[PATCH] net:phy: Fix "Link is Down" issue

Subsystems: ethernet phy library, networking drivers, the rest

STALE1720d

8 messages, 4 authors, 2021-11-25 · open the first message on its own page

[PATCH] net:phy: Fix "Link is Down" issue

From: Dylan Hung <hidden>
Date: 2021-11-24 06:11:15

The issue happened randomly in runtime.  The message "Link is Down" is
popped but soon it recovered to "Link is Up".

The "Link is Down" results from the incorrect read data for reading the
PHY register via MDIO bus.  The correct sequence for reading the data
shall be:
1. fire the command
2. wait for command done (this step was missing)
3. wait for data idle
4. read data from data register

Fixes: a9770eac511a ("net: mdio: Move MDIO drivers into a new subdirectory")
Signed-off-by: Dylan Hung <redacted>
---
 drivers/net/mdio/mdio-aspeed.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/mdio/mdio-aspeed.c b/drivers/net/mdio/mdio-aspeed.c
index cad820568f75..966c3b4ad59d 100644
--- a/drivers/net/mdio/mdio-aspeed.c
+++ b/drivers/net/mdio/mdio-aspeed.c

@@ -61,6 +61,13 @@ static int aspeed_mdio_read(struct mii_bus *bus, int addr, int regnum)
 
 	iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);
 
+	rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl,
+				!(ctrl & ASPEED_MDIO_CTRL_FIRE),
+				ASPEED_MDIO_INTERVAL_US,
+				ASPEED_MDIO_TIMEOUT_US);
+	if (rc < 0)
+		return rc;
+
 	rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_DATA, data,
 				data & ASPEED_MDIO_DATA_IDLE,
 				ASPEED_MDIO_INTERVAL_US,

-- 
2.25.1

Re: [PATCH] net:phy: Fix "Link is Down" issue

From: Joel Stanley <joel@jms.id.au>
Date: 2021-11-24 10:06:01

On Wed, 24 Nov 2021 at 06:11, Dylan Hung [off-list ref] wrote:

The issue happened randomly in runtime.  The message "Link is Down" is
popped but soon it recovered to "Link is Up".

The "Link is Down" results from the incorrect read data for reading the
PHY register via MDIO bus.  The correct sequence for reading the data
shall be:
1. fire the command
2. wait for command done (this step was missing)
3. wait for data idle
4. read data from data register

I consulted the datasheet and it doesn't mention this. Perhaps
something to be added?

Reviewed-by: Joel Stanley <joel@jms.id.au>

Fixes: a9770eac511a ("net: mdio: Move MDIO drivers into a new subdirectory")

I think this should be:

Fixes: f160e99462c6 ("net: phy: Add mdio-aspeed")

We should cc stable too.

quoted hunk

Signed-off-by: Dylan Hung <redacted>
---
 drivers/net/mdio/mdio-aspeed.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/mdio/mdio-aspeed.c b/drivers/net/mdio/mdio-aspeed.c
index cad820568f75..966c3b4ad59d 100644
--- a/drivers/net/mdio/mdio-aspeed.c
+++ b/drivers/net/mdio/mdio-aspeed.c

@@ -61,6 +61,13 @@ static int aspeed_mdio_read(struct mii_bus *bus, int addr, int regnum)

        iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);

+       rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl,
+                               !(ctrl & ASPEED_MDIO_CTRL_FIRE),
+                               ASPEED_MDIO_INTERVAL_US,
+                               ASPEED_MDIO_TIMEOUT_US);
+       if (rc < 0)
+               return rc;
+
        rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_DATA, data,
                                data & ASPEED_MDIO_DATA_IDLE,
                                ASPEED_MDIO_INTERVAL_US,
--

2.25.1

RE: [PATCH] net:phy: Fix "Link is Down" issue

From: Dylan Hung <hidden>
Date: 2021-11-24 10:33:32

-----Original Message-----
From: Joel Stanley [mailto:joel@jms.id.au]
Sent: 2021年11月24日 6:06 PM
To: Dylan Hung <redacted>
Cc: Linux Kernel Mailing List <redacted>; linux-aspeed
[off-list ref]; Linux ARM
[off-list ref]; Networking
[off-list ref]; Andrew Jeffery [off-list ref]; Jakub Kicinski
[off-list ref]; David S . Miller [off-list ref]; Russell King
[off-list ref]; hkallweit1@gmail.com; Andrew Lunn
[off-list ref]; BMC-SW [off-list ref]
Subject: Re: [PATCH] net:phy: Fix "Link is Down" issue

On Wed, 24 Nov 2021 at 06:11, Dylan Hung [off-list ref]
wrote:

quoted

The issue happened randomly in runtime.  The message "Link is Down" is
popped but soon it recovered to "Link is Up".

The "Link is Down" results from the incorrect read data for reading
the PHY register via MDIO bus.  The correct sequence for reading the
data shall be:
1. fire the command
2. wait for command done (this step was missing) 3. wait for data idle
4. read data from data register

I consulted the datasheet and it doesn't mention this. Perhaps something to be
added?

