sfc: QT2025C: Work around PHY bug
If we see the PHY remaining stuck in a link-down state due to PCS being
down while PMA/PMD is up, we briefly switch to PMA/PMD loopback and back,
which usually unsticks it.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sfc/qt202x_phy.c b/drivers/net/sfc/qt202x_phy.c
index 7450e3a..e4590fb 100644
--- a/drivers/net/sfc/qt202x_phy.c
+++ b/drivers/net/sfc/qt202x_phy.c
@@ -52,11 +52,15 @@
struct qt202x_phy_data {
enum efx_phy_mode phy_mode;
+ bool bug17190_in_bad_state;
+ unsigned long bug17190_timer;
};
#define QT2022C2_MAX_RESET_TIME 500
#define QT2022C2_RESET_WAIT 10
+#define BUG17190_INTERVAL (2 * HZ)
+
static int qt2025c_wait_reset(struct efx_nic *efx)
{
unsigned long timeout = jiffies + 10 * HZ;
@@ -96,6 +100,39 @@
return 0;
}
+static void qt2025c_bug17190_workaround(struct efx_nic *efx)
+{
+ struct qt202x_phy_data *phy_data = efx->phy_data;
+
+ /* The PHY can get stuck in a state where it reports PHY_XS and PMA/PMD
+ * layers up, but PCS down (no block_lock). If we notice this state
+ * persisting for a couple of seconds, we switch PMA/PMD loopback
+ * briefly on and then off again, which is normally sufficient to
+ * recover it.
+ */
+ if (efx->link_state.up ||
+ !efx_mdio_links_ok(efx, MDIO_DEVS_PMAPMD | MDIO_DEVS_PHYXS)) {
+ phy_data->bug17190_in_bad_state = false;
+ return;
+ }
+
+ if (!phy_data->bug17190_in_bad_state) {
+ phy_data->bug17190_in_bad_state = true;
+ phy_data->bug17190_timer = jiffies + BUG17190_INTERVAL;
+ return;
+ }
+
+ if (time_after_eq(jiffies, phy_data->bug17190_timer)) {
+ EFX_LOG(efx, "bashing QT2025C PMA/PMD\n");
+ efx_mdio_set_flag(efx, MDIO_MMD_PMAPMD, MDIO_CTRL1,
+ MDIO_PMA_CTRL1_LOOPBACK, true);
+ msleep(100);
+ efx_mdio_set_flag(efx, MDIO_MMD_PMAPMD, MDIO_CTRL1,
+ MDIO_PMA_CTRL1_LOOPBACK, false);
+ phy_data->bug17190_timer = jiffies + BUG17190_INTERVAL;
+ }
+}
+
static int qt202x_reset_phy(struct efx_nic *efx)
{
int rc;
@@ -144,6 +181,8 @@
return -ENOMEM;
efx->phy_data = phy_data;
phy_data->phy_mode = efx->phy_mode;
+ phy_data->bug17190_in_bad_state = false;
+ phy_data->bug17190_timer = 0;
efx->mdio.mmds = QT202X_REQUIRED_DEVS;
efx->mdio.mode_support = MDIO_SUPPORTS_C45 | MDIO_EMULATE_C22;
@@ -184,6 +223,9 @@
efx->link_state.fd = true;
efx->link_state.fc = efx->wanted_fc;
+ if (efx->phy_type == PHY_TYPE_QT2025C)
+ qt2025c_bug17190_workaround(efx);
+
return efx->link_state.up != was_up;
}