From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Daniel Golle <daniel@makrotopia.org>
Cc: linux-mediatek@lists.infradead.org, netdev@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Felix Fietkau <nbd@nbd.name>,
John Crispin <john@phrozen.org>,
Sean Wang <sean.wang@mediatek.com>,
Mark Lee <Mark-MC.Lee@mediatek.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrew Lunn <andrew@lunn.ch>
Subject: Re: [PATCH v3] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access
Date: Mon, 27 Dec 2021 16:21:22 +0000 [thread overview]
Message-ID: <YcnoAscVe+2YILT8@shell.armlinux.org.uk> (raw)
In-Reply-To: <YcnlMtninjjjPhjI@makrotopia.org>
On Mon, Dec 27, 2021 at 04:09:22PM +0000, Daniel Golle wrote:
> Implement read and write access to IEEE 802.3 Clause 45 Ethernet
> phy registers.
> Tested on the Ubiquiti UniFi 6 LR access point featuring
> MediaTek MT7622BV WiSoC with Aquantia AQR112C.
>
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> ---
> v3: return -1 instead of 0xffff on error in _mtk_mdio_write
Oh no, not this "-1 disease" again.
eth->mii_bus->write = mtk_mdio_write;
static int mtk_mdio_write(struct mii_bus *bus, int phy_addr,
int phy_reg, u16 val)
{
struct mtk_eth *eth = bus->priv;
return _mtk_mdio_write(eth, phy_addr, phy_reg, val);
}
This means if you return -1 from _mtk_mdio_write() (which for some
strange reason returns a u32, not an "int") then you actually end
up returning -EPERM. This is not an appropriate errno code.
As a general rule of thumb, if you're returning an "int" and wish
to return "this failed" then always return an appropriate negative
errno code in the kernel so there isn't any possibility of
accidentially returning -EPERM through using "return -1".
This driver needs fixing _both_ due to returning -1, and also the
return type from both _mtk_mdio_write() and _mtk_mdio_read().
To see why it's important to return a proper error code, see
drivers/net/phy/phy_device.c::get_phy_c22_id() where -ENODEV and
-EIO are specifically checked. Any other negative value here will
stop the bus being scanned and cause the bus to be torn down.
Thanks.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
WARNING: multiple messages have this Message-ID (diff)
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Daniel Golle <daniel@makrotopia.org>
Cc: linux-mediatek@lists.infradead.org, netdev@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Felix Fietkau <nbd@nbd.name>,
John Crispin <john@phrozen.org>,
Sean Wang <sean.wang@mediatek.com>,
Mark Lee <Mark-MC.Lee@mediatek.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrew Lunn <andrew@lunn.ch>
Subject: Re: [PATCH v3] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access
Date: Mon, 27 Dec 2021 16:21:22 +0000 [thread overview]
Message-ID: <YcnoAscVe+2YILT8@shell.armlinux.org.uk> (raw)
In-Reply-To: <YcnlMtninjjjPhjI@makrotopia.org>
On Mon, Dec 27, 2021 at 04:09:22PM +0000, Daniel Golle wrote:
> Implement read and write access to IEEE 802.3 Clause 45 Ethernet
> phy registers.
> Tested on the Ubiquiti UniFi 6 LR access point featuring
> MediaTek MT7622BV WiSoC with Aquantia AQR112C.
>
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> ---
> v3: return -1 instead of 0xffff on error in _mtk_mdio_write
Oh no, not this "-1 disease" again.
eth->mii_bus->write = mtk_mdio_write;
static int mtk_mdio_write(struct mii_bus *bus, int phy_addr,
int phy_reg, u16 val)
{
struct mtk_eth *eth = bus->priv;
return _mtk_mdio_write(eth, phy_addr, phy_reg, val);
}
This means if you return -1 from _mtk_mdio_write() (which for some
strange reason returns a u32, not an "int") then you actually end
up returning -EPERM. This is not an appropriate errno code.
As a general rule of thumb, if you're returning an "int" and wish
to return "this failed" then always return an appropriate negative
errno code in the kernel so there isn't any possibility of
accidentially returning -EPERM through using "return -1".
This driver needs fixing _both_ due to returning -1, and also the
return type from both _mtk_mdio_write() and _mtk_mdio_read().
To see why it's important to return a proper error code, see
drivers/net/phy/phy_device.c::get_phy_c22_id() where -ENODEV and
-EIO are specifically checked. Any other negative value here will
stop the bus being scanned and cause the bus to be torn down.
Thanks.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek
WARNING: multiple messages have this Message-ID (diff)
From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Daniel Golle <daniel@makrotopia.org>
Cc: linux-mediatek@lists.infradead.org, netdev@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Felix Fietkau <nbd@nbd.name>,
John Crispin <john@phrozen.org>,
Sean Wang <sean.wang@mediatek.com>,
Mark Lee <Mark-MC.Lee@mediatek.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
Andrew Lunn <andrew@lunn.ch>
Subject: Re: [PATCH v3] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access
Date: Mon, 27 Dec 2021 16:21:22 +0000 [thread overview]
Message-ID: <YcnoAscVe+2YILT8@shell.armlinux.org.uk> (raw)
In-Reply-To: <YcnlMtninjjjPhjI@makrotopia.org>
On Mon, Dec 27, 2021 at 04:09:22PM +0000, Daniel Golle wrote:
> Implement read and write access to IEEE 802.3 Clause 45 Ethernet
> phy registers.
