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Message-ID: <b8764e20-f983-177c-63c5-36bb3b57ba9e@starfivetech.com>
Date:   Sat, 8 Apr 2023 09:15:46 +0800
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Subject: Re: [-net-next v11 5/6] net: stmmac: Add glue layer for StarFive
 JH7110 SoC
Content-Language: en-US
To:     Emil Renner Berthing <emil.renner.berthing@canonical.com>
CC:     <linux-kernel@vger.kernel.org>, <linux-riscv@lists.infradead.org>,
        <devicetree@vger.kernel.org>, <netdev@vger.kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Emil Renner Berthing <kernel@esmil.dk>,
        Pedro Moreira <pmmoreir@synopsys.com>,
        Richard Cochran <richardcochran@gmail.com>,
        Conor Dooley <conor@kernel.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Peter Geis <pgwipeout@gmail.com>,
        Yanhong Wang <yanhong.wang@starfivetech.com>,
        Tommaso Merciai <tomm.merciai@gmail.com>
References: <20230407110356.8449-1-samin.guo@starfivetech.com>
 <20230407110356.8449-6-samin.guo@starfivetech.com>
 <CAJM55Z9jCdPASsk+fw_j+9QH3+Kj28tpCA4PgW_nB_ce7qWL8w@mail.gmail.com>
From:   Guo Samin <samin.guo@starfivetech.com>
In-Reply-To: <CAJM55Z9jCdPASsk+fw_j+9QH3+Kj28tpCA4PgW_nB_ce7qWL8w@mail.gmail.com>
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 Re: [-net-next v11 5/6] net: stmmac: Add glue layer for StarFive JH7110 SoC
From: Emil Renner Berthing <emil.renner.berthing@canonical.com>
to: Samin Guo <samin.guo@starfivetech.com>
data: 2023/4/8

> On Fri, 7 Apr 2023 at 13:05, Samin Guo <samin.guo@starfivetech.com> wrote:
>>
>> This adds StarFive dwmac driver support on the StarFive JH7110 SoC.
>>
>> Tested-by: Tommaso Merciai <tomm.merciai@gmail.com>
>> Co-developed-by: Emil Renner Berthing <kernel@esmil.dk>
>> Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
>> Signed-off-by: Samin Guo <samin.guo@starfivetech.com>
>> ---
>>  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-starfive.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 6b6b67468b8f..46b366456cee 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -19910,6 +19910,7 @@ M:      Emil Renner Berthing <kernel@esmil.dk>
>>  M:     Samin Guo <samin.guo@starfivetech.com>
>>  S:     Maintained
>>  F:     Documentation/devicetree/bindings/net/starfive,jh7110-dwmac.yaml
>> +F:     drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
>>
>>  STARFIVE JH7100 CLOCK DRIVERS
>>  M:     Emil Renner Berthing <kernel@esmil.dk>
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/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.
>>
>> +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 SoCs
>> +
>> +         This selects the StarFive platform specific glue layer support for
>> +         the stmmac device driver. This driver is used for StarFive JH7110
>> +         ethernet controller.
>> +
>>  config DWMAC_STI
>>         tristate "STi GMAC support"
>>         default ARCH_STI
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/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-$(CONFIG_DWMAC_OXNAS)     += dwmac-oxnas.o
>>  obj-$(CONFIG_DWMAC_QCOM_ETHQOS)        += dwmac-qcom-ethqos.o
>>  obj-$(CONFIG_DWMAC_ROCKCHIP)   += dwmac-rk.o
>>  obj-$(CONFIG_DWMAC_SOCFPGA)    += dwmac-altr-socfpga.o
>> +obj-$(CONFIG_DWMAC_STARFIVE)   += dwmac-starfive.o
>>  obj-$(CONFIG_DWMAC_STI)                += dwmac-sti.o
>>  obj-$(CONFIG_DWMAC_STM32)      += dwmac-stm32.o
>>  obj-$(CONFIG_DWMAC_SUNXI)      += 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 <kernel@esmil.dk>
>> + * Copyright (C) 2022 StarFive Technology Co., Ltd.
>> + *
>> + */
>> +
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/of_device.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "stmmac_platform.h"
>> +
>> +struct starfive_dwmac {
>> +       struct device *dev;
>> +       struct clk *clk_tx;
>> +};
>> +
>> +static void starfive_dwmac_fix_mac_speed(void *priv, unsigned int speed)
>> +{
>> +       struct starfive_dwmac *dwmac = priv;
>> +       unsigned long rate;
>> +       int err;
>> +
>> +       rate = clk_get_rate(dwmac->clk_tx);
> 
> Hi Samin,
> 
> 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 you
> just returned early and don't call clk_set_rate at all in case of
> errors.
> 
>> +
>> +       switch (speed) {
>> +       case SPEED_1000:
>> +               rate = 125000000;
>> +               break;
>> +       case SPEED_100:
>> +               rate = 25000000;
>> +               break;
>> +       case SPEED_10:
>> +               rate = 2500000;
>> +               break;
>> +       default:
>> +               dev_err(dwmac->dev, "invalid speed %u\n", speed);
>> +               break;
> 
> That is skip the clk_get_rate above and just change this break to a return.
> 

