 		mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
 			"Buffer outside DMA range 0x%lx, size 0x%zx\n",
@ -682,30 +752,48 @@ static int create_bb(struct mhi_device_ctxt *mhi_dev_ctxt,
 				bb_info->bb_p_addr,
 				bb_info->buf_len,
 				bb_info->dir);
-		mhi_log(mhi_dev_ctxt, MHI_MSG_RAW,
-			"Allocating BB, chan %d\n", chan);
-		bb_info->bb_v_addr = dma_alloc_coherent(
-				&mhi_dev_ctxt->plat_dev->dev,
-				bb_info->buf_len,
-				&bb_info->bb_p_addr,
-				GFP_ATOMIC);
-		if (!bb_info->bb_v_addr)
-			return -ENOMEM;
-		mhi_dev_ctxt->counters.bb_used[chan]++;
-		if (dir == DMA_TO_DEVICE) {
-			mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
-				"Copying client buf into BB.\n");
-			memcpy(bb_info->bb_v_addr, buf, bb_info->buf_len);
-			/* Flush out data to bounce buffer */
-			wmb();
-		}
-		bb_info->bb_active = 1;
+
+		if (likely((mhi_dev_ctxt->flags.bb_required &&
+			    bb_info->pre_alloc_len >= bb_info->buf_len))) {
+			bb_info->bb_p_addr = bb_info->pre_alloc_p_addr;
+			bb_info->bb_v_addr = bb_info->pre_alloc_v_addr;
+			mhi_dev_ctxt->counters.bb_used[chan]++;
+			if (dir == DMA_TO_DEVICE) {
+				mhi_log(mhi_dev_ctxt, MHI_MSG_INFO,
+					"Copying client buf into BB.\n");
+				memcpy(bb_info->bb_v_addr, buf,
+				       bb_info->buf_len);
+			}
+			bb_info->bb_active = 1;
+		} else
+			mhi_log(mhi_dev_ctxt, MHI_MSG_ERROR,
+				"No BB allocated\n");
 	}
 	*bb = bb_info;
 	mhi_log(mhi_dev_ctxt, MHI_MSG_RAW, "Exited chan %d\n", chan);
 	return 0;
 }

+static void disable_bb_ctxt(struct mhi_device_ctxt *mhi_dev_ctxt,
+			    struct mhi_ring *bb_ctxt)
+{
+	if (mhi_dev_ctxt->flags.bb_required) {
+		struct mhi_buf_info *bb =
+			(struct mhi_buf_info *)bb_ctxt->base;
+		int nr_el = bb_ctxt->len / bb_ctxt->el_size;
+		int i = 0;
+
+		for (i = 0; i < nr_el; i++, bb++)
+			dma_pool_free(bb_ctxt->dma_pool, bb->pre_alloc_v_addr,
+				      bb->pre_alloc_p_addr);
+		dma_pool_destroy(bb_ctxt->dma_pool);
+		bb_ctxt->dma_pool = NULL;
+	}
+
+	kfree(bb_ctxt->base);
+	bb_ctxt->base = NULL;
+}
+
 static void free_bounce_buffer(struct mhi_device_ctxt *mhi_dev_ctxt,
 			       struct mhi_buf_info *bb)
 {
@ -714,44 +802,11 @@ static void free_bounce_buffer(struct mhi_device_ctxt *mhi_dev_ctxt,
 		/* This buffer was maped directly to device */
 		dma_unmap_single(&mhi_dev_ctxt->plat_dev->dev,
 				 bb->bb_p_addr, bb->buf_len, bb->dir);
-	else
-		/* This buffer was bounced */
-		dma_free_coherent(&mhi_dev_ctxt->plat_dev->dev,
-				  bb->buf_len,
-				  bb->bb_v_addr,
-				  bb->bb_p_addr);
+
 	bb->bb_active = 0;
 	mhi_log(mhi_dev_ctxt, MHI_MSG_RAW, "Exited\n");
 }

