On 1/10/23 05:38, Stefan Roese wrote:
> In our system using ZynqMP with an external SGMII PHY it's necessary
> to wait for the PCS link and auto negotiation to finish before the xfer
> starts. Otherwise the first packet(s) might get dropped, resulting in a
> delay at the start of the ethernet transfers.
>
> This patch adds the necessary code at the end of zynq_gem_init()
> including a minimal delay of 10ms which fixes problems of dropped
> first packages.
>
> Signed-off-by: Stefan Roese <[email protected]>
> Cc: Michal Simek <[email protected]>
> Cc: T Karthik Reddy <[email protected]>
> Cc: Ramon Fried <[email protected]>
> ---
> drivers/net/zynq_gem.c | 32 +++++++++++++++++++++++++++++++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/zynq_gem.c b/drivers/net/zynq_gem.c
> index 507b19b75975..625b0303d6e2 100644
> --- a/drivers/net/zynq_gem.c
> +++ b/drivers/net/zynq_gem.c
> @@ -125,6 +125,10 @@
> */
> #define PHY_DETECT_MASK 0x1808
>
> +/* PCS (SGMII) Link Status */
> +#define ZYNQ_GEM_PCSSTATUS_LINK BIT(2)
> +#define ZYNQ_GEM_PCSSTATUS_ANEG_COMPL BIT(5)
> +
> /* TX BD status masks */
> #define ZYNQ_GEM_TXBUF_FRMLEN_MASK 0x000007ff
> #define ZYNQ_GEM_TXBUF_EXHAUSTED 0x08000000
> @@ -164,7 +168,8 @@ struct zynq_gem_regs {
> u32 stat[STAT_SIZE]; /* 0x100 - Octects transmitted Low reg */
> u32 reserved9[20];
> u32 pcscntrl;
> - u32 rserved12[36];
> + u32 pcsstatus;
> + u32 rserved12[35];
> u32 dcfg6; /* 0x294 Design config reg6 */
> u32 reserved7[106];
> u32 transmit_q1_ptr; /* 0x440 - Transmit priority queue 1 */
> @@ -522,6 +527,31 @@ static int zynq_gem_init(struct udevice *dev)
> return ret;
> }
> }
> +
> + /* Wait for SGMII link */
> + if (priv->interface == PHY_INTERFACE_MODE_SGMII && priv->int_pcs) {
> + u32 pcsstatus;
> +
> + if (priv->phydev->phy_id == PHY_FIXED_ID)
> + pcsstatus = ZYNQ_GEM_PCSSTATUS_LINK;
> + else
> + pcsstatus = ZYNQ_GEM_PCSSTATUS_LINK |
> + ZYNQ_GEM_PCSSTATUS_ANEG_COMPL;
Use BMSR_LSTATUS/BMSR_ANEGCOMPLETE.
> +
> + ret = wait_for_bit_le32(®s->pcsstatus, pcsstatus,
> + true, 5000, true);
> + if (ret) {
> + dev_err(dev, "no PCS (SGMII) link detected\n");
This should be an info or lower, since this is normal behavior when there
is no link partner (e.g. when the cable is unplugged).
--Seam
> + return ret;
> + }
> +
> + /*
> + * Some additional minimal delay seems to be needed so that
> + * the first packet will be sent correctly
> + */
> + mdelay(10);
> + }
> +
> setbits_le32(®s->nwctrl, ZYNQ_GEM_NWCTRL_RXEN_MASK |
> ZYNQ_GEM_NWCTRL_TXEN_MASK);
>
