Re: [PATCH net-next v2 3/3] net: stmmac: add glue layer for T-HEAD TH1520 SoC

From: Jisheng Zhang
Date: Mon Aug 28 2023 - 11:54:22 EST

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Previous message: Serge Semin: "Re: [PATCH net-next v2 2/3] dt-bindings: net: add T-HEAD dwmac support"
In reply to: Serge Semin: "Re: [PATCH net-next v2 3/3] net: stmmac: add glue layer for T-HEAD TH1520 SoC"
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On Mon, Aug 28, 2023 at 04:40:19PM +0300, Serge Semin wrote:
> On Sun, Aug 27, 2023 at 05:17:10PM +0800, Jisheng Zhang wrote:
> > Add dwmac glue driver to support the dwmac on the T-HEAD TH1520 SoC.
> >
> > Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
> > ---
> > drivers/net/ethernet/stmicro/stmmac/Kconfig | 11 +
> > drivers/net/ethernet/stmicro/stmmac/Makefile | 1 +
> > .../net/ethernet/stmicro/stmmac/dwmac-thead.c | 302 ++++++++++++++++++
> > 3 files changed, 314 insertions(+)
> > create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> >
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > index 06c6871f8788..1bf71804c270 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > @@ -216,6 +216,17 @@ config DWMAC_SUN8I
> > stmmac device driver. This driver is used for H3/A83T/A64
> > EMAC ethernet controller.
> >
> > +config DWMAC_THEAD
> > + tristate "T-HEAD dwmac support"
> > + depends on OF && (ARCH_THEAD || COMPILE_TEST)
> > + select MFD_SYSCON
> > + help
> > + Support for ethernet controllers on T-HEAD RISC-V SoCs
> > +
> > + This selects the T-HEAD platform specific glue layer support for
> > + the stmmac device driver. This driver is used for T-HEAD TH1520
> > + ethernet controller.
> > +
> > config DWMAC_IMX8
> > tristate "NXP IMX8 DWMAC support"
> > default ARCH_MXC
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > index 5b57aee19267..d73171ed6ad7 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > @@ -27,6 +27,7 @@ obj-$(CONFIG_DWMAC_STI) += dwmac-sti.o
> > obj-$(CONFIG_DWMAC_STM32) += dwmac-stm32.o
> > obj-$(CONFIG_DWMAC_SUNXI) += dwmac-sunxi.o
> > obj-$(CONFIG_DWMAC_SUN8I) += dwmac-sun8i.o
> > +obj-$(CONFIG_DWMAC_THEAD) += dwmac-thead.o
> > obj-$(CONFIG_DWMAC_DWC_QOS_ETH) += dwmac-dwc-qos-eth.o
> > obj-$(CONFIG_DWMAC_INTEL_PLAT) += dwmac-intel-plat.o
> > obj-$(CONFIG_DWMAC_GENERIC) += dwmac-generic.o
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > new file mode 100644
> > index 000000000000..85135ef05906
> > --- /dev/null
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-thead.c
> > @@ -0,0 +1,302 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * T-HEAD DWMAC platform driver
> > + *
> > + * Copyright (C) 2021 Alibaba Group Holding Limited.
> > + * Copyright (C) 2023 Jisheng Zhang <jszhang@xxxxxxxxxx>
> > + *
> > + */
> > +
> > +#include <linux/bitfield.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_net.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#include "stmmac_platform.h"
> > +
> > +#define GMAC_CLK_EN 0x00
> > +#define GMAC_TX_CLK_EN BIT(1)
> > +#define GMAC_TX_CLK_N_EN BIT(2)
> > +#define GMAC_TX_CLK_OUT_EN BIT(3)
> > +#define GMAC_RX_CLK_EN BIT(4)
> > +#define GMAC_RX_CLK_N_EN BIT(5)
> > +#define GMAC_EPHY_REF_CLK_EN BIT(6)
> > +#define GMAC_RXCLK_DELAY_CTRL 0x04
> > +#define GMAC_RXCLK_BYPASS BIT(15)
> > +#define GMAC_RXCLK_INVERT BIT(14)
> > +#define GMAC_RXCLK_DELAY_MASK GENMASK(4, 0)
> > +#define GMAC_RXCLK_DELAY_VAL(x) FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > +#define GMAC_TXCLK_DELAY_CTRL 0x08
> > +#define GMAC_TXCLK_BYPASS BIT(15)
> > +#define GMAC_TXCLK_INVERT BIT(14)
> > +#define GMAC_TXCLK_DELAY_MASK GENMASK(4, 0)
> > +#define GMAC_TXCLK_DELAY_VAL(x) FIELD_PREP(GMAC_RXCLK_DELAY_MASK, (x))
> > +#define GMAC_PLLCLK_DIV 0x0c
> > +#define GMAC_PLLCLK_DIV_EN BIT(31)
> > +#define GMAC_PLLCLK_DIV_MASK GENMASK(7, 0)
> > +#define GMAC_PLLCLK_DIV_NUM(x) FIELD_PREP(GMAC_PLLCLK_DIV_MASK, (x))
