[PATCH rtems-libbsd 2/3] freebsd/cgem: Read clock frequency from device tree

[Will]

On Tue, Feb 28, 2023 at 11:57 PM Padmarao Begari <
padmarao.begari at microchip.com> wrote:

> Read the clock frequency from the device tree and use it to
> calculate the mdc clock divider for the MII bus if not found
> then use default clock divider.
> ---
>  freebsd/sys/dev/cadence/if_cgem.c | 39 ++++++++++++++++++++++++++++---
>  1 file changed, 36 insertions(+), 3 deletions(-)
>
> diff --git a/freebsd/sys/dev/cadence/if_cgem.c
> b/freebsd/sys/dev/cadence/if_cgem.c
> index 2888a085..363a9717 100644
> --- a/freebsd/sys/dev/cadence/if_cgem.c
> +++ b/freebsd/sys/dev/cadence/if_cgem.c
> @@ -135,6 +135,7 @@ struct cgem_softc {
>         uint32_t                net_cfg_shadow;
>         int                     neednullqs;
>         int                     phy_contype;
> +       uint32_t                pclk_rate;
>  #endif /* __rtems__ */
>         int                     ref_clk_num;
>  #ifndef __rtems__
> @@ -1238,6 +1239,27 @@ cgem_get_phyaddr(phandle_t node, int *phy_addr)
>         return (0);
>  }
>
> +static uint32_t cgem_mdc_clk_div(struct cgem_softc *sc)
> +{
> +       uint32_t config;
> +       uint32_t pclk_hz = sc->pclk_rate;
> +
> +       if (pclk_hz <= 20000000)
> +               config = CGEM_NET_CFG_MDC_CLK_DIV_8;
> +       else if (pclk_hz <= 40000000)
> +               config = CGEM_NET_CFG_MDC_CLK_DIV_16;
> +       else if (pclk_hz <= 80000000)
> +               config = CGEM_NET_CFG_MDC_CLK_DIV_32;
> +       else if (pclk_hz <= 120000000)
> +               config = CGEM_NET_CFG_MDC_CLK_DIV_48;
> +       else if (pclk_hz <= 160000000)
> +               config = CGEM_NET_CFG_MDC_CLK_DIV_64;
> +       else
> +               config = CGEM_NET_CFG_MDC_CLK_DIV_96;
> +
> +       return config;
> +}
> +
>
Enclose this in a #ifdef __rtems__ guard. I think the suggested style is to
always use braces {} with if/else, even if it's a single line.


>  /* Reset hardware. */
>  static void
>  cgem_reset(struct cgem_softc *sc)
> @@ -1279,12 +1301,16 @@ cgem_reset(struct cgem_softc *sc)
>                 sc->net_cfg_shadow = CGEM_NET_CFG_DBUS_WIDTH_32;
>         }
>
> +       if (sc->pclk_rate != 0) {
> +               sc->net_cfg_shadow |= cgem_mdc_clk_div(sc);
> +       } else {
>  #ifdef CGEM64
> -       sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_48;
> +               sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_48;
>  #else
> -       sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_64;
> +               sc->net_cfg_shadow |= CGEM_NET_CFG_MDC_CLK_DIV_64;
>  #endif
> -       WR4(sc, CGEM_NET_CFG, sc->net_cfg_shadow);
> +               WR4(sc, CGEM_NET_CFG, sc->net_cfg_shadow);
> +       }
>  #endif /* __rtems__ */
>
>         sc->net_ctl_shadow = CGEM_NET_CTRL_MGMT_PORT_EN;
> @@ -2038,6 +2064,13 @@ cgem_attach(device_t dev)
>  #endif /* __rtems__ */
>         /* Get reference clock number and base divider from fdt. */
>         node = ofw_bus_get_node(dev);
> +#ifdef __rtems__
> +       if (OF_getencprop(node, "clock-frequency", &cell, sizeof(cell)) >
> 0)
> +               sc->pclk_rate = cell;
> +       else
> +               sc->pclk_rate = 0;
> +#endif /* __rtems__ */
> +
>         sc->ref_clk_num = 0;
>         if (OF_getprop(node, "ref-clock-num", &cell, sizeof(cell)) > 0)
>                 sc->ref_clk_num = fdt32_to_cpu(cell);
> --
> 2.25.1
>
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>
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