Re: [PATCH v3 3/4] net: stmmac: Add glue layer for Loongson-1 SoC

[Keguang Zhang]

On Sun, Aug 27, 2023 at 4:40 AM Serge Semin <fancer.lancer@xxxxxxxxx> wrote:
>
> On Thu, Aug 24, 2023 at 08:50:11PM +0800, Keguang Zhang wrote:
> > This glue driver is created based on the arch-code
> > implemented earlier with the platform-specific settings.
> >
> > Use syscon for SYSCON register access.
> >
> > Partially based on the previous work by Serge Semin.
> >
> > Signed-off-by: Keguang Zhang <keguang.zhang@xxxxxxxxx>
> > ---
> > V2 -> V3: Determine the device ID by physical
> >           base address(suggested by Serge Semin)
> >           Use regmap instead of regmap fields
> >           Use syscon_regmap_lookup_by_phandle()
> >           Some minor fixes
> > V1 -> V2: Fix the build errors due to CONFIG_OF being unset
> >           Change struct reg_field definitions to const
> >           Rename the syscon property to "loongson,dwmac-syscon"
> >           Add MII PHY mode for LS1C
> >
> >  drivers/net/ethernet/stmicro/stmmac/Kconfig   |  11 +
> >  drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
> >  .../ethernet/stmicro/stmmac/dwmac-loongson1.c | 240 ++++++++++++++++++
> >  3 files changed, 252 insertions(+)
> >  create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-loongson1.c
> >
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > index 06c6871f8788..a2b9e289aa36 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> > @@ -239,6 +239,17 @@ config DWMAC_INTEL_PLAT
> >         the stmmac device driver. This driver is used for the Intel Keem Bay
> >         SoC.
> >
> > +config DWMAC_LOONGSON1
> > +     tristate "Loongson1 GMAC support"
> > +     default MACH_LOONGSON32
> > +     depends on OF && (MACH_LOONGSON32 || COMPILE_TEST)
> > +     help
> > +       Support for ethernet controller on Loongson1 SoC.
> > +
> > +       This selects Loongson1 SoC glue layer support for the stmmac
> > +       device driver. This driver is used for Loongson1-based boards
> > +       like Loongson LS1B/LS1C.
> > +
> >  config DWMAC_TEGRA
> >       tristate "NVIDIA Tegra MGBE support"
> >       depends on ARCH_TEGRA || COMPILE_TEST
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > index 5b57aee19267..80e598bd4255 100644
> > --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> > +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> > @@ -29,6 +29,7 @@ obj-$(CONFIG_DWMAC_SUNXI)   += dwmac-sunxi.o
> >  obj-$(CONFIG_DWMAC_SUN8I)    += dwmac-sun8i.o
> >  obj-$(CONFIG_DWMAC_DWC_QOS_ETH)      += dwmac-dwc-qos-eth.o
> >  obj-$(CONFIG_DWMAC_INTEL_PLAT)       += dwmac-intel-plat.o
> > +obj-$(CONFIG_DWMAC_LOONGSON1)        += dwmac-loongson1.o
> >  obj-$(CONFIG_DWMAC_GENERIC)  += dwmac-generic.o
> >  obj-$(CONFIG_DWMAC_IMX8)     += dwmac-imx.o
> >  obj-$(CONFIG_DWMAC_TEGRA)    += dwmac-tegra.o
> > diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson1.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson1.c
> > new file mode 100644
> > index 000000000000..347d842141e4
> > --- /dev/null
> > +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson1.c
> > @@ -0,0 +1,240 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/*
> > + * Loongson-1 DWMAC glue layer
> > + *
> > + * Copyright (C) 2011-2023 Keguang Zhang <keguang.zhang@xxxxxxxxx>
> > + */
> > +
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/phy.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#include "stmmac.h"
> > +#include "stmmac_platform.h"
> > +
> > +#define LS1X_GMAC0_BASE              (0xe10000)
>
> > +#define LS1X_GMAC1_BASE              (0xe20000)
>
> If LS1C doesn't have the second GMAC then what about changing the
> macros name to LS1B_GMAC1_BASE?
