From: Dylan Hung <dylan_hung@aspeedtech.com>
To: <davem@davemloft.net>, <kuba@kernel.org>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<ratbert@faraday-tech.com>, <linux-aspeed@lists.ozlabs.org>,
<openbmc@lists.ozlabs.org>
Cc: BMC-SW@aspeedtech.com
Subject: [PATCH] net: ftgmac100: Fix missing TX-poll issue
Date: Mon, 19 Oct 2020 15:39:08 +0800 [thread overview]
Message-ID: <20201019073908.32262-1-dylan_hung@aspeedtech.com> (raw)
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
next reply other threads:[~2020-10-19 7:41 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-19 7:39 Dylan Hung [this message]
2020-10-19 8:57 ` [PATCH] net: ftgmac100: Fix missing TX-poll issue Joel Stanley
2020-10-19 9:19 ` Dylan Hung
2020-10-19 19:00 ` Jakub Kicinski
2020-10-19 23:23 ` Benjamin Herrenschmidt
2020-10-20 2:57 ` Jakub Kicinski
2020-10-20 6:15 ` Benjamin Herrenschmidt
2020-10-20 17:24 ` Jakub Kicinski
2020-10-20 6:14 ` Dylan Hung
2020-10-20 13:15 ` David Laight
2020-10-20 22:05 ` Benjamin Herrenschmidt
2020-10-20 19:49 ` Arnd Bergmann
2020-10-20 22:10 ` Benjamin Herrenschmidt
2020-10-20 22:25 ` Andrew Jeffery
2020-10-23 13:08 ` Dylan Hung
2020-10-26 22:21 ` Benjamin Herrenschmidt
2020-10-27 2:18 ` Joel Stanley
2020-10-21 7:16 ` Arnd Bergmann
2020-10-21 12:11 ` Arnd Bergmann
2020-10-22 7:40 ` Benjamin Herrenschmidt
2020-10-23 8:39 ` Arnd Bergmann
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