Merge branch 'ipa-refactoring'

Alex Elder says:

====================
net: ipa: simple refactoring

This series contains some minor code improvements.

The first patch verifies that the configuration is compatible with a
recently-defined limit.  The second and third rename two fields so
they better reflect their use in the code.  The next gets rid of an
empty function by reworking its only caller.

The last two begin to remove the assumption that an event ring is
associated with a single channel.  Eventually we'll support having
multiple channels share an event ring but some more needs to be done
before that can happen.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

7 files changed, 80 insertions, 99 deletions

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 9cfe84319ee4..5b446d2a07c8 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -823,7 +823,7 @@ static void gsi_channel_program(struct gsi_channel *channel, bool doorbell)
 
 	/* Now update the scratch registers for GPI protocol */
 	gpi = &scr.gpi;
-	gpi->max_outstanding_tre = gsi_channel_trans_tre_max(gsi, channel_id) *
+	gpi->max_outstanding_tre = channel->trans_tre_max *
 					GSI_RING_ELEMENT_SIZE;
 	gpi->outstanding_threshold = 2 * GSI_RING_ELEMENT_SIZE;
 
@@ -991,36 +991,22 @@ void gsi_resume(struct gsi *gsi)
 	enable_irq(gsi->irq);
 }
 
-/**
- * gsi_channel_tx_queued() - Report queued TX transfers for a channel
- * @channel:	Channel for which to report
- *
- * Report to the network stack the number of bytes and transactions that
- * have been queued to hardware since last call.  This and the next function
- * supply information used by the network stack for throttling.
- *
- * For each channel we track the number of transactions used and bytes of
- * data those transactions represent.  We also track what those values are
- * each time this function is called.  Subtracting the two tells us
- * the number of bytes and transactions that have been added between
- * successive calls.
- *
- * Calling this each time we ring the channel doorbell allows us to
- * provide accurate information to the network stack about how much
- * work we've given the hardware at any point in time.
- */
-void gsi_channel_tx_queued(struct gsi_channel *channel)
+void gsi_trans_tx_queued(struct gsi_trans *trans)
 {
+	u32 channel_id = trans->channel_id;
+	struct gsi *gsi = trans->gsi;
+	struct gsi_channel *channel;
 	u32 trans_count;
 	u32 byte_count;
 
+	channel = &gsi->channel[channel_id];
+
 	byte_count = channel->byte_count - channel->queued_byte_count;
 	trans_count = channel->trans_count - channel->queued_trans_count;
 	channel->queued_byte_count = channel->byte_count;
 	channel->queued_trans_count = channel->trans_count;
 
-	ipa_gsi_channel_tx_queued(channel->gsi, gsi_channel_id(channel),
-				  trans_count, byte_count);
+	ipa_gsi_channel_tx_queued(gsi, channel_id, trans_count, byte_count);
 }
 
 /**
@@ -1327,17 +1313,29 @@ static int gsi_irq_init(struct gsi *gsi, struct platform_device *pdev)
 }
 
 /* Return the transaction associated with a transfer completion event */
-static struct gsi_trans *gsi_event_trans(struct gsi_channel *channel,
-					 struct gsi_event *event)
+static struct gsi_trans *
+gsi_event_trans(struct gsi *gsi, struct gsi_event *event)
 {
+	u32 channel_id = event->chid;
+	struct gsi_channel *channel;
+	struct gsi_trans *trans;
 	u32 tre_offset;
 	u32 tre_index;
 
+	channel = &gsi->channel[channel_id];
+	if (WARN(!channel->gsi, "event has bad channel %u\n", channel_id))
+		return NULL;
+
 	/* Event xfer_ptr records the TRE it's associated with */
 	tre_offset = lower_32_bits(le64_to_cpu(event->xfer_ptr));
 	tre_index = gsi_ring_index(&channel->tre_ring, tre_offset);
 
-	return gsi_channel_trans_mapped(channel, tre_index);
+	trans = gsi_channel_trans_mapped(channel, tre_index);
+
+	if (WARN(!trans, "channel %u event with no transaction\n", channel_id))
+		return NULL;
+
+	return trans;
 }
 
 /**
@@ -1381,7 +1379,9 @@ static void gsi_evt_ring_rx_update(struct gsi_evt_ring *evt_ring, u32 index)
 	 */
 	old_index = ring->index;
 	event = gsi_ring_virt(ring, old_index);
-	trans = gsi_event_trans(channel, event);
+	trans = gsi_event_trans(channel->gsi, event);
+	if (!trans)
+		return;
 
 	/* Compute the number of events to process before we wrap,
 	 * and determine when we'll be done processing events.
@@ -1493,7 +1493,9 @@ static struct gsi_trans *gsi_channel_update(struct gsi_channel *channel)
 		return NULL;
 
