On Thu, 24 Aug 2023 08:54:37 -0700
Florian Fainelli [off-list ref] wrote:

On 8/24/2023 8:48 AM, Lukasz Majewski wrote:

quoted

The KSZ9477 errata points out the link up/down problem when EEE is
enabled in the device to which the KSZ9477 tries to auto negotiate.

The suggested workaround is to clear advertisement EEE registers
(accessed as per port MMD one).

Signed-off-by: Lukasz Majewski <lukma@denx.de>
---
  drivers/net/dsa/microchip/ksz9477.c | 40
++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1
deletion(-)

diff --git a/drivers/net/dsa/microchip/ksz9477.c

b/drivers/net/dsa/microchip/ksz9477.c index
cb6aa7c668a8..563f497ba656 100644 ---
a/drivers/net/dsa/microchip/ksz9477.c +++
b/drivers/net/dsa/microchip/ksz9477.c @@ -1128,6 +1128,44 @@ int
ksz9477_enable_stp_addr(struct ksz_device *dev) return 0;
  }
  
+static int ksz9477_errata(struct dsa_switch *ds)
+{
+	struct ksz_device *dev = ds->priv;
+	u16 val;
+	int p;
+
+	/* KSZ9477 Errata DS80000754C
+	 *
+	 * Module 4: Energy Efficient Ethernet (EEE) feature
select must be
+	 * manually disabled
+	 *   The EEE feature is enabled by default, but it is not
fully
+	 *   operational. It must be manually disabled through
register
+	 *   controls. If not disabled, the PHY ports can
auto-negotiate
+	 *   to enable EEE, and this feature can cause link drops
when linked
+	 *   to another device supporting EEE.
+	 *
+	 *   Only PHY ports (dsa user) [0-4] need to have the EEE
advertisement
+	 *   bits cleared.
+	 */
+
+	for (p = 0; p < ds->num_ports; p++) {
+		if (!dsa_is_user_port(ds, p))
+			continue;
+
+		ksz9477_port_mmd_read(dev, p,
MMD_DEVICE_ID_EEE_ADV,
+				      MMD_EEE_ADV, &val, 1);
+
+		pr_err("%s: PORT: %d val: 0x%x pc: %d\n",
__func__, p, val,
+		       ds->num_ports);  

Left over debugging?

Yes, correct - I will fix it.

quoted

+
+		val &= ~(EEE_ADV_100MBIT | EEE_ADV_1GBIT);
+		ksz9477_port_mmd_write(dev, p,
MMD_DEVICE_ID_EEE_ADV,
+				       MMD_EEE_ADV, &val, 1);
+	}
+
+	return 0;  

You don't propagate any error, so make this return void?

I will fix this too.


Best regards,

Lukasz Majewski

--

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