net: dsa: mt7530: add EcoNet EN7528 built-in switch support

The EcoNet EN7528 is a MIPS SoC whose platform support is already upstream. It integrates an MT7530 switch, memory-mapped like the built-in switches of the MediaTek MT7988 and Airoha EN7581/AN7583 SoCs, but with a true MT7530 core, four Gigabit PHYs on ports 1-4 and a CPU port at a fixed 1000 Mbps full duplex link.

Patch 1 documents the compatible, patch 2 adds the driver support.

Changes in v2:
- patch 1: reword the commit message to explain what distinguishes the EN7528 from the other built-in switches and why it cannot fall back to one of their compatibles (Conor Dooley).
- patch 2: drop the setup-time EEE advertisement register writes. Instead leave lpi_capabilities empty for the EN7528, so phylink disables EEE on its PHYs via phy_disable_eee() and rejects enabling it from userspace (Andrew Lunn).
- Link to v1:
https://lore.kernel.org/netdev/[email protected]/

Ahmed Naseef (2):
dt-bindings: net: dsa: mediatek,mt7530: add econet,en7528-switch
net: dsa: mt7530: add EN7528 support

 .../bindings/net/dsa/mediatek,mt7530.yaml     |  5 ++
 drivers/net/dsa/mt7530-mmio.c                 |  1 +
 drivers/net/dsa/mt7530.c                      | 58 ++++++++++++++++---
 drivers/net/dsa/mt7530.h                      |  1 +
 4 files changed, 57 insertions(+), 8 deletions(-)

Range-diff against v1:
1: 68e85666b6df ! 1: 2133035bb22e dt-bindings: net: dsa: mediatek,mt7530: add econet,en7528-switch
@@ Commit message
are connected to integrated Gigabit PHYs and its CPU port is connected internally to the SoC Ethernet MAC.

+ Those three switches are MT7531-based, whereas the EN7528 has a genuine
+ MT7530 switch core (its chip revision register reads 0x7530). The two
+ generations differ in their register programming - for example the CPU
+ port is selected through the MT7530-style MFC register rather than the
+ MT7531 CFC register - so the EN7528 is not compatible with the existing
+ switch compatibles and cannot fall back to one of them.
+
Add the econet,en7528-switch compatible, with the same constraints as the other built-in switches.

2: 1865eaedef97 ! 2: 8c7dfabd860a net: dsa: mt7530: add EN7528 support
@@ Commit message
an ID_EN7528 variant bound with the "econet,en7528-switch" compatible, reusing mt7988_setup() and the indirect PHY accessors.

- The switch core, however, is an MT7530 and not an MT7531 derivative: it
- has no MT7531 CFC register, and the CPU port to trap frames to is set
- through the MT7530-style CPU_EN / CPU_PORT fields of the MFC register, so
- add it to the MT7530 handling in mt753x_conduit_state_change(). For the
+ The switch core, however, is an MT7530 and not an MT7531 derivative: the
+ CPU port to trap frames to is set through the MT7530-style CPU_EN /
+ CPU_PORT fields of the MFC register rather than the MT7531 CFC register,
+ so add it to the MT7530 handling in mt753x_conduit_state_change(). For the
same reason the MT7530 mirror and force-mode register layouts already apply to it as the default of the MT753X_*() macros.

@@ Commit message
EN7581 switches, whose CPU ports run at 10 Gbps.

The LAN GPHYs advertise EEE by default, but negotiating EEE with some
- link partners results in an unstable link with dropped frames. Disable
- EEE advertisement on them at setup time, like mt7531_setup() does for the
- MT7531 switch PHYs.
+ link partners results in an unstable link with dropped frames. Leave the
+ LPI capabilities empty for the EN7528 so that phylink disables EEE on
+ these PHYs and refuses to enable it from userspace.