>
> > +
> > +/* Loongson-1 SYSCON Registers */
> > +#define LS1X_SYSCON0         (0x0)
> > +#define LS1X_SYSCON1         (0x4)
> > +
> > +/* Loongson-1B SYSCON Register Bits */
>
> > +#define GMAC1_USE_UART1              BIT(4)
> > +#define GMAC1_USE_UART0              BIT(3)
> > +
> > +#define GMAC1_SHUT           BIT(13)
> > +#define GMAC0_SHUT           BIT(12)
> > +
> > +#define GMAC1_USE_TXCLK              BIT(3)
> > +#define GMAC0_USE_TXCLK              BIT(2)
> > +#define GMAC1_USE_PWM23              BIT(1)
> > +#define GMAC0_USE_PWM01              BIT(0)
> > +
> > +/* Loongson-1C SYSCON Register Bits */
> > +#define GMAC_SHUT            BIT(6)
> > +
> > +#define PHY_INTF_SELI                GENMASK(30, 28)
>
> IMO having the SoC-specific prefixes (LS1B_ and LS1C_) in these names
> would make the driver a bit more readable. But it's up to you to
> decide.
>
> > +#define PHY_INTF_SELI_SHIFT  28
>
> Use FIELD_PREP():
> #define PHY_INTF_MII                    FIELD_PREP(PHY_INTF_SELI, 0)
> #define PHY_INTF_RMII                   FIELD_PREP(PHY_INTF_SELI, 4)
>
> > +
> > +struct ls1x_dwmac_syscon {
> > +     int (*syscon_init)(struct plat_stmmacenet_data *plat);
> > +};
>
> This struct is redundant. See further for details.
>
> > +
> > +struct ls1x_dwmac {
>
> > +     unsigned long reg_base;
>
> this field
>
> > +     struct device *dev;
>
> > +     struct plat_stmmacenet_data *plat_dat;
> > +     const struct ls1x_dwmac_syscon *syscon;
>
> and these fields are also redundant. See further for details.
>
> > +     struct regmap *regmap;
> > +};
> > +
> > +static int ls1b_dwmac_syscon_init(struct plat_stmmacenet_data *plat)
> > +{
> > +     struct ls1x_dwmac *dwmac = plat->bsp_priv;
> > +     struct regmap *regmap = dwmac->regmap;
> > +
>
> > +     if ((dwmac->reg_base & LS1X_GMAC0_BASE) == LS1X_GMAC0_BASE) {
>
> Is it necessary to bitwise-and-ing? What if LS1X_GMAC0_BASE would be
> just a full physical base address? Then you'll be able to just compare
> the base addresses.
>
> > +             switch (plat->phy_interface) {
> > +             case PHY_INTERFACE_MODE_RGMII_ID:
> > +                     regmap_update_bits(regmap, LS1X_SYSCON0,
> > +                                        GMAC0_USE_TXCLK | GMAC0_USE_PWM01,
> > +                                        0);
> > +                     break;
> > +             case PHY_INTERFACE_MODE_MII:
> > +                     regmap_update_bits(regmap, LS1X_SYSCON0,
> > +                                        GMAC0_USE_TXCLK | GMAC0_USE_PWM01,
> > +                                        GMAC0_USE_TXCLK | GMAC0_USE_PWM01);
> > +                     break;
> > +             default:
> > +                     dev_err(dwmac->dev, "Unsupported PHY mode %u\n",
> > +                             plat->phy_interface);
> > +                     return -EOPNOTSUPP;
> > +             }
> > +
> > +             regmap_update_bits(regmap, LS1X_SYSCON0, GMAC0_SHUT, 0);
>
> > +     }
> > +
> > +     if ((dwmac->reg_base & LS1X_GMAC1_BASE) == LS1X_GMAC1_BASE) {
>
> else if?
