Date:   Fri, 3 Mar 2023 17:50:54 +0100
From:   Emil Renner Berthing <emil.renner.berthing@...onical.com>
To:     Samin Guo <samin.guo@...rfivetech.com>
Cc:     linux-riscv@...ts.infradead.org, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        "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>,
        Emil Renner Berthing <kernel@...il.dk>,
        Richard Cochran <richardcochran@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Peter Geis <pgwipeout@...il.com>,
        Yanhong Wang <yanhong.wang@...rfivetech.com>
Subject: Re: [PATCH v5 08/12] net: stmmac: starfive_dmac: Add phy interface settings

On Fri, 3 Mar 2023 at 10:01, Samin Guo <samin.guo@...rfivetech.com> wrote:
>
> dwmac supports multiple modess. When working under rmii and rgmii,
> you need to set different phy interfaces.
>
> According to the dwmac document, when working in rmii, it needs to be
> set to 0x4, and rgmii needs to be set to 0x1.
>
> The phy interface needs to be set in syscon, the format is as follows:
> starfive,syscon: <&syscon, offset, mask>
>
> Signed-off-by: Samin Guo <samin.guo@...rfivetech.com>
> ---
>  .../ethernet/stmicro/stmmac/dwmac-starfive.c  | 46 +++++++++++++++++++
>  1 file changed, 46 insertions(+)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
> index 566378306f67..40fdd7036127 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
> @@ -7,10 +7,15 @@
>   *
>   */
>
> +#include <linux/mfd/syscon.h>
>  #include <linux/of_device.h>
> +#include <linux/regmap.h>
>
>  #include "stmmac_platform.h"
>
> +#define MACPHYC_PHY_INFT_RMII  0x4
> +#define MACPHYC_PHY_INFT_RGMII 0x1

Please prefix these with something like STARFIVE_DWMAC_

>  struct starfive_dwmac {
>         struct device *dev;
>         struct clk *clk_tx;
> @@ -53,6 +58,46 @@ static void starfive_eth_fix_mac_speed(void *priv, unsigned int speed)
>                 dev_err(dwmac->dev, "failed to set tx rate %lu\n", rate);
>  }
>
> +static int starfive_dwmac_set_mode(struct plat_stmmacenet_data *plat_dat)
> +{
> +       struct starfive_dwmac *dwmac = plat_dat->bsp_priv;
> +       struct of_phandle_args args;
> +       struct regmap *regmap;
> +       unsigned int reg, mask, mode;
> +       int err;
> +
> +       switch (plat_dat->interface) {
> +       case PHY_INTERFACE_MODE_RMII:
> +               mode = MACPHYC_PHY_INFT_RMII;
> +               break;
> +
> +       case PHY_INTERFACE_MODE_RGMII:
> +       case PHY_INTERFACE_MODE_RGMII_ID:
> +               mode = MACPHYC_PHY_INFT_RGMII;
> +               break;
> +
> +       default:
> +               dev_err(dwmac->dev, "Unsupported interface %d\n",
> +                       plat_dat->interface);
> +       }
> +
> +       err = of_parse_phandle_with_fixed_args(dwmac->dev->of_node,
> +                                              "starfive,syscon", 2, 0, &args);
> +       if (err) {
> +               dev_dbg(dwmac->dev, "syscon reg not found\n");
> +               return -EINVAL;
> +       }
> +
> +       reg = args.args[0];
> +       mask = args.args[1];
> +       regmap = syscon_node_to_regmap(args.np);
> +       of_node_put(args.np);

I think the above is basically
unsigned int args[2];
syscon_regmap_lookup_by_phandle_args(dwmac->dev_of_node,
"starfive,syscon", 2, args);

..but as Andrew points out another solution is to use platform match
data for this. Eg.

static const struct starfive_dwmac_match_data starfive_dwmac_jh7110_data {
  .phy_interface_offset = 0xc,
  .phy_interface_mask = 0x1c0000,
};

static const struct of_device_id starfive_dwmac_match[] = {
  { .compatible = "starfive,jh7110-dwmac", .data =
&starfive_dwmac_jh7110_data },
  { /* sentinel */ }
};

and in the probe function:

struct starfive_dwmac_match_data *pdata = device_get_match_data(&pdev->dev);

> +       if (IS_ERR(regmap))
> +               return PTR_ERR(regmap);
> +
> +       return regmap_update_bits(regmap, reg, mask, mode << __ffs(mask));
> +}
> +
>  static int starfive_dwmac_probe(struct platform_device *pdev)
>  {
>         struct plat_stmmacenet_data *plat_dat;
> @@ -93,6 +138,7 @@ static int starfive_dwmac_probe(struct platform_device *pdev)
>         plat_dat->bsp_priv = dwmac;
>         plat_dat->dma_cfg->dche = true;
>
> +       starfive_dwmac_set_mode(plat_dat);

The function returns errors in an int, but you never check it :(

>         err = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
>         if (err) {
>                 stmmac_remove_config_dt(pdev, plat_dat);
> --
> 2.17.1
>
>
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> linux-riscv@...ts.infradead.org
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