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[146.241.239.96]) by smtp.gmail.com with ESMTPSA id q17-20020a37f711000000b007468765b411sm3940487qkj.45.2023.04.11.06.16.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Apr 2023 06:16:05 -0700 (PDT) Message-ID: Subject: Re: [-net-next v11 5/6] net: stmmac: Add glue layer for StarFive JH7110 SoC From: Paolo Abeni To: Guo Samin , Emil Renner Berthing , Arun.Ramadoss@microchip.com Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, netdev@vger.kernel.org, "David S . Miller" , Eric Dumazet , Jakub Kicinski , Rob Herring , Krzysztof Kozlowski , Emil Renner Berthing , Pedro Moreira , Richard Cochran , Conor Dooley , Paul Walmsley , Palmer Dabbelt , Albert Ou , Andrew Lunn , Heiner Kallweit , Peter Geis , Yanhong Wang , Tommaso Merciai Date: Tue, 11 Apr 2023 15:16:00 +0200 In-Reply-To: <62fc36bc-7e43-0214-85d7-be66748a901b@starfivetech.com> References: <20230407110356.8449-1-samin.guo@starfivetech.com> <20230407110356.8449-6-samin.guo@starfivetech.com> <62fc36bc-7e43-0214-85d7-be66748a901b@starfivetech.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.4 (3.46.4-1.fc37) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2023-04-10 at 16:29 +0800, Guo Samin wrote: > Re: [-net-next v11 5/6] net: stmmac: Add glue layer for StarFive JH7110 S= oC > From: Emil Renner Berthing > to: Guo Samin > data: 2023/4/9 >=20 > > On Sat, 8 Apr 2023 at 03:16, Guo Samin wro= te: > > >=20 > > > Re: [-net-next v11 5/6] net: stmmac: Add glue layer for StarFive JH7= 110 SoC > > > From: Emil Renner Berthing > > > to: Samin Guo > > > data: 2023/4/8 > > >=20 > > > > On Fri, 7 Apr 2023 at 13:05, Samin Guo = wrote: > > > > >=20 > > > > > This adds StarFive dwmac driver support on the StarFive JH7110 So= C. > > > > >=20 > > > > > Tested-by: Tommaso Merciai > > > > > Co-developed-by: Emil Renner Berthing > > > > > Signed-off-by: Emil Renner Berthing > > > > > Signed-off-by: Samin Guo > > > > > --- > > > > > MAINTAINERS | 1 + > > > > > drivers/net/ethernet/stmicro/stmmac/Kconfig | 12 ++ > > > > > drivers/net/ethernet/stmicro/stmmac/Makefile | 1 + > > > > > .../ethernet/stmicro/stmmac/dwmac-starfive.c | 123 ++++++++++++= ++++++ > > > > > 4 files changed, 137 insertions(+) > > > > > create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-sta= rfive.c > > > > >=20 > > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > > > > index 6b6b67468b8f..46b366456cee 100644 > > > > > --- a/MAINTAINERS > > > > > +++ b/MAINTAINERS > > > > > @@ -19910,6 +19910,7 @@ M: Emil Renner Berthing > > > > > M: Samin Guo > > > > > S: Maintained > > > > > F: Documentation/devicetree/bindings/net/starfive,jh7110-dwm= ac.yaml > > > > > +F: drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c > > > > >=20 > > > > > STARFIVE JH7100 CLOCK DRIVERS > > > > > M: Emil Renner Berthing > > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/driver= s/net/ethernet/stmicro/stmmac/Kconfig > > > > > index f77511fe4e87..5f5a997f21f3 100644 > > > > > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig > > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig > > > > > @@ -165,6 +165,18 @@ config DWMAC_SOCFPGA > > > > > for the stmmac device driver. This driver is used for > > > > > arria5 and cyclone5 FPGA SoCs. > > > > >=20 > > > > > +config DWMAC_STARFIVE > > > > > + tristate "StarFive dwmac support" > > > > > + depends on OF && (ARCH_STARFIVE || COMPILE_TEST) > > > > > + select MFD_SYSCON > > > > > + default m if ARCH_STARFIVE > > > > > + help > > > > > + Support for ethernet controllers on StarFive RISC-V SoC= s > > > > > + > > > > > + This selects the StarFive platform specific glue layer = support for > > > > > + the stmmac device driver. This driver is used for StarF= ive JH7110 > > > > > + ethernet controller. > > > > > + > > > > > config DWMAC_STI > > > > > tristate "STi GMAC support" > > > > > default ARCH_STI > > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drive= rs/net/ethernet/stmicro/stmmac/Makefile > > > > > index 057e4bab5c08..8738fdbb4b2d 100644 > > > > > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile > > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile > > > > > @@ -23,6 +23,7 @@ obj-$(CONFIG_DWMAC_OXNAS) +=3D dwmac-oxnas.