 	/* Get the transaction for the latest completed event. */
-	trans = gsi_event_trans(channel, gsi_ring_virt(ring, index - 1));
+	trans = gsi_event_trans(gsi, gsi_ring_virt(ring, index - 1));
+	if (!trans)
+		return NULL;
 
 	/* For RX channels, update each completed transaction with the number
 	 * of bytes that were actually received.  For TX channels, report
@@ -2001,9 +2003,10 @@ static void gsi_channel_evt_ring_exit(struct gsi_channel *channel)
 	gsi_evt_ring_id_free(gsi, evt_ring_id);
 }
 
-static bool gsi_channel_data_valid(struct gsi *gsi,
+static bool gsi_channel_data_valid(struct gsi *gsi, bool command,
 				   const struct ipa_gsi_endpoint_data *data)
 {
+	const struct gsi_channel_data *channel_data;
 	u32 channel_id = data->channel_id;
 	struct device *dev = gsi->dev;
 
@@ -2019,10 +2022,24 @@ static bool gsi_channel_data_valid(struct gsi *gsi,
 		return false;
 	}
 
-	if (!data->channel.tlv_count ||
-	    data->channel.tlv_count > GSI_TLV_MAX) {
+	if (command && !data->toward_ipa) {
+		dev_err(dev, "command channel %u is not TX\n", channel_id);
+		return false;
+	}
+
+	channel_data = &data->channel;
+
+	if (!channel_data->tlv_count ||
+	    channel_data->tlv_count > GSI_TLV_MAX) {
 		dev_err(dev, "channel %u bad tlv_count %u; must be 1..%u\n",
-			channel_id, data->channel.tlv_count, GSI_TLV_MAX);
+			channel_id, channel_data->tlv_count, GSI_TLV_MAX);
+		return false;
+	}
+
+	if (command && IPA_COMMAND_TRANS_TRE_MAX > channel_data->tlv_count) {
+		dev_err(dev, "command TRE max too big for channel %u (%u > %u)\n",
+			channel_id, IPA_COMMAND_TRANS_TRE_MAX,
+			channel_data->tlv_count);
 		return false;
 	}
 
@@ -2031,22 +2048,22 @@ static bool gsi_channel_data_valid(struct gsi *gsi,
 	 * gsi_channel_tre_max() is computed, tre_count has to be almost
 	 * twice the TLV FIFO size to satisfy this requirement.
 	 */
-	if (data->channel.tre_count < 2 * data->channel.tlv_count - 1) {
+	if (channel_data->tre_count < 2 * channel_data->tlv_count - 1) {
 		dev_err(dev, "channel %u TLV count %u exceeds TRE count %u\n",
-			channel_id, data->channel.tlv_count,
-			data->channel.tre_count);
+			channel_id, channel_data->tlv_count,
+			channel_data->tre_count);
 		return false;
 	}
 
-	if (!is_power_of_2(data->channel.tre_count)) {
+	if (!is_power_of_2(channel_data->tre_count)) {
 		dev_err(dev, "channel %u bad tre_count %u; not power of 2\n",
-			channel_id, data->channel.tre_count);
+			channel_id, channel_data->tre_count);
 		return false;
 	}
 
-	if (!is_power_of_2(data->channel.event_count)) {
+	if (!is_power_of_2(channel_data->event_count)) {
 		dev_err(dev, "channel %u bad event_count %u; not power of 2\n",
-			channel_id, data->channel.event_count);
+			channel_id, channel_data->event_count);
 		return false;
 	}
 
@@ -2062,7 +2079,7 @@ static int gsi_channel_init_one(struct gsi *gsi,
 	u32 tre_count;
 	int ret;
 
-	if (!gsi_channel_data_valid(gsi, data))
+	if (!gsi_channel_data_valid(gsi, command, data))
 		return -EINVAL;
 
 	/* Worst case we need an event for every outstanding TRE */
@@ -2080,7 +2097,7 @@ static int gsi_channel_init_one(struct gsi *gsi,
 	channel->gsi = gsi;
 	channel->toward_ipa = data->toward_ipa;
 	channel->command = command;
-	channel->tlv_count = data->channel.tlv_count;
+	channel->trans_tre_max = data->channel.tlv_count;
 	channel->tre_count = tre_count;
 	channel->event_count = data->channel.event_count;
 
@@ -2295,13 +2312,5 @@ u32 gsi_channel_tre_max(struct gsi *gsi, u32 channel_id)
 	struct gsi_channel *channel = &gsi->channel[channel_id];
 