-void reset_bb_ctxt(struct mhi_device_ctxt *mhi_dev_ctxt,
-			  struct mhi_ring *bb_ctxt)
-{
-	int r = 0;
-	struct mhi_buf_info *bb = NULL;
-
-	mhi_log(mhi_dev_ctxt, MHI_MSG_VERBOSE, "Entered\n");
-	/*
-	  Assumption: No events are expected during or after
-	  this operation is occurring for this channel.
-	  If a bounce buffer was allocated, the coherent memory is
-	  expected to be already freed.
-	  If the user's bounce buffer was mapped, it is expected to be
-	  already unmapped.
-	  Failure of any of the above conditions will result in
-	  a memory leak or subtle memory corruption.
-	 */
-	while (!r) {
-		r = ctxt_del_element(bb_ctxt, (void **)&bb);
-		if (bb)
-			free_bounce_buffer(mhi_dev_ctxt, bb);
-	}
-	bb_ctxt->ack_rp = bb_ctxt->base;
-	bb_ctxt->rp = bb_ctxt->base;
-	bb_ctxt->wp = bb_ctxt->base;
-	mhi_log(mhi_dev_ctxt, MHI_MSG_VERBOSE, "Exited\n");
-}
-
 static int mhi_queue_dma_xfer(
 		struct mhi_client_config *client_config,
 		dma_addr_t buf, size_t buf_len, enum MHI_FLAGS mhi_flags)
@ -1342,7 +1397,6 @@ static int reset_chan_cmd(struct mhi_device_ctxt *mhi_dev_ctxt,
 	struct mhi_chan_ctxt *chan_ctxt;
 	struct mhi_event_ctxt *ev_ctxt = NULL;
 	int pending_el = 0, i;
-	struct mhi_ring *bb_ctxt;
 	unsigned long flags;
 	union mhi_event_pkt *local_rp = NULL;
 	union mhi_event_pkt *device_rp = NULL;
@ -1355,8 +1409,6 @@ static int reset_chan_cmd(struct mhi_device_ctxt *mhi_dev_ctxt,
 		return -EINVAL;
 	}

-	bb_ctxt = &mhi_dev_ctxt->chan_bb_list[chan];
-
 	local_chan_ctxt = &mhi_dev_ctxt->mhi_local_chan_ctxt[chan];
 	chan_ctxt = &mhi_dev_ctxt->dev_space.ring_ctxt.cc_list[chan];
 	ev_ring = &mhi_dev_ctxt->
@ -1426,9 +1478,6 @@ static int reset_chan_cmd(struct mhi_device_ctxt *mhi_dev_ctxt,
 	chan_ctxt->mhi_trb_read_ptr = chan_ctxt->mhi_trb_ring_base_addr;
 	chan_ctxt->mhi_trb_write_ptr = chan_ctxt->mhi_trb_ring_base_addr;

-	mhi_log(mhi_dev_ctxt, MHI_MSG_INFO, "Cleaning up BB list\n");
-	reset_bb_ctxt(mhi_dev_ctxt, bb_ctxt);
-
 	mhi_log(mhi_dev_ctxt, MHI_MSG_INFO, "Reset complete.\n");
 	return ret_val;
 }
@ -1672,14 +1721,17 @@ int mhi_deregister_channel(struct mhi_client_handle *client_handle)
 	int ret_val = 0;
 	int chan;
 	struct mhi_client_config *client_config;
+	struct mhi_device_ctxt *mhi_dev_ctxt;

 	if (!client_handle)
 		return -EINVAL;

 	client_config = client_handle->client_config;
+	mhi_dev_ctxt = client_config->mhi_dev_ctxt;
 	chan = client_config->chan_info.chan_nr;
 	client_config->magic = 0;
-	client_config->mhi_dev_ctxt->client_handle_list[chan] = NULL;
+	mhi_dev_ctxt->client_handle_list[chan] = NULL;
+	disable_bb_ctxt(mhi_dev_ctxt, &mhi_dev_ctxt->chan_bb_list[chan]);
 	kfree(client_config);
 	kfree(client_handle);
 	return ret_val;