lkml.org 
[lkml]   [2020]   [Oct]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] net: ftgmac100: Fix missing TX-poll issue
Date
The cpu accesses the register and the memory via different bus/path on
aspeed soc. So we can not guarantee that the tx-poll command
(register access) is always behind the tx descriptor (memory). In other
words, the HW may start working even the data is not yet ready. By
adding a dummy read after the last data write, we can ensure the data
are pushed to the memory, then guarantee the processing sequence

Signed-off-by: Dylan Hung <dylan_hung@aspeedtech.com>
---
drivers/net/ethernet/faraday/ftgmac100.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 00024dd41147..9a99a87f29f3 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -804,7 +804,8 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb,
* before setting the OWN bit on the first descriptor.
*/
dma_wmb();
- first->txdes0 = cpu_to_le32(f_ctl_stat);
+ WRITE_ONCE(first->txdes0, cpu_to_le32(f_ctl_stat));
+ READ_ONCE(first->txdes0);

/* Update next TX pointer */
priv->tx_pointer = pointer;
--
2.17.1
\
 
 \ /
  Last update: 2020-10-19 09:41    [W:0.120 / U:3.508 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site