 	/* Hardware limit is channel->tre_count - 1 */
-	return channel->tre_count - (channel->tlv_count - 1);
-}
-
-/* Returns the maximum number of TREs in a single transaction for a channel */
-u32 gsi_channel_trans_tre_max(struct gsi *gsi, u32 channel_id)
-{
-	struct gsi_channel *channel = &gsi->channel[channel_id];
-
-	return channel->tlv_count;
+	return channel->tre_count - (channel->trans_tre_max - 1);
 }
diff --git a/drivers/net/ipa/gsi.h b/drivers/net/ipa/gsi.h
index 5d66116b46b0..89dac7fc8c4c 100644
--- a/drivers/net/ipa/gsi.h
+++ b/drivers/net/ipa/gsi.h
@@ -110,7 +110,7 @@ struct gsi_channel {
 	bool toward_ipa;
 	bool command;			/* AP command TX channel or not */
 
-	u8 tlv_count;			/* # entries in TLV FIFO */
+	u8 trans_tre_max;		/* max TREs in a transaction */
 	u16 tre_count;
 	u16 event_count;
 
@@ -189,15 +189,6 @@ void gsi_teardown(struct gsi *gsi);
 u32 gsi_channel_tre_max(struct gsi *gsi, u32 channel_id);
 
 /**
- * gsi_channel_trans_tre_max() - Maximum TREs in a single transaction
- * @gsi:	GSI pointer
- * @channel_id:	Channel whose limit is to be returned
- *
- * Return:	 The maximum TRE count per transaction on the channel
- */
-u32 gsi_channel_trans_tre_max(struct gsi *gsi, u32 channel_id);
-
-/**
  * gsi_channel_start() - Start an allocated GSI channel
  * @gsi:	GSI pointer
  * @channel_id:	Channel to start
diff --git a/drivers/net/ipa/gsi_private.h b/drivers/net/ipa/gsi_private.h
index ea333a244cf5..56450a189907 100644
--- a/drivers/net/ipa/gsi_private.h
+++ b/drivers/net/ipa/gsi_private.h
@@ -105,14 +105,12 @@ void gsi_channel_doorbell(struct gsi_channel *channel);
 void *gsi_ring_virt(struct gsi_ring *ring, u32 index);
 
 /**
- * gsi_channel_tx_queued() - Report the number of bytes queued to hardware
- * @channel:	Channel whose bytes have been queued
+ * gsi_trans_tx_queued() - Report a queued TX channel transaction
+ * @trans:	Transaction being passed to hardware
  *
- * This arranges for the the number of transactions and bytes for
- * transfer that have been queued to hardware to be reported.  It
- * passes this information up the network stack so it can be used to
- * throttle transmissions.
+ * Report to the network stack that a TX transaction is being supplied
+ * to the hardware.
  */
-void gsi_channel_tx_queued(struct gsi_channel *channel);
+void gsi_trans_tx_queued(struct gsi_trans *trans);
 
 #endif /* _GSI_PRIVATE_H_ */
diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c
index 55f8fe7d2668..278e467c5430 100644
--- a/drivers/net/ipa/gsi_trans.c
+++ b/drivers/net/ipa/gsi_trans.c
@@ -340,7 +340,7 @@ struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id,
 	struct gsi_trans_info *trans_info;
 	struct gsi_trans *trans;
 
-	if (WARN_ON(tre_count > gsi_channel_trans_tre_max(gsi, channel_id)))
+	if (WARN_ON(tre_count > channel->trans_tre_max))
 		return NULL;
 
 	trans_info = &channel->trans_info;
@@ -603,7 +603,7 @@ static void __gsi_trans_commit(struct gsi_trans *trans, bool ring_db)
 	if (ring_db || !atomic_read(&channel->trans_info.tre_avail)) {
 		/* Report what we're handing off to hardware for TX channels */
 		if (channel->toward_ipa)
-			gsi_channel_tx_queued(channel);
+			gsi_trans_tx_queued(trans);
 		gsi_channel_doorbell(channel);
 	}
 }
@@ -745,14 +745,10 @@ int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id)
 	 * element is used to fill a single TRE when the transaction is
 	 * committed.  So we need as many scatterlist elements as the
 	 * maximum number of TREs that can be outstanding.
-	 *
-	 * All TREs in a transaction must fit within the channel's TLV FIFO.
-	 * A transaction on a channel can allocate as many TREs as that but
-	 * no more.
 	 */
 	ret = gsi_trans_pool_init(&trans_info->sg_pool,
 				  sizeof(struct scatterlist),
-				  tre_max, channel->tlv_count);
+				  tre_max, channel->trans_tre_max);
 	if (ret)
 		goto err_trans_pool_exit;
 
diff --git a/drivers/net/ipa/ipa_cmd.c b/drivers/net/ipa/ipa_cmd.c
index e58cd4478fd3..6dea40259b60 100644
--- a/drivers/net/ipa/ipa_cmd.c
+++ b/drivers/net/ipa/ipa_cmd.c
@@ -353,13 +353,13 @@ int ipa_cmd_pool_init(struct gsi_channel *channel, u32 tre_max)
 	/* This is as good a place as any to validate build constants */
 	ipa_cmd_validate_build();
 
