linux-kernel - Re: [PATCH v2 05/12] net: stmmac: dwmac-starfive: Add support for JH7100 SoC

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Message-ID: <CAJM55Z8K5QztgU9NYiJ1kv+-BSsgP=LCABN7BYDtQ30_G1Nc7w@mail.gmail.com>
Date:   Tue, 31 Oct 2023 07:33:50 -0700
From:   Emil Renner Berthing <emil.renner.berthing@...onical.com>
To:     Cristian Ciocaltea <cristian.ciocaltea@...labora.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Emil Renner Berthing <kernel@...il.dk>,
        Samin Guo <samin.guo@...rfivetech.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Jose Abreu <joabreu@...opsys.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Richard Cochran <richardcochran@...il.com>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>
Cc:     netdev@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, kernel@...labora.com
Subject: Re: [PATCH v2 05/12] net: stmmac: dwmac-starfive: Add support for
 JH7100 SoC

Cristian Ciocaltea wrote:
> Add a missing quirk to enable support for the StarFive JH7100 SoC.
>
> Additionally, for greater flexibility in operation, allow using the
> rgmii-rxid and rgmii-txid phy modes.
>
> Co-developed-by: Emil Renner Berthing <kernel@...il.dk>
> Signed-off-by: Emil Renner Berthing <kernel@...il.dk>
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@...labora.com>

Hi Cristian,

Thanks for working on this! This driver has code to update the phy clock for
different line speeds. I don't think that will work without the
CLK_SET_RATE_PARENT flag added to the clock in [1] which in turn depends on
[2].

[1]: https://github.com/esmil/linux/commit/b200c3054b58a49ba25af67aff82d9045e3c3666
[2]: https://github.com/esmil/linux/commit/dce189542c16bf0eb8533d96c0305cb59d149dae

Two more comments below..

> ---
>  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  6 ++--
>  .../ethernet/stmicro/stmmac/dwmac-starfive.c  | 32 ++++++++++++++++---
>  2 files changed, 31 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> index a2b9e289aa36..c3c2c8360047 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> @@ -165,9 +165,9 @@ config DWMAC_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.
> +	  This selects the StarFive platform specific glue layer support
> +	  for the stmmac device driver. This driver is used for the
> +	  StarFive JH7100 and JH7110 ethernet controllers.
>
>  config DWMAC_STI
>  	tristate "STi GMAC support"
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
> index 5d630affb4d1..88c431edcea0 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
> @@ -15,13 +15,20 @@
>
>  #include "stmmac_platform.h"
>
> -#define STARFIVE_DWMAC_PHY_INFT_RGMII	0x1
> -#define STARFIVE_DWMAC_PHY_INFT_RMII	0x4
> -#define STARFIVE_DWMAC_PHY_INFT_FIELD	0x7U
> +#define STARFIVE_DWMAC_PHY_INFT_RGMII		0x1
> +#define STARFIVE_DWMAC_PHY_INFT_RMII		0x4
> +#define STARFIVE_DWMAC_PHY_INFT_FIELD		0x7U
> +
> +#define JH7100_SYSMAIN_REGISTER49_DLYCHAIN	0xc8
> +
> +struct starfive_dwmac_data {
> +	unsigned int gtxclk_dlychain;
> +};
>
>  struct starfive_dwmac {
>  	struct device *dev;
>  	struct clk *clk_tx;
> +	const struct starfive_dwmac_data *data;
>  };
>
>  static void starfive_dwmac_fix_mac_speed(void *priv, unsigned int speed, unsigned int mode)
> @@ -67,6 +74,8 @@ static int starfive_dwmac_set_mode(struct plat_stmmacenet_data *plat_dat)
>
>  	case PHY_INTERFACE_MODE_RGMII:
>  	case PHY_INTERFACE_MODE_RGMII_ID:
> +	case PHY_INTERFACE_MODE_RGMII_RXID:
> +	case PHY_INTERFACE_MODE_RGMII_TXID:
>  		mode = STARFIVE_DWMAC_PHY_INFT_RGMII;
>  		break;
>
> @@ -89,6 +98,14 @@ static int starfive_dwmac_set_mode(struct plat_stmmacenet_data *plat_dat)
>  	if (err)
>  		return dev_err_probe(dwmac->dev, err, "error setting phy mode\n");
>
> +	if (dwmac->data) {

I think you want something like this so future quirks don't need to touch this
code:

	if (dwmac->data && dwmac->data->gtxclk_dlychain)

> +		err = regmap_write(regmap, JH7100_SYSMAIN_REGISTER49_DLYCHAIN,
> +				   dwmac->data->gtxclk_dlychain);
> +		if (err)
> +			return dev_err_probe(dwmac->dev, err,
> +					     "error selecting gtxclk delay chain\n");
> +	}
> +
>  	return 0;
>  }
>
> @@ -114,6 +131,8 @@ static int starfive_dwmac_probe(struct platform_device *pdev)
>  	if (!dwmac)
>  		return -ENOMEM;
>
> +	dwmac->data = device_get_match_data(&pdev->dev);
> +
>  	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),
> @@ -144,8 +163,13 @@ static int starfive_dwmac_probe(struct platform_device *pdev)
>  	return stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
>  }
>
> +static const struct starfive_dwmac_data jh7100_data = {
> +	.gtxclk_dlychain = 4

Please add a , at the end of this line. I know it's unlikely that we need to
add more properties, but it's still good practice to do. This way such patches
won't need to touch this line.

> +};
> +
>  static const struct of_device_id starfive_dwmac_match[] = {
> -	{ .compatible = "starfive,jh7110-dwmac"	},
> +	{ .compatible = "starfive,jh7100-dwmac", .data = &jh7100_data },
> +	{ .compatible = "starfive,jh7110-dwmac" },
>  	{ /* sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(of, starfive_dwmac_match);
> --
> 2.42.0
>