Re: [PATCH 1/4] net: ethernet: dwmac: add Ethernet glue logic for stm32 chip

[Joachim Eastwood <manabian@gmail.com>]

On 3 February 2016 at 15:54, Alexandre TORGUE
<alexandre.torgue@gmail.com> wrote:
> stm324xx family chips support Synopsys MAC 3.510 IP.
> This patch adds settings for logical glue logic:
> -clocks
> -mode selection MII or RMII.
>
> Signed-off-by: Alexandre TORGUE <alexandre.torgue@gmail.com>
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> index cec147d..a94dd15 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> @@ -114,6 +114,18 @@ config DWMAC_SUNXI
>           This selects Allwinner SoC glue layer support for the
>           stmmac device driver. This driver is used for A20/A31
>           GMAC ethernet controller.
> +
> +config DWMAC_STM32
> +       tristate "STM32 DWMAC support"
> +       default ARCH_STM32
> +       depends on OF
> +       select MFD_SYSCON
> +       ---help---
> +         Support for ethernet controller on STM32 SOCs.
> +
> +         This selects STM32 SoC glue layer support for the stmmac
> +         device driver. This driver is used on for the STM32 series
> +         SOCs GMAC ethernet controller.
>  endif
>
>  config STMMAC_PCI
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Makefile b/drivers/net/ethernet/stmicro/stmmac/Makefile
> index b390161..9fb2061 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
> +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_DWMAC_SOCFPGA)   += dwmac-socfpga.o
>  obj-$(CONFIG_DWMAC_STI)                += dwmac-sti.o
>  obj-$(CONFIG_DWMAC_SUNXI)      += dwmac-sunxi.o
>  obj-$(CONFIG_DWMAC_GENERIC)    += dwmac-generic.o
> +obj-$(CONFIG_DWMAC_STM32)      += dwmac-stm32.o

Keep these sorted. There also a comment in the Makefile that states
that the generic should always be last.


>  stmmac-platform-objs:= stmmac_platform.o
>
>  obj-$(CONFIG_STMMAC_PCI) += stmmac-pci.o
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
> new file mode 100644
> index 0000000..56ccc20
> --- /dev/null
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
> @@ -0,0 +1,177 @@
> +/*
> + * dwmac-stm32.c - DWMAC Specific Glue layer for STM32 MCU
> + *
> + * Copyright (C) Alexandre Torgue 2015
> + * Author:  Alexandre Torgue <alexandre.torgue@gmail.com>
> + * License terms:  GNU General Public License (GPL), version 2
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/platform_device.h>
> +#include <linux/stmmac.h>
> +#include <linux/phy.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/clk.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_net.h>

Consider sorting the includes.

> +
> +#include "stmmac_platform.h"
> +
> +#define MII_PHY_SEL_MASK       BIT(23)
> +
> +struct stm32_dwmac {
> +       int interface;          /* MII interface */
> +       struct clk *clk_tx;
> +       struct clk *clk_rx;
> +       u32 mode_reg;           /* MAC glue-logic mode register */
> +       struct device *dev;

dev doesn't seem to be used anywhere.

> +       struct regmap *regmap;
> +       u32 speed;
> +};
> +
> +static int stm32_dwmac_init(struct platform_device *pdev, void *priv)
> +{
> +       struct stm32_dwmac *dwmac = priv;
> +       struct regmap *regmap = dwmac->regmap;
> +       int ret, iface = dwmac->interface;
> +       u32 reg = dwmac->mode_reg;
> +       u32 val;
> +
> +       if (dwmac->clk_tx)
> +               ret = clk_prepare_enable(dwmac->clk_tx);

The clk API handles a NULL clk so you don't really need to check for it.


> +               if (ret)
> +                       goto out;
> +
> +       if (dwmac->clk_rx)
> +               ret = clk_prepare_enable(dwmac->clk_rx);

Same here.


> +               if (ret)
> +                       goto out_disable_clk_tx;
> +
> +       val = (iface == PHY_INTERFACE_MODE_MII) ? 0 : 1;
> +       ret = regmap_update_bits(regmap, reg, MII_PHY_SEL_MASK, val);
> +       if (ret)
> +               goto out_disable_clk_tx_rx;
> +
> +       return 0;
> +
> +out_disable_clk_tx_rx:
> +       clk_disable_unprepare(dwmac->clk_rx);
> +out_disable_clk_tx:
> +       clk_disable_unprepare(dwmac->clk_tx);
> +out:
> +       return ret;
> +}
> +
> +static void stm32_dwmac_exit(struct platform_device *pdev, void *priv)
> +{
> +       struct stm32_dwmac *dwmac = priv;
> +
> +       if (dwmac->clk_tx)
> +               clk_disable_unprepare(dwmac->clk_tx);
> +       if (dwmac->clk_rx)
> +               clk_disable_unprepare(dwmac->clk_rx);

Same here.


