[PATCH net-next 07/10] net: ipa: introduce gsi_channel_trans_idle()

[Alex Elder <elder@linaro.org>]

Create a new function that returns true if all transactions for a
channel are available for use.

Use it in ipa_endpoint_replenish_enable() to see whether to start
replenishing, and in ipa_endpoint_replenish() to determine whether
it's necessary after a failure to schedule delayed work to ensure a
future replenish attempt occurs.

Signed-off-by: Alex Elder <elder@linaro.org>
---
 drivers/net/ipa/gsi_trans.c    | 11 +++++++++++
 drivers/net/ipa/gsi_trans.h    | 10 ++++++++++
 drivers/net/ipa/ipa_endpoint.c | 17 +++++------------
 3 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c
index 1544564bc2835..87e1d43c118c1 100644
--- a/drivers/net/ipa/gsi_trans.c
+++ b/drivers/net/ipa/gsi_trans.c
@@ -320,6 +320,17 @@ gsi_trans_tre_release(struct gsi_trans_info *trans_info, u32 tre_count)
 	atomic_add(tre_count, &trans_info->tre_avail);
 }
 
+/* Return true if no transactions are allocated, false otherwise */
+bool gsi_channel_trans_idle(struct gsi *gsi, u32 channel_id)
+{
+	u32 tre_max = gsi_channel_tre_max(gsi, channel_id);
+	struct gsi_trans_info *trans_info;
+
+	trans_info = &gsi->channel[channel_id].trans_info;
+
+	return atomic_read(&trans_info->tre_avail) == tre_max;
+}
+
 /* Allocate a GSI transaction on a channel */
 struct gsi_trans *gsi_channel_trans_alloc(struct gsi *gsi, u32 channel_id,
 					  u32 tre_count,
diff --git a/drivers/net/ipa/gsi_trans.h b/drivers/net/ipa/gsi_trans.h
index 17fd1822d8a9f..af379b49299ee 100644
--- a/drivers/net/ipa/gsi_trans.h
+++ b/drivers/net/ipa/gsi_trans.h
@@ -129,6 +129,16 @@ void *gsi_trans_pool_alloc_dma(struct gsi_trans_pool *pool, dma_addr_t *addr);
  */
 void gsi_trans_pool_exit_dma(struct device *dev, struct gsi_trans_pool *pool);
 
+/**
+ * gsi_channel_trans_idle() - Return whether no transactions are allocated
+ * @gsi:	GSI pointer
+ * @channel_id:	Channel the transaction is associated with
+ *
+ * Return:	True if no transactions are allocated, false otherwise
+ *
+ */
+bool gsi_channel_trans_idle(struct gsi *gsi, u32 channel_id);
+
 /**
  * gsi_channel_trans_alloc() - Allocate a GSI transaction on a channel
  * @gsi:	GSI pointer
diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index fba8728ce12e3..b854a39c69925 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1077,8 +1077,6 @@ static int ipa_endpoint_replenish_one(struct ipa_endpoint *endpoint,
 static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint)
 {
 	struct gsi_trans *trans;
-	struct gsi *gsi;
-	u32 backlog;
 
 	if (!test_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags))
 		return;
@@ -1108,30 +1106,25 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint)
 	clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
 
 	/* The last one didn't succeed, so fix the backlog */
-	backlog = atomic_inc_return(&endpoint->replenish_backlog);
+	atomic_inc(&endpoint->replenish_backlog);
 
 	/* Whenever a receive buffer transaction completes we'll try to
 	 * replenish again.  It's unlikely, but if we fail to supply even
 	 * one buffer, nothing will trigger another replenish attempt.
-	 * Receive buffer transactions use one TRE, so schedule work to
-	 * try replenishing again if our backlog is *all* available TREs.
+	 * If the hardware has no receive buffers queued, schedule work to
+	 * try replenishing again.
 	 */
-	gsi = &endpoint->ipa->gsi;
-	if (backlog == gsi_channel_tre_max(gsi, endpoint->channel_id))
+	if (gsi_channel_trans_idle(&endpoint->ipa->gsi, endpoint->channel_id))
 		schedule_delayed_work(&endpoint->replenish_work,
 				      msecs_to_jiffies(1));
 }
 
 static void ipa_endpoint_replenish_enable(struct ipa_endpoint *endpoint)
 {
-	struct gsi *gsi = &endpoint->ipa->gsi;
-	u32 max_backlog;
-
 	set_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
 
 	/* Start replenishing if hardware currently has no buffers */
-	max_backlog = gsi_channel_tre_max(gsi, endpoint->channel_id);
-	if (atomic_read(&endpoint->replenish_backlog) == max_backlog)
+	if (gsi_channel_trans_idle(&endpoint->ipa->gsi, endpoint->channel_id))
 		ipa_endpoint_replenish(endpoint);
 }
 
-- 
2.32.0