[08/24] staging: ccree: make mem barrier per request

Message ID 1510584358-29473-9-git-send-email-gilad@benyossef.com
State Accepted
Commit 2712dc7b01ec4f76a9aef60699bc4d896e75c427
Headers show
Series
  • [01/24] staging: ccree: fix typos
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Commit Message

Gilad Ben-Yossef Nov. 13, 2017, 2:45 p.m.
The driver was issuing a write memory barrier per each
HW descriptor written but these descriptors are written
in groups and we really only need one per group.

White at it, document memory barrier reason.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>

---
 drivers/staging/ccree/ssi_request_mgr.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

-- 
2.7.4

Patch

diff --git a/drivers/staging/ccree/ssi_request_mgr.c b/drivers/staging/ccree/ssi_request_mgr.c
index e23c656..f5041f7 100644
--- a/drivers/staging/ccree/ssi_request_mgr.c
+++ b/drivers/staging/ccree/ssi_request_mgr.c
@@ -172,7 +172,6 @@  static inline void enqueue_seq(
 		writel_relaxed(seq[i].word[2], (cc_base + CC_REG(DSCRPTR_QUEUE_WORD0)));
 		writel_relaxed(seq[i].word[3], (cc_base + CC_REG(DSCRPTR_QUEUE_WORD0)));
 		writel_relaxed(seq[i].word[4], (cc_base + CC_REG(DSCRPTR_QUEUE_WORD0)));
-		wmb();
 		writel_relaxed(seq[i].word[5], (cc_base + CC_REG(DSCRPTR_QUEUE_WORD0)));
 #ifdef DX_DUMP_DESCS
 		dev_dbg(dev, "desc[%02d]: 0x%08X 0x%08X 0x%08X 0x%08X 0x%08X 0x%08X\n",
@@ -359,6 +358,12 @@  int send_request(
 #ifdef FLUSH_CACHE_ALL
 	flush_cache_all();
 #endif
+	/*
+	 * We are about to push command to the HW via the command registers
+	 * that may refernece hsot memory. We need to issue a memory barrier
+	 * to make sure there are no outstnading memory writes
+	 */
+	wmb();
 
 	/* STAT_PHASE_4: Push sequence */
 	enqueue_seq(cc_base, iv_seq, iv_seq_len);
@@ -417,6 +422,12 @@  int send_request_init(
 
 	set_queue_last_ind(&desc[(len - 1)]);
 
+	/*
+	 * We are about to push command to the HW via the command registers
+	 * that may refernece hsot memory. We need to issue a memory barrier
+	 * to make sure there are no outstnading memory writes
+	 */
+	wmb();
 	enqueue_seq(cc_base, desc, len);
 
 	/* Update the free slots in HW queue */