> Tested on the Ubiquiti UniFi 6 LR access point featuring
> MediaTek MT7622BV WiSoC with Aquantia AQR112C.
>
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> ---
> v3: return -1 instead of 0xffff on error in _mtk_mdio_write
Oh no, not this "-1 disease" again.
eth->mii_bus->write = mtk_mdio_write;
static int mtk_mdio_write(struct mii_bus *bus, int phy_addr,
int phy_reg, u16 val)
{
struct mtk_eth *eth = bus->priv;
return _mtk_mdio_write(eth, phy_addr, phy_reg, val);
}
This means if you return -1 from _mtk_mdio_write() (which for some
strange reason returns a u32, not an "int") then you actually end
up returning -EPERM. This is not an appropriate errno code.
As a general rule of thumb, if you're returning an "int" and wish
to return "this failed" then always return an appropriate negative
errno code in the kernel so there isn't any possibility of
accidentially returning -EPERM through using "return -1".
This driver needs fixing _both_ due to returning -1, and also the
return type from both _mtk_mdio_write() and _mtk_mdio_read().
To see why it's important to return a proper error code, see
drivers/net/phy/phy_device.c::get_phy_c22_id() where -ENODEV and
-EIO are specifically checked. Any other negative value here will
stop the bus being scanned and cause the bus to be torn down.
Thanks.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-12-27 16:21 UTC|newest]
Thread overview: 117+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-26 21:29 [PATCH] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2021-12-26 21:29 ` Daniel Golle
2021-12-26 21:29 ` Daniel Golle
2021-12-26 21:51 ` Andrew Lunn
2021-12-26 21:51 ` Andrew Lunn
2021-12-26 21:51 ` Andrew Lunn
2021-12-26 21:57 ` Russell King (Oracle)
2021-12-26 21:57 ` Russell King (Oracle)
2021-12-26 21:57 ` Russell King (Oracle)
2021-12-26 22:26 ` Andrew Lunn
2021-12-26 22:26 ` Andrew Lunn
2021-12-26 22:26 ` Andrew Lunn
2021-12-26 23:23 ` [PATCH v2] " Daniel Golle
2021-12-26 23:23 ` Daniel Golle
2021-12-26 23:23 ` Daniel Golle
2021-12-27 16:09 ` [PATCH v3] " Daniel Golle
2021-12-27 16:09 ` Daniel Golle
2021-12-27 16:09 ` Daniel Golle
2021-12-27 16:21 ` Russell King (Oracle) [this message]
2021-12-27 16:21 ` Russell King (Oracle)
2021-12-27 16:21 ` Russell King (Oracle)
2021-12-27 17:51 ` [PATCH v4 0/2] net: mtk_soc_eth: " Daniel Golle
2021-12-27 17:51 ` Daniel Golle
2021-12-27 17:51 ` Daniel Golle
2021-12-27 17:51 ` [PATCH v4 1/2] net: mtk_eth_soc: fix return value of MDIO operations Daniel Golle
2021-12-27 17:51 ` Daniel Golle
2021-12-27 17:51 ` Daniel Golle
2021-12-27 17:52 ` [PATCH v4 2/2] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2021-12-27 17:52 ` Daniel Golle
2021-12-27 17:52 ` Daniel Golle
2021-12-27 18:30 ` [PATCH v5 0/2] " Daniel Golle
2021-12-27 18:30 ` Daniel Golle
2021-12-27 18:30 ` Daniel Golle
2021-12-27 18:31 ` [PATCH v5 1/2] net: ethernet: mtk_eth_soc: fix return value of MDIO ops Daniel Golle
2021-12-27 18:31 ` Daniel Golle
2021-12-27 18:31 ` Daniel Golle
2021-12-27 18:31 ` [PATCH v5 2/2] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2021-12-27 18:31 ` Daniel Golle
2021-12-27 18:31 ` Daniel Golle
2021-12-28 0:07 ` [PATCH v6 0/2] " Daniel Golle
2021-12-28 0:07 ` Daniel Golle
2021-12-28 0:07 ` Daniel Golle
2021-12-28 0:08 ` [PATCH v6 1/2] net: ethernet: mtk_eth_soc: fix return value of MDIO ops Daniel Golle
2021-12-28 0:08 ` Daniel Golle
2021-12-28 0:08 ` Daniel Golle
2021-12-28 0:09 ` [PATCH v6 2/2] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2021-12-28 0:09 ` Daniel Golle
