Re: [RFC PATCH 3/6] net: stmmac: dwmac-meson8b: add support for the Amlogic T7

[Neil Armstrong <neil.armstrong@linaro.org>]

On 10/4/26 16:40, Lucas Tanure wrote:
> The glue registers on the T7 are laid out exactly as the G12A ones, RX
> delay field included, so the T7 can reuse the G12A settings.
> 
> What the T7 does not share is how the controller reaches DRAM: the bus
> path goes through a pipeline stage with a gate of its own, and no device
> other than the controller has any use for that gate. Claim it and hold
> it enabled for as long as the controller is bound, otherwise it is
> switched off as unused and a transfer that has been started can never
> complete.
> 
> Give the T7 match data of its own so that only it looks the clock up,
> and require the clock instead of treating it as optional: the controller
> cannot do DMA without it, and failing the probe with a clear message
> beats booting and hitting an undiagnosable hang later.
> 
> Assisted-by: LLM
> Signed-off-by: Lucas Tanure <tanure@linux.com>
> ---
>   .../ethernet/stmicro/stmmac/dwmac-meson8b.c   | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
> index e4d5c41294f4..450f7b4b29a6 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
> @@ -81,6 +81,7 @@ struct meson8b_dwmac;
>   struct meson8b_dwmac_data {
>   	int (*set_phy_mode)(struct meson8b_dwmac *dwmac);
>   	bool has_prg_eth1_rgmii_rx_delay;
> +	bool has_pipeline_clk;
>   };
>   
>   struct meson8b_dwmac {
> @@ -384,6 +385,7 @@ static int meson8b_dwmac_probe(struct platform_device *pdev)
>   	struct plat_stmmacenet_data *plat_dat;
>   	struct stmmac_resources stmmac_res;
>   	struct meson8b_dwmac *dwmac;
> +	struct clk *pipeline_clk;
>   	int ret;
>   
>   	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> @@ -443,6 +445,13 @@ static int meson8b_dwmac_probe(struct platform_device *pdev)
>   	if (IS_ERR(dwmac->timing_adj_clk))
>   		return PTR_ERR(dwmac->timing_adj_clk);
>   
> +	if (dwmac->data->has_pipeline_clk) {
> +		pipeline_clk = devm_clk_get_enabled(dwmac->dev, "pipeline");
> +		if (IS_ERR(pipeline_clk))
> +			return dev_err_probe(dwmac->dev, PTR_ERR(pipeline_clk),
> +					     "missing pipeline clock\n");
> +	}
> +
>   	ret = meson8b_init_rgmii_delays(dwmac);
>   	if (ret)
>   		return ret;
> @@ -479,6 +488,12 @@ static const struct meson8b_dwmac_data meson_g12a_dwmac_data = {
>   	.has_prg_eth1_rgmii_rx_delay = true,
>   };
>   
> +static const struct meson8b_dwmac_data meson_t7_dwmac_data = {
> +	.set_phy_mode = meson_axg_set_phy_mode,
> +	.has_prg_eth1_rgmii_rx_delay = true,
> +	.has_pipeline_clk = true,
> +};
> +
>   static const struct of_device_id meson8b_dwmac_match[] = {
>   	{
>   		.compatible = "amlogic,meson8b-dwmac",
> @@ -500,6 +515,10 @@ static const struct of_device_id meson8b_dwmac_match[] = {
>   		.compatible = "amlogic,meson-g12a-dwmac",
>   		.data = &meson_g12a_dwmac_data,
>   	},
> +	{
> +		.compatible = "amlogic,t7-dwmac",
> +		.data = &meson_t7_dwmac_data,
> +	},
>   	{ }
>   };
>   MODULE_DEVICE_TABLE(of, meson8b_dwmac_match);

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil

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