>
> > +             regmap_update_bits(regmap, LS1X_SYSCON0,
> > +                                GMAC1_USE_UART1 | GMAC1_USE_UART0,
> > +                                GMAC1_USE_UART1 | GMAC1_USE_UART0);
> > +
> > +             switch (plat->phy_interface) {
> > +             case PHY_INTERFACE_MODE_RGMII_ID:
> > +                     regmap_update_bits(regmap, LS1X_SYSCON1,
> > +                                        GMAC1_USE_TXCLK | GMAC1_USE_PWM23,
> > +                                        0);
> > +
> > +                     break;
> > +             case PHY_INTERFACE_MODE_MII:
> > +                     regmap_update_bits(regmap, LS1X_SYSCON1,
> > +                                        GMAC1_USE_TXCLK | GMAC1_USE_PWM23,
> > +                                        GMAC1_USE_TXCLK | GMAC1_USE_PWM23);
> > +                     break;
> > +             default:
> > +                     dev_err(dwmac->dev, "Unsupported PHY mode %u\n",
> > +                             plat->phy_interface);
> > +                     return -EOPNOTSUPP;
> > +             }
> > +
> > +             regmap_update_bits(regmap, LS1X_SYSCON1, GMAC1_SHUT, 0);
>
> > +     }
>
> else {
>         dev_err(...)
>         return -EINVAL;
> }
> ?
>
> * unless you have some more DW GMACs on the SoC which don't require the
> syscon setups.
>
> > +
> > +     return 0;
> > +}
> > +
> > +static int ls1c_dwmac_syscon_init(struct plat_stmmacenet_data *plat)
> > +{
> > +     struct ls1x_dwmac *dwmac = plat->bsp_priv;
> > +     struct regmap *regmap = dwmac->regmap;
> > +
> > +     switch (plat->phy_interface) {
> > +     case PHY_INTERFACE_MODE_MII:
>
> > +             regmap_update_bits(regmap, LS1X_SYSCON1, PHY_INTF_SELI, 0);
>
>
>                 regmap_update_bits(regmap, LS1X_SYSCON1, PHY_INTF_SELI,
>                                    PHY_INTF_MII);
>
> > +             break;
> > +     case PHY_INTERFACE_MODE_RMII:
>
> > +             regmap_update_bits(regmap, LS1X_SYSCON1, PHY_INTF_SELI,
> > +                                4 << PHY_INTF_SELI_SHIFT);
>
>                 regmap_update_bits(regmap, LS1X_SYSCON1, PHY_INTF_SELI,
>                                    PHY_INTF_RMII);
>
> > +             break;
> > +     default:
> > +             dev_err(dwmac->dev, "Unsupported PHY-mode %u\n",
> > +                     plat->phy_interface);
> > +             return -EOPNOTSUPP;
> > +     }
> > +
> > +     regmap_update_bits(regmap, LS1X_SYSCON0, GMAC0_SHUT, 0);
> > +
> > +     return 0;
> > +}
> > +
>
> > +static const struct ls1x_dwmac_syscon ls1b_dwmac_syscon = {
> > +     .syscon_init = ls1b_dwmac_syscon_init,
> > +};
> > +
> > +static const struct ls1x_dwmac_syscon ls1c_dwmac_syscon = {
> > +     .syscon_init = ls1c_dwmac_syscon_init,
> > +};
>
> This can be dropped. See the next comment for details.
>
> > +
> > +static int ls1x_dwmac_init(struct platform_device *pdev, void *priv)
> > +{
> > +     struct ls1x_dwmac *dwmac = priv;
> > +     struct resource *res;
> > +     int ret;
> > +
>
> > +     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +     if (!res) {
> > +             dev_err(&pdev->dev, "Could not get IO_MEM resources\n");
> > +             return -EINVAL;
> > +     }
> > +     dwmac->reg_base = (unsigned long)res->start;
>
> What about moving this to ls1b_dwmac_syscon_init() seeing it's used
> for LS1B only? Thus you won't need to have the reg_base defined in the
> private data and can get rid from the ls1x_dwmac_init() method setting
> the ls1b_dwmac_syscon_init() and ls1c_dwmac_syscon_init() pointers
> directly to the device match data.