Hi Emil,

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/20230106030001.1952-6-yanhong.wang@starfivetech.com)


> +static void starfive_eth_plat_fix_mac_speed(void *priv, unsigned int
> speed)
> +{
> +	struct starfive_dwmac *dwmac = priv;
> +	unsigned long rate;
> +	int err;
> +
> +	switch (speed) {
> +	case SPEED_1000:
> +		rate = 125000000;
> +		break;
> +	case SPEED_100:
> +		rate = 25000000;
> +		break;
> +	case SPEED_10:
> +		rate = 2500000;
> +		break;
> +	default:
> +		dev_err(dwmac->dev, "invalid speed %u\n", speed);
> +		return;

Do we need to return value, since it is invalid speed. But the return
value of function is void.(Arun Ramadoss)


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/20230328062009.25454-6-samin.guo@starfivetech.com)


Best regards,
Samin
>> +       }
>> +
>> +       err = clk_set_rate(dwmac->clk_tx, rate);
>> +       if (err)
>> +               dev_err(dwmac->dev, "failed to set tx rate %lu\n", rate);
>> +}
>> +
>> +static int starfive_dwmac_probe(struct platform_device *pdev)
>> +{
>> +       struct plat_stmmacenet_data *plat_dat;
>> +       struct stmmac_resources stmmac_res;
>> +       struct starfive_dwmac *dwmac;
>> +       struct clk *clk_gtx;
>> +       int err;
>> +
>> +       err = stmmac_get_platform_resources(pdev, &stmmac_res);
>> +       if (err)
>> +               return dev_err_probe(&pdev->dev, err,
>> +                                    "failed to get resources\n");
>> +
>> +       plat_dat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
>> +       if (IS_ERR(plat_dat))
>> +               return dev_err_probe(&pdev->dev, PTR_ERR(plat_dat),
>> +                                    "dt configuration failed\n");
>> +
>> +       dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
>> +       if (!dwmac)
>> +               return -ENOMEM;
>> +
>> +       dwmac->clk_tx = devm_clk_get_enabled(&pdev->dev, "tx");
>> +       if (IS_ERR(dwmac->clk_tx))
>> +               return dev_err_probe(&pdev->dev, PTR_ERR(dwmac->clk_tx),
>> +                                    "error getting tx clock\n");
>> +
>> +       clk_gtx = devm_clk_get_enabled(&pdev->dev, "gtx");
>> +       if (IS_ERR(clk_gtx))
>> +               return dev_err_probe(&pdev->dev, PTR_ERR(clk_gtx),
>> +                                    "error getting gtx clock\n");
>> +
>> +       /* Generally, the rgmii_tx clock is provided by the internal clock,
>> +        * which needs to match the corresponding clock frequency according
>> +        * to different speeds. If the rgmii_tx clock is provided by the
>> +        * external rgmii_rxin, there is no need to configure the clock
>> +        * internally, because rgmii_rxin will be adaptively adjusted.
>> +        */
>> +       if (!device_property_read_bool(&pdev->dev, "starfive,tx-use-rgmii-clk"))
>> +               plat_dat->fix_mac_speed = starfive_dwmac_fix_mac_speed;
>> +
>> +       dwmac->dev = &pdev->dev;
>> +       plat_dat->bsp_priv = dwmac;
>> +       plat_dat->dma_cfg->dche = true;
>> +
>> +       err = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
>> +       if (err) {
>> +               stmmac_remove_config_dt(pdev, plat_dat);
>> +               return err;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct of_device_id starfive_dwmac_match[] = {
>> +       { .compatible = "starfive,jh7110-dwmac" },
>> +       { /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, starfive_dwmac_match);
>> +
>> +static struct platform_driver starfive_dwmac_driver = {
>> +       .probe  = starfive_dwmac_probe,
>> +       .remove = stmmac_pltfr_remove,
>> +       .driver = {
>> +               .name = "starfive-dwmac",
>> +               .pm = &stmmac_pltfr_pm_ops,
>> +               .of_match_table = starfive_dwmac_match,
>> +       },
>> +};
>> +module_platform_driver(starfive_dwmac_driver);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_DESCRIPTION("StarFive DWMAC platform driver");
>> +MODULE_AUTHOR("Emil Renner Berthing <kernel@esmil.dk>");
>> +MODULE_AUTHOR("Samin Guo <samin.guo@starfivetech.com>");
>> --
>> 2.17.1
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv

-- 
Best regards,
Samin