> > +#define GMAC_GTXCLK_SEL 0x18
> > +#define GMAC_GTXCLK_SEL_PLL BIT(0)
> > +#define GMAC_INTF_CTRL 0x1c
> > +#define PHY_INTF_MASK BIT(0)
> > +#define PHY_INTF_RGMII FIELD_PREP(PHY_INTF_MASK, 1)
> > +#define PHY_INTF_MII_GMII FIELD_PREP(PHY_INTF_MASK, 0)
> > +#define GMAC_TXCLK_OEN 0x20
> > +#define TXCLK_DIR_MASK BIT(0)
> > +#define TXCLK_DIR_OUTPUT FIELD_PREP(TXCLK_DIR_MASK, 0)
> > +#define TXCLK_DIR_INPUT FIELD_PREP(TXCLK_DIR_MASK, 1)
> > +
> > +#define GMAC_GMII_RGMII_RATE 125000000
> > +#define GMAC_MII_RATE 25000000
> > +
> > +struct thead_dwmac {
> > + struct plat_stmmacenet_data *plat;
> > + struct regmap *apb_regmap;
> > + struct device *dev;
> > + u32 rx_delay;
> > + u32 tx_delay;
> > +};
> > +
> > +static int thead_dwmac_set_phy_if(struct plat_stmmacenet_data *plat)
> > +{
> > + struct thead_dwmac *dwmac = plat->bsp_priv;
> > + u32 phyif;
> > +
> > + switch (plat->interface) {
> > + case PHY_INTERFACE_MODE_MII:
> > + phyif = PHY_INTF_MII_GMII;
> > + break;
> > + case PHY_INTERFACE_MODE_RGMII:
> > + case PHY_INTERFACE_MODE_RGMII_ID:
> > + case PHY_INTERFACE_MODE_RGMII_TXID:
> > + case PHY_INTERFACE_MODE_RGMII_RXID:
> > + phyif = PHY_INTF_RGMII;
> > + break;
> > + default:
> > + dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > + plat->interface);
> > + return -EINVAL;
> > + };
> > +
> > + regmap_write(dwmac->apb_regmap, GMAC_INTF_CTRL, phyif);
> > +
> > + return 0;
> > +}
> > +
> > +static int thead_dwmac_set_txclk_dir(struct plat_stmmacenet_data *plat)
> > +{
> > + struct thead_dwmac *dwmac = plat->bsp_priv;
> > + u32 txclk_dir;
> > +
> > + switch (plat->interface) {
> > + case PHY_INTERFACE_MODE_MII:
> > + txclk_dir = TXCLK_DIR_INPUT;
> > + break;
> > + case PHY_INTERFACE_MODE_RGMII:
> > + case PHY_INTERFACE_MODE_RGMII_ID:
> > + case PHY_INTERFACE_MODE_RGMII_TXID:
> > + case PHY_INTERFACE_MODE_RGMII_RXID:
> > + txclk_dir = TXCLK_DIR_OUTPUT;
> > + break;
> > + default:
> > + dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > + plat->interface);
> > + return -EINVAL;
> > + };
> > +
> > + regmap_write(dwmac->apb_regmap, GMAC_TXCLK_OEN, txclk_dir);
> > +
> > + return 0;
> > +}
> > +
> > +static void thead_dwmac_fix_speed(void *priv, unsigned int speed, unsigned int mode)
> > +{
> > + struct thead_dwmac *dwmac = priv;
> > + struct plat_stmmacenet_data *plat = dwmac->plat;
> > + unsigned long rate;
> > + u32 div;
> > +
> > + switch (plat->interface) {
> > + /* For MII, rxc/txc is provided by phy */
> > + case PHY_INTERFACE_MODE_MII:
> > + return;
> > +
> > + case PHY_INTERFACE_MODE_RGMII:
> > + case PHY_INTERFACE_MODE_RGMII_ID:
> > + case PHY_INTERFACE_MODE_RGMII_RXID:
> > + case PHY_INTERFACE_MODE_RGMII_TXID:
>
> > + rate = clk_get_rate(plat->stmmac_clk);
> > + if (!rate || rate % GMAC_GMII_RGMII_RATE != 0 ||
> > + rate % GMAC_MII_RATE != 0) {
> > + dev_err(dwmac->dev, "invalid gmac rate %ld\n", rate);
> > + return;
> > + }
> > +
> > + regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV, GMAC_PLLCLK_DIV_EN, 0);
> > +
> > + switch (speed) {
> > + case SPEED_1000:
> > + div = rate / GMAC_GMII_RGMII_RATE;
> > + break;
> > + case SPEED_100:
> > + div = rate / GMAC_MII_RATE;
> > + break;
> > + case SPEED_10:
> > + div = rate * 10 / GMAC_MII_RATE;
> > + break;
> > + default:
> > + dev_err(dwmac->dev, "invalid speed %u\n", speed);
> > + return;
> > + }
> > + regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > + GMAC_PLLCLK_DIV_MASK, GMAC_PLLCLK_DIV_NUM(div));
> > +
> > + regmap_update_bits(dwmac->apb_regmap, GMAC_PLLCLK_DIV,
> > + GMAC_PLLCLK_DIV_EN, GMAC_PLLCLK_DIV_EN);
>
> This chunk looks like a hard-coded implementation of the
> CLK_SET_RATE_GATE Tx-clocks rate setup which parental clock is the
> "stmmaceth" clock. I suggest to move it to the respective driver, add
> a "tx" clock to the bindings and use the common clock kernel API
> methods here only.

