Re: [PATCH net-next v6 3/4] net: stmmac: Add DWMAC glue layer for Renesas GBETH

[Philipp Zabel]

On Di, 2025-04-15 at 13:56 +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> 
> Add the DWMAC glue layer for the GBETH IP found in the Renesas RZ/V2H(P)
> SoC.
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> ---
>  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 ++
>  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
>  .../stmicro/stmmac/dwmac-renesas-gbeth.c      | 148 ++++++++++++++++++
>  3 files changed, 160 insertions(+)
>  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> index 3c820ef56775..2c99b23f0faa 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> @@ -131,6 +131,17 @@ config DWMAC_QCOM_ETHQOS
>  	  This selects the Qualcomm ETHQOS glue layer support for the
>  	  stmmac device driver.
>  
> +config DWMAC_RENESAS_GBETH
> +	tristate "Renesas RZ/V2H(P) GBETH support"
> +	default ARCH_RENESAS
> +	depends on OF && (ARCH_RENESAS || COMPILE_TEST)
> +	help
> +	  Support for Gigabit Ethernet Interface (GBETH) on Renesas
> +	  RZ/V2H(P) SoCs.
> +
> +	  This selects the Renesas RZ/V2H(P) Soc specific glue layer support
> +	  for the stmmac device driver.
> +
>  config DWMAC_ROCKCHIP
>  	tristate "Rockchip dwmac support"
>  	default ARCH_ROCKCHIP
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> index 594883fb4164..91050215511b 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> @@ -20,6 +20,7 @@ obj-$(CONFIG_DWMAC_LPC18XX)	+= dwmac-lpc18xx.o
>  obj-$(CONFIG_DWMAC_MEDIATEK)	+= dwmac-mediatek.o
>  obj-$(CONFIG_DWMAC_MESON)	+= dwmac-meson.o dwmac-meson8b.o
>  obj-$(CONFIG_DWMAC_QCOM_ETHQOS)	+= dwmac-qcom-ethqos.o
> +obj-$(CONFIG_DWMAC_RENESAS_GBETH) += dwmac-renesas-gbeth.o
>  obj-$(CONFIG_DWMAC_ROCKCHIP)	+= dwmac-rk.o
>  obj-$(CONFIG_DWMAC_RZN1)	+= dwmac-rzn1.o
>  obj-$(CONFIG_DWMAC_S32)		+= dwmac-s32.o
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c
> new file mode 100644
> index 000000000000..8674b7605d83
> --- /dev/null
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c
> @@ -0,0 +1,148 @@
> +// 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 "stmmac_platform.h"
> +
> +struct renesas_gbeth {
> +	struct plat_stmmacenet_data *plat_dat;
> +	struct reset_control *rstc;
> +	struct device *dev;
> +	void __iomem *regs;

This doesn't seem to be used anywhere.

> +};
> +
> +static const char *const renesas_gbeth_clks[] = {
> +	"tx", "tx-180", "rx", "rx-180",
> +};
> +
> +static int renesas_gbeth_clks_config(struct renesas_gbeth *gbeth, bool enabled)
> +{
> +	struct plat_stmmacenet_data *plat_dat;
> +	int ret;
> +
> +	plat_dat = gbeth->plat_dat;
> +	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;
> +}

Apart from the plat_dat assignment, this function has two completely
separate paths. I'd fold its contents into renesas_gbeth_init/exit().


regards
Philipp