>
> > +
> > +     if (dwmac->syscon->syscon_init) {
> > +             ret = dwmac->syscon->syscon_init(dwmac->plat_dat);
> > +             if (ret)
> > +                     return ret;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int ls1x_dwmac_probe(struct platform_device *pdev)
> > +{
> > +     struct plat_stmmacenet_data *plat_dat;
> > +     struct stmmac_resources stmmac_res;
> > +     struct regmap *regmap;
> > +     struct ls1x_dwmac *dwmac;
>
> > +     const struct ls1x_dwmac_syscon *syscon;
>
> This can be replaced with just
> int (*init)(struct platform_device *pdev, void *priv);
>
> > +     int ret;
> > +
> > +     ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> > +     if (ret)
> > +             return ret;
> > +
> > +     /* Probe syscon */
> > +     regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
> > +                                              "loongson,ls1-syscon");
> > +     if (IS_ERR(regmap)) {
>
> > +             ret = PTR_ERR(regmap);
> > +             dev_err(&pdev->dev, "Unable to map syscon: %d\n", ret);
> > +             return ret;
>
> return dev_err_probe(&pdev->dev, PTR_ERR(regmap), "Unable to find syscon\n");
>
> > +     }
> > +
>
> > +     syscon = of_device_get_match_data(&pdev->dev);
>
> init = of_device_get_match_data(&pdev->dev);
>
> > +     if (!syscon) {
> > +             dev_err(&pdev->dev, "No of match data provided\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> > +     if (!dwmac)
> > +             return -ENOMEM;
> > +
> > +     plat_dat = stmmac_probe_config_dt(pdev, stmmac_res.mac);
> > +     if (IS_ERR(plat_dat)) {
> > +             dev_err(&pdev->dev, "dt configuration failed\n");
> > +             return PTR_ERR(plat_dat);
> > +     }
> > +
> > +     plat_dat->bsp_priv = dwmac;
>
> > +     plat_dat->init = ls1x_dwmac_init;
>
> plat_dat->init = init;
>
> > +     dwmac->dev = &pdev->dev;
> > +     dwmac->plat_dat = plat_dat;
> > +     dwmac->syscon = syscon;
> > +     dwmac->regmap = regmap;
> > +
> > +     ret = stmmac_pltfr_probe(pdev, plat_dat, &stmmac_res);
> > +     if (ret)
> > +             goto err_remove_config_dt;
> > +
> > +     return 0;
> > +
> > +err_remove_config_dt:
> > +     stmmac_remove_config_dt(pdev, plat_dat);
> > +
> > +     return ret;
> > +}
> > +
> > +static const struct of_device_id ls1x_dwmac_match[] = {
>
> > +     { .compatible = "loongson,ls1b-gmac", .data = &ls1b_dwmac_syscon, },
> > +     { .compatible = "loongson,ls1c-emac", .data = &ls1c_dwmac_syscon, },
>
> { .compatible = "loongson,ls1b-gmac", .data = &ls1b_dwmac_syscon_init, },
> { .compatible = "loongson,ls1c-emac", .data = &ls1c_dwmac_syscon_init, },
>
> Thus you can simplify the driver by:
> 1. dropping ls1x_dwmac_syscon definition and its instances.
> 2. dropping three redundant fields from the ls1x_dwmac structure.
> 3. dropping the ls1x_dwmac_init() method.
> Sounds like worth it.)
>
> Note if no further driver update is planned then you can drop the
> ls1x_dwmac->dev field too. Otherwise you can keep it seeing some of
> the plat_stmmacenet_data data callbacks do have any device instance
> passed.
>
All done in v4.
Thanks!

> -Serge(y)
>
> > +     { }
> > +};
> > +MODULE_DEVICE_TABLE(of, ls1x_dwmac_match);
> > +
> > +static struct platform_driver ls1x_dwmac_driver = {
> > +     .probe = ls1x_dwmac_probe,
> > +     .remove_new = stmmac_pltfr_remove,
> > +     .driver = {
> > +             .name = "loongson1-dwmac",
> > +             .of_match_table = ls1x_dwmac_match,
> > +     },
> > +};
> > +module_platform_driver(ls1x_dwmac_driver);
> > +
> > +MODULE_AUTHOR("Keguang Zhang <keguang.zhang@xxxxxxxxx>");
> > +MODULE_DESCRIPTION("Loongson1 DWMAC glue layer");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.39.2
> >
> >



-- 
Best regards,

Keguang Zhang