net: dsa: microchip: Enable HSR offloading for KSZ9477
authorLukasz Majewski <lukma@denx.de>
Fri, 22 Sep 2023 13:31:08 +0000 (15:31 +0200)
committerPaolo Abeni <pabeni@redhat.com>
Tue, 3 Oct 2023 11:51:02 +0000 (13:51 +0200)
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 - described in AN3474).
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.

Additionally, the KSZ9477 switch has been configured to forward frames
between HSR ports (e.g. 1,2) members to provide support for
NETIF_F_HW_HSR_FWD flag.

Join and leave functions are written in a way, that are executed with
single port - i.e. configuration is NOT done only when second HSR port
is configured.

Co-developed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
drivers/net/dsa/microchip/ksz9477.c
drivers/net/dsa/microchip/ksz9477.h
drivers/net/dsa/microchip/ksz_common.c
drivers/net/dsa/microchip/ksz_common.h

index 9e63ed8..cde8ef3 100644 (file)
@@ -1143,6 +1143,83 @@ 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 - to be more specific; there is a race
+ * condition in hardware such that, when duplicate packets are received
+ * on member ports very close in time to each other, the hardware fails
+ * to detect that they are duplicates.
+ *
+ * Hence, the SW needs to handle those special cases. However, the speed
+ * up gain is considerable when above features are used.
+ *
+ * Moreover, the NETIF_F_HW_HSR_FWD feature is also enabled, as HSR frames
+ * can be forwarded in the switch fabric between HSR ports.
+ */
+#define KSZ9477_SUPPORTED_HSR_FEATURES (NETIF_F_HW_HSR_DUP | NETIF_F_HW_HSR_FWD)
+
+void ksz9477_hsr_join(struct dsa_switch *ds, int port, struct net_device *hsr)
+{
+       struct ksz_device *dev = ds->priv;
+       struct net_device *slave;
+       struct dsa_port *hsr_dp;
+       u8 data, hsr_ports = 0;
+
+       /* Program which port(s) shall support HSR */
+       ksz_rmw32(dev, REG_HSR_PORT_MAP__4, BIT(port), BIT(port));
+
+       /* Forward frames between HSR ports (i.e. bridge together HSR ports) */
+       if (dev->hsr_ports) {
+               dsa_hsr_foreach_port(hsr_dp, ds, hsr)
+                       hsr_ports |= BIT(hsr_dp->index);
+
+               hsr_ports |= BIT(dsa_upstream_port(ds, port));
+               dsa_hsr_foreach_port(hsr_dp, ds, hsr)
+                       ksz9477_cfg_port_member(dev, hsr_dp->index, hsr_ports);
+       }
+
+       if (!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);
+       }
+
+       /* Enable per port self-address filtering.
+        * The global self-address filtering has already been enabled in the
+        * ksz9477_reset_switch() function.
+        */
+       ksz_port_cfg(dev, port, 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;
+}
+
+void ksz9477_hsr_leave(struct dsa_switch *ds, int port, struct net_device *hsr)
+{
+       struct ksz_device *dev = ds->priv;
+
+       /* Clear port HSR support */
+       ksz_rmw32(dev, REG_HSR_PORT_MAP__4, BIT(port), 0);
+
+       /* Disable forwarding frames between HSR ports */
+       ksz9477_cfg_port_member(dev, port, BIT(dsa_upstream_port(ds, port)));
+
+       /* Disable per port self-address filtering */
+       ksz_port_cfg(dev, port, REG_PORT_LUE_CTRL, PORT_SRC_ADDR_FILTER, false);
+}
+
 int ksz9477_switch_init(struct ksz_device *dev)
 {
        u8 data8;
index d7bbd9b..f90e2e8 100644 (file)
@@ -56,6 +56,8 @@ int ksz9477_reset_switch(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);
+void ksz9477_hsr_join(struct dsa_switch *ds, int port, struct net_device *hsr);
+void ksz9477_hsr_leave(struct dsa_switch *ds, int port, struct net_device *hsr);
 
 int ksz9477_port_acl_init(struct ksz_device *dev, int port);
 void ksz9477_port_acl_free(struct ksz_device *dev, int port);
index 6c31d51..b800ace 100644 (file)
@@ -16,6 +16,7 @@
 #include <linux/etherdevice.h>
 #include <linux/if_bridge.h>
 #include <linux/if_vlan.h>
+#include <linux/if_hsr.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/of.h>
@@ -3541,6 +3542,149 @@ static int ksz_setup_tc(struct dsa_switch *ds, int port,
        }
 }
 
