Re: [PATCH net-next 3/3] net: stmmac: Add RK3566/RK3568 SoC support

From: Ezequiel Garcia <ezequiel@collabora.com>
To: "Heiko Stübner" <heiko@sntech.de>, "Peter Geis" <pgwipeout@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>,
	Jose Abreu <joabreu@synopsys.com>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	David Wu <david.wu@rock-chips.com>,
	kernel@collabora.com
Subject: Re: [PATCH net-next 3/3] net: stmmac: Add RK3566/RK3568 SoC support
Date: Wed, 14 Apr 2021 10:48:19 -0300	[thread overview]
Message-ID: <16102d157576bfa7be341ed7508e70d930e40bab.camel@collabora.com> (raw)
In-Reply-To: <2596687.TLnPLrj5Ze@diego>

Hi Peter, Heiko,

On Wed, 2021-04-14 at 13:15 +0200, Heiko Stübner wrote:
> Am Mittwoch, 14. April 2021, 13:03:25 CEST schrieb Peter Geis:
> > On Tue, Apr 13, 2021 at 7:37 PM Ezequiel Garcia <ezequiel@collabora.com> wrote:
> > > > > +static void rk3566_set_to_rmii(struct rk_priv_data *bsp_priv)
> > > > > +{
> > > > > +       struct device *dev = &bsp_priv->pdev->dev;
> > > > > +
> > > > > +       if (IS_ERR(bsp_priv->grf)) {
> > > > > +               dev_err(dev, "%s: Missing rockchip,grf property\n", __func__);
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       regmap_write(bsp_priv->grf, RK3568_GRF_GMAC1_CON1,
> > > > > +                    RK3568_GMAC_PHY_INTF_SEL_RMII);
> > > > > +}
> > > > > +
> > > > > +static void rk3568_set_to_rgmii(struct rk_priv_data *bsp_priv,
> > > > > +                               int tx_delay, int rx_delay)
> > > > > +{
> > > > > +       struct device *dev = &bsp_priv->pdev->dev;
> > > > > +
> > > > > +       if (IS_ERR(bsp_priv->grf)) {
> > > > > +               dev_err(dev, "Missing rockchip,grf property\n");
> > > > > +               return;
> > > > > +       }
> > > > > +
> > > > > +       regmap_write(bsp_priv->grf, RK3568_GRF_GMAC0_CON1,
> > > > > +                    RK3568_GMAC_PHY_INTF_SEL_RGMII |
> > > > > +                    RK3568_GMAC_RXCLK_DLY_ENABLE |
> > > > > +                    RK3568_GMAC_TXCLK_DLY_ENABLE);
> > > > > +
> > > > > +       regmap_write(bsp_priv->grf, RK3568_GRF_GMAC0_CON0,
> > > > > +                    RK3568_GMAC_CLK_RX_DL_CFG(rx_delay) |
> > > > > +                    RK3568_GMAC_CLK_TX_DL_CFG(tx_delay));
> > > > > +
> > > > > +       regmap_write(bsp_priv->grf, RK3568_GRF_GMAC1_CON1,
> > > > > +                    RK3568_GMAC_PHY_INTF_SEL_RGMII |
> > > > > +                    RK3568_GMAC_RXCLK_DLY_ENABLE |
> > > > > +                    RK3568_GMAC_TXCLK_DLY_ENABLE);
> > > > > +
> > > > > +       regmap_write(bsp_priv->grf, RK3568_GRF_GMAC1_CON0,
> > > > > +                    RK3568_GMAC_CLK_RX_DL_CFG(rx_delay) |
> > > > > +                    RK3568_GMAC_CLK_TX_DL_CFG(tx_delay));
> > > > 
> > > > Since there are two GMACs on the rk3568, and either, or, or both may
> > > > be enabled in various configurations, we should only configure the
> > > > controller we are currently operating.
> > 
> > Perhaps we should have match data (such as reg = <0>, or against the
> > address) to identify the individual controllers.
> 
> Hmm, "reg" will be used by the actual mmio address of the controller,
> so matching against that should be the way I guess.
> 
> We're already doing something similar for dsi:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c#n1170
> 

I have to admit, I'm not a fan of hardcoding the registers in the kernel.

David Wu solved this in the downstream kernel by using bus_id,
which parses the devicetree "ethernet@0" node, i.e.:

  plat->bus_id = of_alias_get_id(np, "ethernet");

I'm inclined for this solution. Maybe Jose can suggest how to approach it?

Thanks!
Ezequiel