2021-12-28 0:09 ` Daniel Golle
2021-12-28 1:10 ` [PATCH v7 0/2] net: ethernet: mtk_soc_eth: " Daniel Golle
2021-12-28 1:10 ` Daniel Golle
2021-12-28 1:10 ` Daniel Golle
2021-12-28 1:43 ` Jakub Kicinski
2021-12-28 1:43 ` Jakub Kicinski
2021-12-28 1:43 ` Jakub Kicinski
2021-12-28 1:10 ` [PATCH v7 1/2] net: ethernet: mtk_eth_soc: fix return value of MDIO ops Daniel Golle
2021-12-28 1:10 ` Daniel Golle
2021-12-28 1:10 ` Daniel Golle
2021-12-28 1:11 ` [PATCH v7 2/2] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2021-12-28 1:11 ` Daniel Golle
2021-12-28 1:11 ` Daniel Golle
2021-12-28 11:46 ` Russell King (Oracle)
2021-12-28 11:46 ` Russell King (Oracle)
2021-12-28 11:46 ` Russell King (Oracle)
2021-12-28 21:03 ` [PATCH v8 0/3] net: ethernet: mtk_eth_soc: refactoring and Clause 45 Daniel Golle
2021-12-28 21:03 ` Daniel Golle
2021-12-28 21:03 ` Daniel Golle
2021-12-28 21:05 ` [PATCH v8 1/3] net: mdio: add helpers to extract clause 45 regad and devad fields Daniel Golle
2021-12-28 21:05 ` Daniel Golle
2021-12-28 21:05 ` Daniel Golle
2021-12-28 21:05 ` [PATCH v8 2/3] net: ethernet: mtk_eth_soc: fix return value and refactor MDIO ops Daniel Golle
2021-12-28 21:05 ` Daniel Golle
2021-12-28 21:05 ` Daniel Golle
2021-12-28 21:05 ` [PATCH v8 3/3] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2021-12-28 21:05 ` Daniel Golle
2021-12-28 21:05 ` Daniel Golle
2021-12-31 20:52 ` [PATCH v9 0/3] net: ethernet: mtk_eth_soc: refactoring and Clause 45 Daniel Golle
2021-12-31 20:52 ` Daniel Golle
2021-12-31 20:52 ` Daniel Golle
2021-12-31 20:54 ` [PATCH v9 2/3] net: ethernet: mtk_eth_soc: fix return value and refactor MDIO ops Daniel Golle
2021-12-31 20:54 ` Daniel Golle
2021-12-31 20:54 ` Daniel Golle
2021-12-31 20:54 ` [PATCH v9 3/3] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2021-12-31 20:54 ` Daniel Golle
2021-12-31 20:54 ` Daniel Golle
2021-12-31 20:57 ` [PATCH v9 1/3] net: mdio: add helpers to extract clause 45 regad and devad fields Daniel Golle
2021-12-31 20:57 ` Daniel Golle
2021-12-31 20:57 ` Daniel Golle
2022-01-01 17:20 ` Andrew Lunn
2022-01-01 17:20 ` Andrew Lunn
2022-01-01 17:20 ` Andrew Lunn
2022-01-02 15:47 ` [PATCH v10 0/3] net: ethernet: mtk_eth_soc: refactoring and Clause 45 Daniel Golle
2022-01-02 15:47 ` Daniel Golle
2022-01-02 15:47 ` Daniel Golle
2022-01-02 15:51 ` Russell King (Oracle)
2022-01-02 15:51 ` Russell King (Oracle)
2022-01-02 15:51 ` Russell King (Oracle)
2022-01-02 15:48 ` [PATCH v10 1/3] net: ethernet: mtk_eth_soc: fix return value and refactor MDIO ops Daniel Golle
2022-01-02 15:48 ` Daniel Golle
2022-01-02 15:48 ` Daniel Golle
2022-01-02 16:43 ` Andrew Lunn
2022-01-02 16:43 ` Andrew Lunn
2022-01-02 16:43 ` Andrew Lunn
2022-01-02 15:48 ` [PATCH v10 2/3] net: mdio: add helpers to extract clause 45 regad and devad fields Daniel Golle
2022-01-02 15:48 ` Daniel Golle
2022-01-02 15:48 ` Daniel Golle
2022-01-02 16:44 ` Andrew Lunn
2022-01-02 16:44 ` Andrew Lunn
2022-01-02 16:44 ` Andrew Lunn
2022-01-02 15:49 ` [PATCH v10 3/3] net: ethernet: mtk_eth_soc: implement Clause 45 MDIO access Daniel Golle
2022-01-02 15:49 ` Daniel Golle
2022-01-02 15:49 ` Daniel Golle
[not found] ` <Yc9tk6IZ0ldqHx4Y@makrotopia.org>
2022-01-01 17:18 ` [PATCH v9 1/3] net: mdio: add helpers to extract clause 45 regad and devad fields Andrew Lunn
2022-01-01 17:18 ` Andrew Lunn
2022-01-01 17:18 ` Andrew Lunn
2022-01-01 17:41 ` Daniel Golle
2022-01-01 17:41 ` Daniel Golle
2022-01-01 17:41 ` Daniel Golle
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