-	/* Even though command payloads are allocated one at a time,
-	 * a single transaction can require up to tlv_count of them,
-	 * so we treat them as if that many can be allocated at once.
+	/* Command payloads are allocated one at a time, but a single
+	 * transaction can require up to the maximum supported by the
+	 * channel; treat them as if they were allocated all at once.
 	 */
 	return gsi_trans_pool_init_dma(dev, &trans_info->cmd_pool,
 				       sizeof(union ipa_cmd_payload),
-				       tre_max, channel->tlv_count);
+				       tre_max, channel->trans_tre_max);
 }
 
 void ipa_cmd_pool_exit(struct gsi_channel *channel)
diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index d3b3255ac3d1..66d2bfdf9e42 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1020,7 +1020,7 @@ int ipa_endpoint_skb_tx(struct ipa_endpoint *endpoint, struct sk_buff *skb)
 	 * If not, see if we can linearize it before giving up.
 	 */
 	nr_frags = skb_shinfo(skb)->nr_frags;
-	if (1 + nr_frags > endpoint->trans_tre_max) {
+	if (nr_frags > endpoint->skb_frag_max) {
 		if (skb_linearize(skb))
 			return -E2BIG;
 		nr_frags = 0;
@@ -1368,18 +1368,14 @@ static void ipa_endpoint_status_parse(struct ipa_endpoint *endpoint,
 	}
 }
 
-/* Complete a TX transaction, command or from ipa_endpoint_skb_tx() */
-static void ipa_endpoint_tx_complete(struct ipa_endpoint *endpoint,
-				     struct gsi_trans *trans)
-{
-}
-
-/* Complete transaction initiated in ipa_endpoint_replenish_one() */
-static void ipa_endpoint_rx_complete(struct ipa_endpoint *endpoint,
-				     struct gsi_trans *trans)
+void ipa_endpoint_trans_complete(struct ipa_endpoint *endpoint,
+				 struct gsi_trans *trans)
 {
 	struct page *page;
 
+	if (endpoint->toward_ipa)
+		return;
+
 	if (trans->cancelled)
 		goto done;
 
@@ -1393,15 +1389,6 @@ done:
 	ipa_endpoint_replenish(endpoint);
 }
 
-void ipa_endpoint_trans_complete(struct ipa_endpoint *endpoint,
-				 struct gsi_trans *trans)
-{
-	if (endpoint->toward_ipa)
-		ipa_endpoint_tx_complete(endpoint, trans);
-	else
-		ipa_endpoint_rx_complete(endpoint, trans);
-}
-
 void ipa_endpoint_trans_release(struct ipa_endpoint *endpoint,
 				struct gsi_trans *trans)
 {
@@ -1721,7 +1708,7 @@ static void ipa_endpoint_setup_one(struct ipa_endpoint *endpoint)
 	if (endpoint->ee_id != GSI_EE_AP)
 		return;
 
-	endpoint->trans_tre_max = gsi_channel_trans_tre_max(gsi, channel_id);
+	endpoint->skb_frag_max = gsi->channel[channel_id].trans_tre_max - 1;
 	if (!endpoint->toward_ipa) {
 		/* RX transactions require a single TRE, so the maximum
 		 * backlog is the same as the maximum outstanding TREs.
diff --git a/drivers/net/ipa/ipa_endpoint.h b/drivers/net/ipa/ipa_endpoint.h
index 01790c60bee8..28e0a7386fd7 100644
--- a/drivers/net/ipa/ipa_endpoint.h
+++ b/drivers/net/ipa/ipa_endpoint.h
@@ -142,7 +142,7 @@ enum ipa_replenish_flag {
  * @endpoint_id:	IPA endpoint number
  * @toward_ipa:		Endpoint direction (true = TX, false = RX)
  * @config:		Default endpoint configuration
- * @trans_tre_max:	Maximum number of TRE descriptors per transaction
+ * @skb_frag_max:	Maximum allowed number of TX SKB fragments
  * @evt_ring_id:	GSI event ring used by the endpoint
  * @netdev:		Network device pointer, if endpoint uses one
  * @replenish_flags:	Replenishing state flags
@@ -157,7 +157,7 @@ struct ipa_endpoint {
 	bool toward_ipa;
 	struct ipa_endpoint_config config;
 
-	u32 trans_tre_max;
+	u32 skb_frag_max;	/* Used for netdev TX only */
 	u32 evt_ring_id;
 
 	/* Net device this endpoint is associated with, if any */