I did consider your solution before writing the code, here are the
reasons why I dropped it:

There's no any clk IP here, the HW just puts several
gmac related control bits here, such as rx/tx delay, bypass, invert
interface choice, clk direction. From this point of view, it looks more
like a syscon rather than clk.

Secondly, I see other SoCs did similar for this case, such as
dwmac-visconti, dwmac-meson8b, dwmac-ipq806x, dwmac-socfpga and so on.
They met similar issue as the above.

PS: here is the initial th1520 clk driver, as is seen, the clk IP is
different from the control logic here.

https://lore.kernel.org/linux-riscv/20230515054402.27633-1-frank.li@xxxxxxxx/

Thanks

>
> > + break;
> > + default:
> > + dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > + plat->interface);
> > + return;
> > + }
> > +}
> > +
> > +static int thead_dwmac_enable_clk(struct plat_stmmacenet_data *plat)
> > +{
> > + struct thead_dwmac *dwmac = plat->bsp_priv;
> > + u32 reg;
> > +
> > + switch (plat->interface) {
> > + case PHY_INTERFACE_MODE_MII:
> > + reg = GMAC_RX_CLK_EN | GMAC_TX_CLK_EN;
> > + break;
> > +
> > + case PHY_INTERFACE_MODE_RGMII:
> > + case PHY_INTERFACE_MODE_RGMII_ID:
> > + case PHY_INTERFACE_MODE_RGMII_RXID:
> > + case PHY_INTERFACE_MODE_RGMII_TXID:
> > + /* use pll */
> > + regmap_write(dwmac->apb_regmap, GMAC_GTXCLK_SEL, GMAC_GTXCLK_SEL_PLL);
> > +
>
> > + reg = GMAC_TX_CLK_EN | GMAC_TX_CLK_N_EN | GMAC_TX_CLK_OUT_EN |
> > + GMAC_RX_CLK_EN | GMAC_RX_CLK_N_EN;
>
> Similarly settings these flags looks like just clock gates which can
> also be moved to the clock driver.
>
> > + break;
> > +
> > + default:
> > + dev_err(dwmac->dev, "unsupported phy interface %d\n",
> > + plat->interface);
> > + return -EINVAL;
> > + }
> > +
> > + regmap_write(dwmac->apb_regmap, GMAC_CLK_EN, reg);
> > +
> > + return 0;
> > +}
> > +
> > +static int thead_dwmac_init(struct platform_device *pdev,
> > + struct plat_stmmacenet_data *plat)
> > +{
> > + struct thead_dwmac *dwmac = plat->bsp_priv;
> > + int ret;
> > +
> > + ret = thead_dwmac_set_phy_if(plat);
> > + if (ret)
> > + return ret;
> > +
> > + ret = thead_dwmac_set_txclk_dir(plat);
> > + if (ret)
> > + return ret;
> > +
> > + regmap_write(dwmac->apb_regmap, GMAC_RXCLK_DELAY_CTRL,
> > + GMAC_RXCLK_DELAY_VAL(dwmac->rx_delay));
> > + regmap_write(dwmac->apb_regmap, GMAC_TXCLK_DELAY_CTRL,
> > + GMAC_TXCLK_DELAY_VAL(dwmac->tx_delay));
> > +
> > + thead_dwmac_fix_speed(dwmac, SPEED_1000, 0);
> > +
> > + return thead_dwmac_enable_clk(plat);
> > +}
> > +
> > +static int thead_dwmac_probe(struct platform_device *pdev)
> > +{
> > + struct plat_stmmacenet_data *plat;
> > + struct stmmac_resources stmmac_res;
> > + struct thead_dwmac *dwmac;
> > + struct device_node *np = pdev->dev.of_node;
> > + u32 delay_ps;
> > + int ret;
> > +
> > + ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> > + if (ret)
> > + return dev_err_probe(&pdev->dev, ret,
> > + "failed to get resources\n");
> > +
>
