[PATCH RFC net-next 1/7] net: stmmac: add BASE-X support to integrated PCS
Russell King (Oracle)
rmk+kernel at armlinux.org.uk
Wed Feb 25 03:44:29 PST 2026
The integrated PCS supports 802.3z (BASE-X) modes when the Synopsys
IP is coupled with an appropriate SerDes to provide the electrical
interface. The PCS presents a TBI interface to the SerDes for this.
Thus, the BASE-X related registers are only present when TBI mode is
supported.
dwmac-qcom-ethqos added support for using 2.5G with the integrated PCS
by calling dwmac_ctrl_ane() directly.
Add support for the following to the integrated PCS:
- 1000BASE-X protocol unconditionally.
- 2500BASE-X if the coupled SerDes supports 2.5G speed.
- The above without autonegotiation.
- If the PCS supports TBI, then optional BASE-X autonegotiation for each
of the above.
Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
---
.../net/ethernet/stmicro/stmmac/stmmac_pcs.c | 96 ++++++++++++++++++-
.../net/ethernet/stmicro/stmmac/stmmac_pcs.h | 1 +
include/linux/stmmac.h | 1 +
3 files changed, 95 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.c
index 88fa359ea716..e606dfb85f94 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.c
@@ -16,6 +16,27 @@
#define GMAC_ANE_LPA 0x0c /* ANE link partener ability */
#define GMAC_TBI 0x14 /* TBI extend status */
+static unsigned int dwmac_integrated_pcs_inband_caps(struct phylink_pcs *pcs,
+ phy_interface_t interface)
+{
+ struct stmmac_pcs *spcs = phylink_pcs_to_stmmac_pcs(pcs);
+ unsigned int ib_caps;
+
+ if (phy_interface_mode_is_8023z(interface)) {
+ ib_caps = LINK_INBAND_DISABLE;
+
+ /* If the PCS supports TBI/RTBI, then BASE-X negotiation is
+ * supported.
+ */
+ if (spcs->support_tbi_rtbi)
+ ib_caps |= LINK_INBAND_ENABLE;
+
+ return ib_caps;
+ }
+
+ return 0;
+}
+
static int dwmac_integrated_pcs_enable(struct phylink_pcs *pcs)
{
struct stmmac_pcs *spcs = phylink_pcs_to_stmmac_pcs(pcs);
@@ -36,7 +57,39 @@ static void dwmac_integrated_pcs_get_state(struct phylink_pcs *pcs,
unsigned int neg_mode,
struct phylink_link_state *state)
{
- state->link = false;
+ struct stmmac_pcs *spcs = phylink_pcs_to_stmmac_pcs(pcs);
+ u32 status, lpa;
+
+ status = readl(spcs->base + GMAC_AN_STATUS);
+
+ if (phy_interface_mode_is_8023z(state->interface)) {
+ /* For BASE-X modes, the PCS block supports the advertisement
+ * and link partner advertisement registers using standard
+ * 802.3 format. The status register also has the link status
+ * and AN complete bits in the same bit location. This will
+ * only be used when AN is enabled.
+ */
+ lpa = readl(spcs->base + GMAC_ANE_LPA);
+
+ phylink_mii_c22_pcs_decode_state(state, neg_mode, status, lpa);
+ } else {
+ state->link = false;
+ }
+}
+
+static int dwmac_integrated_pcs_config_aneg(struct stmmac_pcs *spcs,
+ phy_interface_t interface,
+ const unsigned long *advertising)
+{
+ bool changed = false;
+ u32 adv;
+
+ adv = phylink_mii_c22_pcs_encode_advertisement(interface, advertising);
+ if (readl(spcs->base + GMAC_ANE_ADV) != adv)
+ changed = true;
+ writel(adv, spcs->base + GMAC_ANE_ADV);
+
+ return changed;
}
static int dwmac_integrated_pcs_config(struct phylink_pcs *pcs,
@@ -46,13 +99,28 @@ static int dwmac_integrated_pcs_config(struct phylink_pcs *pcs,
bool permit_pause_to_mac)
{
struct stmmac_pcs *spcs = phylink_pcs_to_stmmac_pcs(pcs);
+ bool changed = false, ane = true;
+
+ /* Only configure the advertisement and allow AN in BASE-X mode if
+ * the core supports TBI/RTBI. AN will be filtered out by via phylink
+ * and the .pcs_inband_caps() method above.
