Re: [PATCH v2 1/4] net: ethernet: dwmac: add Ethernet glue logic for stm32 chip

Alexandre Torgue
2016-02-24T09:03:38Z

2016-02-23 23:16 GMT+01:00 Joachim Eastwood <manabian@gmail.com>:
> Hi Alexandre,
>
> On 23 February 2016 at 16:10, 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..f63bdcf 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 && HAS_IOMEM
>> + 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..559086d 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/Makefile
>> +++ b/drivers/net/ethernet/stmicro/stmmac/Makefile
>> @@ -13,6 +13,7 @@ obj-$(CONFIG_DWMAC_ROCKCHIP) += dwmac-rk.o
>> obj-$(CONFIG_DWMAC_SOCFPGA) += dwmac-socfpga.o
>> obj-$(CONFIG_DWMAC_STI) += dwmac-sti.o
>> obj-$(CONFIG_DWMAC_SUNXI) += dwmac-sunxi.o
>> +obj-$(CONFIG_DWMAC_STM32) += dwmac-stm32.o
>

Hi Joachim,

> Put them in alphabetic order. Same goes for the KConfig entry.

Ok

>
>
>> obj-$(CONFIG_DWMAC_GENERIC) += dwmac-generic.o
>> stmmac-platform-objs:= stmmac_platform.o
> ...
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
>> +struct stm32_dwmac {
>> + int interface; /* MII interface */
>> + struct clk *clk_tx;
>> + struct clk *clk_rx;
>> + u32 mode_reg; /* MAC glue-logic mode register */
>> + struct regmap *regmap;
>> + u32 speed;
>> +};
>> +
>> +static int stm32_dwmac_init(void *priv)
>
> If you used 'struct stm32_dwmac *' instead of 'void *' you could skip
> the local variable assignment.
>
> Even better; you could pass 'struct plat_stmmacenet_data *' and use
> it's 'interface' member to set the phy mode. Then you could drop the
> interface member in your priv data struct and remove of_get_phy_mode()
> in stm32_dwmac_parse_data().

Yes, interesting.
>
>
>> +{
>> + struct stm32_dwmac *dwmac = priv;
>> + struct regmap *regmap = dwmac->regmap;
>> + int ret, iface = dwmac->interface;
>> + u32 reg = dwmac->mode_reg;
>> + u32 val;
>> +
>> + ret = clk_prepare_enable(dwmac->clk_tx);
>> + if (ret)
>> + goto out;
>> +
>> + ret = clk_prepare_enable(dwmac->clk_rx);
>> + 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(void *priv)
>> +{
>> + struct stm32_dwmac *dwmac = priv;
>
> Again; instead of 'void *' use 'struct stm32_dwmac *' to avoid the
> local assignment.
>
>
>> +
>> + clk_disable_unprepare(dwmac->clk_tx);
>> + clk_disable_unprepare(dwmac->clk_rx);
>> +}
>
> To be honest I really don't see the point in having a function with
> just two other function calls in it. Consider dropping the function
> altogether and place the clk_disable_unprepare() calls where it's
> called from. If you still want to keep it, please put a more
> descriptive name on it.

It was just to avoid redundant code, but yes there is not a big
interest to do it.

>
>
>> +static int stm32_dwmac_parse_data(struct stm32_dwmac *dwmac,
>> + struct platform_device *pdev)
>
> Since you are only interested in *dev and not *pdev you could pass a
> 'struct dev *' instead.

ok

>
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct device_node *np = dev->of_node;
>> + struct regmap *regmap;
>> + int err;
>> +
>> + /* 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->interface = of_get_phy_mode(np);
>> + dwmac->regmap = regmap;
>
> Why the temporary local regmap variable?
>
> Assigning dwmac->regmap with syscon_regmap_lookup_by_phandle() should
> not exceed 80 chars if that is what you are worried about.

yes you are right.

>
>
>> + 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;
>> +
>> + ret = stm32_dwmac_init(plat_dat->bsp_priv);
>> + if (ret)
>> + return ret;
>> +
>> + return stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
>
> Note that stmmac_dvr_probe() can fail and if so you should disable
> your tx/rx clks before you return.
>
> Consider putting the clk_prepare_enable() directly here and use goto
> labels for the clean up like most other drivers do in probe.

Ok catch.

>
> Also if you put regmap_update_bits() for phy mode above the
> clk_prepare_enable() calls you remove one of the gotos.
> I assume you don't need to enable tx/rx clock before you write to syscon.

I will check.
>
>
>> +static int stm32_dwmac_remove(struct platform_device *pdev)
>> +{
>> + struct net_device *ndev = platform_get_drvdata(pdev);
>> + struct stmmac_priv *priv = netdev_priv(ndev);
>> + int ret = stmmac_dvr_remove(ndev);
>> +
>> + stm32_dwmac_exit(priv->plat->bsp_priv);
>> +
>> + return ret;
>> +}
>> +
>> +#ifdef CONFIG_PM_SLEEP
>> +static int stm32_dwmac_suspend(struct device *dev)
>> +{
>> + struct net_device *ndev = dev_get_drvdata(dev);
>> + struct stmmac_priv *priv = netdev_priv(ndev);
>> + int ret;
>> +
>> + ret = stmmac_suspend(ndev);
>> + stm32_dwmac_exit(priv->plat->bsp_priv);
>> +
>> + return ret;
>> +}
>> +
>> +static int stm32_dwmac_resume(struct device *dev)
>> +{
>> + struct net_device *ndev = dev_get_drvdata(dev);
>> + struct stmmac_priv *priv = netdev_priv(ndev);
>> + int ret;
>> +
>> + ret = stm32_dwmac_init(priv->plat->bsp_priv);
>> + if (ret)
>> + goto out_regmap;
>> +
>> + ret = stmmac_resume(ndev);
>> +
>> +out_regmap:
>> + return ret;
>
> Why the goto?

Sorry no sens. I thought that it was better to avoid multiple return
but it this case it is stupid.

Best regards.

Alexandre

>
> This could be written:
> ret = stm32_dwmac_init(priv->plat->bsp_priv);
> if (ret)
> return ret;
>
> return stmmac_resume(ndev);
>
>
> regards,
> Joachim Eastwood