@@ drivers/net/dsa/mt7530.c: static void en7581_mac_port_get_caps(struct dsa_switch
static void
mt7530_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
phy_interface_t interface)
+@@ drivers/net/dsa/mt7530.c: static void mt753x_phylink_get_caps(struct dsa_switch *ds, int port,
+ struct phylink_config *config)
+ {
+ struct mt7530_priv *priv = ds->priv;
+- u32 eeecr;
+
+ config->mac_capabilities = MAC_ASYM_PAUSE | MAC_SYM_PAUSE;
+
+- config->lpi_capabilities = MAC_100FD | MAC_1000FD | MAC_2500FD;
+-
+- eeecr = mt7530_read(priv, MT753X_PMEEECR_P(port));
+- /* tx_lpi_timer should be in microseconds. The time units for
+- * LPI threshold are unspecified.
++ /* The EN7528 GPHYs report EEE capability, but negotiating EEE with
++ * common link partners (e.g. Realtek GbE NICs) results in an unstable
++ * link with dropped frames. Leave the LPI capabilities empty so that
++ * phylink disables EEE on these PHYs and refuses to enable it from
++ * userspace.
+ */
+- config->lpi_timer_default = FIELD_GET(LPI_THRESH_MASK, eeecr);
++ if (priv->id != ID_EN7528) {
++ u32 eeecr = mt7530_read(priv, MT753X_PMEEECR_P(port));
++
++ config->lpi_capabilities = MAC_100FD | MAC_1000FD | MAC_2500FD;
++ /* tx_lpi_timer should be in microseconds. The time units for
++ * LPI threshold are unspecified.
++ */
++ config->lpi_timer_default = FIELD_GET(LPI_THRESH_MASK, eeecr);
++ }
+
+ priv->info->mac_port_get_caps(ds, port, config);
+ }
@@ drivers/net/dsa/mt7530.c: mt753x_conduit_state_change(struct dsa_switch *ds,
* forwarded to the numerically smallest CPU port whose conduit
* interface is up.
@@ drivers/net/dsa/mt7530.c: mt753x_conduit_state_change(struct dsa_switch *ds,
return;

mask = BIT(cpu_dp->index);
-@@ drivers/net/dsa/mt7530.c: static int mt753x_setup_tc(struct dsa_switch *ds, int port,
- }
- }
-
-+/* The EN7528 LAN ports are integrated GPHYs at MDIO addresses 9..12 (switch -+ * ports 1..4) on the switch internal MDIO bus, reachable only through the PHY -+ * indirect access registers. There is no mdiodev to derive the addresses from. -+ */
-+#define EN7528_GPHY_BASE 9
-+#define EN7528_NUM_GPHYS 4
-+
- static int mt7988_setup(struct dsa_switch *ds)
- {
- struct mt7530_priv *priv = ds->priv;
-+ int i;
-
- /* Reset the switch */
- reset_control_assert(priv->rstc);
-@@ drivers/net/dsa/mt7530.c: static int mt7988_setup(struct dsa_switch *ds)
- /* Reset the switch PHYs */
- mt7530_write(priv, MT7530_SYS_CTRL, SYS_CTRL_PHY_RST);
-
-+ /* The EN7528 LAN GPHYs advertise EEE by default, but negotiating EEE
-+ * with common link partners (e.g. Realtek GbE NICs) results in an
-+ * unstable link with dropped frames. Disable EEE advertisement on
-+ * them.
-+ */
-+ if (priv->id == ID_EN7528)
-+ for (i = EN7528_GPHY_BASE;
-+ i < EN7528_GPHY_BASE + EN7528_NUM_GPHYS; i++)
-+ mt7531_ind_c45_phy_write(priv, i, MDIO_MMD_AN,
-+ MDIO_AN_EEE_ADV, 0);
-+
- return mt7531_setup_common(ds);
- }
-
@@ drivers/net/dsa/mt7530.c: const struct mt753x_info mt753x_table[] = {
.phy_write_c45 = mt7531_ind_c45_phy_write,
.mac_port_get_caps = en7581_mac_port_get_caps,

base-commit: fe3e786ef4eb6e47d2901f568a27bd920477bbe9

2.34.1

The EcoNet EN7528 MIPS SoC integrates an MT7530 Gigabit switch, memory-mapped in the SoC register space like the built-in switches of the MediaTek MT7988 and Airoha EN7581/AN7583 SoCs. Its four user ports are connected to integrated Gigabit PHYs and its CPU port is connected internally to the SoC Ethernet MAC.

