[U-Boot] [PATCH v4 6/6] net: macb: Extend MACB driver for SiFive Unleashed board

[Bin Meng]

Hi Anup,

On Wed, Jun 19, 2019 at 4:26 PM Anup Patel <Anup.Patel at wdc.com> wrote:
>
> The SiFive MACB ethernet has a custom TX_CLK_SEL register to select
> different TX clock for 1000mbps vs 10/100mbps.
>
> This patch adds SiFive MACB compatible string and extends the MACB
> ethernet driver to change TX clock using TX_CLK_SEL register for
> SiFive MACB.
>
> Signed-off-by: Anup Patel <anup.patel at wdc.com>
> ---
>  drivers/net/macb.c | 38 +++++++++++++++++++++++++++-----------
>  drivers/net/macb.h |  1 +
>  2 files changed, 28 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/net/macb.c b/drivers/net/macb.c
> index c5560a7111..31f4d71793 100644
> --- a/drivers/net/macb.c
> +++ b/drivers/net/macb.c
> @@ -107,6 +107,7 @@ struct macb_device {
>         unsigned int            tx_tail;
>         unsigned int            next_rx_tail;
>         bool                    wrapped;
> +       bool                    is_sifive_macb;
>
>         void                    *rx_buffer;
>         void                    *tx_buffer;
> @@ -498,18 +499,11 @@ static int macb_phy_find(struct macb_device *macb, const char *name)
>  int __weak macb_linkspd_cb(struct udevice *dev, unsigned int speed)
>  {
>  #ifdef CONFIG_CLK
> +       struct macb_device *macb = dev_get_priv(dev);
>         struct clk tx_clk;
>         ulong rate;
>         int ret;
>
> -       /*
> -        * "tx_clk" is an optional clock source for MACB.
> -        * Ignore if it does not exist in DT.
> -        */
> -       ret = clk_get_by_name(dev, "tx_clk", &tx_clk);
> -       if (ret)
> -               return 0;
> -
>         switch (speed) {
>         case _10BASET:
>                 rate = 2500000;         /* 2.5 MHz */
> @@ -525,10 +519,29 @@ int __weak macb_linkspd_cb(struct udevice *dev, unsigned int speed)
>                 return 0;
>         }
>
> -       if (tx_clk.dev) {
> -               ret = clk_set_rate(&tx_clk, rate);
> +       if (macb->is_sifive_macb) {
> +               /*
> +                * GEMGXL TX clock operation mode:
> +                *
> +                * 0 = GMII mode. Use 125 MHz gemgxlclk from PRCI in TX logic
> +                *     and output clock on GMII output signal GTX_CLK
> +                * 1 = MII mode. Use MII input signal TX_CLK in TX logic
> +                */
> +               macb_writel(macb, SIFIVE_TX_CLK_SEL, rate != 125000000);
> +       } else {
> +               /*
> +                * "tx_clk" is an optional clock source for MACB.
> +                * Ignore if it does not exist in DT.
> +                */
> +               ret = clk_get_by_name(dev, "tx_clk", &tx_clk);
>                 if (ret)
> -                       return ret;
> +                       return 0;
> +
> +               if (tx_clk.dev) {
> +                       ret = clk_set_rate(&tx_clk, rate);
> +                       if (ret)
> +                               return ret;
> +               }
>         }
>  #endif
>
> @@ -1147,6 +1160,8 @@ static int macb_eth_probe(struct udevice *dev)
>         const char *phy_mode;
>         __maybe_unused int ret;
>
> +       macb->is_sifive_macb = device_is_compatible(dev, "sifive,fu540-macb");
> +
>         phy_mode = fdt_getprop(gd->fdt_blob, dev_of_offset(dev), "phy-mode",
>                                NULL);
>         if (phy_mode)
> @@ -1225,6 +1240,7 @@ static const struct udevice_id macb_eth_ids[] = {
>         { .compatible = "atmel,sama5d3-gem" },
>         { .compatible = "atmel,sama5d4-gem" },
>         { .compatible = "cdns,zynq-gem" },
> +       { .compatible = "sifive,fu540-macb" },
>         { }
>  };
>
> diff --git a/drivers/net/macb.h b/drivers/net/macb.h
> index 3cc27f8560..c3903010df 100644
> --- a/drivers/net/macb.h
> +++ b/drivers/net/macb.h
> @@ -57,6 +57,7 @@
>  #define MACB_USRIO                             0x00c0
>  #define MACB_WOL                               0x00c4
>  #define MACB_MID                               0x00fc
> +#define MACB_SIFIVE_TX_CLK_SEL                 0x10000

The Linux SiFive macb device bindings says: "For "sifive,fu540-macb",
second range is required to specify the address and length of the
registers for GEMGXL Management block.". So in order to really keep
sync with Linux driver, a second reg needs to be parsed from DT.

Regards,
Bin