> +}
> +
> +static int stm32_dwmac_parse_data(struct stm32_dwmac *dwmac,
> +                                 struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct device_node *np = dev->of_node;
> +       struct regmap *regmap;
> +       int err;
> +
> +       if (!np)
> +               return -EINVAL;

Can this ever happen?
This is a DT only driver, right?

> +
> +       /*  Get TX/RX clocks */
> +       dwmac->clk_tx = devm_clk_get(dev, "tx-clk");
> +       if (IS_ERR(dwmac->clk_tx)) {
> +               dev_warn(dev, "No tx clock provided...\n");
> +               dwmac->clk_tx = NULL;
> +       }
> +       dwmac->clk_rx = devm_clk_get(dev, "rx-clk");
> +       if (IS_ERR(dwmac->clk_rx)) {
> +               dev_warn(dev, "No rx clock provided...\n");
> +               dwmac->clk_rx = NULL;
> +       }
> +
> +       /* Get mode register */
> +       regmap = syscon_regmap_lookup_by_phandle(np, "st,syscon");
> +       if (IS_ERR(regmap))
> +               return PTR_ERR(regmap);
> +
> +       err = of_property_read_u32_index(np, "st,syscon", 1, &dwmac->mode_reg);
> +       if (err) {
> +               dev_err(dev, "Can't get sysconfig mode offset (%d)\n", err);
> +               return err;
> +       }
> +
> +       dwmac->dev = dev;
> +       dwmac->interface = of_get_phy_mode(np);
> +       dwmac->regmap = regmap;
> +
> +       return 0;
> +}
> +
> +static int stm32_dwmac_probe(struct platform_device *pdev)
> +{
> +       struct plat_stmmacenet_data *plat_dat;
> +       struct stmmac_resources stmmac_res;
> +       struct stm32_dwmac *dwmac;
> +       int ret;
> +
> +       ret = stmmac_get_platform_resources(pdev, &stmmac_res);
> +       if (ret)
> +               return ret;
> +
> +       plat_dat = stmmac_probe_config_dt(pdev, &stmmac_res.mac);
> +       if (IS_ERR(plat_dat))
> +               return PTR_ERR(plat_dat);
> +
> +       dwmac = devm_kzalloc(&pdev->dev, sizeof(*dwmac), GFP_KERNEL);
> +       if (!dwmac)
> +               return -ENOMEM;
> +
> +       ret = stm32_dwmac_parse_data(dwmac, pdev);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Unable to parse OF data\n");
> +               return ret;
> +       }
> +
> +       plat_dat->bsp_priv = dwmac;
> +       plat_dat->init = stm32_dwmac_init;
> +       plat_dat->exit = stm32_dwmac_exit;

Instead of using these callbacks could you rather implement the PM
callbacks directly in this driver?
I don't think it should add much code and it will make it look more
like standard driver. This will also give you some more control and
flexibility in your code.

> +
> +       ret = stm32_dwmac_init(pdev, plat_dat->bsp_priv);
> +       if (ret)
> +               return ret;
> +
> +       return stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
> +}
> +
> +static const struct of_device_id stm32_dwmac_match[] = {
> +       { .compatible = "st,stm32-dwmac"},
> +       { }
> +};
> +MODULE_DEVICE_TABLE(of, stm32_dwmac_match);
> +
> +static struct platform_driver stm32_dwmac_driver = {
> +       .probe  = stm32_dwmac_probe,
> +       .remove = stmmac_pltfr_remove,

Could you implement the .remove callback in your driver instead of
using stmmac_pltfr_remove?
Same reasons as above.


> +       .driver = {
> +               .name           = "stm32-dwmac",
> +               .pm             = &stmmac_pltfr_pm_ops,
> +               .of_match_table = stm32_dwmac_match,
> +       },
> +};
> +module_platform_driver(stm32_dwmac_driver);
> +
> +MODULE_AUTHOR("Alexandre Torgue <alexandre.torgue@gmail.com>");
> +MODULE_DESCRIPTION("STMicroelectronics MCU DWMAC Specific Glue layer");
> +MODULE_LICENSE("GPL");

Since you state:
> + * License terms:  GNU General Public License (GPL), version 2

You might want to switch use: MODULE_LICENSE("GPL v2");


regards,
Joachim Eastwood