Those three switches are MT7531-based, whereas the EN7528 has a genuine MT7530 switch core (its chip revision register reads 0x7530). The two generations differ in their register programming - for example the CPU port is selected through the MT7530-style MFC register rather than the MT7531 CFC register - so the EN7528 is not compatible with the existing switch compatibles and cannot fall back to one of them.

Add the econet,en7528-switch compatible, with the same constraints as the other built-in switches.

---
 .../devicetree/bindings/net/dsa/mediatek,mt7530.yaml         | 5 +++++
 1 file changed, 5 insertions(+)

index 815a90808901..90b3582b7619 100644
@@ -100,6 +100,10 @@ properties:
           Built-in switch of the Airoha AN7583 SoC
         const: airoha,an7583-switch
 
+      - description:
+          Built-in switch of the EcoNet EN7528 SoC
+        const: econet,en7528-switch
+
   reg:
     maxItems: 1
 

@@ -318,6 +322,7 @@ allOf:
             - mediatek,mt7988-switch
             - airoha,en7581-switch
             - airoha,an7583-switch
+            - econet,en7528-switch
     then:
       $ref: "#/$defs/builtin-dsa-port"
       properties:

2.34.1

Best regards,
Krzysztof

The EcoNet EN7528 SoC integrates an MT7530 switch (the chip revision register reads 0x7530), memory-mapped in the SoC register space and reached through the same MMIO glue used for the built-in switches of the MediaTek MT7988 and Airoha EN7581/AN7583 SoCs. Its reset sequence and its PHY indirect access registers are the same as on those switches, so add an ID_EN7528 variant bound with the "econet,en7528-switch" compatible, reusing mt7988_setup() and the indirect PHY accessors.

The switch core, however, is an MT7530 and not an MT7531 derivative: the CPU port to trap frames to is set through the MT7530-style CPU_EN / CPU_PORT fields of the MFC register rather than the MT7531 CFC register, so add it to the MT7530 handling in mt753x_conduit_state_change(). For the same reason the MT7530 mirror and force-mode register layouts already apply to it as the default of the MT753X_*() macros.

The four user ports (1-4) are connected to integrated Gigabit PHYs at MDIO addresses 9-12 of the switch internal MDIO bus. The CPU port (port
6) is connected to the SoC Ethernet MAC at a fixed 1000 Mbps full duplex link, so the port capabilities cannot be shared with the MT7988 and EN7581 switches, whose CPU ports run at 10 Gbps.

The LAN GPHYs advertise EEE by default, but negotiating EEE with some link partners results in an unstable link with dropped frames. Leave the LPI capabilities empty for the EN7528 so that phylink disables EEE on these PHYs and refuses to enable it from userspace.

---
 drivers/net/dsa/mt7530-mmio.c |  1 +
 drivers/net/dsa/mt7530.c      | 58 ++++++++++++++++++++++++++++++-----
 drivers/net/dsa/mt7530.h      |  1 +
 3 files changed, 52 insertions(+), 8 deletions(-)

index 1dc8b93fb51a..1065671bcdd1 100644
@@ -13,6 +13,7 @@
 static const struct of_device_id mt7988_of_match[] = {
 	{ .compatible = "airoha,an7583-switch", .data = &mt753x_table[ID_AN7583], },
 	{ .compatible = "airoha,en7581-switch", .data = &mt753x_table[ID_EN7581], },
+	{ .compatible = "econet,en7528-switch", .data = &mt753x_table[ID_EN7528], },
 	{ .compatible = "mediatek,mt7988-switch", .data = &mt753x_table[ID_MT7988], },
 	{ /* sentinel */ },
 };

index dd33b0df3419..5f1e841f42c0 100644
@@ -21,6 +21,7 @@ enum mt753x_id {
 	ID_MT7988 = 3,
 	ID_EN7581 = 4,
 	ID_AN7583 = 5,
+	ID_EN7528 = 6,
 };
 
 #define	NUM_TRGMII_CTRL			5

2.34.1