+static int ksz_port_set_mac_address(struct dsa_switch *ds, int port,
+                                   const unsigned char *addr)
+{
+       struct dsa_port *dp = dsa_to_port(ds, port);
+
+       if (dp->hsr_dev) {
+               dev_err(ds->dev,
+                       "Cannot change MAC address on port %d with active HSR offload\n",
+                       port);
+               return -EBUSY;
+       }
+
+       return 0;
+}
+
+/* Program the switch's MAC address register with the MAC address of the
+ * requesting user port. This single address is used by the switch for multiple
+ * features, like HSR self-address filtering and WoL. Other user ports are
+ * allowed to share ownership of this address as long as their MAC address is
+ * the same. The user ports' MAC addresses must not change while they have
+ * ownership of the switch MAC address.
+ */
+static int ksz_switch_macaddr_get(struct dsa_switch *ds, int port,
+                                 struct netlink_ext_ack *extack)
+{
+       struct net_device *slave = dsa_to_port(ds, port)->slave;
+       const unsigned char *addr = slave->dev_addr;
+       struct ksz_switch_macaddr *switch_macaddr;
+       struct ksz_device *dev = ds->priv;
+       const u16 *regs = dev->info->regs;
+       int i;
+
+       /* Make sure concurrent MAC address changes are blocked */
+       ASSERT_RTNL();
+
+       switch_macaddr = dev->switch_macaddr;
+       if (switch_macaddr) {
+               if (!ether_addr_equal(switch_macaddr->addr, addr)) {
+                       NL_SET_ERR_MSG_FMT_MOD(extack,
+                                              "Switch already configured for MAC address %pM",
+                                              switch_macaddr->addr);
+                       return -EBUSY;
+               }
+
+               refcount_inc(&switch_macaddr->refcount);
+               return 0;
+       }
+
+       switch_macaddr = kzalloc(sizeof(*switch_macaddr), GFP_KERNEL);
+       if (!switch_macaddr)
+               return -ENOMEM;
+
+       ether_addr_copy(switch_macaddr->addr, addr);
+       refcount_set(&switch_macaddr->refcount, 1);
+       dev->switch_macaddr = switch_macaddr;
+
+       /* Program the switch MAC address to hardware */
+       for (i = 0; i < ETH_ALEN; i++)
+               ksz_write8(dev, regs[REG_SW_MAC_ADDR] + i, addr[i]);
+
+       return 0;
+}
+
+static void ksz_switch_macaddr_put(struct dsa_switch *ds)
+{
+       struct ksz_switch_macaddr *switch_macaddr;
+       struct ksz_device *dev = ds->priv;
+       const u16 *regs = dev->info->regs;
+       int i;
+
+       /* Make sure concurrent MAC address changes are blocked */
+       ASSERT_RTNL();
+
+       switch_macaddr = dev->switch_macaddr;
+       if (!refcount_dec_and_test(&switch_macaddr->refcount))
+               return;
+
+       for (i = 0; i < ETH_ALEN; i++)
+               ksz_write8(dev, regs[REG_SW_MAC_ADDR] + i, 0);
+
+       dev->switch_macaddr = NULL;
+       kfree(switch_macaddr);
+}
+
+static int ksz_hsr_join(struct dsa_switch *ds, int port, struct net_device *hsr,
+                       struct netlink_ext_ack *extack)
+{
+       struct ksz_device *dev = ds->priv;
+       enum hsr_version ver;
+       int ret;
+
+       ret = hsr_get_version(hsr, &ver);
+       if (ret)
+               return ret;
+
+       if (dev->chip_id != KSZ9477_CHIP_ID) {
+               NL_SET_ERR_MSG_MOD(extack, "Chip does not support HSR offload");
+               return -EOPNOTSUPP;
+       }
+
+       /* KSZ9477 can support HW offloading of only 1 HSR device */
+       if (dev->hsr_dev && hsr != dev->hsr_dev) {
+               NL_SET_ERR_MSG_MOD(extack, "Offload supported for a single HSR");
+               return -EOPNOTSUPP;
+       }
+
+       /* KSZ9477 only supports HSR v0 and v1 */
+       if (!(ver == HSR_V0 || ver == HSR_V1)) {
+               NL_SET_ERR_MSG_MOD(extack, "Only HSR v0 and v1 supported");
+               return -EOPNOTSUPP;
+       }
+
+       /* Self MAC address filtering, to avoid frames traversing
+        * the HSR ring more than once.
+        */
+       ret = ksz_switch_macaddr_get(ds, port, extack);
+       if (ret)
+               return ret;
+
+       ksz9477_hsr_join(ds, port, hsr);
+       dev->hsr_dev = hsr;
+       dev->hsr_ports |= BIT(port);
+
+       return 0;
+}
+
+static int ksz_hsr_leave(struct dsa_switch *ds, int port,
+                        struct net_device *hsr)
+{
+       struct ksz_device *dev = ds->priv;
+
+       WARN_ON(dev->chip_id != KSZ9477_CHIP_ID);
+
+       ksz9477_hsr_leave(ds, port, hsr);
+       dev->hsr_ports &= ~BIT(port);
+       if (!dev->hsr_ports)
+               dev->hsr_dev = NULL;
+
+       ksz_switch_macaddr_put(ds);
+
+       return 0;
+}
+
 static const struct dsa_switch_ops ksz_switch_ops = {
        .get_tag_protocol       = ksz_get_tag_protocol,
        .connect_tag_protocol   = ksz_connect_tag_protocol,
@@ -3560,6 +3704,9 @@ static const struct dsa_switch_ops ksz_switch_ops = {
        .get_sset_count         = ksz_sset_count,
        .port_bridge_join       = ksz_port_bridge_join,
        .port_bridge_leave      = ksz_port_bridge_leave,
+       .port_hsr_join          = ksz_hsr_join,
+       .port_hsr_leave         = ksz_hsr_leave,
+       .port_set_mac_address   = ksz_port_set_mac_address,
        .port_stp_state_set     = ksz_port_stp_state_set,
        .port_teardown          = ksz_port_teardown,
        .port_pre_bridge_flags  = ksz_port_pre_bridge_flags,
index 07c7723..8842efc 100644 (file)
@@ -101,6 +101,11 @@ struct ksz_ptp_irq {
        int num;
 };
 
+struct ksz_switch_macaddr {
+       unsigned char addr[ETH_ALEN];
+       refcount_t refcount;
+};
+
 struct ksz_port {
        bool remove_tag;                /* Remove Tag flag set, for ksz8795 only */
        bool learning;
@@ -170,6 +175,10 @@ struct ksz_device {
        struct mutex lock_irq;          /* IRQ Access */
        struct ksz_irq girq;
        struct ksz_ptp_data ptp_data;
+
+       struct ksz_switch_macaddr *switch_macaddr;
+       struct net_device *hsr_dev;     /* HSR */
+       u8 hsr_ports;
 };
 
 /* List of supported models */