Re: [PATCH net-next v3 3/3] net: stmmac: Add DWMAC glue layer for Renesas GBETH

[Lad, Prabhakar]

Hi Paolo,

Thank you for the review.

On Tue, Mar 18, 2025 at 11:49 AM Paolo Abeni <pabeni@xxxxxxxxxx> wrote:
>
> On 3/11/25 11:17 PM, Prabhakar wrote:
> > @@ -0,0 +1,166 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * dwmac-renesas-gbeth.c - DWMAC Specific Glue layer for Renesas GBETH
> > + *
> > + * The Rx and Tx clocks are supplied as follows for the GBETH IP.
> > + *
> > + *                         Rx / Tx
> > + *   -------+------------- on / off -------
> > + *          |
> > + *          |            Rx-180 / Tx-180
> > + *          +---- not ---- on / off -------
> > + *
> > + * Copyright (C) 2025 Renesas Electronics Corporation
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/device.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reset.h>
> > +
> > +#include "dwmac4.h"
> > +#include "stmmac_platform.h"
> > +
> > +struct renesas_gbeth {
> > +     struct plat_stmmacenet_data *plat_dat;
> > +     struct reset_control *rstc;
> > +     struct device *dev;
> > +     void __iomem *regs;
> > +};
> > +
> > +static const char *const renesas_gbeth_clks[] = {
> > +     "tx", "tx-180", "rx", "rx-180",
> > +};
> > +
> > +static struct clk *renesas_gbeth_find_clk(struct plat_stmmacenet_data *plat_dat,
> > +                                       const char *name)
> > +{
> > +     for (unsigned int i = 0; i < plat_dat->num_clks; i++)
> > +             if (!strcmp(plat_dat->clks[i].id, name))
> > +                     return plat_dat->clks[i].clk;
> > +
> > +     return NULL;
> > +}
> > +
> > +static int renesas_gbeth_clks_config(void *priv, bool enabled)
> > +{
> > +     struct renesas_gbeth *gbeth = priv;
> > +     struct plat_stmmacenet_data *plat_dat = gbeth->plat_dat;
>
> Minor nit: please respect the reverse christmas tree order above:
>
Agreed, I will fix that.

>         struct plat_stmmacenet_data *plat_dat;
>         struct renesas_gbeth *gbeth = priv;
>
> and init plat_dat later.
>
OK.

> > +     int ret;
> > +
> > +     if (enabled) {
> > +             ret = reset_control_deassert(gbeth->rstc);
> > +             if (ret) {
> > +                     dev_err(gbeth->dev, "Reset deassert failed\n");
> > +                     return ret;
> > +             }
> > +
> > +             ret = clk_bulk_prepare_enable(plat_dat->num_clks, plat_dat->clks);
> > +             if (ret)
> > +                     reset_control_assert(gbeth->rstc);
> > +     } else {
> > +             clk_bulk_disable_unprepare(plat_dat->num_clks, plat_dat->clks);
> > +             ret = reset_control_assert(gbeth->rstc);
> > +             if (ret)
> > +                     dev_err(gbeth->dev, "Reset assert failed\n");
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> > +static int renesas_gbeth_probe(struct platform_device *pdev)
> > +{
> > +     struct plat_stmmacenet_data *plat_dat;
> > +     struct stmmac_resources stmmac_res;
> > +     struct device *dev = &pdev->dev;
> > +     struct renesas_gbeth *gbeth;
> > +     unsigned int i;
> > +     int err;
> > +
> > +     err = stmmac_get_platform_resources(pdev, &stmmac_res);
> > +     if (err)
> > +             return dev_err_probe(dev, err,
> > +                                  "failed to get resources\n");
> > +
> > +     plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
> > +     if (IS_ERR(plat_dat))
> > +             return dev_err_probe(dev, PTR_ERR(plat_dat),
> > +                                  "dt configuration failed\n");
> > +
> > +     gbeth = devm_kzalloc(dev, sizeof(*gbeth), GFP_KERNEL);
> > +     if (!gbeth)
> > +             return -ENOMEM;
> > +
> > +     plat_dat->num_clks = ARRAY_SIZE(renesas_gbeth_clks);
> > +     plat_dat->clks = devm_kcalloc(dev, plat_dat->num_clks,
> > +                                   sizeof(*plat_dat->clks), GFP_KERNEL);
> > +     if (!plat_dat->clks)
> > +             return -ENOMEM;
> > +
> > +     for (i = 0; i < plat_dat->num_clks; i++)
> > +             plat_dat->clks[i].id = renesas_gbeth_clks[i];
> > +
> > +     err = devm_clk_bulk_get(dev, plat_dat->num_clks, plat_dat->clks);
> > +     if (err < 0)
> > +             return err;
> > +
> > +     plat_dat->clk_tx_i = renesas_gbeth_find_clk(plat_dat, "tx");
> > +     if (!plat_dat->clk_tx_i)
> > +             return dev_err_probe(dev, -EINVAL,
> > +                                  "error finding tx clock\n");
> > +
> > +     gbeth->rstc = devm_reset_control_get_exclusive(dev, NULL);
> > +     if (IS_ERR(gbeth->rstc))
> > +             return PTR_ERR(gbeth->rstc);
> > +
> > +     gbeth->dev = dev;
> > +     gbeth->regs = stmmac_res.addr;
> > +     gbeth->plat_dat = plat_dat;
> > +     plat_dat->bsp_priv = gbeth;
> > +     plat_dat->set_clk_tx_rate = stmmac_set_clk_tx_rate;
> > +     plat_dat->clks_config = renesas_gbeth_clks_config;
> > +     plat_dat->flags |= STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY |
> > +                        STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP |
>
> The above does not compile:
>
> ../drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c:124:7:
> error: use of undeclared identifier 'STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP'
>
As pointed out by Russell it depends on patch [0].

https://lore.kernel.org/all/E1tsITp-005vG9-Px@xxxxxxxxxxxxxxxxxxxxxx/

>
> > +                        STMMAC_FLAG_SPH_DISABLE;
> > +
> > +     err = renesas_gbeth_clks_config(gbeth, true);
> > +     if (err)
> > +             return err;
> > +
> > +     err = stmmac_dvr_probe(dev, plat_dat, &stmmac_res);
> > +     if (err) {
> > +             renesas_gbeth_clks_config(gbeth, false);
> > +             return err;
>
> Just:
>
>         if (err)
>                 renesas_gbeth_clks_config(gbeth, false);
>
>         return err;
>
Ok, I will update the code as above.

Cheers,
Prabhakar