Re: [PATCH 3/4] hw/net/cadence_gem: Add pcs-enabled property

[Alistair Francis <alistair23@gmail.com>]

On Sun, Oct 5, 2025 at 6:03 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> The Linux kernel checks the PCS disabled bit in the R_DESCONF register
> to determine if SGMII is supported. If the bit is set, SGMII support is
> disabled. Since the Microchip Icicle devicetree file configures SGMII
> interface mode, enabling the Ethernet interfaces fails when booting
> the Linux kernel.
>
> Add pcs-enabled property to to let the driver know if PCS should be
> enabled. Set the flag to false by default (indicating that PCS is disabled)
> to match the exiting code.
>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Acked-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  hw/net/cadence_gem.c         | 7 ++++++-
>  include/hw/net/cadence_gem.h | 1 +
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
> index 520324adfd..44896f1801 100644
> --- a/hw/net/cadence_gem.c
> +++ b/hw/net/cadence_gem.c
> @@ -1477,7 +1477,10 @@ static void gem_reset(DeviceState *d)
>      s->regs[R_TXPARTIALSF] = 0x000003ff;
>      s->regs[R_RXPARTIALSF] = 0x000003ff;
>      s->regs[R_MODID] = s->revision;
> -    s->regs[R_DESCONF] = 0x02D00111;
> +    s->regs[R_DESCONF] = 0x02D00110;
> +    if (!s->pcs_enabled) {
> +        s->regs[R_DESCONF] |= 0x00000001;
> +    }
>      s->regs[R_DESCONF2] = 0x2ab10000 | s->jumbo_max_len;
>      s->regs[R_DESCONF5] = 0x002f2045;
>      s->regs[R_DESCONF6] = R_DESCONF6_DMA_ADDR_64B_MASK;
> @@ -1821,6 +1824,8 @@ static const Property gem_properties[] = {
>                        num_type2_screeners, 4),
>      DEFINE_PROP_UINT16("jumbo-max-len", CadenceGEMState,
>                         jumbo_max_len, 10240),
> +    DEFINE_PROP_BOOL("pcs-enabled", CadenceGEMState,
> +                       pcs_enabled, false),
>      DEFINE_PROP_BOOL("phy-connected", CadenceGEMState, phy_connected, true),
>      DEFINE_PROP_LINK("phy-consumer", CadenceGEMState, phy_consumer,
>                       TYPE_CADENCE_GEM, CadenceGEMState *),
> diff --git a/include/hw/net/cadence_gem.h b/include/hw/net/cadence_gem.h
> index 21e7319f53..e63941f18f 100644
> --- a/include/hw/net/cadence_gem.h
> +++ b/include/hw/net/cadence_gem.h
> @@ -62,6 +62,7 @@ struct CadenceGEMState {
>      uint8_t num_type2_screeners;
>      uint32_t revision;
>      uint16_t jumbo_max_len;
> +    bool pcs_enabled;
>
>      /* GEM registers backing store */
>      uint32_t regs[CADENCE_GEM_MAXREG];
> --
> 2.45.2
>
>