Re: [-net-next v11 5/6] net: stmmac: Add glue layer for StarFive JH7110 SoC
From: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
to: Guo Samin <samin.guo@xxxxxxxxxxxxxxxx>
data: 2023/4/9
> On Sat, 8 Apr 2023 at 03:16, Guo Samin <samin.guo@xxxxxxxxxxxxxxxx> wrote:
>>
>> Re: [-net-next v11 5/6] net: stmmac: Add glue layer for StarFive JH7110 SoC
>> From: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
>> to: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
>> data: 2023/4/8
>>
>>> On Fri, 7 Apr 2023 at 13:05, Samin Guo <samin.guo@xxxxxxxxxxxxxxxx> wrote:
>>>>
>>>> This adds StarFive dwmac driver support on the StarFive JH7110 SoC.
>>>>
>>>> Tested-by: Tommaso Merciai <tomm.merciai@xxxxxxxxx>
>>>> Co-developed-by: Emil Renner Berthing <kernel@xxxxxxxx>
>>>> Signed-off-by: Emil Renner Berthing <kernel@xxxxxxxx>
>>>> Signed-off-by: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
>>>> ---
>>>> 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@xxxxxxxx>
>>>> M: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
>>>> 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@xxxxxxxx>
>>>> 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@xxxxxxxx>
>>>> + * 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@xxxxxxxxxxxxxxxx)
>>
>>
>>> +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@xxxxxxxxxxxxxxxx)
>>
>
> 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.
>
HI Emil,
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 are other solutions?
Best regards,
Samin
>> 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;
>> cons>> + 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@xxxxxxxx>");
>>>> +MODULE_AUTHOR("Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>");
>>>> --
>>>> 2.17.1
>>>>
>>>>
>>>> _______________________________________________
>>>> linux-riscv mailing list
>>>> linux-riscv@xxxxxxxxxxxxxxxxxxx
>>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>>
>> --
>> Best regards,
>> Samin
--
Best regards,
Samin
