[PATCH v2 3/4] net: dsa: hsr: Enable in KSZ9477 switch HW HSR offloading

[Lukasz Majewski]

This patch adds functions for providing in KSZ9477 switch HSR
(High-availability Seamless Redundancy) hardware offloading.

According to AN3474 application note following features are provided:
- TX packet duplication from host to switch (NETIF_F_HW_HSR_DUP)
- RX packet duplication discarding
- Prevention of packet loop

For last two ones - there is a probability that some packets will not
be filtered in HW (in some special cases). Hence, the HSR core code
shall be used to discard those not caught frames.

Moreover, some switch registers adjustments are required - like setting
MAC address of HSR network interface.

Signed-off-by: Lukasz Majewski <lukma@xxxxxxx>
---
Changes for v2:
- Use struct ksz_device to store hsr ports information (not struct dsa)
---
 drivers/net/dsa/microchip/ksz9477.c | 96 +++++++++++++++++++++++++++++
 drivers/net/dsa/microchip/ksz9477.h |  4 ++
 2 files changed, 100 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index 83b7f2d5c1ea..c446eb44ead7 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -1141,6 +1141,102 @@ int ksz9477_tc_cbs_set_cinc(struct ksz_device *dev, int port, u32 val)
 	return ksz_pwrite16(dev, port, REG_PORT_MTI_CREDIT_INCREMENT, val);
 }
 
+/* The KSZ9477 provides following HW features to accelerate
+ * HSR frames handling:
+ *
+ * 1. TX PACKET DUPLICATION FROM HOST TO SWITCH
+ * 2. RX PACKET DUPLICATION DISCARDING
+ * 3. PREVENTING PACKET LOOP IN THE RING BY SELF-ADDRESS FILTERING
+ *
+ * Only one from point 1. has the NETIF_F* flag available.
+ *
+ * Ones from point 2 and 3 are "best effort" - i.e. those will
+ * work correctly most of the time, but it may happen that some
+ * frames will not be caught. Hence, the SW needs to handle those
+ * special cases. However, the speed up gain is considerable when
+ * above features are used.
+ */
+#define KSZ9477_SUPPORTED_HSR_FEATURES NETIF_F_HW_HSR_DUP
+
+int ksz9477_hsr_join(struct dsa_switch *ds, int port, struct net_device *hsr,
+		     struct dsa_port *partner)
+{
+	struct ksz_device *dev = ds->priv;
+	struct net_device *slave;
+	u8 i, data;
+	int ret;
+
+	/* Program which ports shall support HSR */
+	dev->hsr_ports = BIT(port) | BIT(partner->index);
+	ksz_write32(dev, REG_HSR_PORT_MAP__4, dev->hsr_ports);
+
+	/* Enable discarding of received HSR frames */
+	ksz_read8(dev, REG_HSR_ALU_CTRL_0__1, &data);
+	data |= HSR_DUPLICATE_DISCARD;
+	data &= ~HSR_NODE_UNICAST;
+	ksz_write8(dev, REG_HSR_ALU_CTRL_0__1, data);
+
+	/* Self MAC address filtering for HSR frames to avoid
+	 * traverse of the HSR ring more than once.
+	 *
+	 * The HSR port (i.e. hsr0) MAC address is used.
+	 */
+	if (!is_valid_ether_addr(hsr->dev_addr)) {
+		dev_err(dev->dev,
+			"Set valid MAC address to %s for HSR operation!",
+			hsr->name);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < ETH_ALEN; i++) {
+		ret = ksz_write8(dev, REG_SW_MAC_ADDR_0 + i, hsr->dev_addr[i]);
+		if (ret)
+			return ret;
+	}
+
+	/* Enable global self-address filtering if not yet done during switch
+	 * start
+	 */
+	ksz_read8(dev, REG_SW_LUE_CTRL_1, &data);
+	if (!(data & SW_SRC_ADDR_FILTER)) {
+		data |= SW_SRC_ADDR_FILTER;
+		ksz_write8(dev, REG_SW_LUE_CTRL_1, data);
+	}
+
+	/* Enable per port self-address filtering */
+	ksz_port_cfg(dev, port, REG_PORT_LUE_CTRL, PORT_SRC_ADDR_FILTER, true);
+	ksz_port_cfg(dev, partner->index, REG_PORT_LUE_CTRL,
+		     PORT_SRC_ADDR_FILTER, true);
+
+	/* Setup HW supported features for lan HSR ports */
+	slave = dsa_to_port(ds, port)->slave;
+	slave->features |= KSZ9477_SUPPORTED_HSR_FEATURES;
+
+	slave = dsa_to_port(ds, partner->index)->slave;
+	slave->features |= KSZ9477_SUPPORTED_HSR_FEATURES;
+
+	pr_debug("%s: HSR join port: %d partner: %d port_map: 0x%x\n", __func__,
+		 port, partner->index, dev->hsr_ports);
+
+	return 0;
+}
+
+int ksz9477_hsr_leave(struct dsa_switch *ds, int port, struct net_device *hsr,
+		      struct dsa_port *partner)
+{
+	struct ksz_device *dev = ds->priv;
+
+	/* Clear ports HSR support */
+	ksz_write32(dev, REG_HSR_PORT_MAP__4, 0);
+
+	/* Disable per port self-address filtering */
+	ksz_port_cfg(dev, port, REG_PORT_LUE_CTRL, PORT_SRC_ADDR_FILTER, false);
+	ksz_port_cfg(dev, partner->index, REG_PORT_LUE_CTRL,
+		     PORT_SRC_ADDR_FILTER, false);
+
+	return 0;
+}
+
 int ksz9477_switch_init(struct ksz_device *dev)
 {
 	u8 data8;
diff --git a/drivers/net/dsa/microchip/ksz9477.h b/drivers/net/dsa/microchip/ksz9477.h
index b6f7e3c46e3f..634262efb73c 100644
--- a/drivers/net/dsa/microchip/ksz9477.h
+++ b/drivers/net/dsa/microchip/ksz9477.h
@@ -58,5 +58,9 @@ int ksz9477_dsa_init(struct ksz_device *dev);
 int ksz9477_switch_init(struct ksz_device *dev);
 void ksz9477_switch_exit(struct ksz_device *dev);
 void ksz9477_port_queue_split(struct ksz_device *dev, int port);
+int ksz9477_hsr_join(struct dsa_switch *ds, int port, struct net_device *hsr,
+		     struct dsa_port *partner);
+int ksz9477_hsr_leave(struct dsa_switch *ds, int port, struct net_device *hsr,
+		      struct dsa_port *partner);
 
 #endif
-- 
2.20.1