[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <fcu77iilcqssvcondsiwww3e2hlyfwq4ngodb4nomtqglptfwj@mphfr7hpcjsx>
Date: Tue, 24 Sep 2024 10:30:04 +0300
From: Serge Semin <fancer.lancer@...il.com>
To: Shenwei Wang <shenwei.wang@....com>
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, Maxime Coquelin <mcoquelin.stm32@...il.com>, horms@...nel.org,
Alexandre Torgue <alexandre.torgue@...s.st.com>, Jose Abreu <joabreu@...opsys.com>,
Ong Boon Leong <boon.leong.ong@...el.com>, Wong Vee Khee <vee.khee.wong@...el.com>,
Chuah Kim Tatt <kim.tatt.chuah@...el.com>, netdev@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com,
linux-arm-kernel@...ts.infradead.org, imx@...ts.linux.dev, linux-imx@....com,
Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH v3 net] net: stmmac: dwmac4: extend timeout for VLAN Tag
register busy bit check
Hi Shenwei
On Mon, Sep 23, 2024 at 03:26:02PM -0500, Shenwei Wang wrote:
> Increase the timeout for checking the busy bit of the VLAN Tag register
> from 10µs to 500ms. This change is necessary to accommodate scenarios
> where Energy Efficient Ethernet (EEE) is enabled.
>
> Overnight testing revealed that when EEE is active, the busy bit can
> remain set for up to approximately 300ms. The new 500ms timeout provides
> a safety margin.
>
> Fixes: ed64639bc1e0 ("net: stmmac: Add support for VLAN Rx filtering")
> Signed-off-by: Shenwei Wang <shenwei.wang@....com>
> Reviewed-by: Andrew Lunn <andrew@...n.ch>
> Reviewed-by: Serge Semin <fancer.lancer@...il.com>
Please note, you can't add the R-b tag without explicitly getting one
from the reviewer/maintainer/etc. Please read the chapter
"When to use Acked-by:, Cc:, and Co-developed-by:" in
Documentation/process/submitting-patches.rst
> ---
> Changes in V3:
> - re-org the error-check flow per Serge's review.
>
> Changes in v2:
> - replace the udelay with readl_poll_timeout per Simon's review.
>
> ---
> .../net/ethernet/stmicro/stmmac/dwmac4_core.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> index a1858f083eef..0d27dd71b43e 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> @@ -14,6 +14,7 @@
> #include <linux/slab.h>
> #include <linux/ethtool.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include "stmmac.h"
> #include "stmmac_pcs.h"
> #include "dwmac4.h"
> @@ -471,7 +472,7 @@ static int dwmac4_write_vlan_filter(struct net_device *dev,
> u8 index, u32 data)
> {
> void __iomem *ioaddr = (void __iomem *)dev->base_addr;
> - int i, timeout = 10;
> + int ret;
> u32 val;
>
> if (index >= hw->num_vlan)
> @@ -487,16 +488,15 @@ static int dwmac4_write_vlan_filter(struct net_device *dev,
>
> writel(val, ioaddr + GMAC_VLAN_TAG);
>
> - for (i = 0; i < timeout; i++) {
> - val = readl(ioaddr + GMAC_VLAN_TAG);
> - if (!(val & GMAC_VLAN_TAG_CTRL_OB))
> - return 0;
> - udelay(1);
> + ret = readl_poll_timeout(ioaddr + GMAC_VLAN_TAG, val,
> + !(val & GMAC_VLAN_TAG_CTRL_OB),
> + 1000, 500000); //Timeout 500ms
Please drop the comment at the end of the statement. First of all the
C++-style comments are discouraged to be used in the kernel code except
when in the block of the SPDX licence identifier, or when documenting
structs in headers. Secondly the tail-comments are discouraged either
(see Documentation/process/maintainer-tip.rst - yes, it's for
tip-tree, but the rule see informally applicable for the entire
kernel). Thirdly the comment is pointless here since the literal
500000 means exactly that.
-Serge(y)
> + if (ret) {
> + netdev_err(dev, "Timeout accessing MAC_VLAN_Tag_Filter\n");
> + return -EBUSY;
> }
>
> - netdev_err(dev, "Timeout accessing MAC_VLAN_Tag_Filter\n");
> -
> - return -EBUSY;
> + return 0;
> }
>
> static int dwmac4_add_hw_vlan_rx_fltr(struct net_device *dev,
> --
> 2.34.1
>
Powered by blists - more mailing lists