Re: [PATCH net-next 14/15] net: dsa: mt7530: introduce driver for MT7988 built-in switch

From: "Arınç ÜNAL" <arinc.unal@arinc9.com>
To: Daniel Golle <daniel@makrotopia.org>,
	netdev@vger.kernel.org, linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk,
	linux-kernel@vger.kernel.org, Andrew Lunn <andrew@lunn.ch>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno 
	<angelogioacchino.delregno@collabora.com>,
	Sean Wang <sean.wang@mediatek.com>,
	Landen Chao <Landen.Chao@mediatek.com>,
	DENG Qingfang <dqfext@gmail.com>,
	Philipp Zabel <p.zabel@pengutronix.de>
Cc: Sam Shih <Sam.Shih@mediatek.com>,
	Lorenzo Bianconi <lorenzo@kernel.org>,
	John Crispin <john@phrozen.org>, Felix Fietkau <nbd@nbd.name>,
	Luiz Angelo Daros de Luca <luizluca@gmail.com>
Subject: Re: [PATCH net-next 14/15] net: dsa: mt7530: introduce driver for MT7988 built-in switch
Date: Fri, 31 Mar 2023 08:50:28 +0300	[thread overview]
Message-ID: <6a7c5f81-a8a3-27b5-4af3-7175a3313f9a@arinc9.com> (raw)
In-Reply-To: <fef2cb2fe3d2b70fa46e93107a0c862f53bb3bfa.1680180959.git.daniel@makrotopia.org>

On 30.03.2023 18:23, Daniel Golle wrote:
> Add driver for the built-in Gigabit Ethernet switch which can be found
> in the MediaTek MT7988 SoC.
> 
> The switch shares most of its design with MT7530 and MT7531, but has
> it's registers mapped into the SoCs register space rather than being
> connected externally or internally via MDIO.
> 
> Introduce a new platform driver to support that.
> 
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> ---
>   MAINTAINERS                   |   2 +
>   drivers/net/dsa/Kconfig       |  12 ++++
>   drivers/net/dsa/Makefile      |   1 +
>   drivers/net/dsa/mt7530-mmio.c | 101 ++++++++++++++++++++++++++++++++++
>   drivers/net/dsa/mt7530.c      |  86 ++++++++++++++++++++++++++++-
>   drivers/net/dsa/mt7530.h      |  12 ++--
>   6 files changed, 206 insertions(+), 8 deletions(-)
>   create mode 100644 drivers/net/dsa/mt7530-mmio.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 14924aed15ca7..674673dbdfd8b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13174,9 +13174,11 @@ MEDIATEK SWITCH DRIVER
>   M:	Sean Wang <sean.wang@mediatek.com>
>   M:	Landen Chao <Landen.Chao@mediatek.com>
>   M:	DENG Qingfang <dqfext@gmail.com>
> +M:	Daniel Golle <daniel@makrotopia.org>
>   L:	netdev@vger.kernel.org
>   S:	Maintained
>   F:	drivers/net/dsa/mt7530-mdio.c
> +F:	drivers/net/dsa/mt7530-mmio.c
>   F:	drivers/net/dsa/mt7530.*
>   F:	net/dsa/tag_mtk.c
>   
> diff --git a/drivers/net/dsa/Kconfig b/drivers/net/dsa/Kconfig
> index c2551b13324c2..de4d86e37973f 100644
> --- a/drivers/net/dsa/Kconfig
> +++ b/drivers/net/dsa/Kconfig
> @@ -52,6 +52,18 @@ config NET_DSA_MT7530
>   	  Multi-chip module MT7530 in MT7621AT, MT7621DAT, MT7621ST and
>   	  MT7623AI SoCs is supported as well.
>   
> +config NET_DSA_MT7988
> +	tristate "MediaTek MT7988 built-in Ethernet switch support"
> +	select NET_DSA_MT7530_COMMON
> +	depends on HAS_IOMEM
> +	help
> +	  This enables support for the built-in Ethernet switch found
> +	  in the MediaTek MT7988 SoC.
> +	  The switch is a similar design as MT7531, however, unlike
> +	  other MT7530 and MT7531 the switch registers are directly
> +	  mapped into the SoCs register space rather than being accessible
> +	  via MDIO.
> +
>   config NET_DSA_MV88E6060
>   	tristate "Marvell 88E6060 ethernet switch chip support"
>   	select NET_DSA_TAG_TRAILER
> diff --git a/drivers/net/dsa/Makefile b/drivers/net/dsa/Makefile
> index 71250d7dd41af..103a33e20de4b 100644
> --- a/drivers/net/dsa/Makefile
> +++ b/drivers/net/dsa/Makefile
> @@ -8,6 +8,7 @@ endif
>   obj-$(CONFIG_NET_DSA_LANTIQ_GSWIP) += lantiq_gswip.o
>   obj-$(CONFIG_NET_DSA_MT7530_COMMON) += mt7530.o
>   obj-$(CONFIG_NET_DSA_MT7530)	+= mt7530-mdio.o
> +obj-$(CONFIG_NET_DSA_MT7988)	+= mt7530-mmio.o

I'm not fond of this way. Wouldn't it be better if we split the mdio and 
mmio drivers to separate modules and kept switch hardware support on 
mt7530.c?

The mmio driver could be useful in the future for the MT7530 on the 
MT7620 SoCs or generally new hardware that would use MMIO to be controlled.

Luiz did this for the Realtek switches that use MDIO and SMI to be 
controlled.

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/drivers/net/dsa/realtek/Kconfig

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/drivers/net/dsa/realtek/Makefile

Arınç