> > + plat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
>
> This can be replaced with devm_stmmac_probe_config_dt() so the
> stmmac_remove_config_dt() invocation would be dropped.
>
> > + if (IS_ERR(plat))
> > + return dev_err_probe(&pdev->dev, PTR_ERR(plat),
> > + "dt configuration failed\n");
> > +
> > + dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> > + if (!dwmac) {
> > + ret = -ENOMEM;
> > + goto err_remove_config_dt;
> > + }
> > +
> > + if (!of_property_read_u32(np, "rx-internal-delay-ps", &delay_ps))
> > + dwmac->rx_delay = delay_ps;
> > + if (!of_property_read_u32(np, "tx-internal-delay-ps", &delay_ps))
> > + dwmac->tx_delay = delay_ps;
> > +
> > + dwmac->apb_regmap = syscon_regmap_lookup_by_phandle(np, "thead,gmacapb");
> > + if (IS_ERR(dwmac->apb_regmap)) {
> > + ret = dev_err_probe(&pdev->dev, PTR_ERR(dwmac->apb_regmap),
> > + "Failed to get gmac apb syscon\n");
> > + goto err_remove_config_dt;
> > + }
> > +
> > + dwmac->dev = &pdev->dev;
> > + dwmac->plat = plat;
> > + plat->bsp_priv = dwmac;
> > + plat->fix_mac_speed = thead_dwmac_fix_speed;
> > +
>
> > + ret = thead_dwmac_init(pdev, plat);
> > + if (ret)
> > + goto err_remove_config_dt;
> > +
> > + ret = stmmac_dvr_probe(&pdev->dev, plat, &stmmac_res);
>
> This can be replaced with:
> plat->init = thead_dwmac_init;
> ret = devm_stmmac_pltfr_probe();
>
> > + if (ret)
> > + goto err_remove_config_dt;
> > +
> > + return 0;
> > +
>
> > +err_remove_config_dt:
> > + stmmac_remove_config_dt(pdev, plat);
> > +
> > + return ret;
>
> This can be dropped if devm_stmmac_probe_config_dt() is utilized.
>
> > +}
> > +
> > +static const struct of_device_id thead_dwmac_match[] = {
>
> > + { .compatible = "thead,th1520-dwmac" },
>
> See my comment to the bindings about the compatible string suffix.
>
> > + { }
> > +};
> > +MODULE_DEVICE_TABLE(of, thead_dwmac_match);
> > +
> > +static struct platform_driver thead_dwmac_driver = {
> > + .probe = thead_dwmac_probe,
>
> > + .remove_new = stmmac_pltfr_remove,
>
> This can be dropped if devm_stmmac_probe_config_dt() and
> devm_stmmac_pltfr_probe() are utilized.
>
> > + .driver = {
> > + .name = "thead-dwmac",
> > + .pm = &stmmac_pltfr_pm_ops,
> > + .of_match_table = thead_dwmac_match,
> > + },
> > +};
> > +module_platform_driver(thead_dwmac_driver);
> > +
> > +MODULE_AUTHOR("T-HEAD");
> > +MODULE_AUTHOR("Jisheng Zhang <jszhang@xxxxxxxxxx>");
>
> > +MODULE_DESCRIPTION("T-HEAD dwmac platform driver");
> ^
> |
> Capitalize? ------------------+
>
> -Serge(y)
>
> > +MODULE_LICENSE("GPL");
> > --
> > 2.40.1
> >
> >

Next message: Tianyi Liu: "Re: [PATCH] KVM: VMX: Fix NMI event loss"
Previous message: Serge Semin: "Re: [PATCH net-next v2 2/3] dt-bindings: net: add T-HEAD dwmac support"
In reply to: Serge Semin: "Re: [PATCH net-next v2 3/3] net: stmmac: add glue layer for T-HEAD TH1520 SoC"
Next in thread: Emil Renner Berthing: "Re: [PATCH net-next v2 3/3] net: stmmac: add glue layer for T-HEAD TH1520 SoC"
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