[PATCH 3/3] ath10k: add explicit memory barrier for ring index update

[Michal Kazior]

Avery reported he had some issues related to
instructions being re-ordered on his ARM test
system resulting in firmware crashes.

This makes sure that data is in place before CE
ring index is updated telling firmware it can
fetch the data.

Reported-By: Avery Pennarun <apenwarr at gmail.com>
Signed-off-by: Michal Kazior <michal.kazior at tieto.com>
---
 drivers/net/wireless/ath/ath10k/ce.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/ath/ath10k/ce.c b/drivers/net/wireless/ath/ath10k/ce.c
index 966f26e..e66159e 100644
--- a/drivers/net/wireless/ath/ath10k/ce.c
+++ b/drivers/net/wireless/ath/ath10k/ce.c
@@ -63,6 +63,7 @@ static inline void ath10k_ce_dest_ring_write_index_set(struct ath10k *ar,
 						       u32 ce_ctrl_addr,
 						       unsigned int n)
 {
+	mb();
 	ath10k_pci_write32(ar, ce_ctrl_addr + DST_WR_INDEX_ADDRESS, n);
 }
 
@@ -76,6 +77,7 @@ static inline void ath10k_ce_src_ring_write_index_set(struct ath10k *ar,
 						      u32 ce_ctrl_addr,
 						      unsigned int n)
 {
+	mb();
 	ath10k_pci_write32(ar, ce_ctrl_addr + SR_WR_INDEX_ADDRESS, n);
 }
 
-- 
1.8.5.3