+ */
+ if (phy_interface_mode_is_8023z(interface) &&
+ spcs->support_tbi_rtbi) {
+ ane = neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED;
+
+ changed = dwmac_integrated_pcs_config_aneg(spcs, interface,
+ advertising);
+ }
- dwmac_ctrl_ane(spcs->base, 0, 1, spcs->priv->hw->reverse_sgmii_enable);
+ dwmac_ctrl_ane(spcs->base, 0, ane,
+ spcs->priv->hw->reverse_sgmii_enable);
- return 0;
+ return changed;
}
static const struct phylink_pcs_ops dwmac_integrated_pcs_ops = {
+ .pcs_inband_caps = dwmac_integrated_pcs_inband_caps,
.pcs_enable = dwmac_integrated_pcs_enable,
.pcs_disable = dwmac_integrated_pcs_disable,
.pcs_get_state = dwmac_integrated_pcs_get_state,
@@ -84,9 +152,18 @@ void stmmac_integrated_pcs_irq(struct stmmac_priv *priv, u32 status,
int stmmac_integrated_pcs_get_phy_intf_sel(struct phylink_pcs *pcs,
phy_interface_t interface)
{
+ struct stmmac_pcs *spcs = phylink_pcs_to_stmmac_pcs(pcs);
+
if (interface == PHY_INTERFACE_MODE_SGMII)
return PHY_INTF_SEL_SGMII;
+ if (phy_interface_mode_is_8023z(interface)) {
+ if (spcs->support_tbi_rtbi)
+ return PHY_INTF_SEL_TBI;
+ else
+ return PHY_INTF_SEL_SGMII;
+ }
+
return -EINVAL;
}
@@ -104,7 +181,20 @@ int stmmac_integrated_pcs_init(struct stmmac_priv *priv, unsigned int offset,
spcs->int_mask = int_mask;
spcs->pcs.ops = &dwmac_integrated_pcs_ops;
+ /* If the PCS supports extended status, then it supports BASE-X AN
+ * with a TBI interface to the SerDes. Otherwise, we can support
+ * BASE-X without AN using SGMII, which is required for qcom-ethqos.
+ */
+ if (readl(spcs->base + GMAC_AN_STATUS) & BMSR_ESTATEN)
+ spcs->support_tbi_rtbi = true;
+
__set_bit(PHY_INTERFACE_MODE_SGMII, spcs->pcs.supported_interfaces);
+ __set_bit(PHY_INTERFACE_MODE_1000BASEX, spcs->pcs.supported_interfaces);
+
+ /* Only allow 2500BASE-X if the SerDes has support. */
+ if (priv->plat->flags & STMMAC_FLAG_SERDES_SUPPORTS_2500M)
+ __set_bit(PHY_INTERFACE_MODE_2500BASEX,
+ spcs->pcs.supported_interfaces);
priv->integrated_pcs = spcs;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.h b/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.h
index 23bbd4f10bf8..12ea87792fcb 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.h
@@ -32,6 +32,7 @@ struct stmmac_pcs {
void __iomem *base;
u32 int_mask;
struct phylink_pcs pcs;
+ bool support_tbi_rtbi;
};
static inline struct stmmac_pcs *
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index b96ae9dadfab..aa57ee327606 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -192,6 +192,7 @@ enum dwmac_core_type {
#define STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP BIT(12)
#define STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY BIT(13)
#define STMMAC_FLAG_KEEP_PREAMBLE_BEFORE_SFD BIT(14)
+#define STMMAC_FLAG_SERDES_SUPPORTS_2500M BIT(15)
struct mac_device_info;
--
2.47.3
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