= o > > > > > obj-$(CONFIG_DWMAC_QCOM_ETHQOS) +=3D dwmac-qcom-ethqos.o > > > > > obj-$(CONFIG_DWMAC_ROCKCHIP) +=3D dwmac-rk.o > > > > > obj-$(CONFIG_DWMAC_SOCFPGA) +=3D dwmac-altr-socfpga.o > > > > > +obj-$(CONFIG_DWMAC_STARFIVE) +=3D dwmac-starfive.o > > > > > obj-$(CONFIG_DWMAC_STI) +=3D dwmac-sti.o > > > > > obj-$(CONFIG_DWMAC_STM32) +=3D dwmac-stm32.o > > > > > obj-$(CONFIG_DWMAC_SUNXI) +=3D dwmac-sunxi.o > > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c= b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c > > > > > new file mode 100644 > > > > > index 000000000000..4963d4008485 > > > > > --- /dev/null > > > > > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c > > > > > @@ -0,0 +1,123 @@ > > > > > +// SPDX-License-Identifier: GPL-2.0+ > > > > > +/* > > > > > + * StarFive DWMAC platform driver > > > > > + * > > > > > + * Copyright (C) 2021 Emil Renner Berthing > > > > > + * Copyright (C) 2022 StarFive Technology Co., Ltd. > > > > > + * > > > > > + */ > > > > > + > > > > > +#include > > > > > +#include > > > > > +#include > > > > > + > > > > > +#include "stmmac_platform.h" > > > > > + > > > > > +struct starfive_dwmac { > > > > > + struct device *dev; > > > > > + struct clk *clk_tx; > > > > > +}; > > > > > + > > > > > +static void starfive_dwmac_fix_mac_speed(void *priv, unsigned in= t speed) > > > > > +{ > > > > > + struct starfive_dwmac *dwmac =3D priv; > > > > > + unsigned long rate; > > > > > + int err; > > > > > + > > > > > + rate =3D clk_get_rate(dwmac->clk_tx); > > > >=20 > > > > Hi Samin, > > > >=20 > > > > I'm not sure why you added this line in this revision. If it's just= to > > > > not call clk_set_rate on the uninitialized rate, I'd much rather yo= u > > > > just returned early and don't call clk_set_rate at all in case of > > > > errors. > > > >=20 > > > > > + > > > > > + switch (speed) { > > > > > + case SPEED_1000: > > > > > + rate =3D 125000000; > > > > > + break; > > > > > + case SPEED_100: > > > > > + rate =3D 25000000; > > > > > + break; > > > > > + case SPEED_10: > > > > > + rate =3D 2500000; > > > > > + break; > > > > > + default: > > > > > + dev_err(dwmac->dev, "invalid speed %u\n", speed); > > > > > + break; > > > >=20 > > > > That is skip the clk_get_rate above and just change this break to a= return. > > > >=20 > > >=20 > > > Hi Emil, > > >=20 > > > We used the solution you mentioned before V3, but Arun Ramadoss doesn= 't think that's great. > > > (https://patchwork.kernel.org/project/linux-riscv/patch/2023010603000= 1.1952-6-yanhong.wang@starfivetech.com) > > >=20 > > >=20 > > > > +static void starfive_eth_plat_fix_mac_speed(void *priv, unsigned i= nt > > > > speed) > > > > +{ > > > > + struct starfive_dwmac *dwmac =3D priv; > > > > + unsigned long rate; > > > > + int err; > > > > + > > > > + switch (speed) { > > > > + case SPEED_1000: > > > > + rate =3D 125000000; > > > > + break; > > > > + case SPEED_100: > > > > + rate =3D 25000000; > > > > + break; > > > > + case SPEED_10: > > > > + rate =3D 2500000; > > > > + break; > > > > + default: > > > > + dev_err(dwmac->dev, "invalid speed %u\n", speed); > > > > + return; > > >=20 > > > Do we need to return value, since it is invalid speed. But the return > > > value of function is void.(Arun Ramadoss) > > >=20 > > >=20 > > > So in v9, after discussing with Jakub Kicinski, the clk_set_rate was = used to initialize the rate. > > > (It is a reference to Intel's scheme: dwmac-intel-plat.c: kmb_eth_= fix_mac_speed) > > > (https://patchwork.kernel.org/project/linux-riscv/patch/2023032806200= 9.25454-6-samin.guo@starfivetech.com) > > >=20 > >=20 > > Yeah, I think this is a misunderstanding and Arun is considering if we > > ought to return the error which we can't without changing generic > > dwmac code, and Jakub is rightly concerned about using a local > > variable uninitialized. I don't think anyone is suggesting that > > getting the rate just to set it to the exact same value is better than > > just leaving the clock alone. > >=20 > HI Emil, >=20 > Yeah, return early saves time and code complexity, and seems like a good = solution so Yanhong did the same before v3. (Jakub has suggested it before)= , > I wonder if Arun or other maintainers accept this solution or if there ar= e other solutions? I think is not a big deal either way. To avoid too much back and forth I'll stick to the current code. Please address Emil comment on patch 6/6 Thanks! Paolo