We will add this sequence into the datasheet, thank you.

Reviewed-by: Joel Stanley <joel@jms.id.au>

quoted

Fixes: a9770eac511a ("net: mdio: Move MDIO drivers into a new
subdirectory")

I think this should be:

Fixes: f160e99462c6 ("net: phy: Add mdio-aspeed")

I will change this in V2.

We should cc stable too.

I will change this in V2.

quoted

Signed-off-by: Dylan Hung <redacted>
---
 drivers/net/mdio/mdio-aspeed.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/mdio/mdio-aspeed.c

b/drivers/net/mdio/mdio-aspeed.c index cad820568f75..966c3b4ad59d
100644

--- a/drivers/net/mdio/mdio-aspeed.c
+++ b/drivers/net/mdio/mdio-aspeed.c

@@ -61,6 +61,13 @@ static int aspeed_mdio_read(struct mii_bus *bus,

int addr, int regnum)

        iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);

+       rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl,
+                               !(ctrl & ASPEED_MDIO_CTRL_FIRE),
+                               ASPEED_MDIO_INTERVAL_US,
+                               ASPEED_MDIO_TIMEOUT_US);
+       if (rc < 0)
+               return rc;
+
        rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_DATA, data,
                                data & ASPEED_MDIO_DATA_IDLE,
                                ASPEED_MDIO_INTERVAL_US,
--
2.25.1

Re: [PATCH] net:phy: Fix "Link is Down" issue

From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-11-24 15:30:08

We should cc stable too.

https://www.kernel.org/doc/html/v5.12/networking/netdev-FAQ.html#how-do-i-indicate-which-tree-net-vs-net-next-my-patch-should-be-in

	Andrew

Re: [PATCH] net:phy: Fix "Link is Down" issue

From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-11-24 23:30:47

On Wed, 24 Nov 2021 14:10:57 +0800 Dylan Hung wrote:

Subject: [PATCH] net:phy: Fix "Link is Down" issue

Since there will be v2, please also add a space between net: and phy:.

RE: [PATCH] net:phy: Fix "Link is Down" issue

From: Dylan Hung <hidden>
Date: 2021-11-25 01:44:15

-----Original Message-----
From: Jakub Kicinski [mailto:kuba@kernel.org]
Sent: 2021年11月25日 7:31 AM
To: Dylan Hung <redacted>
Cc: linux-kernel@vger.kernel.org; linux-aspeed@lists.ozlabs.org;
linux-arm-kernel@lists.infradead.org; netdev@vger.kernel.org;
andrew@aj.id.au; joel@jms.id.au; davem@davemloft.net;
linux@armlinux.org.uk; hkallweit1@gmail.com; andrew@lunn.ch; BMC-SW
[off-list ref]
Subject: Re: [PATCH] net:phy: Fix "Link is Down" issue

On Wed, 24 Nov 2021 14:10:57 +0800 Dylan Hung wrote:

quoted

Subject: [PATCH] net:phy: Fix "Link is Down" issue

Since there will be v2, please also add a space between net: and phy:.

Should I use "net: mdio: " instead of "net: phy: "? Since this file was moved from net/phy to net/mdio by commit a9770eac511a.

RE: [PATCH] net:phy: Fix "Link is Down" issue

From: Dylan Hung <hidden>
Date: 2021-11-25 03:10:31

-----Original Message-----
From: Andrew Lunn [mailto:andrew@lunn.ch]
Sent: 2021年11月24日 11:30 PM
To: Joel Stanley <joel@jms.id.au>
Cc: Dylan Hung <redacted>; Linux Kernel Mailing List
[off-list ref]; linux-aspeed [off-list ref];
Linux ARM [off-list ref]; Networking
[off-list ref]; Andrew Jeffery [off-list ref]; Jakub Kicinski
[off-list ref]; David S . Miller [off-list ref]; Russell King
[off-list ref]; hkallweit1@gmail.com; BMC-SW
[off-list ref]
Subject: Re: [PATCH] net:phy: Fix "Link is Down" issue

quoted

We should cc stable too.

https://www.kernel.org/doc/html/v5.12/networking/netdev-FAQ.html#how-do-
i-indicate-which-tree-net-vs-net-next-my-patch-should-be-in

	Andrew

Sorry, I got this mail after I sent v2 out.  Should I prepare patch v3 with --subject-prefix='PATCH net'?

Re: [PATCH] net:phy: Fix "Link is Down" issue

From: Jakub Kicinski <kuba@kernel.org>
Date: 2021-11-25 03:20:49

On Thu, 25 Nov 2021 03:08:22 +0000 Dylan Hung wrote:

quoted

We should cc stable too.

https://www.kernel.org/doc/html/v5.12/networking/netdev-FAQ.html#how-do-
i-indicate-which-tree-net-vs-net-next-my-patch-should-be-in

Sorry, I got this mail after I sent v2 out.  Should I prepare patch
v3 with --subject-prefix='PATCH net'?

That's leave it be now, but please keep this in mind in the future.

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