Date:   Tue, 7 Mar 2023 10:16:57 +0800
From:   Guo Samin <samin.guo@...rfivetech.com>
To:     Emil Renner Berthing <emil.renner.berthing@...onical.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



在 2023/3/6 20:49:57, Emil Renner Berthing 写道:
> On Mon, 6 Mar 2023 at 04:07, Guo Samin <samin.guo@...rfivetech.com> wrote:
>> 在 2023/3/4 0:50:54, Emil Renner Berthing 写道:
>>> 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_
>>>
>> Hi, Emil, These definitions come from the datasheet of dwmac. However, add STARDRIVE_ DWMAC is a good idea. I will fix it,thanks.
>>>>  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:
>>>
>> Hi Emil, Yes，this is usually a good solution, and I have considered this plan before.
>> However, gmac0 of jh7110 is different from the reg/mask of gmac1.
>> You can find it in patch-9:
>>
>> &gmac0 {
>>         starfive,syscon = <&aon_syscon 0xc 0x1c0000>;
>> };
>>
>> &gmac1 {
>>         starfive,syscon = <&sys_syscon 0x90 0x1c>;
>> };
>>
>> In this case, using match_data of starfive,jh7110-dwma does not seem to be compatible.
> 
> Ugh, you're right. Both the syscon block, the register offset and the
> bit position in those registers are different from gmac0 to gmac1, and
> since we need a phandle to the syscon block anyway passing those two
> other parameters as arguments is probably the nicest solution. For the
> next version I'd change the 2nd argument from mask to the bit position
> though. It seems the field is always 3 bits wide and this makes it a
> little clearer that we're not just putting register values in the
> device tree. Eg. something like
> 
Yes，the field is always 3 bits wide, the next version will use bit position instead of mask.
Thank you for your advice.
> regmap = syscon_regmap_lookup_by_phandle_args(dev->of_node,
> "starfive,syscon", 2, args);
> ...
> err = regmap_update_bits(regmap, args[0], 7U << args[1], mode << args[1]);
> ...
> 
I also think the current method is relatively simple and compatible.


Best regards,
Samin
> Alternatively we'd put data for each gmac interface in the platform
> data including the syscon compatible string, and use
> syscon_regmap_lookup_by_compatible("starfive,jh7110-aon-syscon"); for
> gmac0 fx. This way the dependency from the gmac nodes to the syscon
> nodes won't be recorded is the device tree though.
> 
> @Andrew is this what you were suggesting?
> 


>>> 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 :(
>>>
>> Thank you for pointing out that it will be added in the next version.
>>>>         err = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
>>>>         if (err) {
>>>>                 stmmac_remove_config_dt(pdev, plat_dat);
>>
>>
>> Best regards,
>> Samin
>>
>>>> --
>>>> 2.17.1
>>>>
>>>>
>>>> _______________________________________________
>>>> linux-riscv mailing list
>>>> linux-riscv@...ts.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>>
>> --
>> Best regards,
>> Samin

-- 
Best regards,
Samin

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